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Nutritional security can be achieved only with the proper intake of fruits and vegetables. However, on an average 30% of the fruit produce are lost between harvest and consumption due to post-harvest spoilage. About 30–40% of total fruits production is lost after harvest. Main causes of postharvest loss include lack of temperature management, rough handling, poor packaging material, and lack of education about the need to maintain quality. There are many ways in which the post-harvest spoilage is managed. Use of chemicals in post-harvest management has direct effect on the consumers and there is a need for alternative strategies. Use of microbial biological control agents have been successfully adopted for soil borne diseases. Registration and biosafety issues make it difficult to use them against post-harvest diseases. Use of volatile organic compounds (VOCs) from bioagents for the post-harvest management provides an opportunity to explore the use of bioagents without having contact with fruits. Many classes of chemicals are produced as volatiles by microbial agents. This chapter describes the potential of VOCs in managing post-harvest diseases, their characterization and identification, biosynthesis, volatiles reported from bacterial, fungal and yeast bioagents, success stories of their use as potential bioagents.
ICAR – Indian Institute of Horticultural Research, Bengaluru, India
Pooja Shekar Patel
Department of Plant Pathology, GKVK, University of Agricultural Sciences, Bengaluru, India
Darisi Venkata Sudhakar Rao
ICAR – Indian Institute of Horticultural Research, Bengaluru, India
Kodthalu Seetharamaiah Shivashankara
ICAR – Indian Institute of Horticultural Research, Bengaluru, India
*Address all correspondence to: subbaraman.sriram@icar.gov.in
1. Introduction
Fruit farming is one of the most important and long-standing traditions throughout the world. The cultivation of fruit crops has a significant impact on the overall well-being of humans and the state of the nation. Fruit crop production can be viewed as an open and complex system in which factors including the sowing or planting method, environmental conditions, soil type, crop management, and their interactions affect the growth, development, and future yield [1].
Fruits and vegetable consumption provides nutritional security and ensures that malnutrition is addressed efficiently. However, the entire product produced do not reach the table of consumers. Due to delicate nature, the post-harvest loss interrupts the reach of fruits to the consumers. Post-harvest loss (PHL) is defined as a measurable quantitative and qualitative loss of an edible food product from harvest to consumption. Increasing post-harvest loss has been highlighted as a global problem in food industries across nations. Food production would need to expand by 70% from present levels by 2050, according to projections, and the situation is significantly more dire in developing nations with poor productivity [2, 3]. As per FAO reports, approximately 14% of produced food was lost after harvest during storage in 2019 with a global net worth of approximately one trillion US dollars but at present up to 30% postharvest loss has been observed in vegetables and fruits.
“An apple a day keeps the doctor away” is a popular saying that emphasizes the importance of fruit crops for the human diet. A diet rich in fruits and vegetables and low in saturated fats is healthy and protective against cardiovascular diseases and certain cancers [4, 5, 6]. The World Health Organization (WHO) recommends a daily intake of at least 400 g of fruits and vegetables per person [7].
Huge pre– and postharvest losses in fruits are caused by various diseases and unfavorable environment leading to the total failure of the crops. It has been estimated that phytopathogenic fungi cause more than 50 per cent of total post-harvest losses. Fruits are prone to number of fungal, bacterial and viral diseases which significantly affect its quality and production. However, fungal diseases inflict huge losses to the crop. Fruits are highly susceptible to postharvest spoilage because of high perishable nature. During the storage conditions numbers of fungi are known to cause spoilage of fruits. Under storage conditions considerable losses occur due to the rots caused by different species belonging to the genera viz., Alternaria, Aspergillus, Bipolaris, Botryodiplodia, Botrytis, Colletotrichum, Curvularia, Fusarium, Penicillium, Rhizopus, etc. [8]. Among these pathogens, green and blue molds, caused by Penicillium digitatum (Pers.: Fr.) Sacc. and P. italicum Wehmer, are the most economically important postharvest diseases of citrus in all production areas [9]. The losses due to penicillium decay are variable and depend upon climatic conditions, orchard factors, citrus cultivar and the extent of physical injury to the fruit during harvest and subsequent handling [10]. It has been estimated that fruit rots caused by Penicillium spp. accounted for 55–80% of total postharvest decay observed in oranges and mandarins during the entire commercialization season, and for 30–55% of decay observed in storage rooms in citrus packing houses [11]. Synthetic fungicides are primarily used for the control of postharvest diseases of fruits and vegetables [12]. However, the trend around the world is shifting towards reduced use of fungicides on produce and thus, there is a strong public and scientific interest in safer and eco-friendly alternatives to reduce the high loss due to decay of harvested commodities. Furthermore, the growing awareness about health hazards and environmental deterioration due to chemical use has necessitated the switching to new non-chemical strategies for the control of postharvest diseases of fruits and vegetables [13].
Among the different biological approaches, use of the microbial antagonists are quite promising and gaining popularity. Microbial bioagents can be used in management of postharvest diseases of fruits and vegetables in two ways. They are use of microorganisms which already exist on the produce itself, which can be promoted and managed or those that can be artificially introduced against postharvest pathogens [12]. Several modes of action have been suggested to explain the biocontrol activity of microbial antagonists, that include competition [14, 15, 16, 17, 18] antibiosis, mycoparasitism, cell wall degrading enzymes, and induced resistance [19, 20, 21].
Antibiotics are microbial toxins which at low concentrations can kill other microbes. Bacteria produced volatile antibiotics viz. hydrogen cyanide, aldehydes, alcohols, ketones, and sulphides and non-volatile antibiotics: polyketides (diacetyl phloroglucinol and mupirocin), heterocyclic nitrogenous compounds (phenazine derivatives: pyocyanin, phenazine-1-carboxylic acid, and hydroxy phenazines) and phenylpyrrole antibiotic (pyrrolnitrin) [22].
There is growing importance for the non-chemical control methods to reduce postharvest decay throughout the world. Volatile organic compounds released by microbial antagonists have shown greater potential and it substitutes to synthetic fungicides for the control of postharvest decay of fruit [23]. Therefore, bioagents have gained the considerable attention and emerge to be a promising as well as a viable alternative to chemical management practices.
Microorganisms have potential of synthesizing numerous volatile substances called as microbial volatile organic compounds (VOCs) with low boiling points, small molecular masses (on average 300 Da) that quickly evaporate at normal temperature and pressure [24]. Both plants and microorganisms produce VOCs that enable them to communicate intra- and inter-specifically. By emitting VOCs, plants defend themselves against herbivores and pathogens, compete with other plants, and/or feed microbial populations. Microorganisms emit VOCs to communicate or attack each other [25]. Production of VOCs with antimicrobial activity has been described in filamentous fungi [26, 27], bacteria [28, 29], yeasts [30, 31], Streptomyces spp. [32, 33], and higher plants [34].
