Agrobacterium – mediated transformation of indica rice under Acetosyringone –free conditions

Abstract

The possibility of developing transgenic indica rices through Agrobacterium –mediated transformation in the absence of Acetosyringone at bacterial preinduction or cocultivation or both stages was assessed. Six weeks old, scutellum derived calluses of 
indica rice viz., ASD 16, White Ponni, Pusa Basmati, Pusa Sugandh 4, Pusa Sugandh 5 were cocultivated with A.tumifaciens strain EHA 105, harbouring the binary vector pCAMBIA 1305.1 with the β-glucouronidase (GUS) and hygromycin phospho transferase genes in the T-DNA region. Addition of Acetosyringone (AS) to the pre induction medium and cocultivation medium induced higher levels of transient GUS expression than that obtained with the addition of AS to either of the stages. Addition of sucrose to both the media revealed that the transient expression levels were similar to those obtained by the addition of AS. The resultant fertile plants were stable transformants as revealed by GUS histochemical assay and PCR analysis for the GUS and HPT genes. The results indicated that the addition of phenolics like AS may not be essential for the induction of vir genes and development of transgenic indica rices are also possible under AS free conditions.