Identification of proteins involved in response to cold stress and genome-wide identification and analysis of the APX gene family in winter rapeseed (Brassica rapa L.)

Abstract Winter Brassica rapa is an important oilseed crop in northern China, but the mechanism of its cold resistance remains unclear. APX plays important roles in response of this plant to abiotic stress and in scavenging free radicals. In this study, 59 DEPs were isolated and identified from winter B. rapa and B. napus using bidirectional electrophoresis, and APX was found to be differentially expressed in these two species. Therefore, the roles of APX proteins in the cold response and superoxide metabolism pathways in both rapeseed species were further investigated. And comprehensive analysis of phylogeny, chromosome distribution, motif identification, sequence structure, gene duplication, and RNA-seq expression profile in APX gene family. Most of the BrAPX genes were specifically expressed under low temperature stress and behaved significantly differently in cold-tolerant and cold-sensitive varieties. qPCR was also used to verify the differences in expression between these two varieties under cold, freezing, drought and heat stress, and these candidate genes and proteins may play important roles in the response of B. rapa to low temperature stress and provide new information for the elucidation of the cold resistance mechanism in B. rapa.