The majority of microbial VOCs have distinct smells [35]. Some of them, which are found in wine, beer, and other fermented foods, have pleasant flavors preferred by people. On the other hand, VOCs are connected to wastelands, deterioration, sewerage facilities, dirty socks, and water-damaged structures also. Hundreds of distinct volatiles, including mixtures of alcohols, ketones, esters, tiny alkenes, thiols, monoterpenes, and sesquiterpenes, can be released simultaneously by any type of microbe [36].
The most interesting developments encompassing about volatile organic compounds come from the study of endophytes, i.e., the microbe that colonize inside the plant tissues without causing any negative effects. Bacterial, fungal and yeast endophytes constitute the plant microbiome. Among them, Muscodor albus which is a nonsporulating, filamentous and VOC-emitting, endophytic, “stinky white” fungus isolated from the spice tree Cinnamomum zeylanicum and was antagonistic to pathogenic bacteria and fungi. More than 28 VOCs were identified from the laboratory cultures of M. albus, comprising acids, alcohols, esters, ketones, and lipids [37]. Therefore, application of these antimicrobial properties of cocktail of VOCs to control microbial contamination has been termed Mycofumigation [38].
The identification and quantification of VOCs have to overcome many technical challenges. As, VOCs are highly evaporative, during sampling, handling and assay procedures the chances of occurrence of compound loss is more [39]. In addition to that the VOCs synthesis at low concentrations in complex mixtures. VOCs identification, collection and quantification depends on either the compounds of interest, the required sensitivity, the intended application, the cost and the ease of use. In classical work, the extraction, separation, and identification steps were separate. Earlier days, the fungal VOCs were identified using the steam distillation method followed by liquid extraction and concentration [40, 41]. Present-day use of Solid phase microextraction (SPME) based gas chromatography (GC) combined with a mass spectrometer (GC–MS) [42], Solvent extraction/liquid–liquid extraction (LLE), stir bar sorptive extraction (SBSE), dynamic headspace (DHS) approaches are used for separation and identification of compounds [43].
Besides these methods, electronic nose or artificial nose combined with multisensory array, an information-processing unit, pattern recognition software, and reference library databases are also used in the identification of VOCs. These resultant electronic fingerprints express unique aroma that helps to detect odor profiles without separation of the mixture into its components [44].
Biosynthesis of VOCs mainly depends on the availability of carbon, nitrogen, sulfur and energy received from the primary metabolism. Therefore, the primary metabolite are considered as a building block of secondary metabolite and exhibits major impact on the concentration of any secondary metabolite, including VOCs. This demonstrates the high degree of connectivity between primary and secondary metabolism. VOCS are divided into different classes based on the biosynthetic origin. The important classes include terpenoids phenylpropanoids/ benzenoids, fatty acid derivatives and amino acid derivatives in addition to a few species−/genus-specific compounds which may not be represented in those major classes. Hence, precursors for VOCs basically originate from the primary metabolism (glycolysis, tricarboxylic acid and pentose phosphate pathway) which helps in the synthesis of VOCs. The four major VOC biosynthetic pathways are the mevalonic acid (MVA), shikimate/phenylalanine, lipoxygenase (LOX) and the methylerythritol phosphate (MEP) pathways lead to the emission of benzenoids/phenylpropanoids, sesquiterpenes, monoterpenes, hemiterpenes, diterpenes, volatile carotenoid derivatives and methyl jasmonate/green leaf volatiles [45].
Though VOCs are considered as secondary metabolites, some researchers argue that they are degradation products of fatty acids, biotransformation products of amino acids, or incidental breakdown products of fungal extracellular enzymes acting on exogenous substrates. The biosynthetic pathways for geosmin which is a vital odor present in soils produced by many streptomycetes, cyanobacteria and fungi [46] and 1-octen-3-ol which is a breakdown product of linoleic acid, also known as mushroom alcohol [34] have been elucidated. Less is known about the biosynthetic pathways that fungi use to produce VOCs [38].
How enzymes are putatively involved in VOCs synthesis has been reported utilizing bioinformatic methods using either terpene or alcohol or ester synthases as an example. The combination of volatilome data collected at various developmental stages with transcriptional data of selected genes makes an effective method for locating enzymes which are likely to be involved in fungal VOC production . Representative pathways for different VOCs are given in Figure 1.
Figure 1.
Three main pathways required for the production of volatile organic compounds (VOCs). (yellow boxes are the volatile organic compounds and blue colored boxes indicate the name of the pathway (Modified figure based on Dudareva et al. [47] and Kaddes et al. [45]).
The selected references on the identification of VOCs for post-harvest pathogens of fruits are listed in Table 1.
S. No
Micro organism
VOCs
Effect
References
1
Bacillus amyloliquefaciens
2,5-Dimethyl pyrazine 2-Dodecanone
Antifungal activity against Fusarium sp. and Colletotrichum gloeosporioides
5. Application of microbial volatile organic compounds
Poveda [25] reviewed the application of microbial volatile organic compounds in plants viz. plant growth promotion, tolerance to abiotic stress, induction of defense mechanism, anti-microbial activity against phytopathogens, attractants or repellents to insect pests and post-harvest disease management.
Plant growth promotion: Acetoin which is a MVOCs produced by B. amyloliquefaciens [49] capable of promoting growth in lettuce by an increase in the number of lateral roots, dry weight, root growth, shoot length and chlorophyll content. MVOC 2,3-butanediol synthesized by B. amyloliquefaciens [47, 61], B. mojavensis [62] or B. subtilis [49], have the ability to promote the growth of A. thaliana. Other MVOCs produced from different Bacillus sp. such as 2-heptanone 2-ethyl-1-hexanol and tetrahydrofuran-3-ol promotes A. thaliana by increasing the endogenous levels of action of auxins and strigolactones, in tomato [60]. The fungal origin MVOCs (Trichoderma genus) have also been described with the ability to promote plant growth in A. thaliana. By exposure to δ-cadinene produced by T. virens [63], leads to an increase in root branching and an increase in total biomass, chlorophyll content and acceleration of flowering by isobutyl alcohol, isopentyl alcohol and 3-methylbutanal produced from T. viride [64] in A. thaliana.
Enhancing tolerance to abiotic stress: The different species of Trichoderma are capable of inducing salt tolerance in A. thaliana plants through protection against oxidative damage, by reducing the accumulation of H2O2 accumulation under salt stress but the exact MVOCs involved have not been determined [65]. Under salt stress, myristic acid, phenol-2-methoxy, stearic acid and tetracontane emitted by Pseudomonas simiae are capable to reduce Na+, and increase K+ and P, content in roots of soybean seedlings, because of an increase in the expression of peroxidase, catalase, vegetative storage protein and nitrite reductase genes [66]. Increased in tolerance to salinity in A. thaliana by downregulating the expression of high-affinity K+ transporter 1 in roots and upregulation in shoots by the 2,3-Butanediol compound released by B. subtilis (Zhang et al. 2008). Acetoin released by B. amyloliquefaciens is able to increase tolerance against salinity in M. piperita, by increasing SA content [67].
