The Contrasting Effects of Elevated CO2 on TYLCV Infection of Tomato Genotypes with and without the Resistance Gene, Mi-1.2

Abstract

Elevated atmospheric CO2 typically enhances photosynthesis of C3 plants and alters primary and secondary metabolites in plant tissue. By modifying the defensive signaling pathways in host plants, elevated CO2 could potentially affect the interactions between plants, viruses, and insects that vector viruses. R gene-mediated resistance in plants represents an efficient and highly specific defense against pathogens and herbivorous insects. The current study determined the effect of elevated CO2 on tomato plants with and without the nematode resistance gene Mi-1.2, which also confers resistance to some sap-sucking insects including whitefly, Bemisia tabaci. Furthermore, the subsequent effects of elevated CO2 on the performance of the vector whiteflies and the severity of Tomato yellow leaf curl virus (TYLCV) were also determined. The results showed that elevated CO2 increased the biomass, plant height, and photosynthetic rate of both the Moneymaker and the Mi-1.2 genotype. Elevated CO2 decreased TYLCV disease incidence and severity for Moneymaker plants but had the opposite effect on Mi-1.2 plants whether the plants were agroinoculated or inoculated via B. tabaci feeding. Elevated CO2 increased the salicylic acid (SA)-dependent signaling pathway on Moneymaker plants but decreased the SA-signaling pathway on Mi-1.2 plants when infected by TYLCV. Elevated CO2 did not significantly affect B. tabaci fitness or the ability of viruliferous B. tabaci to transmit virus regardless of plant genotype. The results indicate that elevated CO2 increases the resistance of Moneymaker plants but decreases the resistance of Mi-1.2 plants against TYLCV, whether the plants are agroinoculated or inoculated by the vector. Our results suggest that plant genotypes containing the R gene Mi-1.2 will be more vulnerable to TYLCV and perhaps to other plant viruses under elevated CO2 conditions.

Combined Effect of CO2 and Temperature on Wheat Powdery Mildew Development

“…In this study, the accumulation of PR genes was found at high CO 2 at low and medium temperatures with respect to ambient CO 2 . The similar findings of PR overexpression under high CO 2 were reported for PR-1 and PR-3 genes on Brassica juncea plants infected by Alternaria brassicae ( Mathur et al, 2018 ), and for PR-1 gene on tomato plants infected by Tomato yellow leaf curl virus ( Guo et al, 2016 ). Finally, a slight accumulation of PR transcripts at high temperatures and both CO 2 conditions, found in asymptomatic plants, might be related to the already activated defense response in wheat due to a high carbohydrate production, as discussed above.…”

Molecular Evidence for the Fitness of Cotton Aphid, Aphis gossypii in Response to Elevated CO2 From the Perspective of Feeding Behavior Analysis

“…For piercing-sucking insects, the results obtained by Sun et al (2013) indicated that the JA-regulated defense against M. persicae was more effective than the SA-regulated defense in Arabidopsis and that elevated CO 2 tends to enhance the ineffective SA signaling pathway and reduce the effective JA signaling pathway against aphids. Later, similar studies in regard to A. pisum reared on M. truncatula also demonstrated that elevated CO 2 enhances the SA-dependent defense pathway and suppresses the JA/ethylene-dependent defense pathway ( Guo et al, 2014b , 2016 ). A recent research on elevated plant resistance in response to CO 2 indicated that the heat shock protein 90 plays a critical role in plant resistance against the aphid under elevated CO 2 ( Sun et al, 2017 ).…”

AMF Inoculation Can Enhance Yield of Transgenic Bt Maize and Its Control Efficiency Against Mythimna separata Especially Under Elevated CO2

“…In this study, the results showed that e CO 2 significantly increased maize ear weight per plant and grain weight per ear, while it did not significantly affect the 100-grain weight. It is mainly because e CO 2 can enhance photosynthesis and in turn, has a positive effect on crop biomass and production (Guo et al, 2016 ; Liu et al, 2019 ). Although the maize yield was improved, the comprehensive nutritional quality of maize grain (100-grain weight) could not be improved; it may be due to the decreased nitrogen content at high CO 2 levels.…”