Investigation of bacterial communities on neutral metalloprotease genes in the vegetable field soils of Tsukuba city, Ibaraki, Japan

Abstract

The proteolytic bacterial communities were investigated with a clone library analysis that targeted the neutral metalloprotease gene (npr). Soil samples were collected from the vegetable fields with different cultivation methods in Tsukuba city, Ibaraki, Japan. The deduced Npr protein sequences from the retrieved npr that indicated 100% similarities to those of B. megaterium and B. butanolivorans were detected in all soil samples, and thus these two genera of Bacillus appeared to exist widely in the fields investigated in this study. On the other hand, the deduced Npr protein sequences that closely related to those of the uncultured bacteria were also detected, suggesting co-existence of unknown proteolytic bacteria. Both the proteolytic bacterial community structure and soil chemical properties tended to differ among the farmers rather than the cultivation methods or sampling seasons according to the principal component analysis. However, none of the soil chemical properties evaluated in this study were strongly related to the proteolytic bacterial community structure in the canonical corresponding analysis.