Co-Overexpression of OsSIZ1 and AVP1 in Cotton Substantially Improves Cotton Growth and Development Under Multiple-Stress Conditions

Environmental stresses such as salt, drought, and heat cause significant losses in crop production. Our laboratories employ genetic engineering to modify gene expression of selected genes to improve plant performance under environmental stress conditions. Previous studies by our group have shown that the overexpression of the rice gene OsSIZ1, a SUMO E3 ligase, resulted in improved heat- and drought-tolerance in cotton. In separated experiments, overexpression of an Arabidopsis vacuolar pyrophosphatase gene, AVP1, improved salt- and drought-tolerance in transgenic plants. We hypothesized that co-overexpression of OsSIZ1 and AVP1 in cotton would simultaneously confer higher heat-, drought-, and salt-tolerance in transgenic cotton and thus reduce loss in fiber yield under stressful growing environments. We introduced both AVP1 and OsSIZ1 into cotton and conducted preliminary experiments to test the performance of the AVP1/OsSIZ1-co-overexpressing cotton plants in laboratory and field conditions. We observed that improved photosynthetic rates were achieved under combined salt and drought stresses, as well as under combined heat and drought stresses. Furthermore, field-grown transgenic cotton plants performed better in rain-fed plots when compared to non-transgenic plants.