Fig. 4

CS-GSNONPs ameliorate drought stress by regulating gene expression. Chitosan-GSNONPs resulted in statistically highest expression of the drought stress marker gene GmDREB1a 7 days of drought stress (A). Furthermore, the expression of the GmP5CS involved in proline biosynthesis and accumulation was also increased after application of GSNO nanoparticles (B). Similarly, expression of the soybean drought-induced proteinase inhibitor GmDEFENSIN markedly increased due to drought stress (C). Transcript accumulation of the soybean galactinol synthase GmGOLS reached maximum levels after 3 days and gradually dropped after 7 days of drought stress (D). Drought stress reduced the expression of the NO-related alcohol dehydrogenase GmGSNOR1, but the expression increased with the applicatin of chitosan and chitosan-encapsulated GSNO nanoparticles (E). On the other hand, the expression of GmNOX1 increased after 7 days of the treatment with CS-GSNONPs compared to the non-treated control plants (F). Each data point represents the average of atleast three replications. Error bars represent standard deviation. Means with significant difference were separated by DMRT following the analysis of variance (ANOVA) at P < .05