【作者】 刘佰明；

【导师】 张友军；

【作者基本信息】 中国农业科学院 ， 农业昆虫与害虫防治， 2012， 博士

【摘要】 烟粉虱是一种由多种生物型组成的世界性重要农业害虫，其中的B型和Q型是入侵性最强、危害最大的两种生物型。B型烟粉虱于20世纪90年代中后期入侵我国，Q型烟粉虱则于2003年最早于云南昆明发现。近些年来，烟粉虱在我国广大地区持续暴发危害，由其传播的番茄黄化曲叶病毒（TYLCV）病更是席卷我国主要番茄产区，给我国农业生产和国民经济造成了巨大损失。本论文利用EPG技术研究了寄主植物、病毒、内共生菌、化学农药等因子对B型和Q型烟粉虱取食行为的影响，相关研究结果对于阐明B型和Q型烟粉虱竞争取代机制以及TYLCV的流行机制具有重要意义。具体研究结果如下：（1）B型和Q型烟粉虱在不同寄主植物上具有不同的取食优势。B型烟粉虱在甘蓝和黄瓜上的取食能力显著强于Q型，而Q型烟粉虱在番茄、棉花和一品红上的取食能力显著强于B型。B型和Q型烟粉虱取食行为的差异表明二者具有寄主适应性差异。（2）TYLCV能以间接（植物感染）和直接（烟粉虱感染）2种方式修饰B型和Q型烟粉虱的取食行为。无论是B型还是Q型，TYLCV感染均能促进烟粉虱唾液分泌来促进病毒自身的快速传播。无论是植物感染还是烟粉虱感染TYLCV，Q型烟粉虱较B型具有适应性和传毒优势。（3）在感染TYLCV的番茄苗上研究噻虫嗪对B型和Q型烟粉虱取食行为的影响发现，噻虫嗪处理后，B型烟粉虱刺吸起始时间提前，而Q型烟粉虱则表现了更强的连续性刺探、分泌了更多的唾液。可见噻虫嗪处理对Q型烟粉虱表现了更强的行为修饰作用，Q型烟粉虱对药剂处理表现了更强的适应性。烟粉虱的唾液分泌行为与TYLCV传播密切相关，显然噻虫嗪处理促进了Q型烟粉虱对TYLCV的传播。（4）经抗生素处理和基因融合获得具有相同遗传背景，分别携带内共生菌Hamiltonella和不含Hamiltonella的两个Q型烟粉虱种群。两种群在黄瓜上的取食行为研究发现，与去除Hamiltonella的Q型烟粉虱相比，携带Hamiltonella的Q型烟粉虱能够较快、较容易的刺探到寄主植物韧皮部，并可显著提高烟粉虱唾液分泌频率。携带Hamiltonella提高Q型烟粉虱对寄主的适应性，同样Hamiltonella有可能通过修饰取食行为来促进TYLCV病毒的传播。（5）将B型烟粉虱分别用甘蓝、番茄和黄瓜隔离饲养6年形成烟粉虱甘蓝种群、番茄种群和黄瓜种群。比较3个寄主种群B型烟粉虱分别在甘蓝、番茄和黄瓜上的取食行为发现，与番茄和黄瓜种群相比，甘蓝种群无论是在其原始寄主甘蓝上、还是在转移寄主番茄和黄瓜上均能较容易地刺探到韧皮部、分泌较多的唾液并具有较强的韧皮部取食能力。显然，长期在单一的寄主植物上取食可以对B型烟粉虱取食行为产生驯化作用，并且这种驯化作用强弱依寄主植物而异。（6）对以上长期寄主隔离的甘蓝种群、番茄种群和黄瓜种群分子标记研究发现，寄主植物的长期隔离可以诱导B型烟粉虱种群发生明显的遗传分化，但是与Q型烟粉虱种群相比，B型烟粉虱不同寄主种群间的遗传距离均小于B和Q型烟粉虱生物型间的遗传距离。综上所述，与B型烟粉虱相比，Q型烟粉虱具有较好的寄主适应性、较高的传毒效率、对化学农药适应性更强等行为优势，这可能是Q型烟粉虱取代B型烟粉虱的重要原因之一。更多还原

