<i>Agrobacterium-mediated </i>Transformation Efficiency in Blackgram and Rice Enhanced by Multiple Copies of pTiBo542 <i>virB </i>and <i>virG</i>

Abstract

Broad host-range Inc W plasm ids pBAL3 with 3' end of <i>virB </i>and complete <i>virG </i>of pTiBoS42 and pToK47 with complete <i>virB </i>and <i>virG </i>were introduced into <i>Agrobacterium tumefaciens vir </i>helper strains harbouring a binary vector pBAL2 (Inc P). Transformation efficiencies of these strains were evaluated by transforming the primary leaf segments of black gram <i>[Vigna mungo </i>(Linn.) Hepper cv. CoS] and the scutellum-derived calli of rice <i>[Oryza sativa </i>Linn. cv. Pusa Basmati 1]. Transformation was evaluated on the basis of GUS staining in stably transformed calli. In the octo pine <i>vir </i>helper strain LBA4404 harbouring pBAL2, the plasmid pBAL3 with the 3' end of <i>virB </i>and complete <i>virG </i>of pTiBoS42 increased transformation efficiency by 141 % to 192%. The plasmid pToK47 that carried pTiBoS42 <i>virB </i>in addition to <i>virG </i>did not promote transformation of blackgram any further. In the L, L-succinamopine <i>vir </i>helper strain EHAI0S, pBAL3 did not improve blackgram transformation. In rice, transformation of LBA4404(pBAL2) occurred only when multiple copies of pTiBoS42 <i>vir </i>genes were present. Transformation efficiencies with pBAL3 and pToK47 were 10 and 18%, respectively. While, multiple copies of 3'end of <i>virB </i>and <i>virG </i>of pTiBoS42 harboured on a compatible replicon were effective in blackgram, complete <i>virB </i>was additionally required for efficient transformation of rice.