Induction of defense mechanism: MVOCs induces the plant defense by activating signaling pathways within the plants. Methyl benzoate which is MVOC emitted by Cladosporium sp. via JA-signaling pathway and m-cresol VOC from Ampelomyces sp. activates SA- and JA-signaling pathways [68]. The MVOCs released from Fusarium oxysporum induce systemic resistance in A. thaliana by activating SA-signaling pathway against Pseudomonas syringae pv. tomato [69]; The MVOC emitted by B. subtilis and B. amyloliquefaciens are capable of activating a systemic resistance in A. thaliana mediated by ethylene- (ET) signaling pathway against Erwinia carotovora subsp. carotovora [70]. Same MVOC from Enterobacter aerogenes involved in the induction of plant resistance against the Northern corn leaf blight fungus Setosphaeria turcica [71].
Inhibition of phytopathogens: The direct antibiosis of different MVOCs against plant pathogens is one of the most studied benefits for plants. The MVOCs produced by B. amyloliquefaciens, such as 2-undecanone, 2-tridecanone and heptadecane inhibits the mobility, biofilm formation and root colonization of pathogenic bacteria. In case of fungi, it inhibits the number of membrane lipids present in the mycelium of the pathogen. It causes abnormal morphology of appressoria, suppresses the mycelial growth and sporulation [72]. MVOs released from Pseudomonas putida such as 1-undecene and dimethyldisulfide showed oomicitidal activity against Phytophthora cactorum, P. nicotianae and Pythium ultimum in vitro [53], Dimethyl hexadecylamine from Arthrobacter agilis is able to inhibit the growth of Phytophthora cinnamomi by decreasing the number of membrane lipids present in the mycelium of the pathogen [73], Bacteriostatic effect also reported by MVOCs toluene, ethyl benzene, m-xylene and benzothiazole from P. fluorescens, restricting the growth and virulence [74].
Attractant or repellent effect on insect pests: In plants MVOCs against insects acts as a direct attractant or repellent of natural enemies. The emission of 2-methyl-1-butanol and 3-methyl- 1-butanol by the yeast Aureobasidium pullulans causes the active attraction of predatory insect-pest wasps such as the western yellowjacket (Vespula pensylvanica) and the German yellowjacket (V. germanica) [75] 2,3-butanediol emitted from Enterbacter aerogenes increases the attraction of parasitoid insect-pest wasps such as Cotesia marginiventris during the interaction with maize roots [70]. MVOCs, such as 1-octen-3-ol and 3-octanol released by Fusarium verticillioides acts as a repellant against insect-pest Sitophilus zeamais in stored maize kernels [76].
6. MVOCs in the management of postharvest diseases of fruits
6.1 VOCs produced by fungi
The use of VOCs for the control of postharvest diseases of fruits is well represented by the report [77]. on an endophytic fungus, Muscodor albus, discovered in C. zeylanicum in a Honduras botanical garden. In the late 1990s, an isolate of M. albus was identified as a good fungal bioagent for the biofumigation of fruits and vegetables after harvest to control apple and peach decay [78], green mold and sour rot of lemon [79] and gray mold of table grapes [80]. The ability of M. albus to manage postharvest diseases depends on the medium that supports the growth of an endophytic fungus which in turn greatly influences the quality, emission and the effectiveness of VOCs. It has also been reported that more than 28 VOCs of five groups of organic compounds such as acids, alcohols, esters, and lipids was identified through GC/MS analysis from an endophytic fungus [37]. About 48.5 per cent of 2-methyl-1-butanol serving a major component along with second and third compound as isobutyric acid (14.9%) and ethyl propionate (9.63%) were identified from M. albus inoculated in an autoclaved rye [78].
Even though Oxyporus latemarginatus is a plant pathogen affecting trees, an isolate of this species EF06 that produced VOCs was isolated from the healthy tissues of pepper plants which acts as a potential biological agent [81]. O. latemarginatus EF06 tested in half-plate divided Petri plates produced VOCs and inhibited the mycelial growth of Alternaria alternata, B. cinerea, C. gloeosporioides, Fusarium oxysporum f. sp. lycopersici, and R. solani. The gaseous VOCs produced by O. latemarginatus EF069 multiplied in a wheat bran–rice hull cultures of 50 g upon exposure to apple fruits in closed container suppressed 98.4 per cent development of Botrytis lesions at 20°C. The hexane extract of wheat bran–rice hull cultures of O. latemarginatus EF069 was used for the identification of an antifungal VOCs by repeated silica gel column chromatography and identified as 5-pentyl-2-furaldehyde (PTF). The purified PTF were effective against various plant pathogens. The mycofumigation with EF069 was also effective in reducing postharvest decay of apple fruits caused by B. cinerea [82].
The most common fungal pathogen during storage conditions is P. expansum [83]. But there are few reports of antifungal VOCs extracted from this species. VOCs from P. expansum R82 have been used to control postharvest diseases of fruits. P. expansum R82 tested in double Petri dish assays was found to be able to inhibit mycelial growth of postharvest pathogens viz., B. cinerea, Monilinia spp., C. acutatum and other strains of P. expansum by producing VOCs [84]. The SPME-GC analysis revealed the presence of geosmin and phenethyl alcohol (PEA) as the major terpenoid and alcohol VOCs produced respectively by the P. expansum R82. Synthetic PEA does not show any inhibitory activity when tested in vitro against the pathogens. Without any direct contact of P. expansum to the fruits, the fungus could be grown in a separate chamber and the produced VOCs can be transferred to the storage room through pump and further can be exposed to fruits to control postharvest diseases [85].
The different VOCs produced by Ceratocystis fimbriata showed strong bioactivity against a wide range of pathogens including postharvest diseases such as peach brown rot and citrus green mold. The volatiles exposure of C. fimbriata in vitro to the peach and citrus fruits against M. fructicola and P. digitatum pathogens showed strong inhibition towards mycelial growth, conidial production and spore germination and the in vivo exposure lead to the reduction of disease over control of 92 and 97 per cent respectively. Exposure to VOCs of C. fimbriata lead to misshapen hyphae and conidia when observed under scanning electron microscopy also their pathogenicity was greatly reduced. The VOCs were identified as butyl acetate, ethyl acetate and ethanol by head space GC–MS [86].
In spite of the fact that the storage temperature may affect either VOC emission or control activity, storage at 20°C was effective compared to 5°C then period of exposure of VOCs can increase from 4 to 24 h, obtaining the same level of efficiency [79].
6.2 VOCs produced by bacteria
Different species of Bacillus and Pseudomonas have displayed inhibitory effect against the growth of postharvest pathogens of fruits with multiple modes of action, including the production of VOCs.
