Venkateswara R. Sripathi

By Seloame T. Nyaku, Yonathan Tilahun, Kathy Lawrence, Venkateswara R. Sripathi, Abreeotta J. Williams and Govind C. Sharma

Among major nematode pests of Upland, cotton production is the reniform nematode, which is a serious threat in various cotton-producing regions. The availability of germplasm lines with tolerance or resistance to this menacing pest is a valued asset. To date, various laboratories and research institutions have collaborated to transfer the reniform nematode resistance from wild gene pools of cotton into widely cultivated Upland cotton, which have led to positive results. This chapter focuses on the current status of these introgressions and resistance mechanisms in cotton. In this overview, four major themes are being pursed: (1) tolerance mechanisms in cotton to the reniform nematode, (2) genotype evaluations, (3) introgression of reniform resistance into Upland cotton, and (4) functional analysis of reniform infection in Upland cotton. Genetic resistance in Upland cotton to the reniform nematode is the only practical solution because conventional control measures are the most cost-effective and environmentally sustainable and therefore have been and will be actively pursued. Resistance genes, if successfully introgressed into crop plants from wild relatives, should complement management of the reniform nematode with traditional methods.

Part of the book: Cotton Research

By Mirzakamol S. Ayubov, Ibrokhim Y. Abdurakhmonov, Venkateswara R. Sripathi, Sukumar Saha, Tokhir M. Norov, Zabardast T. Buriev, Shukhrat E. Shermatov, Khurshida A. Ubaydullaeva, Jack C. McCarty, Dewayne D. Deng and Johnie N. Jenkins

Cotton (Gossypium spp.) produces naturally soft, single-celled trichomes as fiber on the seed coat supplying the main source of natural raw material for the textile industry. It is economically considered as one of the most leading cash crops in the world and evolutionarily very important as a model system for detailed scientific investigations. Cotton production is going through a big transition stage such as losing the market share in competition with the synthetic fibers, high popularity of Bt and herbicide resistance genes in cotton cultivars, and the recent shift of fiber demands to meet the standard fiber quality due to change of textile technologies to produce high superior quality of fibers in the global market. Recently, next-generation sequencing technologies through high-throughput sequencing at greatly reduced costs provided opportunities to sequence the diploid and tetraploid cotton genomes. With the availability of large volume of literatures on molecular mapping, new genomic resources, characterization of cotton genomes, discoveries of many novel genes, regulatory elements including small and microRNAs and new genetic tools such as gene silencing or gene editing technique for genome manipulation, this report attempted to provide the readers a comprehensive review on the recent advances of cotton fiber genomics research.

Part of the book: Past, Present and Future Trends in Cotton Breeding

By Venkateswara R. Sripathi, Varsha C. Anche, Zachary B. Gossett and Lloyd T. Walker

RNA sequencing (RNA-Seq) is the leading, routine, high-throughput, and cost-effective next-generation sequencing (NGS) approach for mapping and quantifying transcriptomes, and determining the transcriptional structure. The transcriptome is a complete collection of transcripts found in a cell or tissue or organism at a given time point or specific developmental or environmental or physiological condition. The emergence and evolution of RNA-Seq chemistries have changed the landscape and the pace of transcriptome research in life sciences over a decade. This chapter introduces RNA-Seq and surveys its recent food and agriculture applications, ranging from differential gene expression, variants calling and detection, allele-specific expression, alternative splicing, alternative polyadenylation site usage, microRNA profiling, circular RNAs, single-cell RNA-Seq, metatranscriptomics, and systems biology. A few popular RNA-Seq databases and analysis tools are also presented for each application. We began to witness the broader impacts of RNA-Seq in addressing complex biological questions in food and agriculture.

Part of the book: Applications of RNA-Seq in Biology and Medicine

By Shalini P. Etukuri, Varsha C. Anche, Mirzakamol S. Ayubov, Lloyd T. Walker and Venkateswara R. Sripathi

The cotton crop is economically important and primarily grown for its fiber. Although the genus Gossypium consists of over 50 species, only four domesticated species produce spinnable fiber. However, the genes determine the molecular phenotype of fiber, and variation in their expression primarily contributes to associated phenotypic changes. Transcriptome analyses can elucidate the similarity or variation in gene expression (GE) among organisms at a given time or a circumstance. Even though several algorithms are available for analyzing such high-throughput data generated from RNA Sequencing (RNA-Seq), a reliable pipeline that includes a combination of tools such as an aligner for read mapping, an assembler for quantitating full-length transcripts, a differential gene expression (DGE) package for identifying differences in the transcripts across the samples, a gene ontology tool for assigning function, and enrichment and pathway mapping tools for finding interrelationships between genes based on their associated functions are needed. Therefore, this chapter first introduces the cotton crop, fiber phenotype, transcriptome, then discusses the basic RNA-Seq pipeline and later emphasizes various transcriptome analyses studies focused on genes associated with fiber quality and its attributes.

Part of the book: Cotton