[Endophytic bacteria isolated from wheat and their antifungal activities to soil-borne disease pathogens].

In this paper, endophytic bacteria (EB) were isolated from the roots, stems, leaves and immature seeds of wheat at its different growth stages. The EB populations in fresh wheat tissues reached 5.0 x 10(5) CFU x g(-1) on average, with a significant difference among different tissues, growth stages and fields. The EB count was 7.8 x 10(5) in wheat roots, 4.8 x 10(5) in stems, 3.2 x 10(5) in leaves, and 2.8 x 10(5) CFU x g(-1) in immature seeds, and was estimated as 3.1 x 10(5), 5.7 x 10(5) and 7.0 x 10(5) CFU x g(-1) at seedling, elongation and filling stages, respectively. A total of 51 antifungal EB isolates were trapped by the wheat pathogenic fungus Gaeumannomyces graminis, and 45 by Rhizoctonia cerealis. Among them, 78 isolates showed antifungal activities in vitro. A total of 23 isolates from roots (6), stems (7), leaves (9) and immature seeds (1) were highly inhibitory to the mycelial growth of G. graminis var. tritici, with the diameters of their inhibition zone exceeding 10 mm. The other twenty isolates from different plant parts were also active against R. cereali. It was revealed that higher ratios of EB isolates with high antifungal activities were found in leaves, as compared with stems, roots and immature seeds.