Shi Xiaoqin, Dai Peng, Liu Deguang, Dai Xinjia, Shang Zheming, Ge Zhaohong, Meng Xiuxiang
State Key Laboratory of Crop Stress Biology for Arid Areas (Northwest A&F University), Yangling, Shaanxi Province 712100, China.
College of Plant Protection, Northwest A&F University, Yangling, Shaanxi Province 712100, China.
Sci Rep. 2016 Mar 16;6:23177. doi: 10.1038/srep23177.
Regiella insecticola has been found to enhance the performance of host aphids on certain plants, but its functional role in adaptation of host aphids to plants is still controversial. Here we evaluate the impacts of R. insecticola infections on vital life-history traits of Sitobion avenae (Fabricius), and their underlying genetic variation and phenotypic plasticity on three plants. It was shown that effects of R. insecticola on S. avenae's fitness (i.e., developmental time and fecundity) were neutral on oat or wheat, but negative on rye. Infections of R. insecticola modified genetic variation that underlies S. avenae's life-history traits. This was demonstrated by comparing life-history trait heritabilities between aphid lines with and without R. insecticola. Moreover, there were enhanced negative genetic correlations between developmental time and fecundity for R. insecticola infected lines, and structural differences in G-matrices of life-history traits for the two types of aphid lines. In R. insecticola-infected aphid lines, there were increases in plasticities for developmental times of first and second instar nymphs and for fecundity, showing novel functional roles of bacterial symbionts in plant-insect interactions. The identified effects of R. insecticola infections could have significant implications for the ecology and evolution of its host populations in natural conditions.
已发现昆虫雷吉氏菌可提高寄主蚜虫在某些植物上的表现，但其在寄主蚜虫适应植物过程中的功能作用仍存在争议。在此，我们评估了昆虫雷吉氏菌感染对麦长管蚜（Fabricius）重要生活史特征的影响，以及它们在三种植物上潜在的遗传变异和表型可塑性。结果表明，昆虫雷吉氏菌对麦长管蚜适合度（即发育时间和繁殖力）的影响在燕麦或小麦上呈中性，但在黑麦上呈负面。昆虫雷吉氏菌感染改变了麦长管蚜生活史特征的潜在遗传变异。通过比较有无昆虫雷吉氏菌的蚜虫品系之间的生活史特征遗传力得以证明。此外，对于感染昆虫雷吉氏菌的品系，发育时间与繁殖力之间的负遗传相关性增强，且两种蚜虫品系生活史特征的G矩阵存在结构差异。在感染昆虫雷吉氏菌的蚜虫品系中，一龄和二龄若虫的发育时间以及繁殖力的可塑性增加，表明细菌共生体在植物 - 昆虫相互作用中具有新的功能作用。所确定的昆虫雷吉氏菌感染的影响可能对其自然条件下寄主种群的生态学和进化具有重要意义。
