Isolation and characterization of three new PGPR and their effects on the growth of <i>Arabidopsis</i> and <i>Datura</i> plants

Abstract

This study characterizes three bacterial strains isolated from plant rhizospheres and evaluates their performance as plant-growth-promoting rhizobacteria. Pseudomonas plecoglossicida strain Pp20 was isolated from the rhizosphere of a date palm in Bechar (Algerian Sahara), Bacillus spec. strain Bt04 isolated from the rhizosphere of pear in Ghardaia (Algerian Sahara) and Lysinibacillus fusiformis strain Lf89 was isolated from the rhizosphere of tomato in Ain Defla (northern Algeria). Their effects on plant growth and development were analyzed in different in vitro cultures: an Arabidopsis thaliana plate assay and two hydroponic systems for Datura stramonium and Datura tatula. Our results show that all strains significantly improve plant growth of the plant species tested and some strains produce a shift in the C/N ratio in A. thaliana. Inoculation had no effect on alkaloid production per gram leaf dry weight in D. stramonium, but specific plant-growth-promoting rhizobacteria interactions may alter the alkaloid composition in the shoot.