Differential effects of an exotic plant virus on its two closely related vectors

Abstract

Concurrent spread of Tomato yellow leaf curl virus (TYLCV) with invasion of Bemisia tabaci Q rather than B in China suggests a more mutualistic relationship between TYLCV and Q than B. To assess this hypothesis, we quantified the impacts of TYLCV on the performance and competitiveness of B and Q in the laboratory. The results showed that relative to their non-infected counterparts feeding on cotton (a non-host for TYLCV), infected B exhibited significant reductions in life-history traits, whereas infected Q only showed marginal reductions. While Q performed better on TYLCV-infected tomato plants than on uninfected ones, the reverse was observed in B. Q displacement by B took one more generation on TYLCV-infected tomato plants than on healthy ones. These results demonstrate that TYLCV was indirectly mutualistic to Q but directly and indirectly parasitic to B.

Is there a role for symbiotic bacteria in plant virus transmission by insects?

“…The populations of the B species in Israel are efficient vectors of begomoviruses mainly Tomato yellow leaf curl virus (TYLCV), whilst populations of the Q species in Israel tend to be poor vectors [6 ]. These observations are in stark contrast to the situation in China [100]. Studies on association between B. tabaci populations and the Hamiltonella symbiont in Israel and China are in line with the previously described greenbug studies [9,79,80 ] that showed correlations between certain symbiont genotypes and the insect's ability to efficiently transmit virus.…”

“…With increasing numbers of conspecifics, each insect transmitting virus at a lower level can compensate for not having the symbiont, somewhat, because of an increasing chance that at least one individual will transmit the virus. Tying this story back to the vector manipulation hypothesis, the Q biotype, which harbors Hamiltonella in China performs better on TYLCVinfected plants than the B biotype, which does not harbor Hamiltonella in China [100]. In the H + strain, the performance benefit was shown to be the result of suppression of the anti-herbivore jasmonic acid plant defense pathway [107 ], data that provide unambiguous support for the hypothesis that symbiotic bacteria influence the plantinsect relationship.…”

Plants, viruses and the environment: Ecology and mutualism

“…These relationships too are quite complex. In some cases the viruses and vectors have a mutualistic relationship, resulting in increased longevity and fecundity of the insects, while in other cases the viruses are antagonistic to the vectors; differences have led to increased invasiveness of some whiteflies (Jiu et al, 2007;Mann et al, 2008;Pan et al, 2013). Recently some of these differences have been attributed to yet another player, a bacterial endosymbiont of the insect vector (Su et al, 2013).…”

Bemisia tabaci Q carrying tomato yellow leaf curl virus strongly suppresses host plant defenses

“…Our recent research showed that TYLCV indirectly benefits B. tabaci Q618 but directly and indirectly harms B. tabaci B6. In this context, indirect benefit or harm is mediated by the host plant.…”