人工饲养不同世代灰飞虱群体传播水稻黑条矮缩病毒的比较

Comparison of RBSDV bearing rates and transmission rates among different generations of artificial reared Laodelphax striatellus Fallén

为明确人工饲养对灰飞虱传毒能力的影响,本文利用人工饲养至第55代、23代和8代的3个无毒灰飞虱群体,研究灰飞虱携带和传播RBSDV能力的差异。每个群体经饲毒、度过循回期后,选择雌、雄成虫各50头,单头单苗接种1叶1心期健康玉米。接种4 d回收灰飞虱,利用RT-PCR检测带毒率,并调查灰飞虱死亡率;接种43~50 d后调查玉米粗缩病发病率。结果表明:人工饲养55代、23代和8代的灰飞虱群体平均带毒率分别为68.24%、58.93%和62.09%,统计分析表明差异不显著;3个群体平均传毒率分别为31.22%、20.32%和29.91%,55代和8代群体均显著高于23代(P<0.05);3个群体平均死亡率分别为54.19%、65.24%和77.72%,其中55代群体极显著低于8代(P<0.01),二者与23代群体差异不显著。3个群体灰飞虱的带毒率63.09%高于传毒率27.15%,差异极显著(P<0.01)。结论:人工群体饲养至第55代的灰飞虱与仅饲养至第8代的灰飞虱在携带和传播RBSDV方面未发现显著差异,且均保持了较好的能力。

A virus-free colony of Laodelphax striatellus Fall6n （small brown planthopper, SBPH） is the solid basis for studies on SBPH vectored viruses. To compare the effectiveness of different generations of SBPH on carrying and transmitting Rice black-streaked dwarf virus （RBSDV）, a study was carded out from 2004 to 2014. In this study, 3 groups of SBPHs were collected from the same area in 2004, 2010 and 2012 respectively, and reared on wheat seedlings continuously till the 55^th generation, 23^rd generation and 8^th generation under green- house conditions. During the study, we exposed the SBPHs to diseased wheat plants which were infected by RBSDV for a 9-day acquisition period. After 24-29 days of incubation on healthy wheat plants, 50 male and 50 female SBPH individuals, respectively, were chosen randomly from each group. Three replications of inoculation were carried out by releasing the SBPHs onto healthy maize plants for 4 days with one vector for each maize plant. To detect the RBSDV bearing rates of the SBPHs, about 1/3 vectors were taken back for RBSDV detec- tion by RT-PCR. To test the transmission rates, at 43-50 days post inoculation （dpi）, disease incidences of maize rough dwarf disease were investigated. The results showed that there was no significant difference in the RBSDV bearing rates among the group 55th, 23rd and 8th（68.24%, 58.93% and 62.09%, respectively）. For RBS- DV transmission rates, there was no significant difference between group 55th and 8th（31.22% and 29.91%, respectively）. However, the transmission rates of the group 55^th and 8^th were significantly higher than the rate of 20.32% for group 23^sd（P〈0.05） .The mortality rate of 54.19% for the group 55th was extremely lower than that of 77.72% for the group 8^th（p〈0.01）. Among all the tested SBPHs, the RBSDV beating rates was significantly higher than the transmission rates （P〈0.01）. Thus we concluded that the artificial reared 55th generation of SBPH under controlled greenhouse conditions still showed ideal capability on RBSDV bearing rates and transmission rates.