AtVIP1 AND GsNAC2 ENHANCE SALINE-ALKALI STRESS TOLERANCE BY PROMOTING PLANT GROWTH AND INDUCING STRESS RESPONSE GENE DURING THE GERMINATION PERIOD OF SORGHUM

Abstract

The quality and yields of Sorghum bicolor (L.) plants are seriously affected by saline-alkali conditions. VIP, and NAC (NAM, ATAF, and CUC) transcription factors are specific, and have various functions in plant development and response to various stresses. To study the tolerance to saline-alkali stress of transgenic sorghum overexpressed by AtVIP1 and GsNAC2 genes, sorghum seeds were treated with stress solution (NaHCO3: Na2CO3 = 5: 1, 75 mM, pH 9.63). After the stress treatment, the growth morphological indexes, stress-resistant physiological indexes and stress-related gene expression levels of sorghum buds were measured. The results show that the transgenic sorghum with overexpressing AtVIP1 and GsNAC2 genes had a higher bud length, fresh weight, and moisture content. Compared to the control, lower H2O2 and O2- levels, relative permeability of the plasma membrane, and MDA content, with higher POD, CAT, and SOD activities were found in transgenic sorghum. Gene expression analysis revealed that several stress response genes were up-regulated. Furthermore, these results suggest that AtVIP1 and GsNAC2 gene play potentially important roles in response to saline-alkali stress, and may be used in breeding new varieties to improve sorghum yields under adverse environmental conditions.