Mechanisms of Pine Disease Susceptibility Under Experimental Climate Change
Mechanisms of Pine Disease Susceptibility Under Experimental Climate Change
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DOI：
10.3389/ffgc.2022.872584
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发表时间：
2022-06
期刊：
影响因子：
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通讯作者：
Soumya Ghosh;J. Slot;E. Visser;S. Naidoo;Michael G. Sovic;Anna O. Conrad;Bethany R. Kyre;V. Vijayakumar;P. Bonello
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文献类型：
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作者：
Soumya Ghosh;J. Slot;E. Visser;S. Naidoo;Michael G. Sovic;Anna O. Conrad;Bethany R. Kyre;V. Vijayakumar;P. Bonello
气候变化(CC)对世界许多温带地区的预测条件，表现为温度过高和水供应不足，将通过非生物胁迫的方式直接影响森林健康，但也通过使树木容易受到病原菌攻击来影响森林健康。然而，我们还不知道这种环境条件如何改变树木的生理和新陈代谢，使它们更容易受到病原体的影响。为了探索这些机制，我们将3年生的奥地利松树苗置于模拟CC环境(干旱和高温)中，然后用两种具有不同攻击性的姊妹真菌种进行病原性接种，这两种真菌分别是侵略性较强的拟南星和侵略性较弱的拟南星。感染后3周测量皮损长度以确定表型，同时对接种后72h在不同分支上形成的皮损边缘组织进行双转录组学分析。正如预期的那样，气候变化条件增加了寄主对侵袭性较弱的病原菌--云纹盘藻的敏感性，达到了与更具攻击性的云纹盘藻在统计学上没有什么不同的水平。在受控气候条件下，石杉诱导抑制与寄主氮和碳代谢相关的关键途径，同时增强自身的碳同化作用。伴随而来的是对宿主防御相关通路的抑制。与之相反，寄主寄主的氮代谢和脂肪酸代谢以及寄主防御反应均被寄主侵染。另一方面，CC处理与抑制关键的寄主碳和氮代谢途径以及防御相关途径有关，以响应这两种病原菌。我们提出了一种新的工作模式，整合了宿主和病原体的并发反应，将CC处理下减弱的宿主表型与特定的代谢室联系起来。我们的结果有助于更丰富地理解在低水分条件下树木对真菌感染的敏感性增加的机制，并开辟了新的研究领域，以进一步整合我们在树木生理和生态这一关键方面的知识。
Climate change (CC) conditions projected for many temperate areas of the world, expressed by way of excessive temperatures and low water availability, will impact forest health directly by means of abiotic stress but also by predisposing trees to pathogenic attack. However, we do not yet know how such environmental conditions alter the physiology and metabolism of trees to render them more susceptible to pathogens. To explore these mechanisms, we conditioned 3-year-old Austrian pine saplings to a simulated CC environment (combined drought and elevated temperatures), followed by pathogenic inoculation with two sister fungal species characterized by contrasting aggressiveness, Diplodia sapinea (aggressive) and D. scrobiculata (less aggressive). Lesion lengths resulting from infection were measured after 3 weeks to determine phenotypes, while dual transcriptomics analysis was conducted on tissues collected from the margins of developing lesions on separate branches 72 h post inoculation. As expected, climate change conditions enhanced host susceptibility to the less aggressive pathogen, D. scrobiculata, to a level that was not statistically different from the more aggressive D. sapinea. Under controlled climate conditions, D. sapinea induced suppression of critical pathways associated with host nitrogen and carbon metabolism, while enhancing its own carbon assimilation. This was accompanied by suppression of host defense-associated pathways. In contrast, D. scrobiculata infection induced host nitrogen and fatty acid metabolism as well as host defense response. The CC treatment, on the other hand, was associated with suppression of critical host carbon and nitrogen metabolic pathways, alongside defense associated pathways, in response to either pathogen. We propose a new working model integrating concurrent host and pathogen responses, connecting the weakened host phenotype under CC treatment with specific metabolic compartments. Our results contribute to a richer understanding of the mechanisms underlying the oft-observed increased susceptibility to fungal infection in trees under conditions of low water availability and open new areas of investigation to further integrate our knowledge in this critical aspect of tree physiology and ecology.