MAPK Signaling Pathway Alters Expression of Midgut ALP and ABCC Genes and Causes Resistance to Bacillus thuringiensis Cry1Ac Toxin in Diamondback Moth

• DOI: 10.1371/journal.pgen.1005124
• Publication Date: 2015-04-15T18:49:42Z
• Authors: Zhaojiang Guo; Shi Kang; Defeng Chen; Qingjun Wu; Shaoli Wang; Wen Xie; Xun Zhu; Simon W. Baxter; Xuguo Zhou; Juan Luis Jurat-F...; Youjun Zhang
• Keywords: Cry1Ac; Bacillus thuringiensis

Insecticidal crystal toxins derived from the soil bacterium Bacillus thuringiensis (Bt) are widely used as biopesticide sprays or expressed in transgenic crops to control insect pests. However, large-scale use of Bt has led field-evolved resistance several lepidopteran Resistance Cry1Ac toxin diamondback moth, Plutella xylostella (L.), was previously mapped a multigenic locus (BtR-1). Here, we assembled 3.15 Mb BtR-1 and found high-level four independent P. strains were all associated with differential expression midgut membrane-bound alkaline phosphatase (ALP) outside this suite ATP-binding cassette transporter subfamily C (ABCC) genes inside locus. The interplay between these is controlled by uncharacterized trans-regulatory mechanism via mitogen-activated protein kinase (MAPK) signaling pathway. Molecular, biochemical, functional analyses have established ALP receptor. Phenotypic association experiments revealed that recessive tightly linked down-regulation ALP, ABCC2 ABCC3, whereas it not up-regulation ABCC1. Silencing ABCC3 susceptible larvae reduced their susceptibility but did affect suppression MAP4K4, constitutively transcriptionally-activated MAPK upstream gene within locus, transient recovery thereby restoring resistant larvae. These results highlight crucial role for ABCC reveal novel responsible modulating pivotal xylostella.