Insight into gene regulatory networks involved in sesame (Sesamum indicum L.) drought response

Drought is one of the most common environmental stresses affecting crops yield and quality. Plants’ responses to drought are controlled by regulatory mechanisms. Sesame is an important oilseed crop that most likely faces drought during its growth due to growing in semi-arid and arid areas. Despite this importance, there is little information about sesame regulatory mechanisms against drought stress. In this study, highly differentially expressed genes were identified using in-silico transcriptome analysis of two sesame genotypes (one sensitive and one tolerant) under drought stress. Interactions between identified genes and regulators including Transcription Factors (TF) and microRNAs (miRNA) were predicted using bioinformatics tools and then related regulatory networks were constructed. A total of 117 TFs and 133 miRNAs that might be involved in drought stress were identified with this approach. Key regulators of sesame under drought stress were detected by network analysis. Regulatory modules involved in drought response were extracted from the integrated networks using the MCODE algorithm, to explore important relationships. Finally, some of the identified drought-tolerance-related genes were examined using qRT-PCR analysis in two contrasting sesame genotypes under drought conditions. Interestingly, the studied genes showed a different expression pattern in the tolerant genotype compared to the sensitive. Taken together, our results suggest that miR530/TGA1/CER1, miR319/NAC29L, and miR171/SUC2L modules might play key roles in sesame drought tolerance by regulating wax biosynthesis, leaf senescence, and sugar transport during drought, respectively. Overall, the identified drought-related genes including TFs and miRNAs along with their relationships could be valuable candidates for future studies and breeding programs on enhancing sesame tolerance under drought stress.