Bacteria help plants grow

Plant roots support an array of microorganisms that can have either a deleterious or beneficial impact on plant health and growth. The use of beneficial microorganisms, called plant growth-promoting rhizobacteria (PGPR), increases plant growth and crop yield. In the March 31 Proceedings of the National Academy of Science, Choong-Min Ryu and colleagues from Auburn University, Alabama, US, show that some PGPRs release a blend of airborne chemicals — volatile organic compounds (VOCs) — that promote the growth of Arabidopsis thaliana seedlings (PNAS, DOI:10.1073/pnas.0730845100, March 31, 2003).

Ryu et al. investigated the role of VOCs from seven strains of PGPRs on total leaf surface area. They showed that 2,3-butanediol and acetonin, released exclusively from two bacterial strains triggered the highest levels of plant growth. Insertional analysis of enzymes involved in the synthesis of these two VOCs resulted in a removal of the growth promotion effect. Further, exogenous application of 2,3-butanediol to ...