Pseudomonas protegens is a rhizosphere pseudomonad with a high agronomical potential (entomopathogenic and beneficial to plants) and bio-catalytic activities, but no selective medium has been described for its isolation. We developed a semi-selective minimum agar medium for the specific isolation and growth of P. protegens. We searched for both (i) a carbon source allowing the growth of P. protegens but potentially inhibiting the growth of other pseudomonads and (ii) an antimicrobial agent suppressing other members of the bacterial rhizosphere community. The M9-PP-agar medium consists of M9 base agar with adipic acid as the only carbon source and Irgasan® as an anti-bacterial agent. We tested the selectivity and sensitivity of M9-PP-agar by measuring the growth of 68 bacterial strains from 36 different species on this medium. Ten of the species tested were able to grow on M9-PP-agar medium: four species from the Pseudomonadaceae (Pseudomonas aeruginosa, Pseudomonas protegens, Pseudomonas putida, Stenotrophomonas maltophilia) as well as Achromobacter xylosoxidans, Agrobacterium tumefaciens, Brevundimonas sp., Serratia liquefaciens, Serratia marcescens and Variovorax paradoxus. All colonies were white, except for those of P. protegens (12 strains), which were typically brown. We demonstrated the efficiency of the M9-PP agar medium for P. protegens isolation, by inoculating two soils with the reference strain P. protegens CHAOT and then reisolating them. We also developed a fitF-PCR test targeting a regulator gene of the insecticidal P. protegens fit locus, for the rapid molecular detection of P. protegens colonies. We, therefore, developed a highly specific process for the routine isolation of new P. protegens strains from the soil environment, based on the use of a semi-selective medium and the specific color of colonies.

中文翻译：

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从土壤样品中分离假单胞菌蛋白质的新型半选择培养基。

假单胞菌蛋白是具有高农学潜力（致病性和有益于植物）和生物催化活性的根际假单胞菌，但是没有描述用于其分离的选择性培养基。我们开发了一种半选择性的最小琼脂培养基，用于特定分离和生长蛋白。我们搜索了（i）允许P. protegens生长但有可能抑制其他拟单核细胞生长的碳源，以及（ii）抑制细菌根际圈其他成员的抗菌剂。M9-PP-琼脂培养基由具有己二酸作为唯一碳源的M9基础琼脂和作为抗菌剂的Irgasan®组成。我们通过测量来自36种不同物种的68种细菌菌株在该培养基上的生长来测试M9-PP-琼脂的选择性和敏感性。测试的10个物种能够在M9-PP-琼脂培养基上生长：假单胞菌科的四个物种（铜绿假单胞菌，蛋白质假单胞菌，恶臭假单胞菌，嗜麦芽单胞菌），木糖氧化无色杆菌，根癌农杆菌，短杆菌。 ，粘质沙雷氏菌和Variovorax paradoxus。除蛋白质假单胞菌（12个菌株）的菌落通常为棕色外，所有菌落均为白色。我们通过用参考菌株P. protegens CHAOT接种两种土壤，然后将其重新分离，证明了M9-PP琼脂培养基对P. protegens分离的效率。我们还开发了针对杀虫运动蛋白适合位点的调节基因的fitF-PCR测试，以快速检测运动蛋白菌落的分子。因此，我们