Yu T, Li X, Coates B-S, Zhang Q, Siegfried B-D, Zhou X
Department of Entomology, University of Kentucky, Lexington, KY, USA.
State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China.
Insect Mol Biol. 2018 Jun;27(3):279-294. doi: 10.1111/imb.12376. Epub 2018 Feb 16.
Transgenic maize hybrids that express insecticidal Bacillus thuringiensis (Bt) crystalline (Cry) protein toxins effectively protect against the European corn borer, Ostrinia nubilalis, a devastating maize pest. Field monitoring and laboratory selections have detected varying levels of O. nubilalis resistance to Cry1Ab toxin. MicroRNAs (miRNAs) are short noncoding RNAs that are involved in post-transcriptional gene regulation. Their potential roles in the evolution of Bt resistance, however, remain largely unknown. Sequencing of small RNA libraries from the midgut of Cry1Ab-susceptible and resistant O. nubilalis larvae resulted in the discovery of 277 miRNAs, including 248 conserved and 29 novel. Comparative analyses of miRNA expression profiles between the laboratory strains predicted 26 and nine significantly up- and down-regulated transcripts, respectively, in the midgut of Cry1Ab resistant larvae. Amongst 15 differentially regulated miRNAs examined by quantitative real-time PCR, nine (60%) were validated as cosegregating with Cry1Ab resistance in a backcross progeny. Differentially expressed miRNAs were predicted to affect transcripts involved in cell membrane components with functions in metabolism and binding, and the putative Bt-resistance genes aminopeptidase N and cadherin. These results lay the foundation for future investigation of the potential role of miRNAs in the evolution of Bt resistance.
表达杀虫苏云金芽孢杆菌（Bt）晶体（Cry）蛋白毒素的转基因玉米杂交种能有效抵御欧洲玉米螟，即一种具有毁灭性的玉米害虫——玉米螟。田间监测和实验室筛选已检测到玉米螟对Cry1Ab毒素存在不同程度的抗性。微小RNA（miRNA）是参与转录后基因调控的短链非编码RNA。然而，它们在Bt抗性进化中的潜在作用仍 largely unknown。对Cry1Ab敏感和抗性玉米螟幼虫中肠的小RNA文库进行测序，发现了277种miRNA，其中包括248种保守的和29种新的。对实验室菌株之间miRNA表达谱的比较分析预测，在Cry1Ab抗性幼虫的中肠中，分别有26种和9种转录本显著上调和下调。在通过定量实时PCR检测的15种差异调节的miRNA中，有9种（60%）在回交后代中被验证与Cry1Ab抗性共分离。差异表达的miRNA预计会影响参与细胞膜成分的转录本，这些转录本在代谢和结合中发挥作用，以及假定的Bt抗性基因氨肽酶N和钙黏蛋白。这些结果为未来研究miRNA在Bt抗性进化中的潜在作用奠定了基础。
