TY - JOUR

T1 - Rhizobacterial mediation of plant hormone status

AU - Dodd, I. C.

AU - Zinovkina, N. Y.

AU - Safronova, V. I.

AU - Belimov, A. A.

PY - 2010

Y1 - 2010

N2 - Plant growth-promoting rhizobacteria are commonly found in the rhizosphere (adjacent to the root surface) and may promote plant growth via several diverse mechanisms, including the production or degradation of the major groups of plant hormones that regulate plant growth and development. Although rhizobacterial production of plant hormones seems relatively widespread (as judged from physico-chemical measurements of hormones in bacterial culture media), evidence continues to accumulate, particularly from seedlings grown under gnotobiotic conditions, that rhizobacteria can modify plant hormone status. Since many rhizobacteria can impact on more than one hormone group, bacterial mutants in hormone production/degradation and plant mutants in hormone sensitivity have been useful to establish the importance of particular signalling pathways. Although plant roots exude many potential substrates for rhizobacterial growth, including plant hormones or their precursors, limited progress has been made in determining whether root hormone efflux can select for particular rhizobacterial traits. Rhizobacterial mediation of plant hormone status not only has local effects on root elongation and architecture, thus mediating water and nutrient capture, but can also affect plant root-to-shoot hormonal signalling that regulates leaf growth and gas exchange. Renewed emphasis on providing sufficient food for a growing world population, while minimising environmental impacts of agriculture because of overuse of fertilisers and irrigation water, will stimulate the commercialisation of rhizobacterial inoculants (including those that alter plant hormone status) to sustain crop growth and yield. Combining rhizobacterial traits (or species) that impact on plant hormone status thereby modifying root architecture (to capture existing soil resources) with traits that make additional resources available (e.g. nitrogen fixation, phosphate solubilisation) may enhance the sustainability of agriculture.

AB - Plant growth-promoting rhizobacteria are commonly found in the rhizosphere (adjacent to the root surface) and may promote plant growth via several diverse mechanisms, including the production or degradation of the major groups of plant hormones that regulate plant growth and development. Although rhizobacterial production of plant hormones seems relatively widespread (as judged from physico-chemical measurements of hormones in bacterial culture media), evidence continues to accumulate, particularly from seedlings grown under gnotobiotic conditions, that rhizobacteria can modify plant hormone status. Since many rhizobacteria can impact on more than one hormone group, bacterial mutants in hormone production/degradation and plant mutants in hormone sensitivity have been useful to establish the importance of particular signalling pathways. Although plant roots exude many potential substrates for rhizobacterial growth, including plant hormones or their precursors, limited progress has been made in determining whether root hormone efflux can select for particular rhizobacterial traits. Rhizobacterial mediation of plant hormone status not only has local effects on root elongation and architecture, thus mediating water and nutrient capture, but can also affect plant root-to-shoot hormonal signalling that regulates leaf growth and gas exchange. Renewed emphasis on providing sufficient food for a growing world population, while minimising environmental impacts of agriculture because of overuse of fertilisers and irrigation water, will stimulate the commercialisation of rhizobacterial inoculants (including those that alter plant hormone status) to sustain crop growth and yield. Combining rhizobacterial traits (or species) that impact on plant hormone status thereby modifying root architecture (to capture existing soil resources) with traits that make additional resources available (e.g. nitrogen fixation, phosphate solubilisation) may enhance the sustainability of agriculture.

KW - ABA

KW - ACC deaminase

KW - auxin

KW - cytokinins

KW - gibberellins

KW - rhizobacteria

KW - root elongation

KW - GROWTH-PROMOTING RHIZOBACTERIA

KW - 1-AMINOCYCLOPROPANE-1-CARBOXYLIC ACID DEAMINASE

KW - INDUCED SYSTEMIC RESISTANCE

KW - PSEUDOMONAS-PUTIDA GR12-2

KW - ABSCISIC-ACID

KW - AZOSPIRILLUM-BRASILENSE

KW - SALICYLIC-ACID

KW - ROOT-GROWTH

KW - BRADYRHIZOBIUM-JAPONICUM

KW - ARABIDOPSIS-THALIANA

U2 - 10.1111/j.1744-7348.2010.00439.x

DO - 10.1111/j.1744-7348.2010.00439.x

M3 - Literature review

VL - 157

SP - 361

EP - 379

JO - Annals of Applied Biology

JF - Annals of Applied Biology

SN - 0003-4746

IS - 3

ER -