臭氧浓度升高对“番茄-烟粉虱-番茄黄化曲叶病毒”互作特性的影响及其作用机理

It has important ecological significance to research the impacts of global climate change on the interactions among tri-trophic levels of plant, insect and virus. Previous study indicated that the viruliferous biotype Q whitefy, Bemisia tabaci infected by tomato yellow leaf curl virus (TYLCV), had significantly higher fecundity and survival rate than those of non-viruliferous biotype Q individuals fed on the wild-type (Wt) and jasmonic acid (JA) defense-enhanced genotype (35S) tomato plants, and the endogenous JA contents were significantly reduced when these two types of tomato plants were damaged by the viruliferous biotype Q whitefy, B. tabaci. To date, there is still lack of research on the virus transmission ability and biological characteristic of biotype Q, B. tabaci, and molecular defense mechanism of TYLCV-infected tomato plants under elevated O3 concentration. This study intends to use the JA tomato mutants (35S, JA-deficient genotype (spr2)) and wild-type (Wt), B. tabaci and its transmitted TYLCV as the research object. From the defense signalling substance accumulation, nutrients and secondary metabolism, disease severity, expression and activation of defense genes of tomato plant, the virus transmission ability, biological characteristic of B. tabaci, we comprehensively examine how the tomato mediated whitefly and its transmitted virus- TYLCV in its response to elevated O3. Thereby we will confirm the interaction theory among plant, insect and virus under elevated O3 level. The outcomes of this project are able to provide scientific basis for the ecological control of tomato viruses under projected rising O3 conditions in the future.

气候变化对“植物-昆虫-病毒”三级营养关系的影响研究具有重要的生态意义。前期结果表明在茉莉酸（jasmonic acid, JA）过表达的番茄突变体（35S）和野生型（WT）上，感染番茄黄化曲叶病毒（TYLCV）的Q型烟粉虱产卵量、存活率等都显著高于不带毒个体，且取食番茄后寄主内JA含量显著下降；但在大气臭氧（O3）浓度升高下，Q型烟粉虱的传毒能力，生物学特性及其分子防御机制等尚不清楚。本项目拟以2种JA番茄突变体（35S，JA缺失突变体spr2）和WT、Q型烟粉虱和TYLCV为研究对象，从番茄突变体防御信号物质积累、营养和次生物质代谢、植株发病率、防御基因表达及烟粉虱的传毒能力、生物学特性等方面系统研究“番茄-烟粉虱-TYLCV”互作及其对O3浓度升高的响应机理，从而明确O3浓度升高下植物-害虫-病毒互作理论，最终为未来O3浓度升高下Q型烟粉虱及其所传病毒病的生态控制提出预警和防控对策。

气候变化对“植物-昆虫-病毒”三级营养关系的影响研究具有重要的生态意义。本项目以野生型番茄Wt和2种茉莉酸（jasmonic acid, JA）番茄突变体（JA过量表达突变体35S，JA缺失突变体spr2）、Q型烟粉虱和TYLCV为研究对象，从番茄突变体防御信号物质积累、营养和次生代谢物质、植株发病率、防御基因表达及烟粉虱的传毒能力、生物学特性等方面系统研究“番茄-烟粉虱-TYLCV”互作及其对O3浓度升高的响应机理，从而明确O3浓度升高下植物-害虫-病毒互作理论。研究结果发现，在三种番茄基因型中，升高的O3浓度显著增加了水杨酸含量（salicylic acid, SA），JA含量及其相关基因的表达量。TYLCV侵染显著增加了SA含量及相关基因PAL和 PR1的表达量，但是TYLCV侵染显著降低了番茄基因型中的JA含量及相关基因LOX和PI1的表达量。在O3+TYLCV处理下，3种番茄基因型的SA含量及相关基因的表达量是最高的。不论O3水平的高低，TYLCV侵染显著增加了3种番茄基因型的SA含量及相关基因的表达量，与之同时，TYLCV侵染显著降低了番茄基因型中的JA含量及相关基因的表达量。同时不论O3水平的高低，TYLCV侵染显著的增加了各种氨基酸组分的含量。升高的O3浓度显著增加了烟粉虱的发育时间，同时显著降低了烟粉虱的繁殖力。TYLCV侵染显著降低了烟粉虱的发育时间，同时显著增加了烟粉虱的繁殖力。不论O3水平的高低，TYLCV感染显著增加了取食番茄基因型的Q型烟粉虱的产卵量。此外，Q型烟粉虱的产卵量及发育速率与番茄中的氨基酸组分含量呈显著正相关，与JA含量及相关基因的表达呈负相关。这些研究结果表明O3浓度升高和TYLCV侵染的相互作用通过显著增加番茄基因型的氨基酸组分含量，降低JA含量和相关基因的相对表达量，导致Q型烟粉虱发育时间的缩短，繁殖力的提高。这些变化表明，随着Q型烟粉虱数量的增加，O3浓度升高会加重TYLCV在番茄中的传播，最终为未来O3浓度升高下Q型烟粉虱及其所传病毒病的生态控制提出预警和防控对策。