Suppression of terpenoid synthesis in tomato plants by a begomovirus
enhances the attraction of its vector
Vectors of viruses and other plant pathogens are known to often be
attracted by pathogen-infected plants, which promotes pathogen spread.
However, few studies have examined how virus-induced changes in plant
volatiles mediate such preference. Previous research has demonstrated
that tomato plants become more attractive to the whitefly Bemisia
tabaci when they are infected by the begomovirus Tomato yellow
leaf curl virus (TYLCV). In the current study, we found that the
increase in attractiveness is associated with TYLCV-repressed terpenoid
synthesis in the virus-infected plants. The observed TYLCV suppression
of terpenoid synthesis is similar to the suppression of terpenoid
synthesis induced by whitefly infestation. Secondary metabolite analyses
and olfactometer experiments with mutant plants revealed that a reduced
release of terpenoids through TYLCV-induced suppression of flavonoid
synthesis causes B. tabaci females to prefers TYLCV-infected
plants over non-infected plants. These results show that TYLCV infection
triggers the same changes in odor signaling as caused by B.
tabaci infestation, such that both B. tabaci infestation and
TYLCV infection increase whitefly aggregation and thereby increase
vector acquisition and spread of TYLCV.