Bacillus subtilis strain CL2 showed antagonistic effect upon producing the VOCs in vitro `against wolfberry postharvest pathogens by inhibiting the hyphal growth of Mucor circinelloides LB1, Fusarium arcuatisporum LB5, Alternaria iridiaustralis LB7, and Colletotrichum fioriniae LB8 using two-sealed-base-plates method. The mycelial morphology of the inhibited pathogens were deformed, twisted, folded, and shrunken when observed under scanning electron microscope. The VOCs could also reduce the weight loss and decay incidence rate of wolfberry fruits infected by the postharvest pathogens. The headspace-gas chromatography-ion mobility spectrometry analysis, revealed the production of seven VOCs by strain CL2. Among them, 2,3-butanedione and 3-methylbutyric acid are the main antifungal active substances [87].
The volatilome produced by three strains of Bacillus velezensis (BUZ-14, I3 and I5) displayed inhibitory effect in vitro against B. cinerea, M. fructicola, M. laxa, Penicillium italicum, P. digitatum and P. expansum. Among three strains I3 and I5 showed 100 per cent inhibition of B. cinerea. The volatile metabolites of I3 also reduced 50 per cent inhibition of grapes gray mold and BUZ-14 decreased apricots brown rot severity by reducing the M. fructicola infection from 60 to 4 mm. The main volatiles responsible for showing its antifungal activity identified from SPME coupled with GC–MS ranged from 12 to 15 compounds including 2-nonanone, 2-undecanone, 2-heptanone, 1-butanol, acetoin, benzaldehyde, butyl formate, diacetyl, nonane, or pyrazine, benzaldehyde and diacetyl. Among those VOCs diacetyl was able to control 60 per cent infection of gray mold in table grapes and blue rot in mandarins with only 0.02 mL L−1 concentration. The diacetyl and benzaldehyde VOCs have been identified as promising compounds and can be applied in active packaging during the postharvest storage, transit and trade of fruit crops. However, prior to the application of any VOCs, it is crucial to determine the active dose as well as the phytotoxicity of the volatiles, since some of the fruits such as apricots and apples have proven to be highly sensitive [88].
In planta prophylactic fumigation of mango fruits cv. Amrapali with 24 h exposure of either endophytic bacteria Pseudomonas putida BP25 or the identified volatile from the bacteria i.e., synthetic VOC 2- ethyl-5-methylpyrazine at 25°C showed a reduction of more than 76 per cent of anthracnose severity on fruit. Additionally, the physicochemical properties of fumigated fruits were also increased representing a new compound for the postharvest management of mango during its commercialization [51].
The downy blight of litchi caused by the oomycete pathogen P. litchii severely suppress the production and quality of litchi fruit. Fumigation of litchi fruits with B. amyloliquefaciens PP19, Exiguobacterium acetylicum SI17 and B. pumilus PI26 volatiles reduced the disease severity of downy blight. The volatile profiles identified from the above-mentioned bacterial strains viz., 1-(2-Aminophenyl) ethenone, benzothiazole and α-farnesene displayed inhibitory effect against the downy blight and serves as promising VOC for the postharvest diseases control of litchi fruits [89].
The VOCs produced from B. thuringiensis and B. pumilus decreased the mango anthracnose infections by 88.5 per cent [90]. When VOCs emitted from B. subtilis and B. amyloliquefaciens were assayed alone or in combination for their antifungal property against Penicillium infection on citrus, the volatile profiles of B. amyloliquefaciens (8 VOCs) and B. subtilis (21 VOCs) reduced the disease incidence of citrus by P. crustosum, but no synergetic effect was exhibited in citrus fruit treated with the antagonist combination. The volatile profile included N-containing compounds, alcohols and ketones were common in both of them. There were morphological abnormalities in P. crustosum when exposed to VOCs. There was a swelling in the hyphae, sporangium and conidia [91].
Upon exposure of VOCs produced by the B. subtilis, there was a retraction of protoplasm with in the hyphal tips and separation of an empty hyphal segments in germinating conidia of B. cinerea. In addition, due to the protoplasm retraction pathogen conidia could not germinate, even after the withdrawal of VOCs, indicating that the protoplasm damage may be irreversible and lethal for pathogens [28].
Streptomyces spp. is group of actinomycete capable of reducing the growth of certain fungal pathogens such as citrus P. italicum [33], gray mold of tomato fruit [92] and strawberries [32] caused by B. cinerea due to the ability of emitting VOCs. Volatiles of S. platensis F-1 displayed a strong reduction in strawberry gray mold incidence by 73 per cent. Among 16 volatiles identified from S. platenesis F-1, VOCs phenylethyl alcohol and (+)-epi-bicycle sesquiphellandrene were previously been detected in M. albus [37] and in the Kleina odora essential oil [93] respectively. Patel et al. (Unpublished data) reported that acetic acid 2-phenylether ester, styrene, β-Phyllandrene and thujopsene were most abundant VOCs released from B. amyloliquefaciens against postharvest pathogens of grapes.
6.3 VOCs produced by yeast
Yeasts as bioagents have been extensively studied since they own many features that satisfy the requirements for being biocontrol agents in fruits [94, 95]. Yeast species usually require a simple nutritional diet, colonizes on dry surfaces for longer periods and can grow rapidly on less expensive substrates in bioreactors [96]. Importantly, they do not produce any kind of allergenic spores or mycotoxins as many fungi or antibiotics which might be produced by bacterial antagonists [97, 98]. In addition, yeasts are a major constituent of the epiphytic microbial community of fruits and vegetables and also phenotypically adapted to this niche.
Candida intermedia 410 inhibited incidence of strawberry gray mold by the production of volatiles. It has been confirmed that VOCs production were the only probable mechanism against B. cinerera because there was no direct contact between the pathogen and yeast cells. The most abundant compounds identified from C. intermedia were 1,3,5,7-cyclooctatetraene, 3- methyl-1-butanol, 2-nonanone, and phenethyl alcohol and confirmed that yeast can be potentially developed as a biofumigant for the control of gray mold of strawberries [99].
Strains belonging to different species of yeasts such as Saccharomyces cerevisiae, Wickerhamomyces anomalus and Metschnikowia pulcherrima showed both in vitro and in vivo inhibitory effect due to the emission of VOCs on B. cinerea causing post-harvest bunch rot of table grapes [100].
The VOCs produced by S. cerevisiae inhibited Phyllosticta citricarpa, causing black spot of citrus. Individual exposure of 3-methyl-1-butanol and 2-methyl-1-butanol controlled the development of new lesions close to 90%, even after removing the fruits from the VOC influence and displayed effective inhibition of mycelial growth, appressorium formation and germination of conidia [101].
