瓜蚜前侵染西瓜植株对烟粉虱的诱导抗性及生化机制初探

Based on the data of a long term field experiment, choosing watermelon as test materials and Bemisia tabaci(Gennadius)-watermelon- Aphis gossypii Glover as research system, the impacts of infestation by B.labaci (Gennadius) on A. gossypii Glover settling on watermelon are determined in the orthogonal design test through manipulations of four factors: durations of aphid infestation, density of aphids, intervals between aphid removal after different durations of infestation and the time of whitefly release, and leaf positions on the plants. The most important factor in the four factors that affected the induced plant defense against whiteflies has been determined. The activities of non-volatile nutrients and secondary metabolism are determined in watermelon leaves of the highest and lowest responses of B. tabaci in the direct and indirect treatments from orthogonal design test. This study emphasized the instantaneous impact induced defense, from the perspective of macro-ecology, plant hoppers is discussed between induced by plant defense for regulating the relationship between the media related, study the effect of watermelon’s defense response induced by A. gossypii to B. tabaci and major effect factors. We also investigate induced resistance mechanism initially. Investigating defense responses of watermelon to B.labaci induced by A. gossypii have important academic meaning for definiting competitive replacement ability of B. tabaci to A. gossypii, showing competitive replacement mechanism of B. tabaci to A. gossypii, and implementing sustainable control effectively

本研究从田间现象入手，以瓜蚜-西瓜-烟粉虱作为研究体系，通过正交设计同时考虑预侵染时间、密度、取走蚜虫释放粉虱的时间间隔、以及系统叶片等几个因素的共同作用的影响，明确不同侵染处理间的作用关系，系统比较各因素对粉虱选择趋性影响的重要性次序；筛选烟粉虱对西瓜选择趋性最少和最多的处理，检测植物体内的非挥发营养物质和次生代谢物质的变化。本研究强调诱导防御的瞬时影响，从宏观定量生态学研究的角度，讨论了植食性昆虫之间以植物诱导防御为调节媒介的相关关系，并进行了瓜蚜为害西瓜对烟粉虱产生防御的抗虫机制初探；对明确烟粉虱对瓜蚜的竞争取代能力，揭示烟粉虱对瓜蚜的种间竞争取代机制，深入认识种群动态机制，有效的实施害虫可持续治理具有指导价值。

西瓜是重要的经济作物，烟粉虱、瓜蚜严重影响其产量和品质。为研究西瓜抗蚜机制及瓜蚜侵染对烟粉虱的影响；杀虫剂 (吡虫啉、噻虫嗪和氟啶虫酰胺) 灌根对植物、土壤理化性质，根际细菌多样性及群落结构的影响；本研究采用室内生测、BIOLOG检测法，并应用Illumina平台Hiseq 2500高通量测序技术对不同杀虫剂灌根处理的根际细菌进行16S rRNA测序。室内研究表明，不同密度瓜蚜取食后，西瓜叶片中可溶性蛋白，超氧化物歧化酶(Superoxide Dismutase，SOD)，过氧化物酶(Polypheno oxidase，POD)，多酚氧化酶(Polyphenol oxidase，PPO)，苯丙氨酸解氨酶(Phenylalanine ammonia-lyase，PAL)，β-1,3葡聚糖酶，几丁质酶含量均有不同程度的上升，且在非瓜蚜为害的系统叶片中有系统传递现象。田间瓜蚜、烟粉虱的发生与季节相关，噻虫嗪、吡虫啉、氟啶虫酰胺、氟啶虫胺腈灌根会降低田间植株上瓜蚜、烟粉虱数量，与对照差异不显著。高通量测序质控后获得3692个操作分类单元(Operational taxonomic units，OTUs)，Chloroflexi、 Actinobacteria、 Bacteroidetes、Proteobacteria 和 Planctomycetes 是其中的优势门，相对丰度在 82.64%-89.44%之间。杀虫剂灌根处理后叶片总可溶性蛋白含量、丙二醛 (Malondialdehyde， MDA) 含量增加，SOD、POD活性降低；其中吡虫啉、氟啶虫酰胺灌根处理叶片总可溶性蛋白含量、SOD活性与对照差异显著；吡虫啉灌根处理的叶片MDA活性显著高于对照。灌根处理对根部总可溶性蛋白、MDA含量及SOD、CAT、POD活性无显著影响。杀虫剂灌根处理的西瓜根际土壤平均颜色变化率AWCD显著高于对照，灌根处理后根际微生物的生理活性显著提高；细菌群落 α 多样性与对照无显著差异。CCA和基于典型相关分析的分区变化分析结果表明：根际细菌群落主要受全磷、pH的影响。上述结果为深入认识种群动态机制，明确烟粉虱对瓜蚜竞争取代机制；在微生物水平上研究不同杀虫剂灌根对土壤微生物的影响，为有效实施害虫综合治理提供依据。