Gene Family Analysis of Eight Rosaceae Genomes Reveals the Genomic Marker of Cold Stress in .

Histone deacetylases (HDACs) play important roles in plant growth, development, and stress response. However, the pattern of how they are expressed in response to cold stress in the ornamental woody plant is poorly understood. Here, we identify 121 from eight Rosaceae plants of which 13 genes are from . A phylogenetic analysis suggests that the family is classified into three subfamilies, , and . We identify 11 segmental duplication gene pairs of and find, via a sequence alignment, that the gene family, especially the plant-specific family, has experienced gene expansion and contraction at a recent genome evolution history. Each of the three subfamilies has its own conserved domains. The expression of in mei is found to be tissue-specific or tissue-wide. RNA-seq data and qRT-PCR experiments in cold treatments suggest that almost all genes-especially , , and -significantly respond to cold stress. Our analysis provides a fundamental insight into the phylogenetic relationship of the family in Rosaceae plants. Expression profiles of in response to cold stress could provide an important clue to improve the cold hardiness of mei.