AUTHOR=Guo Huijuan , Huang Lichao , Sun Yucheng , Guo Honggang , Ge Feng TITLE=The Contrasting Effects of Elevated CO2 on TYLCV Infection of Tomato Genotypes with and without the Resistance Gene, Mi-1.2 JOURNAL=Frontiers in Plant Science VOLUME=7 YEAR=2016 URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2016.01680 DOI=10.3389/fpls.2016.01680 ISSN=1664-462X 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.