Liu Shen, Liu Xiao-Bei, Zhang Tian-Tao, Bai Shu-Xiong, He Kang-Lai, Zhang Yong-Jun, Francis Frédéric, Wang Zhen-Ying
State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China.
Functional and Evolutionary Entomology, Gembloux Agro-Bio Tech, University of Liège, Gembloux, Belgium.
Insect Sci. 2024 Aug 8. doi: 10.1111/1744-7917.13428.
Aphids are sap-feeding plant pests that depend on their symbiotic relationships with the primary endosymbiont Buchnera aphidicola to adapt to impoverished diets. However, how the host plant affects the aphid primary symbiont and aphid adaptation to host plant transfer are poorly known. In this study, aphid symbiont screening and genotype identification were used to establish 2 aphid strains (Rhopalosiphum maidis [Rm] and Rhopalosiphum padi [Rp] strains) containing only Buchnera without any secondary symbionts for both wheat aphid species (R. maidis and R. padi). Aphid fitness and Buchnera titers were unstable on some of these host plants after transferring to novel host plants (G1-G5), which were influenced by host plant species and generations; however, they stabilized after prolonged feeding on the same plants for 10 generations. The electropenetrography (EPG) records showed that the allocation of aphid feeding time was significantly distinct in the 6 host plants; aphids had more intracellular punctures and spent more nonprobing time on green bristlegrass which was not conducive to its growth compared with other plants. The content of soluble sugar, soluble protein, and amino acid in the leaves of the 6 host plants were also clearly separated. The correlation coefficient analysis showed that the nutrient contents of host plants had significant correlations with aphid feeding behaviors, fitness, and Buchnera titers. In the meantime, aphid fitness, and Buchnera titers were also affected by aphid feeding behaviors. Also, Buchnera titers of aphid natural populations on 6 host plants showed a visible difference. Our study deepened our understanding of the interaction among aphids, endosymbionts, and host plants, indicating that the host plant nutrient content is a predominant factor affecting aphid adaptation to their diet, initially affecting aphid feeding behaviors, and further affecting aphid fitness and Buchnera titers, which would further contribute to exploiting new available strategies for aphid control.
蚜虫是以吸食植物汁液为生的害虫，它们依靠与主要内共生菌蚜虫内共生菌的共生关系来适应营养匮乏的食物。然而，宿主植物如何影响蚜虫的主要共生菌以及蚜虫对宿主植物转移的适应性却鲜为人知。在本研究中，通过蚜虫共生菌筛选和基因型鉴定，为两种麦蚜（玉米缢管蚜[Rm]和禾谷缢管蚜[Rp]）建立了仅含蚜虫内共生菌而无任何次生共生菌的2个蚜虫品系。转移到新宿主植物（G1-G5）后，在其中一些宿主植物上，蚜虫的适合度和蚜虫内共生菌滴度不稳定，这受到宿主植物种类和代数的影响；然而，在同一植物上长时间取食10代后它们趋于稳定。刺探电位图谱（EPG）记录表明，蚜虫在6种宿主植物上的取食时间分配存在显著差异；与其他植物相比，蚜虫在不利于其生长的狗尾草上有更多的细胞内穿刺，且非刺探时间更长。6种宿主植物叶片中的可溶性糖、可溶性蛋白和氨基酸含量也明显不同。相关系数分析表明，宿主植物的营养成分与蚜虫的取食行为、适合度和蚜虫内共生菌滴度有显著相关性。同时，蚜虫的适合度和蚜虫内共生菌滴度也受到蚜虫取食行为的影响。此外，6种宿主植物上蚜虫自然种群的蚜虫内共生菌滴度也存在明显差异。我们的研究加深了我们对蚜虫、内共生菌和宿主植物之间相互作用的理解，表明宿主植物营养成分是影响蚜虫对其食物适应性的主要因素，最初影响蚜虫的取食行为，进而影响蚜虫的适合度和蚜虫内共生菌滴度，这将进一步有助于开发新的蚜虫防治策略。
