Gu Xinyue, Berran Mel, Prithiv Sivaji Dorai Ashritha, Yang Qiong, Stelmach Monica, Ross Perran A, Gill Alex, Ansermin Eloïse, Yeatman Ella, Umina Paul A, Hoffmann Ary A
Pest and Environmental Adaptation Research Group, School of BioSciences, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Parkville, Australia.
Section for Bioscience and Engineering, Department of Chemistry and Bioscience, Aalborg University, Aalborg, Denmark.
J Econ Entomol. 2025 Aug 29;118(4):1544-1552. doi: 10.1093/jee/toaf114.
Endosymbionts are widespread in insects, including aphids, and can have multiple effects on insect host fitness, suggesting potential applications for endosymbiont-related pest control. A transinfection of the endosymbiont Rickettsiella viridis into a line of the novel host Myzus persicae has previously shown large deleterious effects on aphid fitness and rapid spread in caged aphid populations under a cool environment. Because host clones can significantly influence endosymbiont effects and fitness-related traits more generally, it is important to test endosymbiont effects across a range of genotypic backgrounds. Here, we developed four Rickettsiella transinfected lines in different M. persicae clones via hemolymph microinjection, including clones with relatively high pesticide resistance. All four lines exhibited consistent fitness costs, reflected in reductions in both fecundity and longevity and reduced heat tolerance, although the magnitude of these effects varied among clones. The lines also resulted in stable and similar shifts in body color, with infected aphids being darker in color, although clonal effects were again observed. Vertical transmission was stable in all clones, and Rickettsiella infection was also shown to be transmitted horizontally between aphid pairs within Petri dishes in each clone. These results demonstrate consistent transmission and deleterious fitness effects of Rickettsiella transinfections, while also highlighting genetic background effects.
内共生菌在包括蚜虫在内的昆虫中广泛存在，并且可对昆虫宿主的适应性产生多种影响，这表明与内共生菌相关的害虫防治具有潜在应用价值。先前将内共生菌绿立克次氏体转染到新型宿主桃蚜品系中，已显示出在凉爽环境下对蚜虫适应性有很大的有害影响，并能在笼养蚜虫种群中迅速传播。由于宿主克隆一般会显著影响内共生菌的作用以及与适应性相关的性状，因此在一系列基因型背景下测试内共生菌的作用很重要。在这里，我们通过血淋巴显微注射在不同的桃蚜克隆中培育了四个绿立克次氏体转染品系，包括具有较高抗药性的克隆。所有四个品系都表现出一致的适应性代价，表现为繁殖力和寿命降低以及耐热性下降，尽管这些影响的程度在不同克隆间有所不同。这些品系还导致体色发生稳定且相似的变化，受感染的蚜虫颜色更深，不过再次观察到了克隆效应。垂直传播在所有克隆中都很稳定，并且还表明绿立克次氏体感染可在每个克隆的培养皿内蚜虫个体对之间水平传播。这些结果证明了绿立克次氏体转染具有一致的传播和有害的适应性影响，同时也突出了遗传背景效应。
