Jasmonic acid-induced resistance to the fall armyworm, Spodoptera frugiperda, in conventional and transgenic cottons expressing Bacillus thuringiensis insecticidal proteins

Abstract

To assess potential interactions between Bacillus thuringiensis Berliner (Bt) proteins and jasmonic acid (JA)‐induced resistance to the fall armyworm, Spodoptera frugiperda Smith & Abbot (Lepidoptera: Noctuidae), three commercial Stoneville cotton cultivars, Gossypium hirsutum L. (Malvaceae) (‘ST 475’, a conventional cultivar; ‘ST 4575 BR’, a Bollgard® cultivar expressing Cry1Ac protein; and ‘ST 4554B2RF’, a Bollgard II® cultivar expressing Cry2Ab2 in addition to Cry1Ac), were treated with JA. Two experiments were conducted with 6‐day‐old S. frugiperda larvae on three cotton cultivars at two phenological stages. The first experiment was conducted under laboratory conditions and used excised cotton leaves; the second experiment was performed under greenhouse conditions on intact cotton plants. Relative growth rates (RGRs) and leaf area consumed by 6‐day‐old S. frugiperda larvae were determined for each combination of treatments. Overall, JA treatment and cultivars significantly impacted RGR and leaf area consumption. Significant JA treatment*cultivar interactions were observed for RGR of larvae in the laboratory experiment and for leaf area consumption in the greenhouse experiment. An additional experiment evaluated S. frugiperda neonates on the same JA and cotton cultivar combinations (at a single phenological stage) under laboratory conditions. Neonate survival was determined after 3, 5, and 10 days of feeding, and final larval weight after 10 days of feeding. Overall, JA treatment and cultivars significantly impacted final weight and survival of S. frugiperda. Significant JA treatment*cultivar interactions were observed for final weight and on overall survival of S. frugiperda. Combination of the cotton tissue expressing pyramided Bt proteins with JA treatment demonstrated the greatest negative impact on larval development. Apparent synergism between Bt proteins and JA‐induced resistance emphasizes that traditional host plant resistance has a role to play in combination with Bt technology.

Interaction of transgenic and natural insect resistance mechanisms against Spodoptera littoralis in cotton

“…That cotton insect resistance traits can increase the efficacy of Cry proteins has been shown in earlier studies. However, previous studies either worked with artificial diet only, with plant material only or did not induce resistance in their plant material . Additionally, only one other study worked with Bt cotton expressing two Cry proteins .…”

“…However, previous studies either worked with artificial diet only, 23 with plant material only 22,25 or did not induce resistance in their plant material. 24 Additionally, only one other study worked with Bt cotton expressing two Cry proteins. 24 The results from these studies are comparable with the observations reported here, although they were conducted with other lepidopteran species.…”

“…24 Additionally, only one other study worked with Bt cotton expressing two Cry proteins. 24 The results from these studies are comparable with the observations reported here, although they were conducted with other lepidopteran species. Especially in the case of artificial diet studies, it was reported that gossypol could increase the efficacy of Cry1Ac.…”

“…An early study found that cotton cultivars producing Cry1Ac in combination with high gossypol concentrations increased mortality of lepidopteran larvae compared with Cry1Ac‐producing cultivars with low concentrations of gossypol . Later studies assessed the interactions of Cry proteins with cotton defense compounds both in planta and in artificial diet systems . A majority of these studies were conducted with plants expressing only Cry1Ac and Bt ‐susceptible species such as H. zea .…”

Effects of prohydrojasmon‐treated corn plants on attractiveness to parasitoids and the performance of their hosts

“…Application of JA has been shown to stimulate resistance to various insects in various plants (e.g. Thaler et al 2001;Omer et al 2000Omer et al , 2001Meszaros et al 2011). cis-Jasmone (CJ), a structurally similar compound to PDJ, is a plant-derived chemical that also enhances direct and indirect plant defence against herbivorous insects (Birkett et al 2000;Bruce et al 2003Bruce et al , 2008Pickett et al 2007;Moraes et al 2009).…”