A Single Point Mutation Resulting in Cadherin Mislocalization Underpins Resistance against Bacillus thuringiensis Toxin in Cotton Bollworm
A Single Point Mutation Resulting in Cadherin Mislocalization Underpins Resistance against Bacillus thuringiensis Toxin in Cotton Bollworm
复制标题
导致钙粘蛋白错位的单点突变增强了棉铃虫对苏云金芽孢杆菌毒素的抵抗力
DOI：
10.1074/jbc.m116.768671
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发表时间：
2017
影响因子：
4.8
通讯作者：
Wu Kongming
中科院分区：
文献类型：
--
作者：
Xiao Yutao;Dai Qing;Hu Ruqin;Pacheco Sabino;Yang Yongbo;Liang Gemei;Soberon Mario;Bravo Alej;ra;Liu Kaiyu;Wu Kongming
Transgenic plants that produceBacillus thuringiensis(Bt) crystalline (Cry) toxins are cultivated worldwide to control insect pests. Resistance toB. thuringiensistoxins threatens this technology, and although different resistance mechanisms have been identified, some have not been completely elucidated. To gain new insights into these mechanisms, we performed multiple back-crossing from a 3000-fold Cry1Ac-resistant BtR strain from cotton bollworm (Helicoverpa armigera), isolating a 516-fold Cry1Ac-resistant strain (96CAD). Cry1Ac resistance in 96CAD was tightly linked to a mutant cadherin allele (mHaCad) that contained 35 amino acid substitutions compared with HaCad from a susceptible strain (96S). We observed significantly reduced levels of the mHaCad protein on the surface of the midgut epithelium in 96CAD as compared with 96S. Expression of both cadherin alleles from 96CAD and 96S in insect cells and immunofluorescence localization in insect midgut tissue sections showed that the HaCAD protein from 96S localizes on the cell membrane, whereas the mutant 96CAD-mHaCad was retained in the endoplasmic reticulum (ER). Mapping of the mutations identified a D172G substitution mainly responsible for cadherin mislocalization. Our finding of a mutation affecting membrane receptor trafficking represents an unusual and previously unrecognizedB. thuringiensisresistance mechanism.
