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ARS Home » Pacific West Area » Aberdeen, Idaho » Small Grains and Potato Germplasm Research » Research » Publications at this Location » Publication #415691

Research Project: Enhancing Barley and Oat Productivity, Quality, and Stress Resistance

Location: Small Grains and Potato Germplasm Research

Title: Development and validation of a quantitative PCR assay method to assess relative resistance of winter wheat to dwarf bunt at early growth stages

Author
item Yimer, Belayneh
item Patterson, Rachel
item KRAUSE, MARGARET - Oregon State University
item MARSHALL, JULIET - University Of Idaho

Submitted to: Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/8/2024
Publication Date: 12/13/2024
Citation: Yimer, B.A., Patterson, R.E., Krause, M.K., Marshall, J. 2024. Development and validation of a quantitative PCR assay method to assess relative resistance of winter wheat to dwarf bunt at early growth stages. Crop Science. 2025;65:e21422. https://doi.org/10.1002/csc2.21422.
DOI: https://doi.org/10.1002/csc2.21422

Interpretive Summary: Dwarf bunt is a disease that causes major production constraints, such as grain contamination in winter wheat and loss for the growers. The fungus that causes dwarf bunt is a quarantine pathogen, and many countries have strict regulations for importing infected wheat grains, thereby, impacting grain trade around the world. The use of host resistance for bunt disease management is often the best option available. However, the conventional approach for evaluating dwarf bunt resistance in wheat cannot be conducted until maturity at the end of the crop cycle. Hence, there is a need to develop a method to determine resistance at an earlier growth stage. To address this challenge a rapid, highly sensitive, and easily applicable DNA-based laboratory method that determines resistance level of wheat varieties at earlier growth stages (at the third leaf stage) was developed and validated. The new method may facilitate wheat breeding programs’ research for dwarf bunt resistance by significantly reducing the time and resources required for resistance evaluation.

Technical Abstract: Dwarf bunt, caused by Tilletia controversa, is a major biotic constraint and grain contaminant in winter wheat production. The conventional approach for evaluating dwarf bunt resistance in wheat cannot be conducted until maturity at the end of the crop cycle. Hence, there is a need to develop a method to determine resistance at an earlier growth stage. To address this challenge, a quantitative polymerase chain reaction (qPCR) assay was developed for the quantification of T. controversa biomass in wheat plants in order to correlate the fungal DNA (fDNA) content in the host tissue with host resistance. A previously developed pathogen primer-probe set and host primer pairs as well as a newly designed host probe were used in the present study. The respective primer-probe sets were specific to T. controversa and wheat. The qPCR assay amplified as little as 0.05 pg of fDNA. The assay was validated in field evaluations conducted at the Utah State University dwarf bunt nursery in Logan, UT using two susceptible and four resistant wheat varieties. The assay detected fDNA in both susceptible varieties at all growth stages. In the resistant varieties, fDNA was detected in the first leaves of all varieties, but only a single plant of the resistant variety ‘Juniper’ exhibited fDNA at the third leaf stage. There was no fDNA detection in plants beyond the third leaf in all the resistant varieties. These results suggest that the qPCR technique is rapid, highly sensitive and easily applicable for the evaluation of dwarf bunt resistance in wheat at an earlier growth stages, thereby significantly reducing the time required to develop resistant varieties compared to the conventional method.