Andreoli Y E, Laich F S, Navarro C A
Facultad de Ciencias Agrarias, Universidad Nacional de Mar del Plata, Argentina.
Rev Argent Microbiol. 1993 Apr-Jun;25(2):70-9.
Thirty six fluorescent Pseudomonas isolates were obtained from the rhizosphere of sunflower plants. By antibiosis tests, the six more efficient strains in Sclerotinia sclerotiorum growth inhibition, were selected. Simultaneously, twenty three fluorescent Pseudomonas isolates were recuperated from the rhizosphere of wheat plants and the five most efficient strains in growth inhibition of the fungi Gaeumannomyces graminis were selected. The strains selected from the rhizosphere of sunflower plants had no antagonistic effect on G. graminis and the bacteria isolated from the wheat rhizosphere showed no fungistatic activity on S. sclerotiorum. These results suggest the existence of a certain degree of plant bacteria pathogenic specificity. Among the selected bacteria, the strain FF5 of P. fluorescens originated the major inhibiting halo in vitro against S. sclerotiorum (Figure 1). In liquid culture medium this bacterium produces an antifungal substance that promotes lysis of fungi mycelium (Figure 2) and inhibition of ascospore germination and is not inhibited by the presence of Fe+3 in the culture medium (Table 1). Its synthesis is not associated with the production of fluorescein. Its action is not enzymatic because it is a substance of low molecular weight (< 2000), resistant to autoclave sterilization and photo-stable. The amount of NH4+ and the high pH values produced by the FF5 strain in the liquid culture medium (Table 2) are not responsible for the antifungalal action.
从向日葵植物根际获得了36株荧光假单胞菌分离株。通过抗菌试验，挑选出了对核盘菌生长抑制作用最强的6株菌株。同时，从小麦植物根际回收了23株荧光假单胞菌分离株，并挑选出了对禾顶囊壳菌生长抑制作用最强的5株菌株。从向日葵植物根际挑选出的菌株对禾顶囊壳菌没有拮抗作用，从小麦根际分离出的细菌对核盘菌没有抑菌活性。这些结果表明存在一定程度的植物细菌致病特异性。在所选细菌中，荧光假单胞菌FF5菌株在体外对核盘菌产生了主要的抑制晕圈（图1）。在液体培养基中，这种细菌产生一种抗真菌物质，可促进真菌菌丝体的溶解（图2），抑制子囊孢子萌发，并且不受培养基中Fe+3存在的抑制（表1）。其合成与荧光素的产生无关。其作用不是酶促作用，因为它是一种低分子量（<2000）的物质，耐高压灭菌且光稳定。FF5菌株在液体培养基中产生的NH4+量和高pH值（表2）与抗真菌作用无关。
