Transgenic indica rice cv. ADT 43 expressing a Δ1-pyrroline-5-carboxylate synthetase (P5CS) gene from Vigna aconitifolia demonstrates salt tolerance

Abstract

To develop salt tolerant rice, the P5CS gene of Vigna aconitifolia, encoding for proline synthesis, was introduced into the popular indica rice cultivar ADT 43. Agrobacterium tumefaciens strain LBA 4404 harboring the binary vector pCAMBIA 1301/P5CS, carrying the proline synthesis encoding gene P5CS, was co-cultivated with embryogenic callus of rice. Adding 100 μM acetosyringone to the Linsmaier and Skoog (LS) liquid and solid co-culture medium, along with 30 mg/l hygromycin and 250 mg/l timentin, contributed to significantly higher efficiency of transformation. Southern blot analysis of T1 independent transformants revealed that the copy number of transgene varied between one and three. When transgenic plants were subjected to salt stress, these plants grew well in the presence of up to 200 mM NaCl, while control plants died within 10 days under these treatment conditions. These transgenic plants grew under salt stress for a period of 4 weeks, and were capable of flowering and set seed. T1 plants segregated into 3:1 ratio suggesting Mendelian segregation pattern of inheritance of the P5CS transgene.