KOREASCHOLAR

Fluorescent bacteria were isolated from sporocarps that browned into various mushrooms during survey at places of the production in Korea. We examined the pathogenicity, biodiversity, and genetic characteristics of the 19 strains identified as Pseudomonas tolaasii by sequence analysis of 16S rRNA and White Line Assay. The results emphasize the importance of rpoB gene system, fatty acid profiles, specific and sensitive PCR assays, and lipopeptide detection for the identification of P. tolaasii. As a result of these various analyses, 17 strains (CHM03~CHM19) were identified as P. tolaasii. The phylogenetic analysis based on the 16S rRNA gene showed that all strains were clustered closest to P. tolaasii lineage, two strains (CHM01, CHM02) were not identified as P. tolaasii and have completely different genetic characteristics as a result of fatty acids profile, specific and sensitive PCR, lipopetide detection, rpoB sequence and REP-PCR analysis. Pathogenicity tests showed 17 strains produce severe brown discolouration symptoms to button mushrooms and watersoaking of sporophore tissue within three days after inoculation. But two strains did not produce discolouration symptoms. Therefore, these two strains will be further investigated for correct species identification by different biological and molecular characteristics.

INTRODUCTION
MATERIALS AND METHODS
    Bacterial culture conditions
    White Line Assay and Lipopeptide detection
    Genomic DNA isolation and sequencing
    Molecular genetic analysis
    Biochemical assays
    In vitro antagonism experiments and necrosis test
    Pathogenicity test
RESULTS AND DISCUSSION
    Biodiversity of the bacterial isolates
    Molecular genetic analysis of isolates
    Detection of lipopeptide metabolites
    Pathogenicity and necrotic properties
ACKNOWLEDGMENTS
REFERENCES

• Chan-Jung Lee(Mushroom Research Division, National Institute of Horticultural & Herbal Science, RDA, Eumseong 27709, Korea) Corresponding author
• Hye-Sung Park(Mushroom Research Division, National Institute of Horticultural & Herbal Science, RDA, Eumseong 27709, Korea)
• Seong-Yeon Jo(Mushroom Research Division, National Institute of Horticultural & Herbal Science, RDA, Eumseong 27709, Korea)
• Gi-Hong An(Mushroom Research Division, National Institute of Horticultural & Herbal Science, RDA, Eumseong 27709, Korea)
• Ja-Yun Kim(Mushroom Research Division, National Institute of Horticultural & Herbal Science, RDA, Eumseong 27709, Korea)
• Kang-Hyo Lee(Mushroom Research Division, National Institute of Horticultural & Herbal Science, RDA, Eumseong 27709, Korea)