B和Q型烟粉虱对寄主营养和抗性物质趋异适应性研究

B and Q biotypes Bemisia tabaci are important invasive pests throughout the world. Q biotype B. tabaci in China is gradually replacing the B biotype and become the dominant biotype in field, however, we know little about its exact mechanisms underlying the competitive displacement of B by Q whitefly. Our previous studies found that Q whitefly performed better on the oligotrophic host plants compared with B whitefly. Q whitefly has a wider host range, Q whitefly could complete growth and development on some host plants, such as peppers and kidney beans, whereas B whitefly is difficult to survive on these plants. Q whitefly is more tolerant to the insect-resistant material derived from host plants than B whitefly. The defense responses of the host plants induced by pest infestation usually decrease host nutrient levels and increase the secondary insect-resistant material content, the tolerance differences between B and Q whitefly to host defense response may mediate the competitive displacement. We therefore speculated that the tolerance differences between B and Q whitefly to host nutrient levels and the secondary insect-resistant substances (constitutive and inducible) may mediate their competitive displacement. In the present study, we compare and determine the asymmetric effects of the nutrient levels and/or secondary insect-resistant substances derived from some pepper and cabbage cultivars differing in resistance to whitefly on B and Q feeding and oviposition, growth and development, reproduction and detoxification enzyme activity. From the perspective of host nutrition and resistance physiology, we aim to elucidate the underlying mechanisms of competitive displacement of B by Q whitefly.

B和Q型烟粉虱是世界重要入侵性害虫。在中国，Q型烟粉虱逐渐取代B型而成为农田优势生物型，其确切取代机制目前所知甚少。我们前期研究发现，Q型烟粉虱较之B型烟粉虱在营养贫乏的寄主植物上表现更好。同时Q型烟粉虱具有更广的寄主范围，如辣椒和菜豆上，Q型烟粉虱生长发育良好，而B型烟粉虱很难存活，Q型烟粉虱可能对寄主抗虫物质耐受性更强。寄主受害虫侵染后诱导防御反应通常降低营养水平和升高次生抗虫物质含量，B和Q型烟粉虱对寄主防御反应耐受性差异也可能介导二者之间的竞争取代。据此我们推测：B和Q型烟粉虱对寄主营养水平和次生抗虫物质（组成型和诱导型）耐受性差异可能介导B和Q型烟粉虱间竞争取代。本研究以B和Q型烟粉虱及不同品种的辣椒和甘蓝为研究体系，比较不同品种寄主营养水平及次生抗虫物质对B和Q型烟粉虱取食和产卵、生长发育、繁殖和解毒酶表达及竞争取代的影响，从营养和和抗性生理角度阐明B和Q型烟粉虱竞争取代机制。

B和Q型烟粉虱是世界重要入侵性害虫。在中国，Q型烟粉虱逐渐取代B型而成为农田优势生物型，其确切取代机制目前所知甚少。我们研究发现，B型烟粉虱对不同质量的寄主植物鉴别能力强，但Q型烟粉虱较之B型烟粉虱更能耐受营养贫乏和抗虫物质含量高的寄主植物。同时提供千红，中椒4号，杭椒和中华红4个辣椒品种，测定B和Q烟粉虱取食和产卵选择性及取食行为。同时，测定4个辣椒品种主要营养和次生抗虫物质含量。中椒4号是高质量寄主（含有高营养和低抗虫物质），而中华红是低质量寄主（含有低营养和高抗虫物质）。EPG取食行为结果也与该结果一致，B和Q在中椒4号上的取食效率显著高于中华红。但B喜好在低质量中华红上取食和产卵，而Q对不同品种辣椒没有选择偏好。我们的结果表明可能不同品种辣椒释放的驱避性挥发物差异介导B和Q取食和产卵行为，中华红虽然质量差，但其释放的驱避性挥发物含量低，导致B烟粉虱偏好在其上取食和产卵。同时提供紫星，宝甘1号，春丰85，京丰1号和中甘19共5个甘蓝品种，测定B和Q烟粉虱取食和产卵选择性。同时，测定5个甘蓝品种主要营养和次生抗虫物质含量。B喜好在中甘19，春丰85和京丰1号上取食和产卵，而不喜好在宝甘1号上取食和产卵，B和Q避免在紫星上取食和产卵，而Q对其它4个品种甘蓝没有选择偏好。尽管5个甘蓝品种总酚，总氨基酸，总氮，总游离蛋白质和主要硫甙存在显著差异，但B和Q烟粉虱寄主选择与甘蓝体内主要硫甙，脂肪族硫甙，芳香族硫甙和总硫甙都没有显著相关，同时与总氨基酸，总氮都没有显著相关，但与多酚存在显著负相关。可见，我们研究结果表明B和Q烟粉虱对甘蓝选择受甘蓝体内多酚含量，而不是硫甙含量调控。与Q烟粉虱前期取食不同，B前期危害后显著提高寄主植物（甘蓝和辣椒）体内多酚含量，从而恶化寄主植物质量，进而导致B烟粉虱被Q取代。寄主受B烟粉虱侵染后诱导防御反应通常积累多酚类次生抗虫物质含量，而Q型烟粉虱前期取食不会导致寄主植物多酚的积累，该趋异性差异极可能是介导二者之间的竞争取代的一种主要机制。