Department of Crop Sciences, University of Illinois, Urbana, IL 61801, USA.
Proc Natl Acad Sci U S A. 2013 Jul 16;110(29):11917-22. doi: 10.1073/pnas.1301886110. Epub 2013 Jun 24.
Insects are constantly adapting to human-driven landscape changes; however, the roles of their gut microbiota in these processes remain largely unknown. The western corn rootworm (WCR, Diabrotica virgifera virgifera LeConte) (Coleoptera: Chrysomelidae) is a major corn pest that has been controlled via annual rotation between corn (Zea mays) and nonhost soybean (Glycine max) in the United States. This practice selected for a "rotation-resistant" variant (RR-WCR) with reduced ovipositional fidelity to cornfields. When in soybean fields, RR-WCRs also exhibit an elevated tolerance of antiherbivory defenses (i.e., cysteine protease inhibitors) expressed in soybean foliage. Here we show that gut bacterial microbiota is an important factor facilitating this corn specialist's (WCR's) physiological adaptation to brief soybean herbivory. Comparisons of gut microbiota between RR- and wild-type WCR (WT-WCR) revealed concomitant shifts in bacterial community structure with host adaptation to soybean diets. Antibiotic suppression of gut bacteria significantly reduced RR-WCR tolerance of soybean herbivory to the level of WT-WCR, whereas WT-WCR were unaffected. Our findings demonstrate that gut bacteria help to facilitate rapid adaptation of insects in managed ecosystems.
昆虫不断适应人类驱动的景观变化；然而，它们肠道微生物群在这些过程中的作用在很大程度上仍然未知。西部玉米根虫（WCR，Diabrotica virgifera virgifera LeConte）（鞘翅目：金龟子科）是一种主要的玉米害虫，在美国已通过玉米（Zea mays）和非寄主大豆（Glycine max）之间的年度轮作来控制。这种做法选择了一种对玉米田产卵忠诚度降低的“轮作抗性”变体（RR-WCR）。当在大豆田时，RR-WCR 还表现出对大豆叶片中表达的抗草食性防御（即半胱氨酸蛋白酶抑制剂）的耐受性升高。在这里，我们表明肠道细菌微生物群是促进这种玉米专家（WCR）对短暂大豆草食性的生理适应的重要因素。RR-WCR 和野生型 WCR（WT-WCR）之间的肠道微生物群比较显示，随着宿主适应大豆饮食，细菌群落结构发生了伴随的变化。抗生素抑制肠道细菌显著降低了 RR-WCR 对大豆草食性的耐受性，使其达到 WT-WCR 的水平，而 WT-WCR 则不受影响。我们的研究结果表明，肠道细菌有助于促进管理生态系统中昆虫的快速适应。
