Proteolytic Activity in the Midgut of Helicoverpa armigera (Noctuidae: Lepidoptera) Larvae Fed on Wild Relatives of Chickpea, Cicer arietinum

Abstract

Wild relatives of crops are an important source of resistance genes against insect pests. However, it is important to identify the accessions of wild relatives with different mechanisms of resistance to broaden the basis and increase the levels of resistance to insect pests. Therefore, we evaluated 15 accessions of wild relatives of chickpea belonging to seven species and five genotypes of cultivated chickpea for their resistance to pod borer, Helicoverpa armigera, which is the most damaging pest of chickpea. The test genotypes were evaluated for resistance to H. armigera using detached pod assay. Data were also recorded on activity of the digestive enzymes in the midgut of the larvae fed on different wild relatives of chickpea. All the wild chickpea genotypes suffered lower pod damage and weight gained by the third-instar larvae of H. armigera was lower when fed on them compared with the cultivated chickpea. The accessions, IG 69979 (Cicer cuneatum), PI 599066, IG 70006, IG 70018, IG 70022 (Cicer bijugum), IG 599076 (Cicer chrossanicum), and IG 72933, IG 72953 (Cicer reticulatum), showed high levels of resistance to H. armigera. There were significant differences in protease activity in larval gut of H. armigera fed on different wild relatives of chickpea. Total protease, trypsin, and chymotrypsin activities were lowest in larva fed on PI 599066 (C. bijugum) compared with that in the larvae fed IG 69979 (C. cuneatum) and IG 70022 (C. bijugum). Aminopeptidase activity was highest in the larvae fed on IG 70022 (C. bijugum) and IG 599076 (C. chrossanicum), whereas lowest activity was recorded in the larvae fed on ICC 3137 and KAK 2 (susceptible checks). The variation in protease activities may be due to the presence of protease inhibitors in the wild relatives or hyperproduction of enzymes by the larvae as result of protease inhibitor activity of the wild relatives, resulting in low weight gain by larvae. The results suggested that wild relatives of chickpea with diverse mechanisms of resistance can be exploited to increase the levels and diversify the basis of resistance to H. armigera in cultivated chickpea.

Overexpression of soybean trypsin inhibitor genes decreases defoliation by corn earworm (Helicoverpa zea) in soybean (Glycine max) and Arabidopsis thaliana

“…Remarkably, the results demonstrated a significant reduction of leaf defoliation (35S-KTI7 = 43.12 ± 4.49%, 35S-BBI5 = 50.87 ± 5.11%, rbcS-SRS4-KTI7 = 48.26 ± 4.61%, and rbcS-SRS4-BBI5 = 53.67 ± 4.28%) compared to nontransgenic plants (80.84 ± 3.48%) (Figures 6, 7). Although several in vitro studies have shown the overexpression of TI gene for the improvement of defense against insects (Azzouz et al, 2005;Srinivasan et al, 2005;Kaur et al, 2017;Golla et al, 2018), the evaluation on whole plant bioassay under greenhouse or field conditions is limited (Qiu, 2008). Our findings further confirm the effectiveness of these soybean TI genes in greenhouse infestation of plants with insects.…”

Expression of Cocculus hirsutus trypsin inhibitor promotes endogenous defensive response against Helicoverpa armigera and enhanced levels of antioxidants

“…Studies also suggest up-regulation of inhibitor insensitive proteinases in chickpea, pigeon pea, and cotton resulting in 35-55% larval growth. Non host plant PIs from Pongamia pinnata, Mucuna pruriens, Capsicum annuum, Nigela sativa and wild relatives of Chickpea (Cicer arietinum) showed maximum inhibitory potential towards HGPs in vivo, also exhibited moderate level of inhibition of pro-proteinases, H. armigera gut pro-proteinases (HGPPs) (Parde et al, 2010;Golla et al, 2018). Plant proteinase inhibitors from groundnut, potato, winged bean caused 80-100% larval mortality (Harsulkar et al, 2002).…”

Legumes: Source of Bioactive Compounds and Their Potential Use in Legume Crops Improvement: A Review

“…This inhibitor was highly stable at 50C in acidic or basic conditions and it contained numerous isoinhibitors that were also shown to be effective against HGPs and shared many similarities with Kunitz-type PIs. Golla et al (2018) reported less pod damage by H. armigera in wild relatives of chickpea, C. arietinum compared to cultivated chickpea due to stronger insect gut trypsin and chymotrypsin inhibition induced by PIs present in wild relatives of chickpea. Similarly, trypsin inhibitor activity also observed in seed flour extracts in some chickpea varieties .…”