Comparative transmission of two cucumber mosaic virus isolates by two color morphs of Acyrthosiphon pisum (Harris).

UNLABELLED: Cucumber mosaic virus (CMV) is one of the most important legume-infecting viruses, which is transmitted effectively by pea aphid Acyrthosiphon pisum (Harris) (Hem: Aphididae). Transmission efficiency of two CMV isolates (As and Kh from cowpea and bean hosts, resp.) by red and green color morphs of pea aphid were evaluated on bean plants. Triple-antibody sandwich ELISA (TAS-ELISA) using CMV-specific monoclonal antibodies revealed that both CMV isolates belonged to the serotype II. Bean plants inoculated by viruliferous aphids were assayed by double-antibody sandwich ELISA (DAS-ELISA) at 16 days post inoculation (dpi). The results showed that the transmission rate of CMV-As by the red morph was significantly higher than by the green morph, resulting in significantly higher transmission rate of the virus (As + Kh) by the red morph than by the green morph, with p≤ 0.1. Similarly, the efficiency of CMV transmission by the red morph of A. pisum was higher than the efficiency of transmission by the green morph. The higher transmission rate and efficiency of CMV by red pea aphid would be important in the epidemiology. Based on these results, we hypothesize that the transmission efficiency of CMV is affected more by the difference in transmission determinants of A. pisum color morphs than by the sequence of virus coat protein determinants. KEYWORDS: Aphididae; Bromoviridae; color polymorphism; transmission efficiency.