Co-overexpression of AtDREB1A and BcZAT12 increases drought tolerance and fruit production in double transgenic tomato (Solanum lycopersicum) plants.

• Double transgenic (AtDREB1A and BcZAT12 gene) with promoter rd29A and lea1. • These showed higher relative water contents, chlorophyll and proline contents. • Double transgenic tomato showed reduced electrolyte leakage and lipid peroxidation. • These showed elevated expression of AtDREB1A, BcZAT12 and P 5 CS gene under drought stress. • Double transgenic tomato plant showed higher yield potential under drought stress. Drought is the major problem in agricultural production due to loss of moisture content in soil as well as climate variations. Our main aim is to enhance drought tolerance and yield potential in the present study pyramided Arabidopsis thaliana Dehydration Responsive Element Binding1A (AtDREB1A) and Brasica caranata Zinc finger proteins (BcZAT12) transcription factor genes driven by ectopic promoter rd29 A of Arabidopsis thaliana and Brassica carinata lea1, respectively. Co-overexpression of both the genes provides tolerance to multiple abiotic stresses but the AtDREB1A overexpression has been reported to cause retarded growth and dwarf phenotype; however BcZAT12 overexpressing transgenic plants does not show retarded growth and dwarf phenotype. Co-overexpressing of AtDREB1A and BcZAT12 in five (DZ1-DZ5) double transgenic (DT) tomato lines has been observed under 0, 07, 14 and 21 Days of Water Deficit (DWD). The DT plants showed enhanced drought tolerance and yield potential than single transgenic (ST) and non transgenic (NT) plants. Furthermore, AtDREB1A and BcZAT12 co-overexpressed plants showed reduced level of electrolyte leakage (EL), hydrogen peroxide and membrane lipid peroxidation and elevated level of relative water content (RWC), proline, chlorophyll color index (CCI) and photosynthetic efficiency as compared to ST and NT. The plant growth and yield attributes were improved by the co-overexpression of AtDREB1A and BcZAT12 in DT plants. The transcript analysis showed the increased level of DREB1A, ZAT12 and P 5 CS genes expression which were higher in DT tomato plants, and indicate that both the genes induce together in the DT plants. The present study which is first report of co-overexpressing AtDREB1A and BcZAT12 in tomato will provide a base for genetic engineering in plants through the multigenic transgenic approach to cope against various biotic and abiotic stresses. [ABSTRACT FROM AUTHOR]