The Overexpression of Solanum nigrum Osmotin (SnOLP) Boosts Drought Response Pathways in Soybean

Environmental stresses are responsible for limiting soybean yield. To mitigate the impacts generated by water deficit, molecular biology tools are being used to develop genetically modified plants. Previous studies showed that two independent events (B1 and B3) of soybean transgenic plants expressing a Solanum nigrum osmotin (SnOLP) had an increment in drought tolerance. The present study aims to investigate the modulated pathways that results in the drought tolerance promoted by osmotin overexpression in soybean. Transgenic and non-transgenic (NT) plants in the vegetative stage were submitted to water deficit by irrigation suppression for seven days. Control plants were kept irrigated. Physiological variables were monitored and confirmed that the transgenic plants present better performance when compared to the NT plants. The total RNA extracted from leaves was sequenced and data was normalized by DESeq2. A total of 2044 and 1505 differentially expressed genes (DEGs) were identified in B1 and B3 events, respectively. Regarding the B1 event, 769 genes were upregulated and 1275 downregulated. For B3, 541 genes were upregulated and 964 genes were downregulated. Excluding common differentially expressed genes (DEGs) between transgenic and non-transgenic (NT) plants yielded 395 upregulated and 234 downregulated genes, which were shared by B1 and B3 events. The metabolic pathways and gene ontology categories identified are known to be involved in plant responses to drought. Hormonal, photosynthetic, carbohydrate and amino acid metabolism, reactive oxygen species, and post-translational modifications pathways were significantly modulated in transgenic plants. Altogether, the results suggest that osmotin promotes tolerance through an increment in the plant responses elicited by drought.