Rhizospheric community of Penicillium spp. in roots of Austrocedrus chilensis plays a key role in plant protection against Phytophthora austrocedri disease in Patagonian native forests. Rhizospheric community of Penicillium spp. in roots of Austrocedrus chilensis

Purpose: To describe rhizospheric Penicillium diversity associated with A. chilensis and evaluate if the community composition could be involved in the protection of healthy seedlings in sites with high incidence of ARD (Austrocedrus root disease). Methods: Samples were taken from sites with high prevalence of ARD, and without plants showing ARD symptoms. Isolations were made in PDAc and Rose Bengal Agar (RBA). Isolates were phenotypically and molecularly identified. Penicillium species agrupation regarding different sites and conditions were compared by multivariate analyses. Finally, the ability of Penicillium isolates to parasitize or degrade P. austrocedri mycelium was evaluated using co-cultures. Results: Richness and abundance was significantly higher in sites with ARD than in healthy sites. Penicillium glabrum, P. swiecickii, P. palitans, P. arizonense, P. bialowiezense, P. fuscum, P. amestolkiae and P. lanosum, were isolated from all sites regardless of the health condition. Other species were exclusively isolated in sites with ARD. Penicillium glabrum sp21, P. crustosum, P. palitans and P. amestolkiae were the isolates with the higher inhibitory effect against Phytophthora.Conclusion: Our results represent an important advance towards the design of a biocontrol strategy, since they highlight the role of the Penicillium community composition in the preservation of the health status of A. chilensis. It was shown that dominant species of Penicillium have a high biocontrol activity suggesting that these species play a key role in the protection of A. chilensis. Moreover, the inoculation of Penicillium species in soil could be a useful tool to control ARD in native forests.

研究目的：解析与智利柏（Austrocedrus chilensis，缩写A. chilensis）根际青霉属（Penicillium）物种多样性，并探究群落组成是否参与在高发生率的智利柏根腐病（Austrocedrus root disease，缩写ARD）疫区中保护健康幼苗的过程。

实验方法：样本采集自智利柏根腐病高流行疫区以及无植株表现出ARD症状的健康样地。采用PDAc培养基与孟加拉红琼脂（Rose Bengal Agar，缩写RBA）进行菌株分离。通过表型特征与分子生物学手段对分离得到的菌株进行鉴定。采用多变量分析方法，对比不同样地与生境条件下青霉属物种的群落聚类模式。最后，通过共培养实验评估青霉分离菌株寄生或降解P. austrocedri菌丝体的能力。

实验结果：疫区样地的青霉属物种丰富度与丰度均显著高于健康样地。光滑青霉（Penicillium glabrum）、斯威青霉（P. swiecickii）、帕利坦青霉（P. palitans）、亚利桑那青霉（P. arizonense）、比亚沃韦扎青霉（P. bialowiezense）、暗棕青霉（P. fuscum）、阿姆斯特尔克青霉（P. amestolkiae）以及绒毛青霉（P. lanosum）可在所有样地中被分离得到，不受样地健康状况影响。其余物种仅在疫区样地中分离获得。其中，光滑青霉sp21、扩展青霉（P. crustosum）、帕利坦青霉与阿姆斯特尔克青霉为对疫霉属（Phytophthora）具有较高抑制活性的分离菌株。

研究结论：本研究结果为生物防治策略的设计提供了重要进展，因研究明确了青霉属群落组成在维持智利柏健康状态中的关键作用。实验证实，优势青霉属物种具有较强的生物防治活性，表明此类物种在保护智利柏的过程中发挥核心作用。此外，向土壤中接种青霉属菌株可作为有效手段，用于天然林内智利柏根腐病的防控。