Overexpression of a Voltage-Dependent Anion-Selective Channel (VDAC) Protein-Encoding Gene, , from Confers Cold and Drought Tolerance to Transgenic Tobacco.

Voltage-dependent anion channels (VDACs) are highly conserved proteins that are involved in the translocation of tRNA and play a key role in modulating plant senescence and multiple pathways. However, the functions of in plants are still poorly understood. Here, a novel gene was isolated and identified from alfalfa ( L.). localized to the mitochondria, and its expression was highest in alfalfa roots and was induced in response to cold, drought and salt treatment. Overexpression of in tobacco significantly increased MDA, GSH, soluble sugars, soluble protein and proline contents under cold and drought stress. However, the activities of SOD and POD decreased in transgenic tobacco under cold stress, while the O content increased. Stress-responsive genes including , and were upregulated in the transgenic plants under cold and drought stress. However, , , , and were upregulated only in the transgenic tobacco plants under cold stress, and , , and were downregulated under drought stress. These results suggest that provides cold tolerance by regulating ROS scavenging, osmotic homeostasis and stress-responsive gene expression in plants, but the improved drought tolerance via may be mainly due to osmotic homeostasis and stress-responsive genes.