Relative Occurrence and Seasonal Variations of Wheat-Infecting Viruses in Texas

Wheat is a top 10 agricultural commodity in Texas, but there is limited understanding of the relative occurrence and seasonal variations of wheat-infecting viruses in the state. In this study, high-throughput sequencing (HTS) was used to profile the wheat virome across the major production regions in Texas, including the Panhandle, Central, and the Southeast. From spring 2021 to spring 2023, a total of 101 wheat samples were obtained through field sampling visits and diagnostic submissions. Four total RNA pools from a subset of these samples (n = 33: 7 to 10 per pool) were subjected to HTS, generating complete or partial genomes of eight wheat-infecting viruses, including barley yellow dwarf virus PAV (BYDV-PAV), cereal yellow dwarf virus RPV (CYDV-RPV), High Plains wheat mosaic virus (HPWMoV), Triticum mosaic virus (TriMV), brome mosaic virus (BMV), wheat streak mosaic virus (WSMV), wheat Eqlid mosaic virus (WEqMV), and wheat umbra-like virus. Subsequent screening of all 101 samples using virus-specific primers revealed varying incidences of WSMV (74.3%), TriMV (68.6%), BYDV-PAV (13.6%), WEqMV (5.7%), HPWMoV (5.0%), BMV (3.0%), and CYDV-RPV (2.0%) across the three seasons. Mixed infections of two to four viruses were more prevalent (65.3%) compared with single infection (18.8%), with coinfections of two wheat curl mite vectored viruses (TriMV and WSMV) being the most common (40%). The study revealed a greater diversity of wheat-infecting viruses in Texas than previously reported and confirmed WSMV and TriMV as the main etiological agents of wheat viral diseases in the state.