Microbiome composition of soil, corn (Zea mays) rhizosphere, and western corn rootworm (Diabrotica virgifera virgifera) larvae from cover crop fields

Planting cover crops is an increasingly prevalent sustainable management technique that can increase soil health by increasing microbial abundance and diversity. These soil microbes can improve plant health and alter plant defenses against insects but less is known how the soil microbiome affects insect pest fitness and microbiome composition. The western corn rootworm (WCR) is a major belowground pest of corn throughout the US Corn Belt. Management relies heavily on the planting of transgenic crops expressing Bacillus thuringiensis (Bt). In this study, we ask how does the soil microbiome impact western corn rootworm fitness, microbiome composition, and transgenic crop effectiveness. To do this, we applied soil microbes from continuously managed cover crop fields and those from traditionally managed fields to Bt and non-Bt corn seedlings. We then reared Bt-resistant and -susceptible WCR for 5 days on treated seedlings. Using 16S sequencing, we characterized bacterial communities of the soil, Bt and non-Bt corn rhizospheres, and Bt-resistant WCR larvae.

种植覆盖作物是一种日益普及的可持续管理技术，可通过提升微生物丰度与多样性来改善土壤健康水平。这类土壤微生物可促进植株健康，并改变植物对昆虫的防御机制，但目前对于土壤微生物组（soil microbiome）如何影响害虫生存适合度及其自身微生物组群落组成的认知仍较为有限。西方玉米根萤叶甲（western corn rootworm, WCR）是美国玉米带范围内危害玉米的主要地下害虫，当前其防控工作高度依赖种植表达苏云金芽孢杆菌（Bacillus thuringiensis, Bt）的转基因作物。本研究旨在探究土壤微生物组如何影响西方玉米根萤叶甲的生存适合度、微生物组群落组成，以及转基因作物的防控效果。为此，我们将长期覆盖作物种植管理田与传统耕作管理田的土壤微生物，分别接种至转Bt基因与非转Bt基因玉米幼苗。随后，将抗Bt与敏感型西方玉米根萤叶甲幼虫置于经处理的玉米幼苗上饲养5天。我们通过16S测序技术，对土壤、转Bt与非转Bt玉米根际以及抗Bt西方玉米根萤叶甲幼虫的细菌群落进行了表征分析。