The psychrotrophic, non-pectinolytic yeast Candida sake grown in apple juice act as a potential biocontrol agent. The antifungal volatile organic compounds produced by C. sake inhibited the growth of five postharvest pathogens of apple (P. expansum, B. cinerea, A. alternata, A. tenuissima and A. arborescens). The VOCs were also effective on in vivo assays to control P. expansum in Red Delicious apples [102]. Patel et al. (Unpublished data) reported that acetic acid 2-phenylether ester, styrene, β-Phyllandrene and thujopsene were most abundant VOCs released Hanseniaspora opuntiae against postharvest pathogens of grapes.
The disease control using VOCs from microbes would be safer to human health and environment as the yeast and their products are Generally Recognized As Safe (GRAS) by the U.S. Food and Drug Administration (FDA), and the yeast is classified as Biosafety Level 1 by U.S. Centres of Disease Control and Prevention (CDC/OHS, 2009), as it is not a human pathogen, it generally does not produce mycotoxins, antibiotics, or other molecules that are unacceptable in foods [100]. Many antimicrobial VOCs, such as decyl alcohol, nonanal, acetoin and phenylethyl alcohol, are already in use as additives in foods and cosmetics and their use can be extended to control postharvest diseases in fruits and vegetables [103]. However, they are reports on the issues related to safety of these mVOCs to human being. For example some mVOCs reported as allergenic and asthmatic agents such as 1-octen-3-ol [104]. Many of the reports arise from analysis of environmental samples from moist and damp rooms or closed places. As mentioned by Piechulla and Degenhardt [105] the use of these compounds in post-harvest disease management depends on their characterization, dose and their mode of action. These mVOCs need to be applied in very low concentration and they are completely degradable. Compared to synthetic fungicides, they are less harmful due to no residual toxicity. To harness the use of mVOCs, a prerequisite is the availability of adequate in vitro test systems to generate the data to facilitate the legal and regulatory authorities in giving permission for their use in agriculture. A review by Ceremi et al. [106] give the list of in vitro systems for the evaluation of mVOCs on human being. They reviewed the submerged cultivation, air-liquid-interface (ALI), spheroids and organoids as well as their advantages and disadvantages. As these mVOCs are suspected to be allergenic, the methods to study the effects on human respiratory tract need to be updated. In our work too, (Pooja et al. unpublished data) though styrene was abundantly produced by Hanseniaspora opuntiae and B. amyloliquefaciens, but we did not use it due its ill effect on human.
Microbes are a remarkable source of active chemicals due to their diverse chemical makeup. VOCs in particular, when compared to traditional products, can offer evident environmental benefits due to their nil residual effect, renewability, biodegradability, and low toxicity. This makes them an effective aspect of an eco-chemical approach in the management of postharvest diseases. As the world is moving towards a green economy, with new production chains that begin in agriculture and end by returning back to agriculture. Products and by-products come together to establish a sustainable economic system that uses renewable resources. Locally and in many agricultural exporting nations, laws to limit chemicals are currently being adopted. In order to counteract the negative effects of microorganism infection during storage, these non-toxic and GRAS-recognized compounds will be added to the postharvest chain. This will improve the protection of human health and the environment. The use of mVOCs in disease management is evolving and its beneficial effect without harming human health need demonstration after in depth molecular studies to confirm their potential use in agriculture. The future thrust areas as suggested by Kanchiswamy [54] include application of nanotechnology in delivering these mVOCs, expanding the database of mVOCs, studies on mode of action of individual compounds and synergistic effect of cocktail of compounds, non-volatile biodegradable precursors of mVOCs and molecular basis of their mode of action.
1.Hanke MD, Flachowsky H. Fruit Crops. Berlin Heidelberg: Springer-Verlag; 2010. pp. 305-348
2.Food and Agriculture Organization of the United Nations (FAO). Sustainability pathway: Food wastage foot print. 2019. Available from: http://www.fao.org/nr/sustainability/food-loss-and-waste
3.Kruijssen F, Tedesco I, Ward A, Pincus L, Love D, Thorne-Lyman AL. Loss and waste in fish value chains: A review of the evidence from low and middle-income countries. Global Food Security. 2020;26:100434
4.Block G, Patterson B, Subar A. Fruit, vegetables and cancer prevention: A review of the epidemiological literature. Nutrition and Cancer. 1992;18:1-29
5.Ferro-Luzzi A, Cialfa E, Leclerq C, Toti E. The Mediteranean diet revisted: Focus on fruit and vegetables. International Journal of Food Sciences and Nutrition. 1994;45:291-300
6.Morris DM, Kritchevsky SB, Davis CE. Serum carotenoids and coronary heart disease: The lipid research clinics coronary primary prevention trial and fellow-up study. Journal of the American Medical Association. 1994;274:1439-1441
7.World Health Organization. Diet, Nutrition and the Prevention of Cronic Diseases: Report of WHO Study Group. WHO technical series report 797. Geneva: World Health Organization; 1990
8.Coates L, Johnson G. Postharvest diseases of fruit and vegetables. In: Brown JF, Ogle HJ, editors. Plant Pathogens and Plant Diseases. Armidale NSW: Rockvale Publications; 1997:533-548
9.Eckert JW, Eaks IL. Postharvest disorders and diseases of citrus fruits. In: Reuter W, Calavan EC, Carman GE, editors. The Citrus Industry. DANR. Berkeley, CA, USA: University of California Press; 1989. pp. 179-260
10.Smilanick JL, Brown GE, Eckert JW. The biology and control of postharvest diseases. In: Wardowski WF, Miller WM, Hall DJ, Grierson W, editors. Fresh Citrus Fruits. Second ed. Longboat Key, FL, USA: Florida Science Source, Inc.; 2006a. pp. 339-396
11.Tuset JJ. Podredumbres de los Frutos Cítricos. Generalitat, Valenciana, Valencia, Spain: Conselleria d’Agricultura i Pesca; 1988
