Screening and identification of a high yield sideropho-res- producing bacteria SS05 isolated from cotton soil

Abstract:

[Objective] The objective of this study was to examine the production of siderophore, taxonomic position and antifungal activity of high yield siderophore-producing bacteria isolated from Xinjiang cotton field soil. [Methods] high yield siderophore-producing bacteria were isolated by modified sugar-aspartic acid (MSA) medium and siderophore activity was measured by spectrophotometer method. The inhibitory effect against fusarium wilt pathogens (Fusarium oxysporum) was measured by mixed culture method. The strain SS05 was identified according to morphological features, physiological and biochemical characteristics and 16S rDNA sequences of the strain. [Results] There were 163 siderophore-producing bacteria strains isolated from cotton soil and 21 of 30 tested strains has high siderophore-producting capacity. The total siderophore relative content of strain SS05 was 98.3%. The supernatant of SS05 cultured with low concentrations of Fe3+ has significant inhibitory effect against F. oxysporum. Strain SS05 was identified as Bacillus sp. and has the closest genetic relationship with Bacillus mojavensis. [Conclusion] Strain SS05 was a high yield siderophore-producing bacterium, had the closest genetic relationship with Bacillus mojavensis. The supernatant of SS05 cultured with low concentrations of Fe3+ has significant inhibitory effect against F. oxysporum.