云南省荞麦茎枯病病原鉴定及其生物学特性研究

Identification and biological characteristics of pathogen causing stem blight of buckwheat in Yunnan province

【目的】旨在明确云南省荞麦茎枯病的病原及其生物学特性,为该病害的科学防控提供理论依据。【方法】从采自云南澄江的荞麦上采用植物真菌组织分离法,通过观察病原形态特征、测定致病性及分析rDNA-ITS序列系统发育树,鉴定引起云南省荞麦茎枯病的病原种类,并研究其生物学特性。【结果】采自云南澄江荞麦基地的典型荞麦茎枯病症状样品上分离到与菌株M38形态一致的病原真菌。经形态学、致病性及分子生物学鉴定,菌株M38的rDNA-ITS序列长度为517 bp(登录号:KP205542.1),与木贼镰刀菌菌株(MG736112.1和MG736187.1)的同源性均为100%,鉴定该病原菌为木贼镰刀菌(Fusarium equiseti)。菌株M38的菌丝在培养基PDA和PSA上最适宜生长,菌落直径大小分别为61.69和57.93 mm;菌丝在25~30℃均适宜生长,最适宜生长的温度为28℃,菌落直径大小为61.23 mm,致死温度为65℃,10 min;菌丝在pH为8.0~10.0均适宜生长,最适宜生长的pH为8.0,菌落直径大小为68.60 mm;在连续黑暗条件下菌丝生长最快,菌落直径大小为59.55 mm;菌丝在可溶性淀粉为碳源的培养基上生长最快,菌落直径大小为66.55 mm;菌丝在硝酸钠为氮源的培养基上生长最快,菌落直径大小为71.16 mm。【结论】引起云南省荞麦茎枯病的病原菌为木贼镰刀菌(F.equiseti);该菌株菌丝生长的最适培养基为PDA和PSA,温度为28℃,菌丝致死条件为65℃处理10 min, pH为8.0,光照条件为连续黑暗,碳源为可溶性淀粉,氮源为硝酸钠。

【Objective】The purpose of the study is to identify the pathogen and biological characteristics of buckwheat stem blight and elucidate its biological characteristics in Yunnan province, and to provide theoretical basis for scientific control of the disease. 【Method】The study used the tissue isolation method of phytopathogenic fungi to isolate the stem blight pathogen of buckwheat collected from Chengjiang, Yunnan. Based on morphological observation, pathogenicity test and analysis of phylogenetic tree of rDNA-sequence, the pathogen of buckwheat stem blight was identified and the biological characteristics of pathogen were studied. 【Result】The same morphological pathogenic fungus as strain M38 was isolated from typical symptomatic blight stem collected from buckwheat planting bases in Chengjiang, Yunnan. The rDNA-ITS sequence of the pathogen strain M38 was 517 bp(Accession No. KP205542.1), and it showed 100% homology with two strains of Fusarium equiseti(Accession No. MG736112.1, MG736187.1). The pathogen causing stem blight of buckwheat in the current study was identified as F. equiseti. The optimum growth media for mycelia growth of strain M38 were PDA and PSA, which colony diameters were 61.69 and 57.93 mm, respectively. The suitable temperature for mycelia growth ranged from 25 ℃ to 30 ℃, and its optimum temperature for growth was 28 ℃, with a colony diameter of 61.23 mm. The temperature when mycelia growth stopped was 65 ℃ for 10 min. The suitable pH for mycelia growth ranged from 8.0 to 10.0, and the optimum pH was 8.0 and the colony diameter reached 68.60 mm. The continuous darkness was most suitable for mycelia growth and the colony diameter was 59.55 mm. The optimum carbon sources for mycelia growth was soluble starch, with a colony diameters of 66.55 mm. The optimum nitrogen source for mycelia growth was sodium nitrate and the colony diameter reached 71.16 mm. 【Conclusion】The pathogen causing stem blight of buckwheat in Yunnan province was identified as F. equiseti. The suitable media for mycelia growth of strain M38 were PDA and PSA, and the most suitable temperature was 28 ℃, and the optimum pH was 8.0, and this fungus grew better in darkness, and the carbon source was soluble starch and the nitrogen source was sodium nitrate.