Powdery mildew-infection changes bacterial community composition in the phyllosphere

Area of Science:

• Microbial Ecology
• Plant Pathology
• Bacteriology

Background:

• Fungal foliar diseases can significantly alter plant-associated microbial communities.
• Understanding epiphytic bacterial responses to powdery mildew is crucial for plant health management.

Purpose of the Study:

• To investigate changes in epiphytic bacterial communities on powdery mildew-infected versus uninfected leaves of cucumber and Japanese spindle.
• To compare bacterial community structure and diversity using culture-dependent and -independent methods.

Main Methods:

• Analysis of epiphytic bacteria from infected and uninfected leaves using dilution plate counting and community-level physiological profiling (CLPP).
• Denaturing gradient gel electrophoresis (DGGE) was employed to assess bacterial genotype diversity and richness.
• Principle component analysis (PCA) was used to differentiate bacterial communities based on infection status and plant species.

Main Results:

• Powdery mildew-infected leaves harbored larger populations of phyllosphere bacteria compared to uninfected leaves.
• Significantly greater functional diversity, richness, and evenness of bacterial communities were observed on infected leaves.
• DGGE analysis revealed higher genotype diversity and richness in infected leaves, with distinct bacterial profiles between cucumber and Japanese spindle.

Conclusions:

• Powdery mildew infection promotes increased bacterial populations and diversity in the phyllosphere.
• The fungal disease alters the structure of the epiphytic bacterial community.
• Plant species-specific bacteria are associated with powdery mildew infection, suggesting host-microbe interactions.