Confirmation of Oat Crown Rust Disease in Taiwan

Area of Science:

• Plant Pathology
• Mycology
• Agricultural Science

Background:

• Oat (Avena sativa) is a minor forage crop in Taiwan with limited historical records of rust diseases.
• The oat rust pathogen population in Taiwan has remained poorly characterized.
• A significant rust-like disease outbreak occurred in 2019, necessitating pathogen identification.

Purpose of the Study:

• To identify the causal agent of the oat rust-like disease outbreak in Taiwan.
• To characterize the oat crown rust pathogen population using molecular and phenotypic methods.
• To report the virulence profiles of Taiwanese oat crown rust isolates.

Main Methods:

• Collection and isolation of oat rust pathogen samples from infected cultivars.
• Phylogenetic analysis using nuclear ribosomal internal transcribed spacer (ITS) sequences.
• Whole-genome phylogeny for confirmation of pathogen identity.
• Phenotyping assays on 36 oat differential lines to assess virulence.

Main Results:

• The oat rust pathogen was identified as Puccinia coronata var. avenae f. sp. avenae (Pca) through molecular diagnostics.
• Phylogenetic analyses confirmed the clustering of the Taiwanese isolate NTU1 with known Pca strains.
• Phenotypic assays revealed that Taiwanese Pca isolates exhibit relatively low virulence across differential oat lines.

Conclusions:

• This study provides the first molecular confirmation of Pca in Taiwan.
• The characterized Pca population in Taiwan demonstrates low virulence.
• Findings contribute to understanding oat rust epidemiology and management in the region.