湖南植保所张德咏团队揭示桃蚜内共生菌通过调节宿主的挥发性物质来促进病毒传播

来源：植物生物学

今天，介绍的是新发表在BMC Plant Biology上，湖南植保所张德咏团队发表的研究文章《Aphidendosymbiont facilitates virus transmission by modulating the volatile profileof host plants》。

作者前期研究发现携带CMV的桃蚜趋向于健康植物，而不带毒桃蚜趋向于感染CMV的植物，同时发现携带CMV的桃蚜其内共生菌Buchneraaphidicola含量显著降低，关于内共生菌在病毒传播中的作用，还很少有研究。

本研究中，作者通过利福平处理降低桃蚜Buchnera含量来模拟带毒桃蚜的Buchnera含量，研究了6个处理对辣椒挥发物的影响：健康辣椒，不带毒桃蚜取食的健康辣椒，利福平处理桃蚜取食的健康辣椒，带毒辣椒，不带毒桃蚜取食的带毒辣椒，利福平处理桃蚜取食的带毒辣椒。分析发现，利福平处理的桃蚜取食健康辣椒和带毒辣椒后，显著降低了挥发物σ-cymene和2-octanol的含量，升高了benzylalcohol和σ-xylene的含量，进一步鉴定了这几种挥发物对健康桃蚜，携带CMV桃蚜和利福平处理的桃蚜的选择性，发现σ-cymene和2-octanol对这三种桃蚜均有驱避作用，而benzylalcohol和σ-xylene均有吸引作用，证实了携带CMV桃蚜取食植物后，Buchnera含量的降低了导致了植物驱避性挥发物含量升高，而吸引性挥发物含量降低，导致桃蚜离开植物。

作者的研究表明，内共生菌介导的挥发性变化将推动对带毒的蚜虫向健康植物转移，从而为带毒蚜虫传毒提供更多的机会，这可能对于CMV的进化，从而更好地借助媒介昆虫传毒是非常重要的。

Most plant viruses rely on vectors for their transmission and spread. One of the outstanding biological questions concerning the vector-pathogen-symbiont multi-trophic interactions is the potential involvement of vector symbionts in the virus transmission process. Here, we used a multi-factorial system containing a non-persistent plant virus, cucumber mosaic virus (CMV), its primary vector, green peach aphid, Myzus persicae, and the obligate endosymbiont, Buchnera aphidicola to explore this uncharted territory.

Based on our preliminary research, we hypothesized that aphid endosymbiont B. aphidicola can facilitate CMV transmission by modulating plant volatile profiles. Gene expression analyses demonstrated that CMV infection reduced B. aphidicola abundance in M. persicae, in which lower abundance of B. aphidicola was associated with a preference shift in aphids from infected to healthy plants. Volatile profile analyses confirmed that feeding by aphids with lower B. aphidicola titers reduced the production of attractants, while increased the emission of deterrents. As a result, M. persicae changed their feeding preference from infected to healthy plants.

We conclude that CMV infection reduces the B. aphidicola abundance in M. persicae. When viruliferous aphids feed on host plants, dynamic changes in obligate symbionts lead to a shift in plant volatiles from attraction to avoidance, thereby switching insect vector’s feeding preference from infected to healthy plants.