Transcriptomic Profiling Reveals Metabolic and Regulatory Pathways in the Desiccation Tolerance of Mungbean (Vigna radiata [L.] R. Wilczek)

Abstract Mungbean (Vigna radiate L. Wilczek) is an important legume crop for its valuable nutritional and health benefits. Desiccation tolerance is a capacity of seeds to survive and maintain physiological activities during storage and under stress conditions. Many studies of desiccation tolerance have been reported in other legume crop, such as soybean and Medicago truncatula with little studies in the mungbean. In this study, the transcript profiles of mungbean seeds under different imbibition times were investigated for desiccation tolerance using RNA-sequencing (RNA-seq). A total of 3,210 differentially expressed genes (DEGs) were found at the key period of desiccation tolerance (3h to 18h of imbibition). GO and KEGG analysis showed that ‘response to stimulus’, ‘transcription regulator’, ‘methylation’ and ‘starch and sucrose metabolism’ were enriched for desiccation tolerance. Clustering analysis also showed that many transcription factors (MYB, AP2, and NAC), HSPs, embryogenesis abundant (LEA) proteins, and genes encoding methyltransferase and histone were differentially expressed. Nine of these DEGs were further validated by quantitative RT-PCR (qRT-PCR). Our study extends our knowledge of mungbean transcriptomes and further provides insight into the molecular mechanism of desiccation tolerance as well as new strategies for developing drought-tolerant crops.