6K1, NIa-VPg, NIa-Pro, and CP of Wheat Streak Mosaic Virus Are Collective Determinants of Wheat Streak Mosaic Disease in Wheat

Authors: Tatineni, Satyanarayana - Ts; Alexander, Jeffrey; NUNNA, HARITHA - University Of Nebraska

Submitted to: Phytopathology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/19/2022
Publication Date: 8/10/2023
Citation: Tatineni, S., Alexander, J.A., Nunna, H. 2023. 6K1, NIa-VPg, NIa-Pro, and CP of Wheat Streak Mosaic Virus Are Collective Determinants of Wheat Streak Mosaic Disease in Wheat. Phytopathology. 113(6)1115-1127. https://doi.org/10.1094/PHYTO-10-22-0401-R.
DOI: https://doi.org/10.1094/PHYTO-10-22-0401-R

Interpretive Summary: Wheat streak mosaic virus (WSMV) is the most economically important viral disease in wheat, which accounts for 5 to 7% annual yield losses in the Great Plains region. Wheat resistance against WSMV across a wide range of temperatures is not available; hence, the development of novel management strategies is required. Viral proteins are involved in disease development through interaction with wheat host proteins. Identifying viral components required for disease development will facilitate the determination of wheat proteins also needed in disease development. These wheat proteins required by the virus are potential targets for engineering virus-resistant wheat through genome editing approaches. This study found that WSMV proteins 6K1, NIa-VPg, NIa-Pro, and coat protein are collectively involved in different stages of wheat streak mosaic disease development in wheat. Wheat streak mosaic disease management strategies should be focused on the disruption of interactions between these WSMV proteins and their partner protein in wheat.

Technical Abstract: Wheat streak mosaic virus (WSMV; genus Tritimovirus; family Potyviridae) is the causal agent of the most economically important wheat streak mosaic disease of wheat in the Great Plains region of the USA. WSMV determinants responsible for wheat streak mosaic disease in wheat are not known. In this study, wheat-infecting Triticum mosaic virus was used as an expression vector for the transient expression of each of the WSMV-encoded cistrons in wheat. WSMV-encoded 6K1, NIa-VPg, NIa-Pro, or CP cistrons elicited severe symptoms specific to different stages of wheat streak mosaic disease without significantly affecting the genomic RNA accumulation. WSMV 6K1 produced early wheat streak mosaic disease-like symptoms of severe chlorotic streaks and patches. NIa-VPg and CP caused severe chlorotic streaks, followed by moderate (NIa-VPg) or mild stunting (CP) of wheat, mimicking early- and mid-stage symptoms of wheat streak mosaic disease. WSMV NIa-Pro caused mild chlorotic streaks, followed by dark green leaves with severe stunting, representing the late symptoms of wheat streak mosaic disease. Collectively, these data suggest that cumulative effects of WSMV-encoded 6K1, NIa-VPg, NIa-Pro, and CP are responsible for different stages of wheat streak mosaic disease symptoms in wheat. Furthermore, deletion analysis of wheat streak mosaic disease determinants revealed that complete 6K1 and NIa-Pro, amino acids 3-60 and 121-197 of NIa-VPg, and amino acids 101-294 of CP are responsible for wheat streak mosaic disease-like symptoms in wheat. This study suggests that management strategies for wheat streak mosaic disease in wheat should target WSMV determinants of the disease phenotype.