Poster Session: Biology and Disease Management - Virology
117-P
Effect of temperature on Wheat streak mosaic virus replication and movement in resistant and susceptible winter wheat varieties.
E. N. WOSULA (1), S. Tatineni (2), S. N. Wegulo (1), G. L. Hein (1)
(1) University of Nebraska-Lincoln, Lincoln, NE, U.S.A.; (2) United States Department of Agriculture-Agricultural Research Service and University of Nebraska-Lincoln, Lincoln, NE, U.S.A.
Wheat streak mosaic virus (WSMV) is an economically important virus causing annual average yield losses of ~2% in winter wheat across the Great Plains. Temperature is an important factor that influences disease development and severity. The objective of this study was to determine the extent of WSMV replication and movement in winter wheat varieties ‘Mace’ (resistant) and ‘Tomahawk’ (susceptible) at 10, 15, 20 and 25°C. The number of days to WSMV expression at the point of inoculation increased as temperatures decreased from 4 to 18 days, but differences were not seen between the two varieties. WSMV in plants held at 10°C failed to move systemically at 21 days post inoculation, but those at 25°C were systemically infected within 10 days. After 21 days at the treatment temperatures, plants were moved to 27°C for 14 days, and systemic infection in Mace (70%) was slightly lower than in Tomahawk (97%). However, even with systemic infection, Mace plants did not display symptoms, while Tomahawk plants showed typical WSMV symptoms. Regrowth, from cut back plants previously held at 10 and 15°C with no systemic infection, expressed WSMV in 20-85% of the plants within 14 days at 27°C. This study demonstrates that WSMV moves at undetectable levels under suboptimal temperatures, but rapidly begins to replicate and induce symptoms in wheat plants under optimal temperatures. This helps explain the pattern of infection and the development of symptoms under field conditions.