12.Sharma RR, Singh D, Singh R. Biological control of postharvest diseases of fruits and vegetable by microbial antagonist: A review. Biological Control. 2009;50:205-221
13.Mari M, Neri F, Bertolini P. Novel approaches to prevent and control postharvest diseases of fruit. In: Stewart Postharvest Review, 3(6): Article 4. London, UK: Stewart Postharvest Solutions Ltd.; 2007
14.Droby S, Chalutz E, Wilson CL, Wisniewski ME. Biological control of postharvest diseases: A promising alternative to the use of synthetic fungicides. Phytoparasitica. 1992;20:1495-1503
15.Wilson CL, Wisniewski ME, Droby E, Chalutz E. A selection strategy for microbial antagonists to control postharvest diseases of fruit and vegetables. Scientia Horticulturae. 1993;53:183-189
16.Filonow AB, Vishniac HS, Anderson JA, Janisiewicz WJ. Biological control of Botrytis cinerea in apple by yeasts from various habitats and their putative mechanism of antagonism. Biological Control. 1996;17(2):212-220
17.Ippolito A, El-Ghaouth A, Wilson CL, Wisniewski MA. Control of postharvest decay of apple fruit by Aureobasidium pullulans and induction of defense responses. Postharvest Biology and Technology. 2000;19:265-272
18.Jijakli MH, Grevesse C, Lepoivre P. Modes of action of biocontrol agents of postharvest diseases: Challenges and difficulties. Bulletin-OILB/SROP. 2001;24(3):317-318
19.Janisiewicz WJ, Tworkoski TJ, Sharer C. Characterizing the mechanism of biological control of postharvest diseases on fruit with a simple method to study competition for nutrients. Phytopathology. 2000;90(11):1196-1200
20.Barkai-Golan R. Postharvest Diseases of Fruit and Vegetables: Development and Control. Amasterdam, The Netherlands: Elsevier Sciences; 2001
21.El-Ghaouth A, Wilson CL, Wisniewski ME. Biologically based alternatives to synthetic fungicides for the postharvest diseases of fruit and vegetables. In: Naqvi SAMH, editor. Diseases of Fruit and Vegetables. Vol. 2. The Netherlands: Kluwer Academic Publishers; 2004. pp. 511-535
22.Ahmad F, Ahmad I, Khan MS. Screening of free-living rhizospheric bacteria for their multiple plant growth promoting activities. Microbiological Research. 2008;163:173-181
23.Janisiewicz WJ, Korsten L. Biological control of postharvest diseases of fruit. Annual Review of Phytopathology. 2002;40:411-441
24.Veselova MA, Plyuta VA, Khmel IA. Volatile compounds of bacterial origin: Structure, biosynthesis, and biological activity. Microbiology. 2019;88:261-274
25.Poveda J. Beneficial effects of microbial volatile organic compounds (MVOCs) in plants. Applied Soil Ecology. 2021;168:104-118
26.Stinson M, Ezra D, Hess WM, Sears J, Strobel G. An endophytic Gliocladium sp. of Eucryphia cordifolia producing selective volatile antimicrobial compounds. Plant Science. 2003;165:913-922
27.Koitabashi M. New biocontrol method for parsley powdery mildew by the antifungal volatiles-producing fungus Kyu-W63. Journal of General Plant Pathology. 2005;71:280-284
28.Chen H, Xiao X, Wang J, Wu LJ, Zheng ZM, Yu ZL. Antagonistic effects of volatiles generated by Bacillus subtilis on spore germination and hyphal growth of the plant pathogen, Botrytis cinerea. Biotechnology Letters. 2008;30:919-923
29.Gu YQ, Mo MH, Zhou JP, Zou CS, Zhang KQ. Evaluation and identification of potential organic nematicidal volatiles from soil bacteria. Soil Biology and Biochemistry. 2007;39:2567-2575
30.Fialho MB, Toffano L, Pedroso MP, Augusto F, Pascholati SF. Volatile organic compounds produced by Saccharomyces cerevisiae inhibit the in vitro development of Guignardia citricarpa, the causal agent of citrus black spot. World Journal of Microbiology and Biotechnology. 2010;26:925-932
31.Bruce A, Verrall S, Hackett CA, Wheatley RE. Identification of volatile organic compounds (VOCs) from bacteria and yeast causing growth inhibition of sapstain fungi. Holzforschung. 2004;58:193-198
32.Wan MG, Li GQ, Zhang JB, Jiang DH, Huang HC. Effect of volatile substances of Streptomyces platensis F-1 on control of plant fungal diseases. Biological Control. 2008;46:552-559
33.Li QL, Ning P, Zheng L, Huang JB, Li GQ, Hsiang T. Fumigant activity of volatiles of Streptomyces globisporus JK-1 against Penicillium italicum on Citrus microcarpa. Postharvest Biology and Technology. 2010;58:157-165
34.Kulakiotu EK, Thanassoulopoulos CC, Sfakiotakis EM. Postharvest biological control of Botrytis cinerea on kiwifruit by volatiles of ‘Isabella’ grapes. Phytopathology. 2004;94:1280-1285
35.Schulz S, Dickschat J. Bacterial volatiles: The smell of small organisms. Natural Product Reports. 2007;24:814-842
36.Korpi A, Pasanen AL, Pasanen P. Volatile compounds originating from mixed microbial cultures on building materials under various humidity conditions. Applied and Environmental Microbiology. 1998;64:2914-2919
37.Strobel GA, Dirksie E, Sears J, Markworth C. Volatile antimicrobials from Muscodor albus, a novel endophytic fungus. Microbiology. 2001;147:2943-2950
38.Inamdar AA, Morath S, Bennett JW. Fungal volatile organic compounds: More than just a funky smell? Annual Review of Microbiology. 2020;74:101-116
39.Garcia-Alcega S, Nasir ZA, Ferguson R, Whitby C, Dumbrell AJ. Fingerprinting outdoor air environment using microbial volatile organic compounds (MVOCs)—A review. Trends in Analytical Chemistry. 2017;86:75-83
40.Kaminski E, Libbey L, Stawicki S, Wasowicz E. Identification of the predominant volatile compounds produced by Aspergillus flavus. Applied Microbiology. 1972;24:721-726
41.Seifert R, King A. Identification of some volatile constituents of Aspergillus clavatus. Journal of Agricultural and Food Chemistry. 1982;30:786-790
42.Zhao L, Ni Y, Su M, Li H, Dong F. High throughput and quantitative measurement of microbial metabolome by gas chromatography/mass spectrometry using automated alkyl chloroformate derivatization. Analytical Chemistry. 2017;89:5565-5577
43.Orban AM, Rühl M. Identification of volatile producing enzymes in higher fungi: Combining analytical and bioinformatic methods. Methods in Enzymology. 2022;664:221-242
44.Wilson AD, Baietto M. Advances in electronic-nose technologies developed for biomedical applications. Sensors. 2011;11:1105-1176
45.Kaddes A, Fauconnier ML, Sassi K, Nasraoui B, Jijakli MH. Endophytic fungal volatile compounds as solution for sustainable agriculture. Molecules. 2019;24:1065
