Wheat Cultivar-Specific Disease Synergism and Alteration of Virus Accumulation During Co-Infection with Wheat streak mosaic virus and Triticum mosaic virus

Abstract

Triticum mosaic virus (TriMV), the type member of the newly proposed Poacevirus genus, and Wheat streak mosaic virus (WSMV), the type member of Tritimovirus genus of the family Potyviridae, infect wheat naturally in the Great Plains and are transmitted by wheat curl mites. In this study, we examined the ability of these viruses to infect selected cereal hosts, and found several differential hosts between TriMV and WSMV. Additionally, we examined the interaction between WSMV and TriMV in three wheat cultivars at two temperature regimens (19 and 20 to 26 degrees C), and quantified the virus concentration in single and double infections by real-time reverse-transcription polymerase chain reaction. Double infections in wheat cvs. Arapahoe and Tomahawk at both temperature regimens induced disease synergism with severe leaf deformation, bleaching, and stunting, with a 2.2- to 7.4-fold increase in accumulation of both viruses over single infections at 14 days postinoculation (dpi). However, at 28 dpi, in double infections at 20 to 26 degrees C, TriMV concentration was increased by 1.4- to 1.8-fold in Arapahoe and Tomahawk but WSMV concentration was decreased to 0.5-fold. WSMV or TriMV replicated poorly in Mace at 19 degrees C with no synergistic interaction whereas both viruses accumulated at moderate levels at 20 to 26 degrees C and induced mild to moderate disease synergism in doubly infected Mace compared with Arapahoe and Tomahawk. Co-infections in Mace at 20 to 26 degrees C caused increased TriMV accumulation at 14 and 28 dpi by 2.6- and 1.4-fold and WSMV accumulated at 0.5- and 1.6-fold over single infections, respectively. Our data suggest that WSMV and TriMV induced cultivar-specific disease synergism in Arapahoe, Tomahawk, and Mace, and these findings could have several implications for management of wheat viruses in the Great Plains.

Occurrence and Distribution of Triticum mosaic virus in the Central Great Plains

“…Recent studies have shown that co-infection of wheat with WSMV and TriMV results in synergism that increases symptom severity, elevates titers of both viruses (26), and exacerbates biomass and yield loss (2,28). Therefore, knowing the extent of the distribution of TriMV and the frequency of its co-infection of wheat with WSMV or HPV will assist in estimating the potential risk TriMV poses to wheat production.…”

Wheat streak mosaic virus Coat Protein Deletion Mutants Elicit More Severe Symptoms Than Wild-Type Virus in Multiple Cereal Hosts

“…Total RNA extracted from upper fully expanded symptomatic wheat leaves at 14 dpi (McNeil et al 1996) was used as a template for first-strand cDNA synthesis in a 10-µl volume with random primers (Promega), as described by Tatineni et al (2010). One microliter of the first-strand cDNA was used for PCR in a 25-µl reaction with primers XV1 and XC1, flanking either side of the CP cistron, using a PCR program described by .…”

“…Total RNA was extracted from the same wheat leaves used for total protein with TriPure reagent (Roche, Indianapolis, IN, U.S.A.) as described by Tatineni et al (2010). Total RNA was extracted from 200 mg of infected leaf tissue, in triplicates, from each CP mutant.…”

“…One microgram of total RNA was used to prepare the first-strand cDNA in a 10-µl volume, using random primers. The cDNAs were diluted to 1:10 and 1 µl of diluted cDNAs were used for real-time PCR, using WSMV CP-specific primers and probe, as described by Tatineni et al (2010).…”

“…However, WSMV does not induce extensive leaf chlorosis in wheat under greenhouse conditions (Stenger et al 1998;Tatineni et al 2010). Plant viruses encode proteins for pathogenicity, including suppressors of RNA silencing (Pruss et al 1997;Voinnet et al 2000).…”