Tae Yoon Kim1, Ja Yeong Jang1, Nan Hee Yu1, Won Jae Chi2, Chang-Hwan Bae2, Joo Hong Yeo2, Ae Ran Park1, Jae-Seon Hur3, Hae Woong Park4, Ji-Yeon Park5, Jong-Hwan Park5, Sung Ki Lee6, Jin-Cheol Kim1. 1. Division of Applied Bioscience and Biotechnology, Institute of Environmentally Friendly Agriculture, College of Agriculture and Life Sciences, Chonnam National University, Gwangju, Republic of Korea. 2. Biological and Genetic Resources Assessment Division, National Institute of Biological Resources, Incheon, Republic of Korea. 3. Korean Lichen Research Institute, Suncheon National University, Suncheon, Republic of Korea. 4. R&D Division, World Institute of Kimchi, Gwangju, Republic of Korea. 5. Laboratory of Animal Medicine, College of Veterinary Medicine and BK21 PLUS Project Team, Chonnam National University, Gwangju, Republic of Korea. 6. Department of Obstetrics and Gynecology, College of Medicine, Konyang University, Daejeon, Republic of Korea.
Abstract
BACKGROUND: The endolichenic fungus Xylaria grammica KCTC 13121BP showed strong nematicidal activity against Meloidogyne incognita. This study aimed to identify the nematicidal metabolites and to evaluate the efficacy of the strain as a biocontrol agent under pot and field conditions. RESULTS: Bioassay-guided fractionation and instrumental analyses led to grammicin being identified as the nematicidal metabolite. Because patulin is a mycotoxic isomer of grammicin and is known to have strong antibacterial and cytotoxic activities, several biological activities of the two compounds were compared. Grammicin showed strong second-stage juvenile killing and egg-hatching inhibitory effects, with a 50% effective concentration at 72 h (EC50/72 h ) of 15.9 µg/mL and a 50% effective concentration at 14 days (EC50/14 days ) of 5.87 µg/mL, respectively, whereas patulin was virtually inactive in both respects. Patulin was strongly active toward various phytopathogenic bacteria in vitro, whereas grammicin was weakly so. Patulin at the concentration range of 0.1-10 µg/mL also showed dose-dependent cytotoxicity toward the human first-trimester trophoblast cell line SW.71, whereas grammicin was not toxic toward this cell line. In pot and field experiments, a wettable powder-type formulation and fermentation broth filtrate of X. grammica KCTC 13121BP effectively suppressed the development of root-knot nematode disease on tomato and melon plants. CONCLUSION: The results suggest that X. grammica and grammicin may have potential applications for control of root-knot nematode disease of various crops.
BACKGROUND: The endolichenic fungus Xylaria grammica KCTC 13121BP showed strong nematicidal activity against Meloidogyne incognita. This study aimed to identify the nematicidal metabolites and to evaluate the efficacy of the strain as a biocontrol agent under pot and field conditions. RESULTS: Bioassay-guided fractionation and instrumental analyses led to grammicin being identified as the nematicidal metabolite. Because patulin is a mycotoxic isomer of grammicin and is known to have strong antibacterial and cytotoxic activities, several biological activities of the two compounds were compared. Grammicin showed strong second-stage juvenile killing and egg-hatching inhibitory effects, with a 50% effective concentration at 72 h (EC50/72 h ) of 15.9 µg/mL and a 50% effective concentration at 14 days (EC50/14 days ) of 5.87 µg/mL, respectively, whereas patulin was virtually inactive in both respects. Patulin was strongly active toward various phytopathogenic bacteria in vitro, whereas grammicin was weakly so. Patulin at the concentration range of 0.1-10 µg/mL also showed dose-dependent cytotoxicity toward the human first-trimester trophoblast cell line SW.71, whereas grammicin was not toxic toward this cell line. In pot and field experiments, a wettable powder-type formulation and fermentation broth filtrate of X. grammica KCTC 13121BP effectively suppressed the development of root-knot nematode disease on tomato and melon plants. CONCLUSION: The results suggest that X. grammica and grammicin may have potential applications for control of root-knot nematode disease of various crops.
Authors: Van Thi Nguyen; Nan Hee Yu; Yookyung Lee; In Min Hwang; Hung Xuan Bui; Jin-Cheol Kim Journal: Front Microbiol Date: 2021-11-24 Impact factor: 5.640