Agrobacterium-mediated genetic transformation of chickpea for insect resistance

Abstract:

Can genetic transformation overcome limited breeding success in chickpea against pod borer? This research examined Agrobacterium tumefaciens-mediated transformation of chickpea (Cicer arietinum L.) using a synthetic cry1Ac gene under the CaMV 35S promoter for resistance to Helicoverpa armigera. Five explant types were tested with Agrobacterium strain EHA105 carrying pCAMBIA2301-cry1Ac. Cotyledonary nodes gave the highest transformation efficiency at 14.7%, while epicotyl segments showed only 4.1%. PCR screening confirmed cry1Ac presence in 83.6% of regenerated shoots surviving selection. Southern blot analysis of T0 plants indicated one to three transgene copies. Insect bioassays with neonate H. armigera larvae on detached transgenic leaves showed 71.8% larval mortality after 96 hours versus 8.3% on controls. Cry1Ac protein ranged from 0.09 to 0.34 µg/g fresh weight by ELISA. Results point to cotyledonary nodes as the preferred explant and confirm that cry1Ac expression at these levels can reduce pod borer survival under controlled conditions.