DISSERTATION RESEARCH: Ecology of fungal Wood Decomposition and its Effect on Soil Buffering Capacity: a Molecular Approach Using Quantitative Real-Time PCR (qPCR)

森林地面上的木材主要由丝状真菌分解。这些真菌独特地适应于代谢顽固但富含碳的木材，它们经常产生羧酸阴离子草酸盐而不是二氧化碳，作为碳代谢的更节能的产物。木材中的草酸水平是可变的，很大程度上取决于在木材上定居的真菌种类。这一生理现象引起了人们的兴趣，因为草酸盐可能为从森林土壤中输入的钙创造一个重要的汇。钙是一种极为重要的植物养分和缓冲离子，但在过度采伐和酸胁迫的森林中，钙对耗竭非常敏感。该论文项目由美国国家科学基金会博士论文改进基金（DDIG）资助，旨在量化受现有森林管理实践（木材种类、温度和土壤湿度）影响的环境变量如何影响真菌竞争、木材定植以及随后的草酸盐和钙积累。该研究将采用分子方法（qPCR）来量化几种具有不同草酸生产模式的真菌物种之间的竞争成功，因为它们同时竞争木质基质。这种qPCR方法允许在腐烂期间的观察直接与更自然的系统中的每个测试真菌联系起来。这些数据将与降解木材中随后的草酸盐和钙模式相关联，并将评估这些处理变量影响木材钙富集的总体潜力。本研究可直接应用于森林木屑管理，并对木材分解和真菌生态在维持森林健康中的作用具有更广泛的意义。

Wood on the forest floor is decomposed primarily by filamentous fungi. These fungi are uniquely adapted to metabolize recalcitrant yet carbon-rich wood, and they often produce the carboxylic anion oxalate instead of CO2 as a more energy-efficient product of carbon metabolism. Oxalate levels in wood are variable and depend largely on the species of fungus colonizing the wood. There is emergent interest in this physiological phenomenon because oxalate may create a significant sink for calcium imported from forest soils. Calcium is an extremely important plant nutrient and buffering ion, yet it is sensitive to depletion in over-harvested and acid-stressed forests. The dissertation project funded by this NSF Doctoral Dissertation Improvement Grant (DDIG) aims to quantify how environmental variables affected by existing forest management practices (wood species, temperature, and soil moisture) affect fungal competition, wood colonization, and subsequent oxalate and calcium accumulation. The research will incorporate a molecular approach (qPCR) to quantify competitive success among several fungal species with distinct oxalate production patterns as they simultaneously compete for woody substrate. This qPCR approach allows observations during decay to be linked directly to each test fungus in a more natural system. This data will be correlated with subsequent oxalate and calcium patterns in the degraded wood, and the overall potential for these treatment variables to affect wood calcium enrichment will be assessed. This research has direct application to forest woody debris management and has broader implications on the role of wood decomposition and fungal ecology in maintaining forest health.