Grapevine (Vitis vinifera) Crown Galls Host Distinct Microbiota

Area of Science:

• Plant pathology
• Microbiology
• Agricultural science

Background:

• Crown gall disease, caused by virulent Agrobacterium strains, impacts grapevine yield and quality.
• The associated microbial communities in grapevine plants and their role in disease development are not well understood.

Purpose of the Study:

• To investigate and compare the endophytic microbiota of grapevine organs and surrounding soil in plants with and without crown gall disease.
• To determine the influence of crown gall disease on the stability and composition of grapevine microbiota.

Main Methods:

• Amplicon-based community profiling (16S rRNA gene sequencing) was used to analyze microbial communities.
• Samples included grapevine organs (root, graft union, cane) and soil collected over one year.
• Agrobacterium vitis infection was tested in vitro on grapevine plantlets.

Main Results:

• Microbial diversity decreased from soil to roots to graft unions, with sample site being the primary driver of differences, not disease status.
• Graft union microbiota was significantly affected by crown gall, showing higher species richness and stability with consistent dominant bacteria (Pseudomonas sp., Enterobacteriaceae sp., Agrobacterium vitis) in diseased plants.
• Agrobacterium vitis infection alone caused crown gall in plantlets, indicating the microbial community is not essential for disease outbreak.

Conclusions:

• Crown gall disease alters the stability and composition of the grapevine graft union microbiota.
• The study highlights the potential of microbial community analysis for disease diagnosis and management in agriculture.
• While Agrobacterium vitis is the causal agent, the associated microbiota plays a role in the disease microenvironment.