Expression of a synthetic cry1AcF gene in transgenic Pigeon pea confers resistance to Helicoverpa armigera

Abstract

Pigeon pea is an important legume. Yield losses due to insect pests are enormous in the cultivation of this crop. Expression of cry proteins has led to increased resistance to pests in several crops. We report in this paper, expression of a chimeric cry1AcF (encoding cry1Ac and cry1F domains) gene in transgenic pigeon pea and its resistance towards Helicoverpa armigera. PCR, Southern hybridization, RT‐PCR and Western analysis confirmed stable integration and expression of the cry1AcF gene in pigeon pea transgenics. When screened for efficacy of the transformants for resistance against H. armigera, the transgenics showed not only high mortality of the larva but could also resist the damage caused by the larvae. Analysis for the stable integration, expression and efficacy of the transgenics resulted in the identification of four T3 plants arising from two T1 backgrounds as highly promising. The results demonstrate potentiality of the chimeric cry1AcF gene in developing H. armigera‐resistant pigeon pea.

Achievements and Challenges in Legume Breeding for Pest and Disease Resistance

“…For instance, this method reduced the generation time by three months in pea (Hassan et al, 2009). Alternatively, in-planta transformation that may circumvent the need of tissue culture regeneration steps has been reported for M. truncatula (Trieu et al, 2000), peanuts (Rohini and Rao, 2000), pea (Chowrira et al, 1998), pigeonpea (Ramu et al, 2012), cowpea (Adesoye et al, 2008), as well as lentil and soybean (Chowrira et al, 1996).…”

“…This strategy has worked well for corn and cotton to increase the durability of the resistance and is especially important for insect resistance management (Roush et al, 1998). So far, the transgenic lines of pigeonpea, chickpea, cowpea and soybean resistant to the lepidopterans Helicoverpa armigera, Spodoptera litura, Maruca vitrata, H. zea, Anticarsia gemmatalis and Pseudoplusia includens, respectively, contain only single cry genes, although in some cases an option exists for stacking two different genes by crossing (Walker et al, 2000;Sanyal et al, 2005;Surekha et al, 2005;Adesoye et al, 2008;Ramu et al, 2012; Table 2). …”

Conventional and Molecular Approaches towards Genetic Improvement in Pigeonpea for Insects Resistance

“…Several events of transgenic pigeonpea were produced by this method that showed stable integration, inheritance, and expression of the introduced genes in subsequent generations [79]. Recently, cry1AcF gene has been shown to be conferring resistance to Helicoverpa in pigeonpea [92].…”

Synthetic cry1AcF Gene Imparts Resistance to Spodoptera litura (F.) and Amsacta albistriga Walker in Peanut (Arachis hypogaea L.) cv. VRI-2

“…The transgenic Pigeon pea plants expresiing synthetic cry1AcF showed resistance against Helicoverpa armigera with high larval mortality also showed resistance to Spodoptera litura in peanut and cotton (Ramu et al, 2012;Keshavareddy et al, 2013). Peanut transgenics with such novel hybrid construct therefore, would be ideal to tackle a range of caterpillar pests that attack them in the semi-arid tracts of South India.…”