DISSERTATION RESEARCH: Metatranscriptomics links phenology with community dynamics and ecosystem function in wood decay fungi

George Washington University, Washington DC

Investigators

Abstract

Forests contain half of the world's terrestrial carbon, much of which is stored over long time periods in forest trees. This carbon is typically released after tree death through the actions of fungi and other microorganisms that consume woody debris, breaking it down and releasing carbon into the soil and atmosphere (as carbon dioxide). Most of what is known about wood decay fungi comes from observations of reproductive fruiting bodies, such as mushrooms, but this is only one stage of the life cycle of these fungi. In this project, fungal activities will be studied over the course of the forest growing season and over the developmental life cycle of fungi to measure the amount of wood decay activity, and to determine the factors that control the process. These results will significantly improve our understanding of the role wood decay fungi play in releasing stored carbon now and under changing global conditions. This project will provide needed insight into the functioning of wood decay fungal communities by examining the phenology of extracellular enzyme production throughout the year. The researchers will use recent advances in sequencing methods to determine when fungi are actively expressing decay genes, and how decay activity is affected by community diversity, substrate quality, and environmental conditions. High throughput sequencing will be used to compare decay gene expression through time by capturing populations of messenger RNAs, and to identify shifts in the active fungal community using ribosomal RNA. Sequencing data will be complemented with extracellular enzyme assays and measurements of respiration, to quantify the activity levels of enzymes targeting specific wood components and rate of carbon dioxide released to the atmosphere, respectively. The drivers of decay activity and fungal community changes will be compared with those affecting fruiting body production.