Azospirillum brasilense ameliorates the response of Arabidopsis thaliana to drought via enhancement of ABA levels

COHEN A.; BOTTINI R.; PONTIN M.; MORENO D.; BERLI F.; PICCOLI P.

Shangai

Congreso; XXI International Plant Growth Substances Association (IPGSA) Meeting; 2013

Plant Growth Regulation Society of America (PGRSA) and the Japanese Society for the Chemical Regulation of Plants (JSCRP)

Most plant growth-promoting rhizobacteria (PGPR), like Azospirillum sp., benefit plant growth by producing phytohormones, but little is known regarding the stress-related hormone abscisic acid (ABA) produced by PGPR on plants. Azospirillum sp. is considered one of the most important genus of PGPR for improving plant growth under a variety of environmental and soil conditions. In this study in vitro and pot-grown A. thaliana Col-0 and aba2-1 mutant to assess morpho-physiological and biochemical modifications under drought. Azospirillum increased leaf area, number of lateral roots, augmented photosynthetic and photoprotective pigments levels, and retarded water losses in correlation with increments of ABA. Also inoculation increased growth, fresh and dry weight, number of flowers, seed yield, carotenoids, chlorophylls, total phenolic compounds, anthocyanins, ABA and proline and decreased stomatal conductance so improving survival in plants submitted to water restriction. This is the first study showing physiological mechanisms by which Azospirillum is able to counteract drought effects in Arabidopsis plants via ABA produced by the bacteria (or inducing its synthesis by the plant) helping the plant tissues to tolerate conditions of drought.