Scientists Uncover Vast Microbial Diversity of Carnivorous Pitcher Plant

The microbial ecosystem inside the carnivorous pitcher plant is vastly more diverse than previously thought according to research published in the March 2010 issue of the journalApplied and Environmental Microbiology.

Researchers from Louisiana State University used genomic fingerprinting technology to assess the bacterial diversity inside leaves of Sarracenia alata, commonly known as the pitcher plant. A pitcher plant is a carnivorous plant that lives in nitrogen poor soil augmenting the inadequate nitrogen by trapping and digesting insects. It has tubular shaped leaves that contain a liquid that is used for digestion. Over the past 35 years studying these plants using traditional culture-based methods, scientists have only identified 20 distinct bacteria in the pitcher.

"The microbial richness associated with the pitcher fluid from Sarracenia alata is high, with more than 1,000 phylogroups identified across at least seven phyla and over 50 families," say the researchers, who studied 10 plants in a Louisiana wildlife management area for 5 months during the spring and summer of 2009.

The researchers noted as well that approximately a third of all the bacteria were unidentifiable. They also observed that not only were the bacterial populations distinctly different from nearby soil samples, they started out different in each plant but over time they became more similar to one another.

"These findings indicate that the bacteria associated with pitcher plant leaves are far from random assemblages and represent an important step toward understanding this unique plant-microbe interaction," say the researchers.

(M.M. Koopman, D.M. Fuselier, S. Hird, B.C. Carstens. 2010. The carnivorous pale pitcher plant harbors diverse, distinct, and time-dependent bacterial communities. Applied and Environmental Microbiology, 76. 6: 1851-1860.)