Genetic stability of azospirillum brasilense after passing through the root interior of sugarcane

Abstract

In this work we investigated the genetic stability of Azospirillum brasilense after passing four times through the root interior of sugarcane. This study is based on the observation of a wide genetic diversity by using the RAPD-PCR method of this species in the sugarcane cropping region of Tucumán, Argentina. Some phenotypic (e.g. motility, formation of a sub-superficial pellicle, shape, size, color of the colonies, production of melanine-like dark pigment) and genetic characteristics of a local endophytic strain of A. brasilense isolated form sugarcane root, used in this study, were analyzed. RAPD genomic fingerprints and plasmid profiles were used to detect genetic variations. No phenotypic change or genomic rearrangement was detected, according to the analysis of phenotypic characteristics, to the genomic DNA and plasmid profiles carried out of the original and reisolated strains of Azospirillum. After these results we conclude that the root interior of sugarcane constitutes a stable environment for Azospirillum, and preserves its characteristics as a strain under changing environmental conditions, when colonizing sugarcane roots.