Differentially Expressed Genes Identification of Kohlrabi Seedlings (<i>Brassica oleracea</i> var. <i>caulorapa</i> L.) under Polyethylene Glycol Osmotic Stress and <i>AP2/ERF</i> Transcription Factor Family Analysis

Abstract

Osmotic stress is a condition in which plants do not get enough water due to changes in environmental factors. Plant response to osmotic stress is a complex process involving the interaction of different stress-sensitive mechanisms. Differentially expressed genes and response mechanisms of kohlrabi have not been reported under osmotic stress. A total of 196,642 unigenes and 33,040 differentially expressed unigenes were identified in kohlrabi seedlings under polyethylene glycol osmotic stress. AP2/ERF, NAC and eight other transcription factor family members with a high degree of interaction with CAT and SOD antioxidant enzyme activity were identified. Subsequently, 151 AP2/ERF genes were identified and analyzed. Twelve conserved motifs were searched and all AP2/ERF genes were clustered into four groups. A total of 149 AP2/ERF genes were randomly distributed on the chromosome, and relative expression level analysis showed that BocAP2/ERF genes of kohlrabi have obvious specificity in different tissues. This study lays a foundation for explaining the osmotic stress resistance mechanism of kohlrabi and provides a theoretical basis for the functional analysis of BocAP2/ERF transcription factor family members.

Keywords

• kohlrabi (<i>Brassica oleracea</i> L. var. <i>caulorapa</i> L.)
• polyethylene glycol osmotic stress
• differentially expressed genes
• <i>AP2</i>/<i>ERF</i> transcription factor
• gene expression