Walking in an Autumn Wonderland

leavesA recent paper in the Proc. Natl. Acad. Sci. USA. by Delmotte et al. gives me countless new worlds to contemplate as I stroll along the walking paths on crisp Wisconsin autumn days.

Each one of the leaves that decorate the landscape along my walk is home to an entire of community of microorganisms. It’s a harsh world of high temperatures, significant UV exposure, periods of drought, and limited nutrients. The phyllosphere, the place where plant surface meets air, is a busy place and is the largest biological interface on Earth. Here carbon dioxide is fixed and oxygen is released. Microorganisms found here, bearing such names as Sphinogmonas and Methylobacterium, are major players in carbon and nitrogen cycles, air cleaning, decomposition and composting. Understanding the members of these communities will go a long way toward helping us understand our environment.

Delmotte et al. conducted a “community proteogenomics” study of the phyllosphere, investigating the bacterial populations from soybean, clover and Arabidopsis thaliana. To investigate the prokaryotic members of the communities they studied, the researchers sampled plant leaves, harvested the bacteria on them, extracted proteins and DNA from the harvested organisms and then used large-scale proteomics and genomics analysis to determine what organisms were present and how prevalent they were. Proteins were identified after MS analysis and searching against known sequences as well as translated sequences from the metagenomic data generated from the community analyses.

This study identified proteins and key enzymes involved in global carbon and nitrogen cycles, the metabolism of methanol and the assimilation of ammonia. This study also identified proteins of unknown function that were present across members of many bacterial genera in these communities.

So as I shuffle through the pile of leaves on the corner, I am surrounded by a thousand microuniverses, all part of Earth’s largest interface, busy recycling centers for nutrients and essential elements, even as they add beauty to the landscape.

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Michele Arduengo

Social Media Manager at Promega Corporation
Michele earned her B.A. in biology at Wesleyan College in Macon, GA, and her PhD through the BCDB Program at Emory University in Atlanta, GA. Michele is the social media manager at Promega and managing editor of the Promega Connections blog. She enjoys getting lost in a good book, trumpet playing, knitting, and snowshoeing.

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