Chen Chun, Ye Sudan, Hu Huajun, Xue Chengmei, Yu Xiaoping
China Jiliang University, Zhejiang Provincial Key Laboratory of Biometrology and Inspection & Quarantine, Hangzhou 310018, China.
Zhejiang Economic & Trade Polytechnic, Hangzhou 310018, China.
J Insect Physiol. 2018 Jan;104:9-14. doi: 10.1016/j.jinsphys.2017.11.003. Epub 2017 Nov 10.
A real-time qPCR method was developed, validated, and used to quantity the fungal pathogen, P. neoaphidis, within aphids at different times during infection; colonization rate fitted the Gompertz model well (R = 0.9356). Feeding behaviour of P. neoaphidis-infected and uninfected M. persicae were investigated, for the first time, using DC-electrical penetration graphs (DC-EPG) that characterized the waveforms made during different aphid stylet probing periods corresponding to epidermis penetration, salivation and ingestion. In the 6 h following the 12-h incubation period (to achieve infection), there were significant differences in the number of events of Np (non-probing) and C (stylet pathway) between infected and uninfected aphids. However, the difference between total duration of Np and C were not significantly different between infected and uninfected aphids. There were no significant differences in the number of events or total duration of E1 (phloem salivation) or E2 (phloem ingestion) between infected and uninfected aphids. There were significant differences in mean number of events and total duration of the pd waveform (intracellular punctures) in infected and uninfected aphids. In the 16 h prior to death, the same differences in behaviour were observed but they were even more obvious. Furthermore, the total duration time of E2 was significantly greater in uninfected aphids than infected aphids, a change that had not been observed in the first 6 h observation period. In conclusion, qPCR quantification demonstrated 'molecular' colonization levels throughout infection, and EPG data analysis during the two periods (during early infection and then during late infection just prior to death) demonstrated the actual physical effects of fungal infection on feeding behaviour of M. persicae; this has the potential to decrease the aphid's capacity of transmission and dispersal. These studies increase our understanding of the interaction between P. neoaphidis and its host aphid.
开发并验证了一种实时定量聚合酶链反应（qPCR）方法，用于在感染过程中的不同时间对蚜虫体内的真菌病原体新蚜虫疠霉进行定量；定殖率与冈珀茨模型拟合良好（R = 0.9356）。首次使用直流电穿透图（DC-EPG）研究了感染新蚜虫疠霉和未感染新蚜虫疠霉的桃蚜的取食行为，该图描绘了蚜虫口针在对应于表皮穿透、唾液分泌和取食的不同探测时期所产生的波形。在12小时潜伏期（以实现感染）后的6小时内，感染和未感染蚜虫之间的Np（非探测）和C（口针路径）事件数量存在显著差异。然而，感染和未感染蚜虫之间Np和C的总持续时间差异不显著。感染和未感染蚜虫之间E1（韧皮部唾液分泌）或E2（韧皮部取食）的事件数量或总持续时间没有显著差异。感染和未感染蚜虫的pd波形（细胞内穿刺）的平均事件数量和总持续时间存在显著差异。在死亡前的16小时内，观察到相同的行为差异，但更为明显。此外，未感染蚜虫的E2总持续时间显著长于感染蚜虫，这一变化在最初的6小时观察期内未观察到。总之，qPCR定量显示了整个感染过程中的“分子”定殖水平，并且在两个时期（早期感染期间以及随后在死亡前的晚期感染期间）的EPG数据分析表明真菌感染对桃蚜取食行为的实际物理影响；这有可能降低蚜虫的传播和扩散能力。这些研究增进了我们对新蚜虫疠霉与其寄主蚜虫之间相互作用的理解。
