Bud dormancy in deciduous fruit trees is an important adaptive mechanism for their survival in cold climates. The WRKY genes participate in several developmental and physiological processes, including dormancy. However, the dormancy mechanisms of WRKY genes have not been studied in detail. We conducted a genome-wide analysis and identified 58 WRKY genes in peach. These putative genes were located on all eight chromosomes. In bioinformatics analyses, we compared the sequences of WRKY genes from peach, rice, and Arabidopsis. In a cluster analysis, the gene sequences formed three groups, of which group II was further divided into five subgroups. Gene structure was highly conserved within each group, especially in groups IId and III. Gene expression analyses by qRT-PCR showed that WRKY genes showed different expression patterns in peach buds during dormancy. The mean expression levels of six WRKY genes (Prupe.6G286000, Prupe.1G393000, Prupe.1G114800, Prupe.1G071400, Prupe.2G185100, and Prupe.2G307400) increased during endodormancy and decreased during ecodormancy, indicating that these six WRKY genes may play a role in dormancy in a perennial fruit tree. This information will be useful for selecting fruit trees with desirable dormancy characteristics or for manipulating dormancy in genetic engineering programs.Electronic supplementary materialThe online version of this article (doi:10.1007/s00438-016-1171-6) contains supplementary material, which is available to authorized users.

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Strawberry fruits (cv. Benihoppe, Tochiotome, Sachinoka, and Guimeiren) were harvested and evaluated the flavor and nutritional parameters. By principal component analysis and hierarchical clustering analysis, differences were observed based on the volatile compounds composition, sugar and acid concentration, sweetness, and total soluble sugars/total organic acids of the four varieties. A total of 37, 48, 65, and 74 volatile compounds were identified and determined in cv. Benihoppe, Tochiotome, Sachinoka, and Guimeiren strawberry fruits extracted by head‐space solid‐phase microextraction (HS‐SPME), respectively. Esters significantly dominated the chemical composition of the four varieties. Furaneol was detected in cultivars of Sachinoka and Guimeiren, but mesifuran was only found in cv. Tochiotome. Tochiotome and Sachinoka showed higher content of linalool and (E)‐nerolidol. Sachinoka showed the highest content of total sugars and total acids. Guimeiren showed higher sweetness index than the other three cultivars. Firmness of Tochiotome was highest among all the varieties. The highest total soluble solids TSS value was found in cv. Sachinoka, followed by the Guimeiren and Tochiotome varieties. Sachinoka had the highest titratable acidity TA value. The content of ascorbic acid (AsA) of cv. Tochiotome was higher than the others, but there was no significant difference in cultivars of Benihoppe, Tochiotome, and Sachinoka. Fructose and glucose were the major sugars in all cultivars. Citric acid was the major organic acid in cv. Tochiotome, cv. Sachinoka, and cv. Guimeiren. Tochiotome had higher ratios of TSS/TA and total sugars/total organic acids than others, arising from its lower acid content. The order of the comprehensive evaluation score was Sachinoka>Guimeiren>Tochiotome>Benihoppe.

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