46.Bentley R, Meganathan R. Geosmin and methylisoborneol biosynthesis in streptomycetes: Evidence for an isoprenoid pathway and its absence in non-differentiating isolates. FEBS Letters. 1981;125:220-222
47.Dudareva N, Klempien A, Muhlemann JK, Kaplan I. Biosynthesis, function and metabolic engineering of plant volatile organic compounds. New Phytologist. 2013;198(1):16-32
48.Guevara-Avendano E, Bejarano-Bolivar AA, Kiel-Martinez AL, Ramirez-Vazquez M, Mendez-Bravo A, Von Wobeser EA. Avocado rhizobacteria emit volatile organic compounds with antifungal activity against Fusarium solani, Fusarium sp. associated with Kuroshio shot hole borer, and Colletotrichum gloeosporioides. Microbiological Research. 2019;219:74-83
49.Asari S, Matzen S, Petersen MA, Bejai S, Meijer J. Multiple effects of Bacillus amyloliquefaciens volatile compounds: Plant growth promotion and growth inhibition of phytopathogens. FEMS Microbiology Ecology. 2016;92:fiw070
50.Gotor-Vila A, Teixido N, Di Francesco A, Usall J, Ugolini L, Torres R, et al. Antifungal effect of volatile organic compounds produced by Bacillus amyloliquefaciens CPA-8 against fruit pathogen decays of cherry. Food Microbiology. 2017;64:219-225
51.Archana TJ, Gogoi R, Kaur C, Varghese E, Sharma RR, Srivastav M, et al. Bacterial volatile mediated suppression of postharvest anthracnose and quality enhancement in mango. Postharvest Biology and Technology. 2021;177:111525
52.Rajaofera MJN, Wang Y, Dahar GY, Jin P, Fan L, Xu L. Volatile organic compounds of Bacillus atrophaeus HAB-5 inhibit the growth of Colletotrichum gloeosporioides. Pesticide Biochemistry and Physiology. 2019;156:170-176
53.Giorgio A, de Stradis A, Cantore P, Iacobellis NS. Biocide effects of volatile organic compounds produced by potential biocontrol rhizobacteria on Sclerotinia sclerotiorum. Frontiers in Microbiology. 2015;6:1056
54.Kanchiswamy CN, Malnoy M, Maffei ME. Chemical diversity of microbial volatiles and their potential for plant growth and productivity. Frontiers in Plant Science. 2015;6:151. DOI: 10.3389/fpls.2015.00151
55.Gao H, Li P, Xu X, Zeng Q, Guan W. Research on volatile organic compounds from Bacillus subtilis CF-3: Biocontrol effects on fruit fungal pathogens and dynamic changes during fermentation. Frontiers in Microbiology. 2018;9:456
56.Gao Z, Zhang B, Liu H, Han J, Zhang Y. Identification of endophytic Bacillus velezensis ZSY-1 strain and antifungal activity of its volatile compounds against Alternaria solani and Botrytis cinerea. Biological Control. 2017;105:27-39
57.Wang L, Dou G, Guo H, Zhang Q, Qin X, Yu W. Volatile organic compounds of Hanseniaspora uvarum increase strawberry fruit flavor and defense during cold storage. Food Science & Nutrition. 2019;7:2625-2635
58.Ezra D, Hess WM, Strobel GA. New endophytic isolates of Muscodor albus, a volatile-antibiotic-producing fungus. Microbiology. 2004;150:4023-4031
59.Pena LC, Jungklaus GH, Savi DC, Ferreira-Maba L, Servienski A, Maia BH. Muscodor brasiliensis sp. nov. produces volatile organic compounds with activity against Penicillium digitatum. Microbiological Research. 2019;221:28-35
60.Jiang CH, Xie YS, Zhu K, Wang N, Li ZJ, Yu GJ, et al. Volatile organic compounds emitted by Bacillus sp. JC03 promote plant growth through the action of auxin and strigolactone. Plant Growth Regulation. 2019;87:317-328
61.Ryu CM, Farag MA, Hu CH, Reddy MS, Wei HX, Paré PW, et al. Bacterial volatiles promote growth in Arabidopsis. Proceedings of the National Academy of Sciences of the United States of America. 2003;100:4927-4932
62.Rath M, Mitchell TR, Gold SE. Volatiles produced by Bacillus mojavensis RRC101 act as plant growth modulators and are strongly culture-dependent. Microbiological Research. 2018;208:76-84
63.Contreras-Cornejo HA, Macías-Rodríguez L, Herrera-Estrella A, Lopez-Bucio J. The 4-phosphopantetheinyl transferase of Trichoderma virens plays a role in plant protection against Botrytis cinerea through volatile organic compound emission. Plant and Soil. 2014;379:261-274
64.Hung R, Lee S, Bennett JW. Arabidopsis thaliana as a model system for testing the effect of Trichoderma volatile organic compounds. Fungal Ecology. 2013;6:19-26
65.Jalali F, Zafari D, Salari H. Volatile organic compounds of some Trichoderma spp. increase growth and induce salt tolerance in Arabidopsis thaliana. Fungal Ecology. 2017;29:67-75
66.Vaishnav A, Kumari S, Jain S, Varma A, Choudhary DK. Putative bacterial volatile-mediated growth in soybean (Glycine max L. Merrill) and expression of induced proteins under salt stress. Journal of Applied Microbiology. 2015;119:539-551
67.del Rosario-Cappellari L, Banchio E. Microbial volatile organic compounds produced by Bacillus amyloliquefaciens GB03 ameliorate the effects of salt stress in Mentha piperita principally through acetoin emission. Journal of Plant Growth Regulation. 2019;39:764-775
68.Naznin HA, Kiyohara D, Kimura M, Miyazawa M, Shimizu M, Hyakumachi M. Systemic resistance induced by volatile organic compounds emitted by plant growth-promoting fungi in Arabidopsis thaliana. PLoS One. 2014;9:e86882
69.Li N, Kang S. Do volatile compounds produced by Fusarium oxysporum and Verticillium dahliae affect stress tolerance in plants? Mycology. 2018;9:166-175
70.Ryu CM, Farag MA, Hu CH, Reddy MS, Kloepper JW, Paré PW. Bacterial volatiles induce systemic resistance in Arabidopsis. Plant Physiology. 2004;134:1017-1026
71.D’Alessandro M, Erb M, Ton J, Brandenburg A, Karlen D, Zopfi J, et al. Volatiles produced by soil-borne endophytic bacteria increase plant pathogen resistance and affect tritrophic interactions. Plant, Cell & Environment. 2014;37:813-826
72.Raza W, Ling N, Liu D, Wei Z, Huang Q, Shen Q. Volatile organic compounds produced by Pseudomonas fluorescens WR-1 restrict the growth and virulence traits of Ralstonia solanacearum. Microbiological Research. 2016b;192:103-113
73.Velazquez-Becerra C, Macías-Rodríguez LI, Lopez-Bucio J, Flores-Cortez I, Santoyo G, Hernandez-Soberano C, et al. The rhizobacterium Arthrobacter agilis produces dimethyl hexadecylamine, a compound that inhibits growth of phytopathogenic fungi in vitro. Protoplasma. 2013;250:1251-1262
74.Raza W, Yousaf S, Rajer FU. Plant growth promoting activity of volatile organic compounds produced by biocontrol strains. Science Letters. 2016a;4:40-43
75.Davis TS, Boundy-Mills K, Landolt PJ. Volatile emissions from an epiphytic fungus are semiochemicals for eusocial wasps. Microbial Ecology. 2012;64:1056-1063
