THE ECOLOGICAL SIGNIFICANCE OF BIOFILM FORMATION BY PLANT-ASSOCIATED BACTERIA

Bacteria associated with plants have been observed frequently to form assemblages referred to as aggregates, microcolonies, symplasmata, or biofilms on leaves and on root surfaces and within intercellular spaces of plant tissues. In a wide range of habitats, biofilms are purported to be microniches of conditions markedly different from those of the ambient environment and drive microbial cells to effect functions not possible alone or outside of biofilms. This review constructs a portrait of how biofilms associated with leaves, roots and within intercellular spaces influence the ecology of the bacteria they harbor and the relationship of bacteria with plants. We also consider how biofilms may enhance airborne dissemination, ubiquity and diversification of plant-associated bacteria and may influence strategies for biological control of plant disease and for assuring food safety.

Trapped by a nexus, coordinates uncertain

Ever expanding or contracting

Cannibalistic and scavenging sorties

Excavations through signs of past alliances

Consensus signals sound revelry

Then time warped by viscosity

Genomes showing codependence

A virtual microbial beach party

With no curfew and no time-out

A few estranged cells seeking exit options,

Looking for another menagerie.

David Sands, Montana State University, Bozeman, February 2003