Fluorescent <i>Pseudomonas</i> diversity in different soil management and crop rotation systems

Abstract

The objective of this work was to evaluate the effects of different soil management (no-tillage and conventional system) and crop rotation systems on the diversity of fluorescent Pseudomonas obtained from the rhizoplane and soil samples of wheat interlines, assessed by morphological and genotypic data. Morphological data analysis indicates that the majority of the isolates from the rhizoplane show characteristics of P. fluorescens, while the isolates from the soil have characteristics of P. putida. The correspondence analysis based on morphological data showed that the soil isolates are more similar to the ones of a forest area than the ones of the rhizoplane. Pseudomonas population from the rhizoplane is very homogeneous, without any effect of both management system and crop rotation. On the other hand, population from the interline soil samples formed two groups, one for the no-tillage system and another for the conventional system. ARDRA analysis showed three genotypic groups, dominated by the isolates obtained from the rhizoplane, with morphological characteristics of P. fluorescens. These data indicate a selection process on the bacterial community controlled by the plant, where the presence of fluorescent Pseudomonas with morphological characteristics of P. fluorescens in the wheat rhizoplane is prevalent.