Occurrence of Wheat Curl Mite and Mite-Vectored Viruses of Wheat in Colorado and Insights into the Wheat Virome

Abstract

The wheat curl mite (WCM) is a vector of three important wheat viruses in the U.S. Great Plains, wheat streak mosaic virus (WSMV), triticum mosaic virus (TriMV), and High Plains wheat mosaic virus (HPWMoV). This study was conducted to determine the current profile of WCM and WCM-transmitted viruses of wheat and their occurrence in Colorado, including novel wheat viruses via virome analysis. There was a high rate of virus incidence in symptomatic wheat samples collected in 2019 (95%) and 2020 (77%). Single infection of WSMV was most common in both years followed by coinfection with WSMV + TriMV and WSMV + HPWMoV. Both Type 1 and Type 2 mite genotypes were found in Colorado. There was high genetic diversity of WSMV and HPWMoV isolates, whereas TriMV isolates showed minimal sequence variation. Analysis of WSMV isolates revealed novel virus variants including one isolate from a variety trial, where severe disease symptoms were observed on wheat varieties carrying Wsm2, a known virus resistance loci. Virome analysis identified between two to four sequence variants of all eight RNA segments of HPWMoV, which suggests co-occurrence of multiple genotypes within host populations and presence of a possibly novel variant of HPWMoV. A possible novel virus, Tombusviridae sp. and several mycoviruses were identified. Overall, the data presented here highlights the need to define the effect of novel WCM-transmitted virus variants on disease severity, as well as the role of novel viruses.

Untitled

“…As noted by E. de Lillo et al (2018), many species of Eriophioid mites are considered economically important because of certain damages such as chlorotic spots, galls, blotches, stunting, or curling of leaf edges that they can cause. Some species can transmit phytopathogenic viruses (Kubota et al, 2022;Albrecht et al, 2022).…”

Genomic And Molecular Characterization Of The Wheat Streak Mosaic Virus Resistance Locus 2 (Wsm2) In Common Wheat (Triticum Aestivum. L)

“…Over the last 15 years, Wsm2 has provided strong resistance to WSMV (Seifers et al, 2006; Lu et al, 2012), leading to low WSMV incidence in field conditions (McKelvy et al, 2021). However, WSMV resistance-breaking strains have been reported in infected wheat carrying Wsm2 (Fellers et al, 2019; Redila et al, 2021; Albrecht et al, 2022) and from Setaria viridis (Kumssa et al, 2019). Although Wsm2 is temperature sensitive and less effective in the field at temperatures above 18 (Seifers et al, 2006), there is no evidence that it has deleterious impacts on yield or other agronomic traits (Lu et al, 2012).…”

Genomic and Molecular Characterization of Wheat Streak Mosaic Virus Resistance Locus 2 (Wsm2) in Common Wheat (Triticum aestivum L.)

“…Over the last 15 years, Wsm2 has provided strong resistance to WSMV (Seifers et al, 2006;Lu et al, 2012), leading to low WSMV incidence in field conditions (McKelvy et al, 2021). However, WSMV resistance-breaking strains have been reported in infected wheat carrying Wsm2 (Fellers et al, 2019;Redila et al, 2021;Albrecht et al, 2022) and from Setaria viridis (Kumssa et al, 2019). Although Wsm2 is temperature sensitive and less effective in the field at temperatures above 18 • C (Seifers et al, 2006), there is no evidence that it has deleterious impacts on yield or other agronomic traits (Lu et al, 2012).…”