PLOS Genetics：中国农业科学院揭示小菜蛾Bt抗性分子机制

摘要 : 近日，中国农业科学院蔬菜花卉所研究员张友军领衔的蔬菜虫害防控创新团队与国外同行合作，在小菜蛾抗Bt(苏云金芽孢杆菌)分子机制领域取得重要进展。相关成果已发表于《公共科学图书馆·遗传学》上。

近日，中国农业科学院蔬菜花卉所研究员张友军领衔的蔬菜虫害防控创新团队与国外同行合作，在小菜蛾抗Bt(苏云金芽孢杆菌)分子机制领域取得重要进展。相关成果已发表于《公共科学图书馆·遗传学》上。

小菜蛾是一种世界性重要农业害虫，每年因小菜蛾造成的损失高达40亿~50亿美元。Bt是一种革兰氏阳性菌，能产生多种特异性杀死害虫的杀虫晶体蛋白，因其对害虫高效，对人畜环境安全而在世界范围内得到广泛应用。然而，Bt转基因农作物和Bt制剂的应用正面临着致命的威胁，即害虫对Bt产生抗药性，小菜蛾是世界上第一个对Bt产生抗药性的害虫。

张友军团队利用一些特异的实验材料，系统揭示了小菜蛾对Bt杀虫剂的抗性遗传方式、抗性适合度以及交互抗性谱，并通过生物化学、分子生物学和细胞学的手段，揭示了MAPK(丝裂原活化蛋白激酶)信号途径反式调控ALP(碱性磷酸酶)和ABC转运蛋白导致了小菜蛾对Bt杀虫剂的高抗性。研究结果对开发早期的Bt抗性分子检测技术，制定针对Bt杀虫剂或转Bt基因植物的抗药性治理策略具有重要的理论与实践意义。

原文链接：

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

原文摘要：

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

DOI: 10.1371/journal.pgen.1005124

作者：生物帮

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