Grapevine is one of the most abundant crops worldwide, with varieties destined for fresh and dry consumption, as well as wine production. Unfortunately, grapevine plants are affected by both biotic and abiotic stresses, generating significant economic losses. These conditions can negatively impact grape cultivation at different stages: plant and berry development during pre- and post-harvest, production, fresh fruit processing and export, along with wine quality. Most of the grapevine varieties are susceptible to several pathogens and within this chapter, particular attention is given to fungi (Botrytis cinerea and Erysiphe necator) and viruses, since they are a worldwide concern. Within the latter, special focus is given to the grapevine leafroll disease, a complex and destructive infection. On the other hand, abiotic stress is also relevant in grapevine, and in this chapter it will be exemplified by UV-B radiation and its impact on growth and fruit development, plant adaptive responses and its relationship with the quality of grape berries for winemaking. The main biotic and abiotic grapevine stress factors are reviewed in this chapter, considering a special focus on biotechnological approaches carried out in order to address them and minimize their detrimental consequences.
Part of the book: Grape and Wine Biotechnology
Successfully gene editing (GE) in Prunus spp. has been delayed due to its woody nature presenting additional difficulties in both, proper regeneration protocols and designing efficient gene transfer techniques. The availability of adequate, single cell culture techniques for GE such as protoplast regeneration, is a limiting step for the genus and for this reason, the improvement of regular regeneration protocols and finding more efficient techniques for the delivery of the “editing reagents” seem to be a reasonable strategy to incorporate GE in the genus. During the last 10 years, we have focused our efforts optimizing some previous regeneration and gene transfer procedures for Japanese plum (P. salicina), sweet cherry (P. avium) and peach (P. persica) to incorporate them into a GE technology on these species. In parallel, delivery techniques for the CRISPR/Cas9 editing components, i.e., guide RNA (gRNA) and Cas9, have been developed with the aim of improving gene targeting efficiencies. In that line, using DNA virus-based replicons provides a significant improvement, as their replicational release from their carriers enables their enhanced expression. Here, we make a brief overview of the tissue culture and regeneration protocols we have developed for P. salicina, P. avium and P. persica, and then we proceed to describe the use of Bean yellow dwarf virus (BeYDV)-derived replicon vectors to express the editing reagents in vivo and to evaluate their editing capability on individuals derived from Agrobacterium-mediated gene transfer experiments of these species. We show part of our characterization assays using new BeYDV-derived vectors harboring multiple gRNAs, the Cas9 gene, and the green fluorescent protein reporter gene. We also describe a dedicated genome analysis tool, by which gRNA pairs can be designed to address gene deletions of the target genes and to predict off-target sequences. Finally, as an example, we show the general results describing GE of the peach TERMINAL FLOWER 1 gene and some preliminary characterizations of these materials.
Part of the book: Prunus