【Abstract】 The whitefly Bemisia tabaci (Gennadius)(Hemiptera: Aleyrodidae) is a complex speciescomposed of at least24morphologically indistinguishable biotypes. Among them, biotypes B and Q areregarded as the two most invasive and destructive whiteflies. In China, B biotype was first detected inthe mid-1990s. Since then, B has gradually replaced the indigenous species, and has been the majorwhitefly pest till2007. The situation started to change in2003when Q arrived in Yunnan Province,China. In the following years, biotype Q has rapidly displaced B in most part of China and has becomethe most dominant whitefly. In recent years, B. tabaci causes excessive crop losses through directfeeding and transmission of plant viruses. For example, Tomato yellow leaf curl virus (TYLCV),transmitted by B. tabaci in a circulative manner, caused disease epidemics in many regions of China. Inthis study, we used the electrical penetration graph (EPG) toolkit to look at elements from both theinsect (feeding behavior) and plant (host suitability) perspective to better understand the factorsinvolved in the competitive displacement of B. tabaci biotype B by Q. The main findings are listed asfollows.(1) Pair-wise comparisons of B. tabaci biotypes B and Q feeding on each of the five host plantsindicates that Q feeds better on tomato, cotton, and poinsettia, while B thrives on cabbage and cucumber.Our current results suggest that tomato, cotton and poinsettia are more suited for Q, while cabbage andcucumber are more suited for B. combined results from both insect and host plants suggest that hostsuitability and feeding behaviors displayed by adult whiteflies can affect their interaction and maycontribute to the rapid competitive displacement observed in China over the past6years.(2) The indirect (plant infection) and direct (whitefly infection) effects of TYLCV on the feedingbehaviors of B. tabaci biotypes B and Q were evaluated using EPG technique. When non-viruliferouswhiteflies fed on healthy and TYLCV-infected plants, respectively, B. tabaci Q engaged in more phloemsalivation and phloem sap ingestion than B. Plant infection by virus significantly affected10of24feeding behavior parameters. When non-viruliferous and viruliferous whiteflies infested healthy plants,B. tabaci Q fed more readily than B on tomatoes, regardless of the infection status of whitefly. Whiteflyinfection significantly affected9of24feeding parameters. Viruliferous whiteflies engaged insignificantly more phloem salivation, which associated with inoculation of TYLCV. These combinedresults support the hypothesis that B. tabaci Q is a more efficient vector than B, and that whiteflyinfection by the virus directly modifies the vector’s feeding behavior in a manner which enhances viraltransmission.(3) Pair-wise comparisons of the feeding behaviors between B. tabaci biotypes B and Q onthiamethoxam treated and untreated TYLCV-infected tomatoes were carried out. The results showedthat biotype B probed more rapidly, while biotype Q fed more continuously and secreted more saliva on thiamethoxam treated tomatoes than on control ones. This indicated that thiamethoxam brought aboutgreater modification on the feeding behaviors for biotype Q than B, and biotype Q has more suitabilityto thiamethoxam treatment. The whitefly salivation is closely associated with TYLCV transmission.Thus the thiamethoxam treatment improved the TYLCV transmission in this study.(4) To evaluate the effects of endosymbiont, Hamiltonella, on feeding behaviors of B. tabaci, twoB. tabaci biotype Q colonies with the same genetic background, Hamiltonella-infeced (H+) anduninfected (H-), were established by antibiotic treatments and introgression. Comparisons of the feedingbehaviors on cucumber between the two colonies revealed that the Hamiltonella-infeced biotype Q(H+Q) reach the phloem phase more rapidly and easily than Hamiltonella-uninfeced biotype Q (H-Q).Obviously, the infection of Hamiltonella improved the fitness of whitefly. Meanwhile, the H+Q havehigher salivation frequency than H-Q, which indicated that the Hamiltonella is likely to improve theTYLCV transmission.(5) Feeding behavioral characters of long-term host isolated B. tabaci were examined. Three hostpopulations of B. tabaci biotype B with the same genetic background were established through rearingthe whiteflies segregated on cabbage, tomato, and cucumber for6years (hereafter referred to asCa-population, To-population, and Cu-population, respectively). Feeding behavior comparisons amongthe three host populations were carried out on each of the cabbage, tomato and cucumber plant,respectively. The results showed that Ca-population reached to the phloem phase more readily, secretemore saliva, and feed better than the other two host populations on any of the3host plants. Evidently,the feeding behaviors of B biotype were domesticated by adaptation for a long time on a specific hostplant, and the domestication degree varied with the host plants species.(6) Understanding the feeding behavior differences of the host specific B. tabaci biotype Bpopulations, the genetic differentiations of the3B biotype populations above and1additional Q biotypepopulation were further studied through AFLP and ISSR markers. The results indicated that thelong-term isolation of host plants induced a significant genetic differentiation for B biotype. However,the genetic distances among the three B biotype host populations were all lower than that between Band Q biotypes.In conclusion, B. tabaci biotype Q exhibited stronger host suitability, higher virus transmissionefficiency, and more adaption to the pesticide than B biotype. These factors may contribute to thecompetitive displacement of biotype B by Q.更多还原