The NIa‐Pro protein of Turnip mosaic virus improves growth and reproduction of the aphid vector, Myzus persicae (green peach aphid)

Abstract

SUMMARYMany plant viruses depend on aphids and other phloem-feeding insects for transmission within and among host plants. Thus, viruses may promote their own transmission by manipulating plant physiology to attract aphids and increase aphid reproduction. Consistent with this hypothesis, Myzus persicae (green peach aphids) prefer to settle on Nicotiana benthamiana infected with Turnip mosaic virus (TuMV) and fecundity on virus-infected N. benthamiana and Arabidopsis thaliana (Arabidopsis) is higher than on uninfected controls. TuMV infection suppresses callose deposition, an important plant defense, and increases the amount of free amino acids, the major source of nitrogen for aphids. To investigate the underlying molecular mechanisms of this phenomenon, 10 TuMV genes were over-expressed in plants to determine their effects on aphid reproduction. Production of a single TuMV protein, nuclear inclusion a-protease domain (NIa-Pro), increased M. persicae reproduction on both N. benthamiana and Arabidopsis. Similar to the effects that are observed during TuMV infection, NIa-Pro expression alone increased aphid arrestment, suppressed callose deposition and increased the abundance of free amino acids. Together, these results suggest a function for the TuMV NIa-Pro protein in manipulating the physiology of host plants. By attracting aphid vectors and promoting their reproduction, TuMV may influence plant-aphid interactions to promote its own transmission.

Determining the duration of Aphis glycines (Hemiptera: Aphididae) induced susceptibility effect in soybean

“…Additional evidence that a plant virus is unlikely responsible for the obviation of resistance is the reduction in the response populations at 120 and 216 h for the virulent inducer population treatment. This observation is not consistent with results from other studies of plant virus infection on aphid populations in which the virus infection improved aphid populations for up to one week post-infection (Casteel et al 2014). Due to the asymptomatic nature of our plants and the reduction of the effect over time, we conclude that a plant virus was not the cause of the obviation of resistance.…”

Spider mites suppress tomato defenses downstream of jasmonate and salicylate independently of hormonal crosstalk

“…Some phytopathogens, vectored by arthropods, have been implicated in the suppression of plant defenses, putatively to (indirectly) enhance their own fitness (Belliure et al ., 2005; Sugio et al ., 2011; Casteel et al ., 2012, 2014; Zhang et al ., 2012; Chung et al ., 2013). Preliminary data, though, indicate that spider mite-associated microbes do not mediate suppression of plant defenses (data not shown).…”

Bean Common Mosaic Virus and Bean Common Mosaic Necrosis Virus

“…The effects of potyviruses on plant-aphid interactions are conditioned by specific viral gene products. Aphid (Myzus persicae) performance was enhanced on plants of A. thaliana and N. benthamiana following infection with TuMV (Casteel et al, 2014). In these TuMV-infected plants, it was found that deposition of callose (which has defensive properties against aphids) was decreased and the levels of certain amino acids were elevated in the phloem sap and that these changes were attributable to the TuMV NIa-Pro (Casteel et al, 2014).…”

“…Aphid (Myzus persicae) performance was enhanced on plants of A. thaliana and N. benthamiana following infection with TuMV (Casteel et al, 2014). In these TuMV-infected plants, it was found that deposition of callose (which has defensive properties against aphids) was decreased and the levels of certain amino acids were elevated in the phloem sap and that these changes were attributable to the TuMV NIa-Pro (Casteel et al, 2014). In contrast, Westwood et al (2014) found that infection of N. benthamiana plants with PVY decreased the reproduction of Myzus persicae although the growth of the individual aphids placed on the infected plants was not inhibited.…”