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Abstract：
BACKGROUND: Alternaria alternata is the primary pathogen of potato leaf spot disease, resulting in significant potato yield losses globally. Endophytic microorganism-based biological control, especially using microorganisms from host plants, has emerged as a promising and eco-friendly approach for managing plant diseases. Therefore, this study aimed to isolate, identify and characterize the endophytic fungi from healthy potato leaves which had great antifungal activity to the potato leaf spot pathogen of A. alternata in vitro and in vivo.
RESULTS: An endophytic fungal strain SD1-4 was isolated from healthy potato leaves and was identified as Talaromyces muroii through morphological and sequencing analysis. The strain SD1-4 exhibited potent antifungal activity against the potato leaf spot pathogen A. alternata Lill, with a hyphal inhibition rate of 69.19%. Microscopic and scanning electron microscope observations revealed that the strain SD1-4 grew parallel to, coiled around, shrunk and deformed the mycelia of A. alternata Lill. Additionally, the enzyme activities of chitinase and β-1, 3-glucanase significantly increased in the hyphae of A. alternata Lill when co-cultured with the strain SD1-4, indicating severe impairment of the cell wall function of A. alternata Lill. Furthermore, the mycelial growth and conidial germination of A. alternata Lill were significantly suppressed by the aseptic filtrate of the strain SD1-4, with inhibition rates of 79.00% and 80.67%, respectively. Decrease of leaf spot disease index from 78.36 to 37.03 was also observed in potato plants treated with the strain SD1-4, along with the significantly increased plant growth characters including plant height, root length, fresh weight, dry weight, chlorophyll content and photosynthetic rate of potato seedlings.
CONCLUSIONS: The endophyte fungus of T. muroii SD1-4 isolated from healthy potato leaves in the present study showed high biocontrol potential against potato leaf spot disease caused by A. alternata via direct parasitism or antifungal metabolites, and had positive roles in promoting potato plant growth.
RESULTS: An endophytic fungal strain SD1-4 was isolated from healthy potato leaves and was identified as Talaromyces muroii through morphological and sequencing analysis. The strain SD1-4 exhibited potent antifungal activity against the potato leaf spot pathogen A. alternata Lill, with a hyphal inhibition rate of 69.19%. Microscopic and scanning electron microscope observations revealed that the strain SD1-4 grew parallel to, coiled around, shrunk and deformed the mycelia of A. alternata Lill. Additionally, the enzyme activities of chitinase and β-1, 3-glucanase significantly increased in the hyphae of A. alternata Lill when co-cultured with the strain SD1-4, indicating severe impairment of the cell wall function of A. alternata Lill. Furthermore, the mycelial growth and conidial germination of A. alternata Lill were significantly suppressed by the aseptic filtrate of the strain SD1-4, with inhibition rates of 79.00% and 80.67%, respectively. Decrease of leaf spot disease index from 78.36 to 37.03 was also observed in potato plants treated with the strain SD1-4, along with the significantly increased plant growth characters including plant height, root length, fresh weight, dry weight, chlorophyll content and photosynthetic rate of potato seedlings.
CONCLUSIONS: The endophyte fungus of T. muroii SD1-4 isolated from healthy potato leaves in the present study showed high biocontrol potential against potato leaf spot disease caused by A. alternata via direct parasitism or antifungal metabolites, and had positive roles in promoting potato plant growth.
摘要：
背景：链格孢是马铃薯叶斑病的主要病原，导致全球马铃薯产量大幅下降。基于内生微生物的生物防治,特别是利用寄主植物的微生物，已成为管理植物病害的一种有前途且生态友好的方法。因此,这项研究旨在隔离，从健康的马铃薯叶片中鉴定和表征对马铃薯叶斑病菌具有强抗真菌活性的内生真菌。
结果：从健康的马铃薯叶片中分离出1株内生真菌菌株SD1-4，通过形态学和测序分析，鉴定为莫罗兰酵母。菌株SD1-4对马铃薯叶斑病病原体A.alternataLill表现出有效的抗真菌活性，菌丝抑制率为69.19%。显微镜和扫描电子显微镜观察表明，菌株SD1-4平行生长，盘绕在周围，AlternataLill的菌丝体缩小并变形。此外,当与菌株SD1-4共培养时，几丁质酶和β-1，3-葡聚糖酶的酶活性在A.alternataLill的菌丝中显着增加，表明A.alternataLill的细胞壁功能严重受损。此外，菌株SD1-4的无菌滤液显著抑制了AlternataLill的菌丝生长和分生孢子萌发，抑制率分别为79.00%和80.67%，分别。在用菌株SD1-4处理的马铃薯植物中，也观察到叶斑病指数从78.36下降到37.03，以及植物生长特征显着增加，包括植物高度，根长,鲜重,干重,马铃薯幼苗叶绿素含量和光合速率.
结论：本研究中从健康马铃薯叶片中分离出的T.muroiiSD1-4内生真菌对直接寄生或抗真菌代谢产物引起的马铃薯叶斑病具有很高的生物防治潜力，对马铃薯植株生长有积极的促进作用。
结果：从健康的马铃薯叶片中分离出1株内生真菌菌株SD1-4，通过形态学和测序分析，鉴定为莫罗兰酵母。菌株SD1-4对马铃薯叶斑病病原体A.alternataLill表现出有效的抗真菌活性，菌丝抑制率为69.19%。显微镜和扫描电子显微镜观察表明，菌株SD1-4平行生长，盘绕在周围，AlternataLill的菌丝体缩小并变形。此外,当与菌株SD1-4共培养时，几丁质酶和β-1，3-葡聚糖酶的酶活性在A.alternataLill的菌丝中显着增加，表明A.alternataLill的细胞壁功能严重受损。此外，菌株SD1-4的无菌滤液显著抑制了AlternataLill的菌丝生长和分生孢子萌发，抑制率分别为79.00%和80.67%，分别。在用菌株SD1-4处理的马铃薯植物中，也观察到叶斑病指数从78.36下降到37.03，以及植物生长特征显着增加，包括植物高度，根长,鲜重,干重,马铃薯幼苗叶绿素含量和光合速率.
结论：本研究中从健康马铃薯叶片中分离出的T.muroiiSD1-4内生真菌对直接寄生或抗真菌代谢产物引起的马铃薯叶斑病具有很高的生物防治潜力，对马铃薯植株生长有积极的促进作用。
