Gill P R, Warren G J
Advanced Genetic Sciences, Inc., Oakland, California 94608.
J Bacteriol. 1988 Jan;170(1):163-70. doi: 10.1128/jb.170.1.163-170.1988.
Fluorescent rhizosphere Pseudomonas sp. strain NZ130 promotes plant growth, and may do so in part because of its production of a growth inhibitory factor that is active against phytopathogenic fungi. Analysis of the inhibitory factor that is active against the phytopathogen Pythium ultimum showed that its activity is antagonized at iron concentrations above 10 microM. The iron-antagonized inhibitor was separated from the fluorescent siderophore of this pseudomonad by gel filtration. Mutants that lacked either the iron-antagonized inhibitor or the fluorescent siderophore were isolated. Results of complementation analysis of these mutants by use of a cosmid library indicated that distinct DNA sequences are required for the production of each factor. Analysis of isogenic mutant strains showed that the genetic requirements for the production of the iron-antagonized inhibitor and the fluorescent siderophore are different, and that only the fluorescent siderophore is required for iron assimilation. Fusions of these same sequences to a beta-galactosidase gene were used to show that the regions required for the production of both the fluorescent siderophore and the iron-antagonized inhibitor were iron-regulated.
荧光根际假单胞菌属菌株NZ130可促进植物生长，其部分原因可能是它产生了一种对植物病原真菌有活性的生长抑制因子。对这种对终极腐霉有活性的抑制因子的分析表明，在铁浓度高于10微摩尔时其活性受到拮抗。通过凝胶过滤将铁拮抗的抑制剂与该假单胞菌的荧光铁载体分离。分离出了缺失铁拮抗抑制剂或荧光铁载体的突变体。利用黏粒文库对这些突变体进行互补分析的结果表明，每种因子的产生都需要不同的DNA序列。对同基因突变菌株的分析表明，铁拮抗抑制剂和荧光铁载体产生的遗传需求不同，并且铁同化只需要荧光铁载体。将这些相同序列与β-半乳糖苷酶基因融合，以表明荧光铁载体和铁拮抗抑制剂产生所需的区域受铁调控。
