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。这些真菌特别适合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，作为一种更节能的碳代谢产物。木材中的草酸水平是不同的，很大程度上取决于寄生在木材上的真菌种类。人们对这种生理现象很感兴趣，因为草酸可能会为从森林土壤中输入的钙创造一个重要的汇。钙是一种极其重要的植物营养和缓冲离子，但在过度采伐和酸胁迫的森林中，它对枯竭很敏感。这项由NSF博士论文改进基金资助的论文项目旨在量化现有森林管理实践(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、木材定居以及随后的草酸和钙积累。这项研究将结合分子方法(QPCR)来量化几个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底物。这种定量聚合酶链式反应方法允许腐烂过程中的观察直接与更自然系统中的每一种试验真菌联系起来。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浓缩的总体潜力。这项研究直接应用于森林木质废弃物管理，并对木材分解和真菌生态在维护森林健康中的作用具有更广泛的影响。

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.