广西杉木炭疽病病原鉴定及生物学特性测定

【目的】明确广西杉木炭疽病的病原种类及生物学特性,为杉木抗病育种及杉木炭疽病的防治技术研究提供科学依据。【方法】采集广西河池、百色、桂林、柳州、贺州和南宁市杉木种子园及林地炭疽病样品,采用常规组织和单孢分离法获得杉木炭疽病病原菌菌株,通过形态特征结合病原菌核糖体内转录间隔区(ITS)、几丁质合成酶(CHS1)、3-磷酸甘油醛脱氢酶(GPDH)、微管蛋白(TUB2)和肌动蛋白(ACT)多基因分子系统学分析,对获得的炭疽病菌菌株进行鉴定;采用平板培养法测定病原菌生物学特性。【结果】从杉木炭疽病样品中共分离获得60株炭疽菌属真菌,均具有致病性,但致病力存在差异。通过形态学结合病原菌多位点基因系统发育分析,确定广西杉木炭疽病病原菌种类为核果炭疽菌(Colletotrichum fructicola)和山茶炭疽菌(C. camelliae)。生物学特性测定结果显示,C. fructicola和C. camelliae菌丝生长及产孢最适温度分别为28和25℃;光照对C. fructicola菌丝生长无明显影响,但有利于C. camealliae菌丝生长,黑暗有利于2种病原菌产孢;pH 4时最适宜2种病原菌菌丝生长,pH 4最适宜C. fructicola产孢,pH 5最适宜C. camealliae产孢;2种病原菌对D-麦芽糖利用最好,乳糖和D-山梨醇最有利于C. fructicola产孢,可溶性淀粉和阿拉伯糖最有利于C. camelliae产孢;蛋白胨和酵母粉均有利于2种病原菌菌丝生长,酵母粉有利于C. fructicolaz产孢,酵母粉和牛肉膏有利于C. camelliae产孢。【结论】广西杉木炭疽病病原为核果炭疽菌(C. fructicola)和山茶炭疽菌(C. camelliae)。温度、pH和碳氮源对2种病原菌菌丝生长及产孢影响明显,光照对2种病原的影响略有不同。

Identification and biological characteristics of the pathogens of Chinese fir anthracnose in Guangxi

【Objective】To identify and determine the biological characteristics of the pathogens causing Chinese fir anthracnose in Guangxi to provides a basis for their control.【Method】Typical anthracnose samples were collected from Chinese fir seed orchards and woodlands in Hechi,Baise,Guilin,Liuzhou,Hezhou,and Nanning,in Guangxi,and thefungiwere isolated by tissue separation and purification. Their pathogenicity was tested according to Koch's method and their identity determined through morphological studies and multi-gene phylogenetic analysis of their internal transcribed spacer(ITS),chitin synthelase 1(CHS1),glyceraldehyde 3-phosphoric acid dehydrogenase(GPDH),tubnlin2(TUB2),actin(ACT)sequences.The biological characteristics of Colletotrichum fructicola and C. camelliae were determined by the plate culture method.【Result】A total of 60 strains of anthracnose fungi were isolated from collection sites and the all of the isolates could infect healthy Chinese fir leaves,but with different pathogenicities. The pathogens were identified as C. fructicola and C. camelliae from their phenotypic characteristics and multilocus sequence analysis. The study of their biological characteristics indicated that the optimum temperature for mycelial growth and sporulation of C. fructicola and C. camelliae was 28 and 25 ℃,respectively. Light had no obvious effect on the mycelial growth of C. fructicola,but was beneficial to the mycelial growth of C. camelliae. Complete darkness was beneficial to the spore production of the two pathogens. The optimum p H value for mycelial growth of the two pathogens was 4,and the optimum pH value for spore production was 4 and 5 for C. fructicola and C. camelliae,respectively. The better carbon sources for C. fructicola and C. camelliae was D-maltose for mycelium growth,whereas the optimal carbon source for spore germination was lactose and D-sorbitol for C. fructicola,and soluble starch and arabinose in C. camelliae. The best nitrogen sources for C. fructicola and C. camelliae were peptone and yeast powder during mycelium growth,and the optimal nitrogen for spore germination was yeast powder in C. fructicola,and yeast powder and beef extract in C. camelliae.【Conclusion】The pathogens of Chinese fir anthracnose in Guangxi are identified as C. fructicola and C. camelliae. Temperature,pH,carbon and nitrogen sources have significant effects on mycelial growth and sporulation of C. fructicola and C. camelliae,while the effects of light on the two pathogens are slightly different.