Comprehensive Genomic Analysis of SnRK in Rosaceae and Expression Analysis of RoSnRK2 in Response to Abiotic Stress in Rubus occidentalis

The sucrose nonfermenting 1-related protein kinase (SnRK) plays an important role in responding to abiotic stresses by phosphorylating the target protein to regulate various signaling pathways. However, little is known about the characteristics, evolutionary history, and expression patterns of the SnRK family in black raspberry (Rubus occidentalis L.) or other Rosaceae family species. In this study, a total of 209 SnRK genes were identified in 7 Rosaceae species and divided into 3 subfamilies (SnRK1, SnRK2, and SnRK3) based on phylogenetic analysis and specific motifs. Whole-genome duplication (WGD) and dispersed duplication (DSD) were considered to be major contributions to the SnRK family expansion. Purifying selection was the primary driving force in the SnRK family evolution. The spatial expression indicated that the RoSnRK genes may play important roles in different tissues. In addition, the expression models of 5 RoSnRK2 genes in response to abiotic stresses were detected by qRT-PCR. The proteins encoded by RoSnRK2 genes localize to the cytoplasm and nucleus in order to perform their respective functions. Taken together, this study provided an analysis of the SnRK gene family expansion and evolution, and contributed to the current knowledge of the function of 5 RoSnRK2 genes, which in turn expanded understanding of the molecular mechanisms of black raspberry responses to abiotic stress.