No abstract

A mesophilic bacterium, strain 15-52 T , was isolated from the rhizosphere of Chinese cabbage (Brassica campestris). On the basis of phenotypic and genotypic characteristics, the bacterium was identified as representing a novel species belonging to the genus Pedobacter. The strain is non-flagellated, non-spore-forming and grows at temperatures in the range 1-37 6C. Physiological tests of the strain showed the presence of oxidase, catalase, protease (gelatin and casein hydrolysis), b-glucosidase and b-galactosidase activities. The highest levels of 16S rRNA gene sequence similarity were found with respect to Pedobacter roseus CL-GP80 T (97.3 %) and Pedobacter sandarakinus DS-27 T (97.2 %). A phylogenetic analysis based on 16S rRNA gene sequence data indicated that strain 15-52 T is a member of the genus Pedobacter. DNA-DNA hybridization analysis revealed low levels of relatedness (<42.3 %) between the isolate and two phylogenetically related type strains, P. roseus KCCM 42272 T and P. sandarakinus KCTC 12559 T . The DNA G+C content is 44.2 mol% and the predominant fatty acids are iso-C 15 : 0 (35.4 %), iso-C 15 : 0 2-OH and/or C 16 : 1 v7c (27.8 %) and iso-C 17 : 0 3-OH (15.8 %). On the basis of these data, strain 15-52 T represents a novel species of the genus Pedobacter, for which the name Pedobacter suwonensis sp. nov. is proposed. The type strain is 15-52 T (=KACC 11317 T =DSM 18130 T ).

A total of 520 overwintered sclerotia were collected from surface of soil under mulberry trees in six locations in Korea during February in 2006 and 2007. The collected sclerotia were tested for their germination in vitro and identified based on their morphological characteristics. Out of all sclerotia tested, 52.3% of the sclerotia germinated and produced two types of apothecia. The two types of fungi occurred from the sclerotia at the ratio of 49.8 vs. 50.2. The fungal type with cup-shaped apothecia was identified as Ciboria shiraiana and another type of fungus with club-shaped apothecia as Scleromitrula shiraiana. Taxonomy and distribution of the two sclerotial fungi were described and discussed.

Twenty isolates of Bacillus species obtained from livestock manure composts and cotton-waste composts were tested for their antagonistic effects in vitro against three green mold pathogens of mushrooms (Trichoderma harzianum, T. koningii, and T. viridescens). However, there exists a possibility Bacillus species may have antagonistic effects against mushrooms themselves, and thus the same 20 isolates were tested in vitro against three species of mushrooms (Flammulina velutipes, Lentinus edodes, and Pleurotus ostreatus). Of the 20 Bacillus species isolates tested, two inhibited mycelial growth of T. harzianum, seven that of T. koningii, and eight that of T. viridescens. Importantly, the bacterial isolates M27 and RM29 strongly inhibited mycelial growth of all the Trichoderma spp. isolates tested. The isolate M27 was subsequently identified as the most effective in inhibiting mycelial growth of all the Trichoderma species. Interesting results of the effect Bacillus isolates had upon the mushroom species followed. It was found that most Bacillus isolates except 5T33 at least somewhat inhibited mycelial growth of the three mushroom species or some of the mushrooms. Furhermore, the antagonistic effects of the bacterial isolates against the three species of mushrooms varied depending on the mushroom species, suggesting a role for mushroom type in the mechanism of inhibition. The bacterial isolates M27 and RM29 were identified as having the most antagonistic activity, inhibiting mycelial growth of all the Trichoderma spp. as well as mycelial growth of the three species of mushrooms. These results suggest that the bacterial isolates and their antagonistic effects on green mold pathogens should be further studied for their practical use for biological control of green mold in the growing room of the mushrooms.