First report of Trichoderma roseum causing tea leaf rot in China

Area of Science:

• Plant Pathology
• Mycology
• Agricultural Science

Background:

• Tea (Camellia sinensis) is a globally significant crop, with China as the leading producer.
• Leaf spot diseases can significantly impact tea yield and quality.
• Emerging plant pathogens pose a continuous threat to agricultural production.

Purpose of the Study:

• To identify and characterize the causal agent of a newly observed leaf spot disease on tea plants in Yunnan, China.
• To confirm the pathogenicity of the isolated fungus on tea leaves and plants.
• To provide the first report of this specific pathogen affecting tea in China.

Main Methods:

• Isolation and morphological characterization of fungal pathogens from infected tea leaves.
• Molecular identification using ribosomal internal transcribed spacer (ITS) and large subunit (LSU) gene sequencing.
• Phylogenetic analysis to confirm species identification.
• Pathogenicity tests on detached leaves and potted tea plants to fulfill Koch's postulates.

Main Results:

• A fungal pathogen was consistently isolated from symptomatic tea leaves, exhibiting pale pink to orange-pink colonies.
• Morphological and molecular analyses identified the pathogen as Trichoderma roseum.
• Pathogenicity tests confirmed T. roseum as the causal agent, inducing characteristic leaf lesions on inoculated tea leaves and plants.
• Koch's postulates were successfully fulfilled, confirming the pathogen's role in the observed tea leaf rot.

Conclusions:

• Trichoderma roseum is identified as the causative agent of a novel tea leaf rot disease in Yunnan, China.
• This finding represents the first documented occurrence of T. roseum causing leaf rot in tea plants in China.
• The identification and confirmation of this pathogen are crucial for developing effective disease management strategies in Chinese tea plantations.