Host-pathogen interactions are central components of ecological networks where the MAPK signaling pathways act as central hubs of these complex interactions. We have previously shown that an insect hormone modulated MAPK signaling cascade participates as a general switch to trans-regulate differential expression of diverse midgut genes in the diamondback moth, Plutella xylostella (L.) to cope with the insecticidal action of Cry1Ac toxin, produced by the entomopathogenic bacterium Bacillus thuringiensis (Bt). The relationship between topology and functions of this four-tiered phosphorylation signaling cascade, however, is an uncharted territory. Here, we carried out a genome-wide characterization of all the MAPK orthologs in P. xylostella to define their phylogenetic relationships and to confirm their evolutionary conserved modules. Results from quantitative phosphoproteomic analyses, combined with functional validations studies using specific inhibitors and dsRNAs lead us to establish a MAPK “road map”, where p38 and ERK MAPK signaling pathways, in large part, mount a resistance response against Bt toxins through regulating the differential expression of multiple Cry toxin receptors and their non-receptor paralogs in P. xylostella midgut. These data not only advance our understanding of host-pathogen interactions in agricultural pests, but also inform the future development of biopesticides that could suppress Cry resistance phenotypes.
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This work was supported by the National Natural Science Foundation of China (31701813 and 32022074 to ZG; 31901917 to SK; 31630059 to YZ; funder website: http://www.nsfc.gov.cn/english/site_1/index.html), the Beijing Key Laboratory for Pest Control and Sustainable Cultivation of Vegetables and the Science and Technology Innovation Program of the Chinese Academy of Agricultural Sciences (CAAS-ASTIP-IVFCAAS) to YZ.
The final cloned full-length cDNA sequences of P. xylostella MAPK cascade genes were deposited in the GenBank database (Accession nos. MN211342-MN211357).
Guo, Zhaojiang; Kang, Shi; Wu, Qingjun; Wang, Shaoli; Crickmore, Neil; Zhou, Xuguo; Bravo, Alejandra; Soberón, Mario; and Zhang, Youjun, "The Regulation Landscape of MAPK Signaling Cascade for Thwarting Bacillus thuringiensis Infection in an Insect Host" (2021). Entomology Faculty Publications. 223.