ARS | Publication request: Triticum mosaic virus isolates in the southern Great Plains

Submitted to: Plant Disease
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: July 5, 2011
Publication Date: July 19, 2011
Repository URL: http://doi: 10.1094/PDIS-04-11-0281
Citation: Fuentes-Bueno, I., Price, J., Rush, C., Seifers, D., Fellers, J.P. 2011. Triticum mosaic virus isolates in the southern Great Plains. Plant Disease. DOI: 10.1094/PDIS-04-11-0281.

Interpretive Summary: In 2006, a new virus was isolated in Western Kansas from the cultivar RonL. The virus was named Triticum mosaic virus (TriMV) and analysis showed that it was a very unique virus. The genome was sequenced, compared to other viruses, and no other virus is like TriMV in nucleotide or amino acid sequence. Since its discovery, TriMV has been found from Wyoming to Texas. This study was undertaken to determine how variable the virus is in terms of its nucleotide sequence. The coat protein gene from fourteen TriMV isolates from Texas, Oklahoma, and Kansas were sequenced and only thirteen changes were found in the gene. As is often the case, Wheat streak mosaic virus (WSMV) was also found in the same plants as TriMV. This study also looked at the coat protein gene of WSMV isolates within the same samples. Sixty-five nucleotide differences were found. This study shows that TriMV appears to be genetically very stable, while WSMV is very variable.

Technical Abstract: In 2006, a Wheat streak mosaic virus (WSMV)-resistant wheat variety RonL was found to have mosaic symptoms similar to WSMV. The virus inducing the symptoms was determined to be previously unknown and given the name Triticum mosaic virus (TriMV). Since, TriMV has been found in plant samples isolated from all across the Great Plains. Even though it can infect singularly, TriMV is mostly found together with WSMV as a co-infection. The potential for TriMV to cause economic loss is significant, but very little is known about the virus. The objective of this study was to survey the TriMV population for genetic variation by nucleotide sequencing and to determine the variability of the virus across a geographical region. A secondary objective was to characterize the WSMV isolates that are being co-transmitted with TriMV. Fourteen different TriMV isolations were taken from locations in Texas, Oklahoma and Kansas and the coat protein cDNA was sequenced. Thirteen nucleotide differences in total were found in the TriMV isolates and the majority are in the 5’ end of the coat protein RNA. Only three of the polymorphisms are synonymous and induce amino acid changes. Our results indicate that the TriMV virus population is genetically very stable while the coat protein sequences of WSMV genotypes are variable. There is also no singular WSMV genotype found associated with TriMV co-infection. With the lack of variants, it appears that the field population of TriMV is very homogeneous.