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

Abstract

The concurrence of tomato yellow leaf curl virus (TYLCV) with the spread of its vector Bemisia tabaci Q rather than B in China suggests a more mutualistic relationship between TYLCV and Q. Here, we investigated the hypothesis that viruliferous B and Q have different effects on plant defenses. We found the fecundity of nonviruliferous B, nonviruliferous Q, viruliferous Q and viruliferous B was 11.080, 12.060, 10.760, and 11.220 respectively on plants previously attacked by the other biotype, however, on their respective noninfested control leaves fecundity was 12.000, 10.880, 9.760, and 8.020 respectively. Only viruliferous B had higher fecundity on viruliferous Q-infested plants than on control plants. The longevity of viruliferous B showed the same phenomenon. At 1 d infestion, the jasmonic acid content in leaves noninfested and in leaves infested with nonviruliferous B, nonviruliferous Q, viruliferous B and viruliferous Q was 407.000, 281.333, 301.333, 266.667 and 134.000 ng/g FW, respectively. The JA content was lowest in viruliferous Q-infested leaves. The proteinase inhibitor activity and expression of JA-related upstream gene LOX and downstream gene PI II showed the same trend. The substantial suppression of host defenses by Q carrying TYLCV probably enhances the spread of Q and TYLCV in China.

Host Manipulation by Parasites: Cases, Patterns, and Remaining Doubts

“…One of the most intriguing examples is Cucumber mosaic virus: the bouquet of VOCs emitted by infected plants is altered, making the plants more attractive to the aphids that vector this virus, even though the nutritional quality of infected plants is lower (Mauck et al, 2010). By contrast, other viruses enhance the nutritional quality of the infected plant for vectors such as the whitefly Bemisia tabaci (Fang et al, 2013;Luan et al, 2013;Shi et al, 2014).…”

“…Leucochloridium spp. change the color and shape of the tentacles of snails that serve as their intermediate hosts and make them pulsate in response to light, thereby Fang et al, 2013;Shi et al, 2014 attracting predatory birds that represent the final hosts (Kagan, 1951). Dicrocoelium dendriticum-infected ants start to climb and bite into the tips of grasses, particularly at low temperatures, and thereby facilitate predation by ruminants (Moore, 2002).…”

“…Because plants are sessile, many pathogens of plants use the same strategies for their transmission as the agents of vectorborne human diseases (Guiguet et al, 2016) and, for example, change the behavior of their vectors to enhance transmission from infected to healthy plants hosts (Stafford et al, 2011;Ingwell et al, 2012;Rajabaskar et al, 2014), alter the emission of volatile organic compounds (VOCs) from the infected host (Mauck et al, 2010), or enhance the nutritional quality of the infected plant for herbivores that serve as their vectors (Fang et al, 2013;Luan et al, 2013;Shi et al, 2014). One of the most intriguing examples is Cucumber mosaic virus: the bouquet of VOCs emitted by infected plants is altered, making the plants more attractive to the aphids that vector this virus, even though the nutritional quality of infected plants is lower (Mauck et al, 2010).…”

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

“…Increasing evidence suggests that vector-borne pathogens can alter the quality of their hosts in ways that influence the abundance of herbivores [15,16,20]. Although several studies have documented how changes in nutrients or resistance of virus-infected plants affect the performance of herbivorous insects [20,21], little is known about how the combined effects of changes in nutrients and resistance caused by virus infection affect the performance of herbivorous insects. …”

“…Both plant viruses and elevated O 3 can induce hormone-mediated resistance that, in turn, affects herbivorous insects [10,21]. SA and JA are regarded as the most important hormonal mediators of induced defenses of plants against pathogens, ozone, herbivores, and other stressors [22,23,24,25].…”