Magagula Phinda, Swart Velushka, Fourie Arista, Vermeulen Alicia, Nelson Johannes Harold, van Rooyen Zelda, van den Berg Noëlani
Department of Plant and Soil Sciences, University of Pretoria, Pretoria, South Africa.
Hans Merensky Chair in Avocado Research, Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, Pretoria, South Africa.
Front Microbiol. 2025 May 23;16:1583797. doi: 10.3389/fmicb.2025.1583797. eCollection 2025.
The avocado rhizosphere supports diverse microbial communities essential for plant health and defence against pathogens. This study aimed to investigate the impact of , the causal agent of white root rot (WRR), on the microbial composition and soil physicochemical properties of infected and non-infected avocado trees in two South African orchards.
ITS and 16S metabarcoding was used to compare the composition and diversity of the rhizosphere microbiome. Soil physicochemical properties were also assessed, and culturable bacterial and fungal isolates from the rhizosphere were screened for antagonistic activity against .
We found that did not significantly alter overall microbial diversity but influenced relative abundance of specific taxa. In Orchard A, dominant bacterial genera included and , while Orchard B featured and while beneficial microbes such as and were enriched in WRR non-infected (WRR-N) soils. The fungal profiles revealed and as potential biocontrol agents enriched in WRR-N soils. Furthermore, dual-culture assays demonstrated that and isolates inhibited , highlighting their biocontrol potential. Key parameters, such as soil pH and iron (Fe), correlated strongly with microbial composition, suggesting they play an important role in pathogen resilience.
These findings underscore the complexity of the avocado rhizosphere and its role in managing WRR, offering a foundation for developing integrated disease management strategies to enhance avocado productivity.
鳄梨根际支持着对植物健康和抵御病原体至关重要的多样微生物群落。本研究旨在调查白色根腐病（WRR）的病原体对南非两个果园中受感染和未受感染鳄梨树的微生物组成及土壤理化性质的影响。
使用ITS和16S宏条形码技术比较根际微生物组的组成和多样性。还评估了土壤理化性质，并对根际可培养的细菌和真菌分离株进行了针对该病原体的拮抗活性筛选。
我们发现该病原体并未显著改变整体微生物多样性，但影响了特定分类群的相对丰度。在果园A中，优势细菌属包括[具体属名1]和[具体属名2]，而果园B的特征是[具体属名3]和[具体属名4]，同时诸如[有益微生物属名1]和[有益微生物属名2]等有益微生物在未感染白色根腐病（WRR-N）的土壤中富集。真菌图谱显示[具体真菌属名1]和[具体真菌属名2]是在WRR-N土壤中富集的潜在生物防治剂。此外，双培养试验表明[分离株1]和[分离株2]抑制了该病原体，突出了它们的生物防治潜力。关键参数，如土壤pH值和铁（Fe），与微生物组成密切相关，表明它们在病原体抗性方面发挥着重要作用。
这些发现强调了鳄梨根际的复杂性及其在管理白色根腐病中的作用，为制定综合病害管理策略以提高鳄梨产量提供了基础。
