Transgenic indica Rice cv IR-50 Over-expressing Vigna aconitifolia Δ1-Pyrroline -5- Carboxylate Synthetase cDNA Shows Tolerance to High Salt

Abstract

Oryza sativa subspecies indica cultivar IR-50 was transformed with Vigna aconitifolia P5CS cDNA under the control of Ubiquitin (Ub) promoter and nos terminator using PDS 1000 He particle bombardment system. Integration of transgene was confirmed by Southern analysis. Transgene expressed itself making mRNA and protein as evidenced by Northern and Western analysis of T2 plants. Active nature of protein made was substantiated by over-accumulation of proline in transgenic plants as compared to control. Transgene followed a 3:1 Mendelian ratio of inheritance. Marker free plants could be obtained due to segregation between marker gene and gene of interest in T2 generation. The transgenic plants showed better root growth and biomass development when grown in 200 mM NaCl, while control plants died within 20 days of salt stress. In one of the transgenic line with single copy transgene, plasmid rescue and the sequence analysis of the genomic region suggests that the P5CS transgene has got integrated into a region of chromosome 3.