Mitigating abiotic stress in crop plants by microorganisms

Abstract

Microorganisms could play an important role in adaptation strategies and increase of tolerance to abiotic stresses in agricultural plants. Plant-growth-promoting rhizobacteria (PGPR) mitigate most effectively the impact of abiotic stresses (drought, low temperature, salinity, metal toxicity, and high temperatures) on plants through the production of exopolysaccharates and biofilm formation. PGPR mitigate the impact of drought on plants through a process so-called induced systemic tolerance (IST), which includes: a) bacterial production of cytokinins, b) production of antioxidants and c) degradation of the ethylene precursor ACC by bacterial ACC deaminase. Symbiotic fungi (arbuscular mycorrhizal fungi) and dual symbiotic systems (endophytic rhizospheric bacteria and symbiotic fungi) also tend to mitigate the abiotic stress in plants.

Mikroorganizmi mogu imati značajnu ulogu u strategijama adaptacija i povećanju tolerantnosti poljoprivrednih biljnih vrsta na abiotičke stresove. Najveći uticaj ublažavanja abiotičkih stresova na biljku (suša, niske temperature, salinitet, toksičnost metala i visoke temperature) imaju mikroorganizmi koji naseljavaju rizosferno zemljište, a promoteri su biljnog rasta (PGPR), kroz produkciju egzopolisaharida i formiranjem biofilma. PGPR ublažavaju uticaj suše na biljke indukovanim sistemom tolerancije (IST): a) produkcijom bakterijskog citokinina b) produkcijom antioksidanata i c) degradacijom etilen prekursora ACC bakterijskim ACC-deaminazom. Takođe i simbiozne gljive (abscular mycorrhizal fungi) i dual simbiozni sistemi (rhizosphere, endophytic bacteria i symbiotic fungi) utiču na ublažavanje abiotičkih stresova u biljkama.