大气CO_2浓度升高对取食不同基因型拟南芥上桃蚜转录组基因表达的影响

The effect of elevated atmospheric CO_2 concentration on gene expression of peach aphid fed on different genotypes of Arabidopsis

【目的】近年来,温室气体尤其是CO_2浓度的持续升高给自然界造成的影响一直深受关注,但大部分以植物为对象研究其对CO_2浓度升高的响应,而针对植食性昆虫为对象着重昆虫的研究较少。【方法】本实验以在两种不同基因型拟南芥(野生型wt和水杨酸途径信号缺失体npr1)上取食的桃蚜Myzus persicae为研究对象,以大气CO_2浓度为影响因子,利用高通量筛选技术研究了大气CO_2浓度升高对桃蚜转录组基因表达的影响。【结果】研究表明:大气CO_2浓度升高仅增加了npr1突变体上的桃蚜体重,而对野生型上的桃蚜体重没有影响。此外,正常CO_2浓度下取食npr1突变体的蚜虫相较于取食野生型体重显著降低。通过对不同处理下桃蚜的转录组数据进行分析发现:正常CO_2浓度下,取食npr1突变体相较于取食野生型wt拟南芥,蚜虫体内基因有661条表达上产生显著差异变化,主要富集于12条通路;CO_2浓度升高条件下,取食不同基因型拟南芥的蚜虫体内差异基因降至536条,主要富集于15条通路;不同CO_2浓度下,取食wt植株的蚜虫有220条基因产生差异表达,主要富集于9条通路;不同CO_2浓度下,取食npr1突变体的蚜虫有274条差异基因,主要富集于16条通路。正常CO_2浓度下取食不同基因型拟南芥与不同CO_2浓度下取食npr1突变体的蚜虫共同富集于4条通路:内质网内蛋白加工,蛋白酶体,丙酮酸代谢以及抗原的加工与呈递过程。【结论】CO_2浓度升高对蚜虫生长发育的影响存在寄主基因型特异性,CO_2浓度升高对取食npr1植株上蚜虫生长发育的促进作用主要通过增加蚜虫体内氨基酸、糖类以及脂肪等基础代谢进行调节。

[Objectives] Global atmospheric CO2 concentration which has been increasing at an accelerating rate attracted widespread attention. Most of studies were focused on the response of plant to elevated CO2, but little was known about whether elevated CO2 can change the performance of herbivorous insects. [Methods] In this experiment, the effects of elevated CO2 were evaluated on the transcriptome changes of green peach aphid Myzus persicae fed on two Arabidopsis genotypes, a nprl mutant （deficient in salicylic acid signaling pathway） and wild-type control （wt） by using high-throughput screening technology. [Results] The study showed that the increase of atmospheric CO2 concentration only promoted the weight of green peach aphid fed on nprl mutant but had little effect on aphid fed on wild type plants. In addition, the weight of aphids fed on nprl genotype were significantly lower than those of the wild type under ambient CO2. Furthermore, we used pathway enrichment analysis to identify metabolic pathways or signal transduction pathways that were significantly enriched in DEGs （Differential Expressed Gene） relative to the whole transcriptome background of green peach aphid associated with different treatments. Among all the genes, 220, 274, 661 and 536 genes were significantly enriched in DEGs when aphids responded to elevated CO2 fed on wt plants, elevated CO2 fed on nprl plants, plant genotypes under ambient COz, plant genotypes under elevated CO2, respectively. Among all the genes subjected to KEGG pathway annotation and enrichment analysis, 9, 16, 12 and 15 pathways were significantly enriched in DEGs when aphids responded to elevated CO2 fed on wt plants, elevated CO2 fed on nprl plants, plant genotypes under ambient CO2, plant genotypes under elevated CO2, respectively. The common pathways significantly enriched in DEGs when aphids responded to plant genotypes under ambient CO2 and elevated CO2 fed on nprl plants： protein processing in endoplasmic reticulum, proteasome, pyruvate metabolism and antigen processing and presentation. [Conclusion] The effects of elevated CO2 on aphid weight exhibit host plant genotype-specific. The enhancement of elevated CO2 on the body weight of aphids associated with nprl mainly due to the increase of aphid primary metabolism including amino acid metabolism, fatty acid metabolism as well as carbohydrate metabolism.