The potential of transgenic chickpeas for pest control and possible effects on non-target arthropods

Abstract

Chickpea, Cicer arietinum, is the third most important grain legume crop in the world, with India being the largest producer. Insect pests are a major constraint to chickpea production. In India, the legume pod borer Helicoverpa armigera is the major insect pest of chickpeas. However, sap-sucking insects that act as vectors for viral diseases and bruchid beetles in storage are also considered important pests. Here we give an overview over the different management options to control these pests. There is a growing interest in the genetic modification of crops to enhance their resistance against insect pests. Here we present the state-of-theart of chickpea transformation and give an overview on the available insecticidal genes that could be deployed to increase insect resistance in chickpea. Prior to commercialization, transgenic crops have to be assessed for their effects on the environment including the possible impact on non-target arthropods, many of which are important for biological pest control. Therefore, the arthropod-food web in the Indian chickpea system is described. Possible routes through which entomophagous insects could be exposed to insecticidal proteins expressed by genetically modified chickpeas are discussed, and species that could be selected for prerelease risk assessment are recommended.

Pyramiding of modified cry1Ab and cry1Ac genes of Bacillus thuringiensis in transgenic chickpea (Cicer arietinum L.) for improved resistance to pod borer insect Helicoverpa armigera

“…In spite of its large demand, the global yield of chickpea and some other large seeded grain legumes is stagnating for last two decades primarily due to large number of biotic and abiotic stresses and slow progress of genetic improvements for yield parameters (Popelka et al 2004;Dita et al 2006). Grain yield of chickpea suffers massive loss due to field infestation of lepidopteran pod borer Helicoverpa armigera and few other insects (Romeis et al 2004). Development of improved varieties of grain legumes particularly of chickpea for resistance to pathogens and insect pests by conventional breeding has been slow and difficult due to narrow genetic base, limited genetic diversity for these traits, barriers for sexual incompatibility and high degree of autogamy (Ahmad et al 1988;Van Rheenen et al 1993;Somers et al 2003).…”

Effectiveness of Bacillus thuringiensis -Transgenic Chickpeas and the Entomopathogenic Fungus Metarhizium anisopliae in Controlling Helicoverpa armigera (Lepidoptera: Noctuidae)

“…As with cotton, the expression of B. thuringiensis cry genes is an option to protect chickpeas from damage by H. armigera (41). Chickpea plants that express either Cry1Ac or Cry2Aa, or both proteins, are currently under development and could become commercially available in the future (28,43).…”

Breeding Food Legumes for Resistance to Storage Insect Pests: Potential and Limitations

“…Molecular techniques have also a lot of technical limitations as for instance, efficient methods of introducing foreign genes into desirable genotypes are still lacking [63]. In Australia an α-amylase inhibitor gene was successfully transferred from Phaseolus vulgaris into a non-native host Pisum sativum.…”

“…Chickpeas transformed for a bean α-amylase inhibitor were also found to strongly inhibit the development of storage pests particularly Callosobruchus maculatus and C. Chinensis [63,64] but food safety is untested, although the α-amylase inhibitor is heat labile and denatured by cooking [38]. Nevertheless, single-gene resistances may need supplementation by other methods thus avoiding the selection pressure that is likely to cause rapid emergence of bruchid strains that are not affected by the inhibitor [63]. The use of transgene from wide hybridization, found to be so effective, could result in selection pressure causing rapid emergence of pest strains not affected by host resistance mechanisms.…”

“…Although transformation of the latter, in terms of resistance gene was successful, consumption of the transgenic Pisum resulted in an inflammatory response in the experimental mice [56]. Chickpeas transformed for a bean α-amylase inhibitor were also found to strongly inhibit the development of storage pests particularly Callosobruchus maculatus and C. Chinensis [63,64] but food safety is untested, although the α-amylase inhibitor is heat labile and denatured by cooking [38]. Nevertheless, single-gene resistances may need supplementation by other methods thus avoiding the selection pressure that is likely to cause rapid emergence of bruchid strains that are not affected by the inhibitor [63].…”