高产铁载体棉田土壤细菌SS05的筛选与鉴定

【目的】研究从棉田土壤中筛选得到的高产铁载体细菌产铁载体能力、分类地位和抑菌活性。【方法】通过改良蔗糖-天冬氨酸培养基选择性筛选产铁载体细菌,通过分光光度计法测定铁载体活性,通过混菌法测定产铁载体细菌上清液对棉花枯萎病致病菌尖孢镰刀菌(Fusarium oxysporum)的抑菌效果,采用形态学、生理生化鉴定及16S rDNA序列系统发育分析对高产铁载体菌株进行鉴定。【结果】从棉田土壤中筛选到162株产铁载体细菌,30株产铁载体能力较强的细菌中21株具有较高产铁载体能力,菌株SS05的铁载体活性单位达到98.3%;在低铁条件下,SS05上清液对F.oxysporum具有显著的抑制作用;SS05与莫哈韦芽孢杆菌(Bacillus mojavensis)最为接近。【结论】SS05是高产铁载体菌株,与莫哈韦芽孢杆菌(Bacillus mojavensis)最为接近,在低铁培养条件下其上清液对F.oxysporum具有显著的抑制作用。

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

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.