Nitrogen Fixing Bacteria Isolated From Maize Root and Antagonistic Activity Against Fusarium Sp

Abstract

Enterobacter sp. is the major group of nitrogen fIxing bacteria commonly found associated with maize roots grown in different Yugoslavian soils (chernozem, alluvial soil, pseudogley and smonitza). Nitrogen fIxing ability of isolates was demonstrated with growth on N-free agar plates and acetylene reduction activity in N-free semisolid medium. Several of these nitrogen fIxing bacteria, when tested in vitro, were shown to be able to restrict the growth of some Fusarium sp. causing maize root rot. These bacterial strains were found to suppress pigmentation and growth of Fusarium cultures. Culture discoloration was associated with poor growth of surface mycelia. Bacterial strain Enterobacter cloacae ZP 101 has a good nitrogen fIXing potential and was the most promising in suppressing the growth of Fusarium sp. No differences in colony formation of Fusarium species were noticed in interaction with investigated non nitrogen-fIxing bacterial strain. Introduction of biological control agents to soil born and seed born pathogens could potentially control maize root rot.