Two-component systems (TCSs) have been shown to participate in plant responses to drought. In this study, results of real-time quantitative PCR (RT-qPCR) of 26 selected dehydration-responsive TCS-related genes in roots and shoots of two Vietnamese soybean cultivars (DT51 and MTD720) with contrasting drought-tolerant phenotypes suggest a positive correlation between the number of droughtinducible TCS genes and their drought-tolerant ability. In addition, expression analyses of the roots and shoots indicated that DT51 and MTD720 had distinct drought-responsive TCS expression profiles, suggesting that expression of TCS-related genes are genotype and tissue dependent. Furthermore, nine TCS genes (GmHK07, 16, GmHP08, GmRR04, 16, 32, 34, GmPRR39, and 44) potentially associated with enhanced drought tolerance were identified. Particularly, GmRR34, showing its higher expression levels under both normal and drought conditions in DT51 roots versus MTD720 roots, might be a potential positive regulator of drought tolerance. On the other hand, GmPRR44 was highly recommended as a potential negative regulator of drought tolerance because it exhibited lower expression levels in both tissues of the drought-tolerant DT51 than in those of the drought-sensitive MTD720 under both stressed and unstressed conditions. These two genes deserve in-depth characterization as promising candidates for development of soybean cultivars with improved drought tolerance by using genetic engineering.

Members of the DJ-1 protein family are multifunctional enzymes whose loss increases the susceptibility of the cell to oxidative stress. However, little is known about the function of the plant DJ-1 homologs. Therefore, we analyzed the effect of oxidation on the structure and function of chloroplastic AtDJ-1B and studied the phenotype of T-DNA lines lacking the protein. In vitro oxidation of AtDJ-1B with H2O2 lowers its glyoxalase activity, but has no effect on its holdase chaperone function. Remarkably, upon oxidation, the thermostability of AtDJ-1B increases with no significant alteration of the overall secondary structure. Moreover, we found that AtDJ-1B transcript levels are invariable, and loss of AtDJ-1B does not affect plant viability, growth and stress response. All in all, two discrete functions of AtDJ-1B respond differently to H2O2, and AtDJ-1B is not essential for plant development under stress.