Plant growth-promoting rhizobacteria (PGPR): emergence in agriculture

Plant growth-promoting rhizobacteria (PGPR)
aretherhizospherebacteriathatcanenhanceplantgrowthbya
wide variety of mechanisms like phosphate solubilization,
siderophore production, biological nitrogen fixation, rhizo
sphere engineering, production of 1-Aminocyclopropane-1
carboxylate deaminase (ACC), quorum sensing (QS) signal
interference and inhibition of biofilm formation, phytohor
moneproduction,exhibitingantifungalactivity,productionof
volatile organic compounds (VOCs), induction of systemic
resistance, promoting beneficial plant-microbe symbioses,
interference with pathogen toxin production etc. The poten
tiality of PGPR in agriculture is steadily increased as it offers
an attractive way to replace the use of chemical fertilizers,
pesticides and other supplements. Growth promoting sub
stances are likely to be produced in large quantities by these
rhizosphere microorganisms that influence indirectly on the
overall morphology of the plants. Recent progress in our
understanding on the diversity of PGPR in the rhizosphere
along with their colonization ability and mechanism of action
should facilitate their application as a reliable component in
the management of sustainable agricultural system. The pro
gress to date in using the rhizosphere bacteria in a variety of
applications related to agricultural improvement along with
their mechanism of action with special reference to plant
growth-promotingtraits are summarizedand discussed inthis
review.