Cazorla Francisco M, Duckett Simon B, Bergström Ed T, Noreen Sadaf, Odijk Roeland, Lugtenberg Ben J J, Thomas-Oates Jane E, Bloemberg Guido V
Departamento de Microbiología, Facultad de Ciencias, Universidad de Málaga, Campus Universitario de Teatinos, s/n, 29071-Málaga, Spain.
Mol Plant Microbe Interact. 2006 Apr;19(4):418-28. doi: 10.1094/MPMI-19-0418.
A collection of 905 bacterial isolates from the rhizospheres of healthy avocado trees was obtained and screened for antagonistic activity against Dematophora necatrix, the cause of avocado Dematophora root rot (also called white root rot). A set of eight strains was selected on the basis of growth inhibitory activity against D. necatrix and several other important soilborne phytopathogenic fungi. After typing of these strains, they were classified as belonging to Pseudomonas chlororaphis, Pseudomonas fluorescens, and Pseudomonas putida. The eight antagonistic Pseudomonas spp. were analyzed for their secretion of hydrogen cyanide, hydrolytic enzymes, and antifungal metabolites. P. chlororaphis strains produced the antibiotic phenazine-1-carboxylic acid and phenazine-1-carboxamide. Upon testing the biocontrol ability of these strains in a newly developed avocado-D. necatrix test system and in a tomato-F oxysporum test system, it became apparent that P. fluorescens PCL1606 exhibited the highest biocontrol ability. The major antifungal activity produced by strain P. fluorescens PCL1606 did not correspond to any of the major classes of antifungal antibiotics produced by Pseudomonas biocontrol strains. This compound was purified and subsequently identified as 2-hexyl 5-propyl resorcinol (HPR). To study the role of HPR in biocontrol activity, two Tn5 mutants of P. fluorescens PCL1606 impaired in antagonistic activity were selected. These mutants were shown to impair HRP production and showed a decrease in biocontrol activity. As far as we know, this is the first report of a Pseudomonas biocontrol strain that produces HPR in which the production of this compound correlates with its biocontrol activity.
从健康鳄梨树的根际获取了905株细菌分离株，并对其进行筛选，以检测其对引起鳄梨白绢根腐病（又称白根腐病）的齐整小核菌的拮抗活性。基于对齐整小核菌和其他几种重要的土传植物病原真菌的生长抑制活性，挑选出一组8个菌株。对这些菌株进行分型后，它们被归类为属于嗜麦芽窄食单胞菌、荧光假单胞菌和恶臭假单胞菌。分析了这8种拮抗假单胞菌属菌株分泌氰化氢、水解酶和抗真菌代谢产物的情况。嗜麦芽窄食单胞菌菌株产生抗生素吩嗪-1-羧酸和吩嗪-1-甲酰胺。在一个新开发的鳄梨-齐整小核菌测试系统和番茄-尖孢镰刀菌测试系统中测试这些菌株的生物防治能力时，发现荧光假单胞菌PCL1606表现出最高的生物防治能力。荧光假单胞菌PCL1606菌株产生的主要抗真菌活性与假单胞菌生物防治菌株产生的任何一类主要抗真菌抗生素都不对应。该化合物被纯化，随后被鉴定为2-己基-5-丙基间苯二酚（HPR）。为了研究HPR在生物防治活性中的作用，选择了荧光假单胞菌PCL1606的两个拮抗活性受损的Tn5突变体。这些突变体被证明损害了HPR的产生，并表现出生物防治活性的降低。据我们所知，这是关于一种产生HPR的假单胞菌生物防治菌株的首次报道，其中该化合物的产生与其生物防治活性相关。
