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POSTERS: Biological Control II

P-048 - Isolation, Characterization, and Biocontrol Potential of Pythium oligandrum in Taiwan

Tuesday, August 5, 2025
9:30 AM - 10:15 AM HST
Location: Exhibit Hall 3

    Presenting Author(s)

  • CW

    Chao-Jen Wang

    Taichung District Agricultural Research and Extension Station, MOA
    Changhua County, TAIWAN

    • Author(s)

  • CH

    ChingChing Hsu

    Taichung District Agricultural Research and Extension Station, MOA
    Changhus, Changhua, Taiwan (Republic of China)

  • YH

    YuFang Huang

    Taichung District Agricultural Research and Extension Station, MOA
    Taichung, Taichung, Taiwan (Republic of China)

  • TJ

    TinYao Jiang

    Agriculture Bureau, New Taipei City Government
    Taichung, Taichung, Taiwan (Republic of China)

Abstract Text: Pythium oligandrum has attracted global interest as a promising biocontrol agent; however, its presence in field soils in Taiwan has not yet been well documented. In this study, 42 soil samples were collected from central Taiwan and plated on PARP medium, yielding 131 aquatic fungal isolates. Morphological and molecular analyses identified 32 of these isolates as P. oligandrum. Representative strains (P21, P34, and P69-2) were tested for efficacy against cucumber damping-off (caused by P. spinosum ) and pea seedling blight (caused by Rhizoctonia solani) , resulting in an 8.3–63.3% reduction in disease incidence—indicative of strong biocontrol potential. Although direct antagonism was not detected, microscopic observations revealed that these strains coiled around and penetrated the hyphae of P. spinosum and R. solani, suggesting a mycoparasitic mode of action. Moreover, fermentation broth or filtrate of P. oligandrum strain P69-2 induced cucumber disease resistance within 48 hours via both salicylic (PAL, PR1a) and jasmonic acid (PR3, LOX1) pathways, whereas strain P34 triggered resistance solely through the jasmonic acid pathway. Collectively, these findings confirm the presence of P. oligandrum in Taiwan and underscore its potential as a biocontrol resource. Further exploration of its mycoparasitic mechanisms and ability to induce plant defenses will contribute to the development of sustainable crop protection strategies.