Purpose of Review

Holm oak is a relevant species, both for its distribution and ecological importance. Among the risks looming over this species, oak decline—influenced by extreme climatic events, and alien-invasive species—is considered the main factor causing the loss of holm oak in Mediterranean open woodlands. The aim of this review is to identify and summarize the effects of drought and pathogen root rot, focusing on tree physiology, and the relationship between the stressors (biotic and abiotic) and the tree response.

Recent Findings

Symptoms of root rot are often associated with drought. However, it has been shown the presence of a differential response to root rot and severe drought is related with general defence mechanisms triggered by the plant. Soil microbiota has also been shown to be a key factor influencing health status and soil pathogen abundance. The application of next-generation sequencing techniques to forest pathology allows us to study complex relationships between soil, plant and microorganisms.

Summary

Tolerance of holm oak against Phytophthora cinnamomi root rot is related to specific hydric and photosynthetic mechanisms that differ from those associated with drought. This response involves changes in the metabolism of the photosynthetic organs of the plant which can be linked with changes in functional traits. Studies of the soil microbiome have identified several pathogens, apart from P. cinnamomi, involved in holm oak decline, and the relevance of key fungal species in the management of this syndrome. In this regard, the presence of beneficial microorganisms such as Trichoderma spp. or ectomycorrhizae influences the physiological status of trees affected by root rot.

中文翻译：

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霍姆栎衰退中疫霉根腐病和干旱胁迫的参与：从生态生理到微生物组的影响

审查目的

栎木在其分布和生态重要性方面都是相关物种。在该物种面临的种种风险中，橡树的衰落（受到极端气候事件的影响以及外来入侵物种的影响）被认为是造成地中海开放林地圣栎损失的主要因素。这篇综述的目的是确定并总结干旱和病原体根腐病的影响，重点是树木生理以及压力源（生物和非生物）与树木响应之间的关系。

最近的发现

根腐病的症状通常与干旱有关。然而，已经显示出对根腐病的不同反应的存在和严重干旱与植物触发的一般防御机制有关。土壤微生物群也已被证明是影响健康状况和土壤病原体丰富度的关键因素。下一代测序技术在森林病理学中的应用使我们能够研究土壤，植物和微生物之间的复杂关系。

概要

圣栎对肉桂疫霉根腐病的耐受性与不同于干旱的特定水分和光合作用机制有关。这种反应涉及植物光合器官代谢的改变，这可能与功能性状的改变有关。对土壤微生物组的研究已经确定了除P. cinnamomi之外的几种病原体，这些病原体与圣栎的衰落有关，并且与关键真菌物种在控制该综合征中的相关性。在这方面，存在有益的微生物，例如木霉属。或外生菌根会影响受根腐病影响的树木的生理状况。