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ARS Home » Plains Area » Lincoln, Nebraska » Wheat, Sorghum and Forage Research » Research » Publications at this Location » Publication #408722
Research Project: Identification, Characterization, and Utilization of Priority Traits for the Genetic Improvement of Winter Wheat and Barley Germplasm Adapted to the Great Plains

Location: Wheat, Sorghum and Forage Research

Title: HC-Pro cistron of Triticum mosaic virus is dispensable for systemic infection in wheat but is required for symptom phenotype and efficient genome amplification

Author
item Tatineni, Satyanarayana - Ts
item Alexander, Jeffrey
item KOVACS, FRANK - University Of Nebraska

Submitted to: Virus Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/16/2023
Publication Date: 12/1/2023
Citation: Tatineni, S., Alexander, J.A., Kovacs, F. 2023. HC-Pro cistron of Triticum mosaic virus is dispensable for systemic infection in wheat but is required for symptom phenotype and efficient genome amplification. Virus Research. 339(2024):199277. https://doi.org/10.1016/j.virusres.2023.199277.
DOI: https://doi.org/10.1016/j.virusres.2023.199277

Interpretive Summary: Triticum mosaic virus (TriMV) is transmitted by the wheat curl mite, which is one of the components of the wheat streak mosaic disease complex in the U.S. Great Plains. Wheat streak mosaic disease is the most economically important viral disease of wheat, accounting for 5 to 7% annual yield losses in the Great Plains. This study examined the functions of HC-Pro, one of the proteins encoded by TriMV, in the virus life cycle. This study found that the HC-Pro gene can be deleted entirely from the virus genome, and TriMV without the HC-Pro gene still infects wheat plants with mild symptoms. This finding will facilitate the examination of the role of HC-Pro in wheat curl mite transmission of TriMV and may lead to the development of methods to stop the transmission of TriMV by the wheat curl mite.

Technical Abstract: Triticum mosaic virus (TriMV), the type species of the genus Poacevirus in the family Potyviridae, is an economically important wheat curl mite-transmitted wheat-infecting virus in the Great Plains region of the USA. In this study, the functional genomics of helper component-proteinase (HC-Pro) encoded by TriMV was examined using an infectious cDNA clone. TriMV with complete deletion of HC-Pro cistron elicited systemic infection in wheat, indicating that HC-Pro cistron is dispensable for TriMV systemic infection. However, TriMV lacking HC-Pro caused delayed systemic infection with mild symptoms that resulted in little or no stunting of plants with a significant reduction in the accumulation of genomic RNA copies and coat protein (CP). These data suggest that HC-Pro is required for TriMV symptom induction and efficient viral genomic RNA amplification. Sequential deletion mutagenesis in the HC-Pro cistron of the TriMV genome revealed that deletions within amino acids 3 to 25, except for amino acids 3 and 4, elicited mild symptoms with reduced accumulation of genomic RNA and CP. Surprisingly, TriMV with deletion of amino acids 3 to 50 or 3 to 125 in HC-Pro elicited severe symptoms with stunting of plants with a substantial increase in genomic RNA copies but a drastic reduction in CP accumulation. Moreover, TriMV with a heterologous HC-Pro cistron from turnip mosaic virus, tobacco etch virus, or wheat streak mosaic virus elicited mild symptom phenotypes with a drastic reduction in accumulation of genomic RNA and CP mimicking the TriMV without HC-Pro. This suggests that heterologous HC-Pros of other potyvirid species were not effective in complementing TriMV in wheat.