การคัดเลือกเชื้อราเอ็นโดไฟท์จากใบทำมังสำหรับควบคุมเชื้อโรคใบใหม้ข้าว

บทคัดย่อ

Sixty-six fungal endophytes were isolated from the leaves of Litsea petiolata Hook. f. collected in Chiang Rai, Thailand. Crude extracts obtained from macerated endophytic fungi with ethyl acetate were used to screen their antifungal activity against two isolates (THL084 and THL861) of rice blast disease, Magnaporthe oryzae. Based on agar paper disc diffusion assay, crude extract of Fusarium sp. MFLUCC16-1462 exhibited high antifungal activity against isolate THL084. Inhibition zone of mycelial growth of M. oryzae isolate THL084 was 6.75 cm. The Fusarium sp. MFLUCC16-1462 also greatly reduced the growth of isolate THL861. At 96 h after dual cultures with Fusarium sp. MFLUCC16-1462, mycelium growth of THL084 and THL 861 were inhibited 61.96% and 31.74 %, respectively. The chemical composition of fungal extract Fusarium sp. MFLUCC16-1462 was further identified using a gas chromatographic-mass spectrometric method with their retention indices. Seventy constituents representing 95.92% of the crude extract from Fusarium sp. MFLUCC16-1462 were identified. Major components were pregeijerene B, callitrin, drimenol, ?-calacorene, benzyl acetylacetate and angustione. Antifungal activity of crude extract Fusarium sp. MFLUCC16-1462 could be involved to a combination of chemical constituents such as pregeijerene B, callitrin, drimenol, angustione, Z-lanceol acetate, nor-davanone, 1,4-cineole and 1,8-cineole. These active components could damage cellular membrane and leakage inhibiting spore germination, proliferation, and cellular respiration. It was indicated that the endophytic fungus Fusarium sp. MFLUCC16-1462 may suggest an evolutionarily important role for endophytic fungi, associating L. petiolata Hook. f. leaves, against fungal plant pathogens, and could be used in agricultural management in the future.

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