Grape transcriptomes at germplasm level reveal new insights into non-climacteric fruit ripening

To gain a systems-level understanding of non-climacteric fruit ripening, in this study we used RNA-seq to survey and compare the transcriptomes of grape berries at the two most important berry development stages, green hard (termed GH hereafter) and the onset of ripening or veraison (termed V hereafter). A total of 51 Vitis accessions were selected for analysis, including wild species, table-fruit and wine cultivars, and hybrids from widely distributed geographic origins . This large diversity of genotypes provided a unique dataset ideal for identifying the most pertinent conserved genes. Moreover, genome-wide association studies based on variation in single nucleotide polymorphisms (SNPs) in exons and transcript abundance have highlighted candidate genes associated with the time between flowering and berry maturity, an important trait in fruit ripening. In addition to a rich database capturing transcriptome remodeling in grape, our results provide a foundation for understanding how fruit ripening is triggered in a non-climacteric fruit.