New insights on the regulatory network of drought-responsive key genes in Arabidopsis thaliana.

Drought stress is complex abiotic stress that seriously affects crop productivity and yield. Many genes with various functions are induced in response to drought stress. The present study aimed to identify drought-responsive hub genes and their related regulation network in Arabidopsis thaliana under drought stress. In this study, RNA-sequencing data of well-watered and drought treatment samples of Arabidopsis were analyzed, and differential expression genes were identified. The gene ontology enrichment and protein-protein interaction network analyses were performed for differential expression genes. Then, the most important hub genes, gene ontology enrichment, co-expression network, and prediction of related miRNAs of hub genes were investigated by in silico approaches. A total of 2462 genes were expressed differentially, of which 1926 transcripts were up-regulated under drought stress, and the rest were down-regulated. WRKY33, WRKY40, AT1G19020, STZ, SYP122, CNI1, CML37, BCS1, AT3G02840, and AT5G54490 were identified as hub genes in drought stress. The gene ontology analysis showed that hub genes significantly enriched in response to hypoxia, chitin, wounding, and salicylic acid-mediated signaling pathway. The hub genes were co-expressed with important drought-responsive genes such as WRKY46, WRKY60, CML38, ERF6, ERF104, and ERF1A. They were regulated by many stress-responsive miRNAs, such as ath-miR5021, miR413, miR5998, and miR162, that could be used as candidate miRNAs for regulating key genes under drought stress. It seems that the regulation network was involved in signaling pathways and protein degradation under drought stress, and it consists of several important genes and miRNAs that are potential candidates for plant improvement and breeding programs.