Bioprospecting Of Endophytic Bacteria With Plant Growth Promoting Activity Associated With Rice Varieties From The Colombian Caribbean

Abstract

Endophytic bacteria have been studied for carrying out important processes within plant tissues. Among the diverse processes are plant growth-promoting activities such as nitrogen fixation, phosphate solubilisation and indole-3-acetic acid (IAA) production. The aim of this study was to evaluate in vitro the efficiency of rice tissue-associated endophytic bacteria with potential activity for nitrogen fixation, indole acetic acid production and phosphate solubilization. The population density of endophytic bacteria was shown from highest to lowest as follows: FMocarí 8.25x10⁹, F473 7.30 x10⁹, F2000 9.15x10⁸, F733 8.25x10⁸ CFU/g tissue. The root tissue in all the varieties under study was the most colonised. From the 16S rRNA gene sequences, Burkholderia cepacia, B. diazotrophica, B. tropica, Pseudomona fluorescens, Bacillus pumilis, B. thuringiensis and Herbaspirillum rubrisubalbicans were identified. All species had the ability to solubilise phosphate, fix nitrogen and produce IAA. Endophytic bacteria with plant growth promoting activity play an important role on plant growth and development. In this study, Burkholderia cepacia, B. diazotrophica, B. tropica, Pseudomona fluorescens, Bacillus pumilis, B. thuringiensis and Herbaspirillum rubrisubalbicans promoted plant growth in vitro. This makes them an excellent alternative for the application to soils with low fertility and to increase the production of crops of economic interest.