David Deshpande, “Metabolic Fingerprints of Pitcher Plant Microbiomes Show Dynamic Community Succession”
Mentor: Erica Young, Biological Sciences
Poster #9

The carnivorous pitcher plant Sarracenia purpurea supplements its nutrient needs with pitcher-shaped leaves that trap insect prey, which are digested and release nutrients for plant uptake. Microbes are recruited into the originally sterile pitcher environment and produce enzymes critical for prey breakdown. However, little is known about how the metabolic functional capacities of the microbial community change during succession from pitcher opening to a mature pitcher microbiome. Biolog EcoPlates^TM supply 31 carbon substrates for screening metabolic capacity in microbial communities; capacity to metabolize substrates indicates microbial diversity. Pitcher plants in the Cedarburg Bog were identified and water was sampled from 6 newly opened pitchers 5 times over the 27 days after opening. Samples were screened using EcoPlate^TM, and with fluorometric activity assays of hydrolytic enzymes chitinase and lipase. There were drastic changes in metabolic function of the microbial communities during early succession, with no metabolic capacity in communities immediately after opening (indicating sterility) to use of most substrates in all communities by day 6. Substrate use patterns over day 3 – 27 showed marked differences between replicate pitcher communities. By day 27, there was diverse substrate use capacity and principal component analysis (PCA) demonstrated functional convergence between the 6 pitcher communities. PCA also showed more similar responses across communities for amino acids than across all substrate types. Chitinase and lipase activities varied by pitcher, but chitinase activity peaked on day 13 while lipase increased through day 27. Application of Ecoplate^TM and biochemical enzyme assays to pitcher microbial communities demonstrates rapid acquisition of community metabolic functions during microbiome recruitment and succession in S. purpurea. These findings emphasize the importance of microbiome diversity in nutrient breakdown that supports the host plant.