|Byamukama, Emmanual -|
|Hein, Gary -|
|Baenziger, Peter -|
|Wegulo, Stephen -|
Submitted to: Plant Disease
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: January 13, 2012
Publication Date: June 1, 2012
Citation: Byamukama, E., Tatineni, S., Hein, G., Graybosch, R.A., Baenziger, P., French, R.C., Wegulo, S. 2012. Effects of single and double infections of winter wheat by Triticum mosaic virus and Wheat streak mosaic virus on yield determinants. Plant Disease. 96:859-864. Interpretive Summary: Triticum mosaic virus (TriMV) and Wheat streak mosaic virus (WSMV) are economically important viruses infecting wheat in the Great Plains region of the United States. Both TriMV and WSMV are transmitted by wheat curl mites (Aceria tosichella Keifer) and co-transmission of both viruses may contribute to double infections in wheat. Previously, we reported that the occurrence of TriMV and WSMV in the same wheat crop can exacerbate yield loss due to the synergistic interaction of these two viruses when they co-infect individual wheat plants. In this study, we quantified the effects on yield determinants (chlorophyll content, number of tillers per plant, fresh and dry weight of shoot and root, and total nitrogen and carbon content) of single and double infections of a WSMV-susceptible cultivar (Millennium) and a WSMV-resistant cultivar (Mace) by TriMV and/or WSMV. We demonstrated that under greenhouse conditions a synergistic, negative effect on yield determinants when Mace and Millennium were co-infected with TriMV and WSMV. These effects were more pronounced in the susceptible Millennium cultivar compared to the resistant Mace cultivar and were correlated to symptom severity.
Technical Abstract: Triticum mosaic virus (TriMV) is a recently discovered virus infecting wheat (Triticum aestivum L.) in the Great Plains region of the United States. It is transmitted by wheat curl mites (Aceria tosichella Keifer) which also transmit Wheat streak mosaic virus (WSMV) and Wheat mosaic virus. In a greenhouse experiment, winter wheat cultivars Millennium (WSMV-susceptible) and Mace (WSMV-resistant) were mechanically inoculated with TriMV, WSMV, TriMV+WSMV, or sterile water at the 2-leaf growth stage. At 28 days after inoculation, final chlorophyll meter (SPAD) readings, area under the SPAD progress curve (AUSPC), the number of tillers per plant (TPP), shoot and root weight, and total nitrogen and carbon content were determined. In Millennium, all measured variables were significantly reduced by single or double virus infections, with the greatest reductions occurring in the double infection treatment. In Mace, only final SPAD readings, AUSPC, and total nitrogen were significantly reduced by single or double virus infections. There was a significant (P = 0.05), positive linear relationship between SPAD readings and shoot weight in Millennium, but not in Mace. The relationship between total nitrogen and shoot weight was positive, linear, and significant in both cultivars. The results from this study indicate that Mace, a WSMV-resistant cultivar, is also resistant to TriMV, and double infection of winter wheat by TriMV and WSMV exacerbates symptom expression and loss of biomass in susceptible cultivars.