Submitted to: Phytopathology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: June 25, 2010
Publication Date: November 1, 2010
Repository URL: http://hdl.handle.net/10113/45355
Citation: Todd, J.C., Ammar, E., Redinbaugh, M.G., Hoy, C., Hogenhout, S.A. 2010. Plant host range and leafhopper transmission of Maize fine streak virus. Phytopathology. 100(11):1138-1145. Interpretive Summary: Maize fine streak virus (MFSV) was discovered in maize growing in southern Georgia several years ago, and we showed that the virus could be transmitted to corn plants by the black-faced leafhopper (Graminella nigrifrons). In order to better understand how this virus might spread in nature, we wanted to know more about what plants this virus might infect and how the virus was transmitted by leafhoppers. We found that, in addition to corn, wheat, oats, rye, barley, foxtail, annual ryegrass and quackgrass can become infected by MFSV. This means that there is potential for this virus to cause disease in several crops and that there is at least one perennial virus host that could provide a source for virus infections between growing seasons. We found that MFSV infects and is transmitted by the leafhopper in a manner similar to related plant viruses. We also found that the black-faced leafhopper is not a very good vector of MFSV. Less than 10% of the leafhoppers that feed on MFSV-infected plants can transmit the virus. We think that this might be part of the reason there are few reports of this virus in crops. Our results help us to understand how this virus might cause disease in crops, and will help us to prevent economically important outbreaks from occurring.
Technical Abstract: Maize fine streak virus (MFSV), an emerging rhabdovirus species in the genus Nucleorhabdovirus, is persistently transmitted by the black-faced leafhopper, Graminella nigrifrons (Forbes). MFSV was transmitted to maize, wheat, oats, rye, barley, foxtail, annual ryegrass and quackgrass by G. nigrifrons. Parameters affecting the efficiency of MFSV acquisition (infection) and transmission (inoculation) to maize were evaluated using single leafhopper inoculations and ELISA. MFSV was detected in about 20% of leafhoppers that fed on infected plants, but less than 10% of insects transmitted the virus. Nymphs became infected earlier and supported higher viral titers than adults, but developmental stage did not affect the rate of MFSV transmission. Viral titer and transmission also increased with longer post-first access to diseased periods (PADP). The length of the inoculation access period was more important for virus accumulation in adults, and the length of the interval between feeding and transmission was more important in nymphs. A threshold viral titer was needed for transmission, but no transmission occurred, irrespective of titer, with PADP less than four weeks. MFSV was first detected by immunoflourescence confocal laser scanning microscopy at 2 wk PADP in midgut cells, hemocytes and neural tissues; 3 wk PADP in tracheal cells; and at 4 wk PADP in salivary glands coinciding with the time of transmission to plants.