Elevated O3 and TYLCV Infection Reduce the Suitability of Tomato as a Host for the Whitefly Bemisia tabaci

The effects of elevated atmospheric ozone (O₃) levels on herbivorous insects have been well studied, but little is known about the combined effects of elevated O₃ and virus infection on herbivorous insect performance. Using open-top chambers in the field, we determined the effects of elevated O₃ and Tomato yellow leaf curl virus (TYLCV) infection on wild-type (Wt) tomato and 35S tomato (jasmonic acid (JA) defense-enhanced genotype) in association with whitefly, Bemisia tabaci Gennadius biotype B. Elevated O₃ and TYLCV infection, alone and in combination, significantly reduced the contents of soluble sugars and free amino acids, increased the contents of total phenolics and condensed tannins, and increased salicylic acid (SA) content and the expression of SA-related genes in leaves. The JA signaling pathway was upregulated by elevated O₃, but downregulated by TYLCV infection and O₃ + TYLCV infection. Regardless of plant genotype, elevated O₃, TYLCV infection, or O₃ + TYLCV infection significantly decreased B. tabaci fecundity and abundance. These results suggest that elevated O₃ and TYLCV infection, alone and in combination, reduce the nutrients available for B. tabaci, increase SA content and SA-related gene expression, and increase secondary metabolites, resulting in decreases in fecundity and abundance of B. tabaci in both tomato genotypes.