76.Usseglio VL, Pizzolitto RP, Rodriguez C, Zunino MP, Zygadlo JA, Areco VA, et al. Volatile organic compounds from the interaction between Fusarium verticillioides and maize kernels as a natural repellents of Sitophilus zeamais. Journal of Stored Products Research. 2017;73:109-114
77.Strobel GA. Muscodor species-endophytes with biological promise. Phytochemistry Reviews. 2011;10:163-172
78.Mercier J, Jimenez B. Control of fungal decay of apples and peaches by the biofumigant fungus Muscodor albus. Postharvest Biology and Technology. 2004;31:1-8
79.Mercier J, Smilanick JL. Control of green mold and sour rot of stored lemon by biofumigation with Muscodor albus. Biological Control. 2005;32:401-407
80.Mlikota Gabler F, Fassel R, Mercier J, Smilanick JL. Influence of temperature, inoculation interval, and dosage on biofumigation with Muscodor albus to control postharvest gray mold on table grapes. Plant Disease. 2006;90:1019-1025
81.Kim HY, Choi GJ, Lee HB, Lee S-W, Lim HK, Jang KS, et al. Some fungal endophytes from vegetable crops and their anti-oomycete activities against tomato late blight. Letters in Applied Microbiology. 2007;44:332-337
82.Lee SO, Kim HY, Choi GJ, Lee HB, Jang KS, Choi YH, et al. Mycofumigation with Oxyporus latemarginatus EF069 for control of postharvest apple decay and Rhizoctonia root rot on moth orchid. Journal of Applied Microbiology. 2009;106:1213-1219
83.Warner G. Pear rot emerging as postharvest problem. Good-Fruit-Grower. 1993;44:25
84.Rouissi W, Ugolini L, Martini C, Lazzeri L, Mari M. Control of postharvest fungal pathogens by antifungal compounds from Penicillium expansum. Journal of Food Protection. 2013;76(11):1879-1886
85.Mari M, Bautista-Banos S, Sivakumar D. Decay control in the postharvest system: Role of microbial and plant volatile organic compounds. Postharvest Biology and Technology. 2016;122:70-81
86.Li Q, Wu L, Hao J, Luo L, Cao Y, Li J. Biofumigation on post-Harvest diseases of fruits using a new volatile-producing fungus of Ceratocystis fimbriata. PLoS One. 2015;10(7):e0132009
87.Ling L, Zhao Y, Tu Y, Yang C, Ma C, Feng S, et al. The inhibitory effect of volatile organic compounds produced by Bacillus subtilis CL2 on pathogenic fungi of wolfberry. Journal of Basic Microbiology. 2021;61:110-121
88.Calvo H, Mendiara I, Arias E, Gracia AP, Blanco D, Venturini ME. Antifungal activity of the volatile organic compounds produced by Bacillus velezensis strains against postharvest fungal pathogens. Postharvest Biology and Technology. 2020;166:111208
89.Zheng L, Situ JJ, Zhu QF, Xi PG, Zheng Y, Liu HX, et al. Identification of volatile organic compounds for the biocontrol of postharvest litchi fruit pathogen Peronophythora litchii. Postharvest Biology and Technology. 2019;155:37-46
90.Zheng M, Shi J, Shi J, Wang Q, Li Y. Antimicrobial effects of volatiles produced by two antagonistic Bacillus strains on the anthracnose pathogen in postharvest mangos. Biological Control. 2013;65:200-206
91.Arrebola E, Sivakumar D, Korsten L. Effect of volatile compounds produced by Bacillus strains on postharvest decay. Biological Control. 2010;53:122-128
92.Li Q, Ning P, Zheng L, Huang J, Li G, Hsiang T. Effects of volatile substances of Streptomyces globisporus JK-1 on control of Botrytis cinerea on tomato fruit. Biological Control. 2012;61:113-120
93.AL-Taweel AM, El-Deeb KS, AL-Muhtadi FJ. Chemical composition and antimicrobial activity of the essential oil of Kleina odora. Saudi Pharmaceutical Journal. 2004;J.12:47-50
94.Santos A, Sanchez A, Marquina D. Yeasts as biological agents to control Botrytis cinerea. Microbiological Research. 2004;159:331-338
95.Liu J, Sui Y, Wisniewski M, Droby S, Liu Y. Review: Utilization of antagonistic yeasts to manage postharvest fungal diseases of fruit. International Journal of Food Microbiology. 2013;167:153-160
96.Chanchaichaovivat A, Ruenwongsa P, Panijpan B. Screening and identification of yeast strains from fruits and vegetables: Potential for biological control of postharvest chilli anthracnose (Colletotrichum capsici). Biological Control. 2007;42:326-335
97.El-Tarabily KA, Sivasithamparam K. Potential of yeasts as biocontrol agents of soil-borne fungal plant pathogens and as plant growth promoters. Mycoscience. 2006;47:25-35
98.Nunes CA. Biological control of postharvest diseases of fruit. European Journal of Plant Pathology. 2012;133:181-196
99.Huang R, Li GQ, Zhang J, Yang L, Che HJ, Jiang DH, et al. Control of postharvest Botrytis fruit rot of strawberry by volatile organic compounds of Candida intermedia. Phytopathology. 2011;101(7):859-869
100.Parafati L, Vitale A, Restuccia C, Cirvilleri G. Biocontrol ability and action mechanism of food-isolated yeast strains against Botrytis cinerea causing post-harvest bunch rot of table grape. Food Microbiology. 2015;47:85-92
101.Toffano L, Fialho MB, Pascholati SF. Potential of fumigation of orange fruits with volatile organic compounds produced by Saccharomyces cerevisiae to control citrus black spot disease at postharvest. Biological Control. 2017;108:77-82
102.Arrarte E, Garmendia G, Rossini C, Wisniewski M, Vero S. Volatile organic compounds produced by Antarctic strains of Candida sake play a role in the control of postharvest pathogens of apples. Biological Control. 2017;109:14-20
103.Zhang Y, Li T, Liu Y, Li X, Zhang C, Feng Z, et al. Volatile organic compounds produced by Pseudomonas chlororaphis subsp. aureofaciens SPS-41 as biological fumigants to control Ceratocystis fimbriata in postharvest sweet potatoes. Journal of Agricultural and Food Chemistry. 2019;67:3702-3710. DOI: 10.1021/acs.jafc.9b00289
104.Araki A, Kanazawa A, Kawai T, Eitaki Y, Morimoto K, Nakayama K, et al. The relationship between exposure to microbial volatile organic compound and allergy prevalence in single-family homes. Science of the Total Environment. 2012;423:18-26. DOI: 10.1016/j.scitotenv.2012.02.026
105.Piechulla B, Degenhardt J. The emerging importance of micro- biolvolatile organic compounds. Plant, Cell & Environment. 2014;37:811-812. DOI: 10.1111/pce.12254
106.Cerimi K, Jackel U, Meyer V, Daher U, Reinert J, Klar S. In vitro systems for toxicity evaluation of microbial volatile organic compounds on humans: Current status and trends. Journal of Fungi. 2022;8:75. DOI: 10.3390/jof8010075
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