Genome-Wide Identification and Expression Analysis of Family Reveal Its Potential Functions in the Developmental Switch and Stresses Response During Grapevine Development.

Plant-specific YABBY (YAB) transcription factors play multiple roles in plant growth and development process. However, no comprehensive study has been performed in grapevines, especially to determine their roles in berry development and abiotic stress response. A total of seven allocated to six chromosomal positions in grapevines were identified and classified into five subfamilies based on phylogenetic and structural analysis. Promoter element analysis and tissue-specific transcriptional response of suggested that might play vital roles in plant growth and development. , , , and showed significantly higher expression levels in vegetative/green organs than in mature/woody tissues, implying that might be involved in the regulatory switch from immature to mature developmental phases. The expression of , 2, 3, and were gradually downregulated during berry developmental and ripening, which can be considered as putative molecular biomarkers between vegetative/green and mature/woody samples, and were used to identify key developmental and metabolic processes in grapevines. Furthermore, expression was not markedly increased by gibberellic acid (GA) treatment alone, but displayed significant upregulation when GA in combination with N-(2-chloro-4-pyridyl)-N'-phenylurea (CPPU) were applied, suggesting an involvement of in fruit expansion by mediating cytokinin signaling pathway. Additionally, microarray and RNA-seq data suggested that showed transcriptional regulation in response to various abiotic and biotic stresses, including salt, drought, , , and GLRaV-3 infection. Overall, our results provide a better understanding of the classification and functions of during berry development and in response to abiotic and biotic stresses in grapevines.