Avocado rhizosphere community profiling: white root rot and its impact on microbial composition

Area of Science:

• Plant Pathology
• Microbial Ecology
• Agricultural Science

Background:

• The avocado rhizosphere harbors diverse microbes crucial for plant health and pathogen defense.
• White root rot (WRR), caused by *Dematophora necatrix*, is a significant disease affecting avocado production.
• Understanding the impact of WRR on the rhizosphere microbiome is essential for developing effective disease management strategies.

Purpose of the Study:

• To investigate the effects of *Dematophora necatrix* infection on avocado rhizosphere microbial composition.
• To analyze changes in soil physicochemical properties in response to WRR.
• To identify potential biocontrol agents from the avocado rhizosphere with activity against *D. necatrix*.

Main Methods:

• ITS and 16S metabarcoding for rhizosphere microbiome analysis.
• Assessment of soil physicochemical properties (pH, iron).
• Screening of culturable bacterial and fungal isolates for antagonistic activity against *D. necatrix* via dual-culture assays.

Main Results:

• *D. necatrix* infection altered the relative abundance of specific microbial taxa but not overall diversity.
• Beneficial microbes (*Streptomyces*, *Bacillus*, *Trichoderma*, *Penicillium*) were enriched in non-infected soils.
• *Bacillus*, *Pseudomonas*, *Penicillium*, and *Trichoderma* isolates demonstrated significant inhibition of *D. necatrix* growth.
• Soil pH and iron content correlated with microbial composition and pathogen resilience.

Conclusions:

• The avocado rhizosphere microbiome plays a complex role in managing WRR.
• Specific bacterial and fungal genera show promise as biocontrol agents against *D. necatrix*.
• Soil physicochemical properties are critical factors influencing disease management and avocado productivity.