Dynamics of cultivable arylsulfatase-producing bacterial and fungal communities along the phenology of field-grown rape

Abstract

The dynamics of bacterial and fungal communities possessing arylsulfatase (ARS) activity were followed in the rhizosphere of field-grown rape from stem elongation to seed maturity. Soil ARS activity as well as density, structure and diversity of both cultivable ARS bacterial (ARS-BC) and fungal (ARS-FC) communities were determined. ARS activities evolved along the phenology of rape and were correlated at reproductive stages with the densities of ARS-BC and ARS-FC communities. However, at vegetative stage, ARS activities were only significantly correlated with the sizes of ARS-FC but not with those of ARS-BC. Significant temporal shifts in the structure of ARS-BC and ARS-FC were observed. Furthermore, the more pronounced shifts observed in ARS-BC than in ARS-FC, suggests that ARS bacterial communities had a higher dynamic throughout plant development. Concerning the specific taxonomic groups, Actinobacteria, Trichoderma sp. and Eupenicillium sp. were dominant whatever the developmental stage of rape whereas Proteobacteria such as Pseudomonas sp., Klebsiella sp. and Raoultella sp. were presented at the later reproductive stages. This study suggests that arylsulfatase expressing bacterial and fungal communities were affected differently during rape development.