Aphid-resistance of Oilseed Rape (Brassica napus) does not Necessarily Impede Turnip Mosaic Virus Transmission

Plant viruses improve transmission efficiency by directly and indirectly influencing vector behavior, but the impact of plant cultivars on these modifications is rarely studied. Using electropenetrography (EPG) technology, a comparative study of the effects of turnip mosaic virus (TuMV) infection on quantitative probing behaviors of the cabbage aphid (Brevicoryne brassicae) was conducted on two oilseed rape cultivars (‘Deleyou6’ and ‘Zhongshuang11’). Compared to mock-inoculated plants, cabbage aphids on infected plants increased the frequency of brief probing, cell penetration, and salivation. On the aphid-susceptible cultivar ‘Deleyou6’, in addition, aphids were more likely to acquire and vector TuMV than on resistant cultivars, as evidenced by the lengthened cell penetration time, and decreased ingestion caused by TuMV infection. TuMV also affected aphid probing behavior directly. Viruliferous aphids reduced the pathway duration, secreted more saliva, and ingested less sap than non-viruliferous aphids. In comparison with non-viruliferous aphids, viruliferous aphids started the first probe earlier, and increased brief probing and cell penetration frequencies on the aphid-resistant cultivar ‘Zhongshuang11’. Based on these observations, viruliferous aphids can inoculate TuMV more efficiently on ‘Zhongshuang11’ than on ‘Deleyou6’. Although aphid resistance and TuMV infection may influence aphid probing behavior, oilseed rape resistance to aphids does not impede TuMV transmission effectively.植物病毒可通过直接与间接调控介体昆虫行为提升自身传播效率，但植物品种对这类病毒介导的介体行为改变的影响却鲜有研究。本研究利用电刺探电位图谱（electropenetrography, EPG）技术，针对两个油菜品种（‘德油6号’与‘中双11号’），对比分析了芜菁花叶病毒（turnip mosaic virus, TuMV）侵染对甘蓝蚜（Brevicoryne brassicae）定量刺探行为的影响。与模拟接种的对照植株相比，染毒植株上的甘蓝蚜会提升短暂刺探、细胞穿透以及唾液分泌的发生频率。在感蚜品种‘德油6号’上，相较于抗蚜品种，甘蓝蚜更易获得并传播TuMV，这一现象可通过TuMV侵染导致的细胞穿透时长延长与取食时长缩短得到佐证。TuMV还可直接调控蚜虫的刺探行为：带毒蚜虫相较于不带毒蚜虫，其取食路径时长更短、唾液分泌量更多、植物汁液取食量更少。在抗蚜品种‘中双11号’上，带毒蚜虫相较于不带毒蚜虫，首次刺探启动更早，且短暂刺探与细胞穿透的发生频率更高。基于上述观测结果，带毒蚜虫在‘中双11号’上的TuMV接种效率要高于‘德油6号’。尽管蚜虫抗性与TuMV侵染均可调控蚜虫的刺探行为，但油菜对蚜虫的抗性并不能有效阻碍TuMV的传播。