Ectopic Expression of Mulberry G-Proteins Alters Drought and Salt Stress Tolerance in Tobacco

Heterotrimeric guanine-nucleotide-binding proteins (G-proteins) play key roles in responses to various abiotic stress responses and tolerance in plants. However, the detailed mechanisms behind these roles remain unclear. Mulberry ( L.) can adapt to adverse abiotic stress conditions; however, little is known regarding the associated molecular mechanisms. In this study, mulberry G-protein genes, , , , and , were independently transformed into tobacco, and the transgenic plants were used for resistance identification experiments. The ectopic expression of in tobacco decreased the tolerance to drought and salt stresses, while the overexpression of , , and increased the tolerance. Further analysis showed that mulberry G-proteins may regulate drought and salt tolerances by modulating reactive oxygen species' detoxification. This study revealed the roles of each mulberry G-protein subunit in abiotic stress tolerance and advances our knowledge of the molecular mechanisms underlying G-proteins' regulation of plant abiotic stress tolerance.