不同环境条件下的西花蓟马种群对高温胁迫的适应性及其机制

Western flower thrips, Frankliniella occidentalis, an important worldwide quarantine pest, caused serious damage on many vegetable and ornamental crops after invading China. The research will answer the following question "Western flower thrips outbreak is closely related with it's strong adaptability to high temperature" from experimental biology, ecology, physiology and molecules. This research focus on the thermotolerance difference between field population and indoor population of western flower thrips, the effect of field continued high temperature on the thermotolerance of western flower thrips population, constructing population life table, revealing the biological adaptability of western flower thrips population to high temperature; focus on revealing the relationship between low molecular weight protective substances accumulation and thermotolerance of western flower thrips by establishing the quantitative evaluation system aiming at the change of content of low molecular weight protective substances and mannitol and relative enzyme activity; focus on determining the expression of five heat shock proteins (Hsps) using real-time PCR, thereby obtain the relationship between heat resistant and Hsps of western flower thrips. All the results will contribute to uncover the function mechanism of extremely high temperature to western flower thrips from population level, physiological level and molecule level. At the same time, the results can provide objective basis for designing energy-efficient high temperature technique for pest control and establishing scientific and reasonable measures, and lay the foundation of research on the heat resistance of western flower thrips.

世界性危险害虫西花蓟马入侵我国后给蔬菜花卉生产造成了严重危害。本研究围绕"西花蓟马灾变与其较强的高温适应性密切相关"这一科学问题，采用实验生物学、生态学、生理学与分子生物学相结合的方法，重点研究西花蓟马田间种群与室内种群耐热性差异，田间持续高温热驯化对西花蓟马种群耐热性的影响，建立种群生命表，揭示种群对高温的生物学适应性；研究并建立热胁迫下西花蓟马体内低分子量保护物质及其相关代谢酶的活力变化的定量评价体系，揭示该蓟马的耐热性和低分子量保护物质累积的关系；通过实时定量PCR测定热激蛋白的表达，探索该蓟马耐热性的获得与热激蛋白的相关性。这些研究将会从种群、生理、分子水平上系统揭示高温对西花蓟马种群热胁迫适应性的影响及其机制；研究成果将为高温物理防控技术，制定科学合理的防控措施提供客观依据；同时也为揭示外来种入侵生态机制奠定基础。

世界性危险害虫西花蓟马入侵我国后给蔬菜花卉生产造成了严重危害。本研究围绕西花蓟马灾变与其较强的高温适应性密切相关这一科学问题，采用实验生物学、生态学、生理学与分子生物学相结合的方法，研究了西花蓟马不同种群不同虫态以及性别间的耐热性差异，高温热激频率对西花蓟马种群动态的持续影响，构建了不同西花蓟马种群生命表，研究结果表明，在41℃和43℃高温条件下，预蛹期和伪蛹期的耐热性最强，但是45℃高温条件下蓟马的成虫期是最耐热的；西花蓟马亲代成虫热激后雌性成虫的寿命缩短、后代若虫和成虫数量减少、存活率降低，雌雄性比下降，并且随着处理时间的延长及次数的增加，受到的影响更加明显，但是蓟马种群具有较强的恢复能力，通常高温热激可持续影响2代；研究了热胁迫下西花蓟马体内分子保护物质海藻糖含量、山梨醇含量、丙二醛（MDA）浓度及其相关代谢酶乙酰胆碱酯酶比活力、超氧化物歧化酶（SOD）比活力的变化，蓟马通过调节小分子物质含量和相关酶的活性来应对高温热胁迫；通过实时定量PCR测定了Hsps（Hsp90、Hsp701、Hsp702和Hsp60）热激蛋白的表达，处理后4个Hsps基因的表达量都明显上升，成虫的Hsp90和Hsp60表达量高于幼虫的；幼虫的Hsp701和Hsp702高于成虫的。测定了西花蓟马体内与卵巢和卵黄蛋白含量相关的物质甘油三酯和蜕皮激素（20-羟基蜕皮酮）含量，电泳结合不同的染色方法证明西花蓟马的卵黄蛋白为一种磷酸化、糖基化的脂蛋白，由3个亚基组成，分子量分别为116，70 和47 kDa；通过显微摄影技术，观察了西花蓟马雌虫生殖器官及胚胎发育过程的形态变化，高温导致西花蓟马卵巢管数量减少，卵巢管和胚胎发育畸形，热激导致卵黄蛋白合成受到抑制，且对卵黄蛋白相对含量的影响持续到F1代。研究结果为揭示外来种入侵生态机制奠定了基础,为制定科学合理的高温物理防控措施提供依据。