云南省荞麦褐斑病病原鉴定及其生物学特性分析

Identification and biological characteristics of pathogen causing brown spot of buckwheat in Yunnan province

【目的】研究明确云南省荞麦褐斑病病原菌的种类及其生物学特性,为荞麦褐斑病的防控提供理论依据。【方法】通过测定病原菌的致病性、观察孢子形态及分析rDNA-ITS序列的系统发育树,对云南省荞麦褐斑病的病原菌种类进行鉴定,并测定其生物学特性。【结果】菌株S62R5的rDNA-ITS序列长度为553 bp(登录号:KR002908.1),与稻黑孢菌菌株(登录号:EU529994.1)的同源性达100%。菌丝生长的最适培养基为PDA、PSA,最适菌丝生长温度25、28℃,致死温度为53℃,10 min;菌丝适宜生长的pH为5~9,最适pH为6;光照对菌丝生长影响不显著;菌丝生长的最适碳源为葡萄糖和蔗糖,最适氮源为氯化铵。【结论】引起云南省荞麦褐斑病的病原菌为稻黑孢菌(Nigrospora oryzae)。

【Objective】The present research was to identify the species and biological characteristics of the pathogen of buckwheat brown spot in Yunnan province so as to provide theoretical basis for controlling buckwheat brown spot.【Method】 Based on pathogenicity test, morphological observation and analysis of phylogenetic tree of rDNA-sequence, the pathogen of brown spot of buckwheat was identified and the biological characteristics of pathogen were studied.【Result】 The rDNA-ITS sequence of the strain S62 R5 of the pathogen was 553 bp(Accession NO.KR002908.1)in length, which showed 100% homology with the strain of Nigrospora oryzae(Accession NO.EU529994.1).The optimum media for mycelia growth of strain S62 R5 were PDA and PSA.The optimum temperature for growth was 25 and 28 ℃.The lethal temperature for mycelia growth was 53 ℃ for 10 min.The suitable pH for mycelia growth ranged from 5 to 9,and the optimum pH was 6.The light had no significant effect on the mycelia growth.The optimum carbon sources for mycelia growth were glucose and sucrose.The optimum nitrogen source for mycelia growth was ammonium chloride.【Conclusion】 The pathogen causing brown spot of buckwheat in Yunnan province was Nigrospora oryzae.