Knockdown of the MAPK p38 pathway increases the susceptibility of Chilo suppressalis larvae to Bacillus thuringiensis Cry1Ca toxin

• Published in: Scientific reports Vol. 7; no. 1; p. 43964
• Main Authors: Qiu, Lin, Fan, Jinxing, Liu, Lang, Zhang, Boyao, Wang, Xiaoping, Lei, Chaoliang, Lin, Yongjun, Ma, Weihua
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 06.03.2017; Nature Publishing Group
• Subjects: 38/39; 38/89; 631/326; 631/601; Animals; Bacterial Proteins - toxicity; Cloning, Molecular; Endotoxins - toxicity; Extracellular signal-regulated kinase; Gene Expression Profiling; Gene Knockdown Techniques; Gene regulation; Hemolysin Proteins - toxicity; Herbivores; Humanities and Social Sciences; JNK protein; Kinases; Larva - drug effects; Larva - enzymology; Larva - genetics; Lepidoptera - drug effects; Lepidoptera - enzymology; Lepidoptera - genetics; MAP kinase; MAP Kinase Kinase 4 - antagonists & inhibitors; MAP Kinase Kinase 4 - genetics; MAP Kinase Signaling System; Mitogen-Activated Protein Kinase 1 - antagonists & inhibitors; Mitogen-Activated Protein Kinase 1 - genetics; Mitogen-Activated Protein Kinase 3 - antagonists & inhibitors; Mitogen-Activated Protein Kinase 3 - genetics; multidisciplinary; p38 Mitogen-Activated Protein Kinases - antagonists & inhibitors; p38 Mitogen-Activated Protein Kinases - genetics; Pests; Protein kinase; RNA Interference; RNA-mediated interference; Science; Survival Analysis
• ISSN: 2045-2322; 2045-2322
• DOI: 10.1038/srep43964

The bacterium Bacillus thuringiensis (Bt) produces a wide range of toxins that are effective against a number of insect pests. Identifying the mechanisms responsible for resistance to Bt toxin will improve both our ability to control important insect pests and our understanding of bacterial toxicology. In this study, we investigated the role of MAPK pathways in resistance against Cry1Ca toxin in Chilo suppressalis , an important lepidopteran pest of rice crops. We first cloned the full-length of C. suppressalis mitogen-activated protein kinase (MAPK) p38, ERK1 , and ERK2 , and a partial sequence of JNK (hereafter Csp38, CsERK1, CsERK2 and CsJNK ). We could then measure the up-regulation of these MAPK genes in larvae at different times after ingestion of Cry1Ca toxin. Using RNA interference to knockdown Csp38, CsJNK, CsERK1 and CsERK2 showed that only knockdown of Csp38 significantly increased the mortality of larvae to Cry1Ca toxin ingested in either an artificial diet, or after feeding on transgenic rice expressed Cry1Ca. These results suggest that MAPK p38 is responsible for the resistance of C. suppressalis larvae to Bt Cry1Ca toxin.