Response Of Nicotiana Attenuate-Cucumber Mosaic, Virus-Myzus Persicae To Elevated CO₂

Constantly rising of the concentrations of atmospheric carbon dioxide?CO₂? has been impacting the agricultural ecosystem which arouses the scientists' enormous interest. In order to explore the relationship of plant-virus-insect vectors under elevated CO₂ concentrations, we used Myzus persicae?Sulzer?, Cucumber mosaic virus?CMV? and different varieties of tobacco, including Nicotiana attenuate, Nicotiana benthamiana and16 c mutant plant, in combination with the Cucumber mosaic virus?CMV? and 2b protein mutant virus to analyze the effects of elevated CO₂ on the interaction of the plant-virus-insect vectors. In this paper, we mainly research the phenotype of the tobacco infected with the Cucumber mosaic virus?CMV?, RNA silencing system, resistance signaling pathways?MAPK signaling pathway and plant hormone signaling pathway? and Myzus persicae?Sulzer? feeding behavior to illuminate the interactions of the plant-virus-insect vectors under elevated CO₂ concentration. It aimed at providing the theory of controlling the outbreak of the virus and insect vectors under elevated CO₂ concentrations in the future. The main results in this study are as follows:1) Using the green fluorescent protein?GFP? technology to study phenotype of the Nicotiana benthamiana infected with the Cucumber mosaic virus?CMV? and silencing suppressor protein 2b under double current CO₂ concentrations?750 PPM vs. 375 PPM?.Our results showed that elevated CO₂ decreased the role of 2b protein in RNA silencing system, in favors of virus RNA silencing and resistance of Nicotiana benthamiana to virus.2) We further use Q-PCR technology to quantitatively analysis the key genes of Nicotiana attenuata resistance to virus silencing under elevated CO₂ concentrations. Our results showed that expression of AGO1, DCL1, DCL2 and DCL4 had been decreased in Nicotiana attenuata infected with Cucumber mosaic virus?CMV? under elevated CO₂ concentrations. Reverse validation was conducted by using 2b protein mutant virus. It was found that 2b protein mutant decreased the expression of AGO1, AGO4, DCL1, DCL2,DCL3 and DCL4. Our study also showed that by reducing the expression of 2b protein, the RNA silencing system was depressed at the same time.3) Exploration was carred out about whether the inhibition of virus silencing by Cucumber mosaic virus?CMV? 2b protein is caused by acting on MAPK signaling pathways to regulate plant hormone levels so as to achieve the inhibition on virus infection.Our results showed that Cucumber mosaic virus?CMV? could regulate JA and SA signaling pathways through regulating the expression of WIPK and MPK4. Elevated CO₂ concentrations did not reduce the expression of WIPK with the aid of 2b protein, resulting in decreasing expression of JA signaling pathways gene?AOC and MYC2?.Feeding behavior of Myzus persicae?Sulzer? was comparatively studied under ambient CO₂ concentrations and elevated CO₂ concentrations. It was found that when the aphid feeded the virus infected tobacco increasing the total time of feeding wave E2 under elevated CO₂ concentrations and this was helpful for aphid feeding.