Turnip aphids (Lipaphis erysimi) discriminate host plants based on the strain of Cauliflower mosaic virus infection
The degree of vector preference for virus-infected plants can alter the progress of virus epidemics. The objective of this study is to test whether infection of turnip plants with different strains of Cauliflower mosaic virus (CaMV) can influence the feeding preference of the turnip aphid (Lipaphis erysimi). Three different strains of CaMV that cause different types of symptoms on turnips were used in this study. These strains were NY8153 (severe, causes necrosis of the midrib and mottling with severe stunting), W260 (mild, causes mosaic with moderate stunting) and H12 (symptomless). Results showed that turnip aphids preferred W260-infected plants, in general. When given a choice, aphids chose W260-infected plants significantly more often than NY8153-infected or healthy plants. W260-infected vs. H12-infected plants showed a trend in the same direction. Also, aphids chose plants infected with H12 more often than healthy plants when given a choice. By contrast, turnip aphids showed no preference between NY8153-infected and healthy plants, or between NY8153-infected and H12-infected plants. Therefore, we conclude that aphids can recognize plants infected with different strains of CaMV and will choose plants with specific strains over others. Specifically, aphids prefer W260-infected turnips over other choices. These results suggest that virus infection affects the aphid host choice and this may have implications for the spread of different virus strains.