Bacterial volatiles promote growth in Arabidopsis

Abstract

Several chemical changes in soil are associated with plant growth-promoting rhizobacteria (PGPR). Some bacterial strains directly regulate plant physiology by mimicking synthesis of plant hormones, whereas others increase mineral and nitrogen availability in the soil as a way to augment growth. Identification of bacterial chemical messengers that trigger growth promotion has been limited in part by the understanding of how plants respond to external stimuli. With an increasing appreciation of how volatile organic compounds signal plants and serve in plant defense, investigations into the role of volatile components in plant–bacterial systems now can follow. Here, we present chemical and plant-growth data showing that some PGPR release a blend of volatile components that promote growth of Arabidopsis thaliana. In particular, the volatile components 2,3-butanediol and acetoin were released exclusively from two bacterial strains that trigger the greatest level of growth promotion. Furthermore, pharmacological applications of 2,3-butanediol enhanced plant growth whereas bacterial mutants blocked in 2,3-butanediol and acetoin synthesis were devoid in this growth-promotion capacity. The demonstration that PGPR strains release different volatile blends and that plant growth is stimulated by differences in these volatile blends establishes an additional function for volatile organic compounds as signaling molecules mediating plant–microbe interactions

Phaeobacter gallaeciensis genomes from globally opposite locations reveal high similarity of adaptation to surface life

“…In both as well as three genes that are part of the biosynthetic pathway for acetoin and 2,3-butanediol, indicating the possible production of these compounds by the strain. These compounds can act as nutrient source as well as plant growth-promoting molecules (Ryu et al, 2003;Rudrappa et al, 2010), which might facilitate the interaction with algal hosts. Genes for the complete multi-peptide urease (ureA-G; PGA2_c31970-c32030) and three genes probably coding for surface antigens (PGA2_c18820-PGA2_c18840) are also unique in strain 2.10.…”

Survey of Plant Drought-Resistance Promoting Bacteria from Populus euphratica Tree Living in Arid Area

“…PGPB promote growth of plants in a variety of environments by direct and indirect mechanisms. Direct mechanisms have so far been identified and include: regulation or production of phytohormones [4], release of volatile compounds including 3-hydroxy-2-butanone (acetoin) and 2,3-butanediol that both affect plant signaling pathways [5], or enhancing plant uptake of nitrogen, phosphorous [6] and iron [7]. The indirectly beneficial effects act via suppression of deleterious microorganisms and plant pathogens mainly by production of antimicrobial metabolites and hydrolytic enzymes, competition for space and nutrients within the rhizosphere, inhibition of pathogen-produced enzymes or toxins, and triggering host induced systemic resistance [8].…”

Plant responses to plant growth-promoting rhizobacteria

“…The compound 2,3-butanediol is produced by Bacillus spp. and not only elicits ISR, but is also involved in promoting growth in Arabidopsis (Ryu et al 2003). How 2,3-butanediol exerts its action and how far both mechanisms are connected, is presently unclear.…”