Genome-Wide Identification and Expression Analysis of AS2 Genes in Brassica rapa Reveal Their Potential Roles in Abiotic Stress

The ( ) gene family plays a pivotal role in plant growth, induction of phytohormones, and the abiotic stress response. However, the gene family in has yet to be investigated. In this study, we identified 62 genes in the genome, which were classified into six subfamilies and distributed across 10 chromosomes. Sequence analysis of promotors showed that there are several typical -elements involved in abiotic stress tolerance and stress-related hormone response. Tissue-specific expression analysis showed that exhibited ubiquitous expression in all tissues, indicating it may be involved in many biological processes. Gene expression analysis showed that the expressions of and were significantly downregulated under cold stress, heat stress, drought stress, and salt stress, while expression was significantly upregulated under heat stress. RT-qPCR also confirmed that the expression of and was significantly downregulated under cold stress, drought stress, and salt stress, and in addition and also changed significantly under the three stresses. In addition, protein-protein interaction (PPI) network analysis revealed that the genes (homologous gene of and ) and (homologous gene of ) can interact with NIN-like protein 7 (NLP7), which has been previously reported to play a role in resistance to adverse environments. In summary, our findings suggest that among the gene family, and have the most potential for the regulation of abiotic stress tolerance. These results will facilitate future functional investigations of genes in .