Читать книгу Cucurbits - James R. Myers - Страница 39

With the advent of next-generation sequencing technologies, genomes of some of the major cucurbits have been sequenced, creating new sets of resources for these crops. Genomes of watermelon, melon, cucumber, squash (C. pepoand C. moschata), pumpkin (C. maxima), and bottle gourd (L. siceraria) are now available, and the list will continue to grow as sequencing costs decrease (see Table 3.1). The information is available on the Cucurbit Genomics Database maintained by J. Fei at Boyce Thompson Institute (Cornell University, Ithaca, New York).

Cucumber, the first cucurbit genome to be sequenced (2009), enabled scientists, including plant breeders, to identify novel biosynthetic pathways and to develop molecular markers. With each cucurbit species genome that has been sequenced, we have obtained a greater understanding of the evolution of the Cucurbitaceae as well as the function of genes shared across species. The high synteny between genetic sequences of cucumber and melon showed the chromosome fusions that led to cucumber from melon. The bottle gourd genome, one of the most recent species sequenced, brought new evidence that ancient cucurbits had 12 chromosomes. While most major cucurbit crops have had whole-genome sequencing completed, many minor cucurbits have had partial genome sequencing performed. Through these studies, novel and species-specific genes have been identified for bitter gourd (Behera et al., 2016), wax gourd (Jiang et al., 2013), wild Cucumis species (Ling et al., 2017) and other cucurbits, including the creeping perennial, Gynostemma pentaphyllum (Chen et al., 2016).

These resources have been leveraged for dozens of studies on transcriptome analyses of developing fruit, disease resistance or susceptibility, growth under abiotic stress conditions, and many other stages of plant growth in cultivated and wild cucurbits. Many transcriptome studies to date in cucurbits have focused on cucumber because of its economic importance (Ando et al., 2012; Kong et al., 2015; Wyatt et al., 2016; Li et al., 2017; Sun et al., 2017). While few cucurbit transcriptome studies have resulted in the identification of a single gene controlling a specific trait, these large-scale transcriptome studies provide valuable information on genetic pathways, patterns of expression, and candidates for breeding and genetic transformation technologies.