Effects of infection by Turnip mosaic virus on the population growth of generalist and specialist aphid vectors on turnip plants

Abstract

Recent studies have revealed that relationships between plant pathogens and their vectors differ depending on species, strains and associated host plants. Turnip mosaic virus (TuMV) is one of the most important plant viruses worldwide and is transmitted by at least 89 aphid species in a non-persistent manner. TuMV is fundamentally divided into six phylogenetic groups; among which Asian-BR, basal-BR and world-B groups are known to occur in Japan. In Kyushu Japan, basal-BR has invaded approximately 2000 and immediately replaced the predominant world-B virus group. To clarify the relationships between TuMV and vector aphids, we examined the effects of the TuMV phylogenetic group on the population growth of aphid vectors in turnip plants. The population growth of a generalist aphid, Myzus persicae, was not significantly different between non-infected and TuMV-infected treatments. The population growth of a specialist aphid, Lipaphis erysimi, was higher in TuMV-infected plants than non-infected ones. Similar results were obtained in experiments using world-B and basal-BR groups of TuMV. Therefore, we conclude that L. erysimi is more mutualistic with TuMV than M. persicae, and differences in TuMV phylogenetic groups do not affect the growth of aphid vectors on turnip plants.

Fig 1

Mean number of (a) M. persicae and (b) L. erysimi on non-infected and world-B infected turnip plants. Vertical bars represent ±1 standard error of the mean. Asterisk and “NS” indicate significant and non-significant differences, respectively, between non-infected and world-B infected turnip plants (p < 0.05).

Fig 2

Mean number of (a) M. persicae and (b) L. erysimi on non-infected and basal-BR infected turnip plants. Vertical bars represent ±1 standard error of the mean. “NS” indicates no significant difference between non-infected and basal-BR infected turnip plants (p < 0.05).