Characterization and Aggressiveness of Take-All Root Rot Pathogens Isolated from Symptomatic Bermudagrass Putting...

Area of Science:

• Plant Pathology
• Agronomy
• Molecular Diagnostics

Background:

• Take-all root rot (TR) affects ultradwarf bermudagrass putting greens.
• Causal agents include Gaeumannomyces graminis (Gg), Gaeumannomyces sp. (Gx), Gaeumannomyces graminicola (Ggram), Candidacolonium cynodontis (Cc), and Magnaporthiopsis cynodontis (Mc).
• Etiology and epidemiology of TR are not fully understood.

Purpose of the Study:

• Identify and characterize TR pathogens affecting bermudagrass.
• Assess pathogen aggressiveness and optimal growth temperatures.
• Develop a molecular tool for rapid pathogen detection.

Main Methods:

• Isolation of Gg, Gx, Ggram, Cc, and Mc from infected bermudagrass.
• In planta aggressiveness assay using 'Champion' bermudagrass.
• Growth curve analysis at various temperatures (10–35°C).
• Development of a real-time PCR high-resolution melt assay.

Main Results:

• Ggram, Gg, and Gx showed the highest aggressiveness; Cc and Mc were moderately aggressive.
• Pathogens were more aggressive at 30°C than 20°C.
• Optimal growth occurred between 24.4–27.8°C; limited growth at 35°C, no growth at 10°C.
• A single primer pair real-time PCR assay successfully differentiated all five pathogens.

Conclusions:

• Provides crucial data on TR pathogen aggressiveness and temperature optima.
• The developed PCR assay enables rapid and accurate detection directly from plant tissue.
• Findings will enhance understanding and inform management strategies for take-all root rot.