论文标题:高尔夫球场狗牙根叶斑病病原学的研究
Study on Etiology of Cynodon Leaf Spot in Golf Course
论文作者
论文导师 黄俊斌,论文学位 硕士,论文专业 植物病理学
论文单位 华中农业大学,点击次数 699,论文页数 53页File Size2847K
2006-06-01论文网 http://www.lw23.com/lunwen_651947/
pathogen identification;Biolaris australiensis(Cochliobolus australiensis);pathogenicity tests;biological characteristic;infection process
狗牙根草坪叶斑病是发生在高尔夫球场上的一种重要病害。2003-2005年，从湖北省武汉市金银湖高尔夫球场与红莲湖高尔夫球场上采集狗牙根草叶斑病标本。对叶部病斑进行组织分离，并将分离的菌株进行单孢纯化和致病性测定。对致病菌株进行了形态学与分子鉴定、生物学特性研究以及对四种草坪草的侵染过程观察，研究结果如下。 1．形态学鉴定的结果表明该菌株为澳大利亚平脐蠕孢(Bipolaris australiensis)。核糖体内转录间隔区(rDNA-ITS)序列测定的结果表明，该菌株与GenBank中登陆号为AY923860的澳大利亚旋孢腔菌(Cochliobolus australiensis)序列同源性达到99.61％。 2．致病性测定结果表明，菌丝块接种及孢子悬浮液接种均能使健康植株叶片出现圆形或者不规则形褐色病斑，而且从病斑边缘病健交界处又重新分离到该病原菌。综合致病性测定和形态学及分子鉴定结果，确认该病病原为Bipolaris australiensis，这是中国关于澳大利亚平脐蠕孢在高尔夫球场狗牙根草坪草上引起叶斑病的首次报道。 3．寄主范围测定结果表明，小麦、水稻、玉米、早熟禾、日本结缕草、高羊茅、黑麦草、匍匐剪股颖均为澳大利亚平脐蠕孢的寄主。 4．生物学特性研究结果表明，病原菌在15-35℃温度范围内都能够产孢，以20-30℃最为适宜。在10-30℃范围内随着温度的升高，产孢量逐渐增加，到30℃产孢量达到高峰。适合菌丝体生长的温度为15-38℃，以25-35℃最为适宜。40℃菌丝停止生长。pH值在2.76-10.75范围内菌丝体均能生长，其中以4.84-8.65最为适宜。在pH值在2.76-10.75范围内均可产孢，其中产孢最适宜pH值范围为4.84-6.41，偏酸性条件下有利于产孢。在供试的7种碳源中，以甘露醇和乳糖菌丝体生长势最好，以麦芽糖菌丝长势最差。产孢量则以乳糖为最高，以蔗糖最低。在供试的7种氮源之中，NaNO3最有利于菌丝生长，而菌丝体利用蛋白胨和甘氨酸效果最差。含KNO3培养基产孢量最高，含蛋白胨培养基产孢量最低。 PDA平板毒力测定结果表明，10％多氧霉素B粉剂、25％阿米西达乳油、80％代森锰锌粉剂、50％克菌丹粉剂、50％多菌灵粉剂、30％爱苗乳油、10％世高颗粒剂，其EC50依次为5912.965μg／ml、1135.283μg／ml、21.33029μg／ml、18.24744μg／ml、9．6468μg／ml、1.148368μg／ml、0.526344μg／ml。其中10％世高颗粒剂抑菌效果最好，10％多氧霉素B粉剂抑菌效果最差。 5．将浓度为5×10~6个孢子／ml澳大利亚平脐蠕孢分生孢子悬浮液喷施于生长20d左右的杂交狗牙根、高羊茅、早熟禾、黑麦草、早熟禾等几种草坪草活体叶片上，
Cynodon leaf spot is an important disease in golf courses. The samples is collected from Wuhan Gold-Silver Lake golf course and E-zhou Red Lotus Lake golf course from 2003 to 2005. The pathogen was isolated from the leaf spot and the isolate were purified by single sporing approaches. And then Pathogenicity tests, morphological and molecular identification, biological characteristic of this fungus and infection process on four turfgrass species were studied.This fugus was identified to be Bipolaris australiensis according to the morphology of conidia and conidiophore. The sequencing of the internal transcribed spacer region of this fungus showed 99.61% identity with Cochliobolus australiensis assession AY923860 in the GenBank. The pathogenicity tests showed that the same symptom as seen in the golf courses appeared on the same variety of Cynodon hybrid after inoculation with mycelial plugs or conidial suspension. Reisolation from the margin of symptomic tissue (leaf spot) were successful done to complete fully the Koch"s postulates. To the best of our knowledge, this is the first report of leaf spot caused by Bipolaris australiensis on cynodon in Hubei province, China.The result of determining of host range shows that Oryzae sativa, Zea mays, Poa pratensis, Zoysia japonica, Festuca arundinacea, Lolium perenne,Agrostis stolonifera are among the hosts of Bipolaris australiensis.The research on the biological characteristic of Bipolaris australiensis are as follows. This fungus could sporulate under the temperature from 15℃to 35℃, with the most appropriate temperature from 20℃ to 30℃. While the mycelium could grow under the temperature from 10℃ to 38℃, and ceased to grow under 40℃, with the most appropriate from 25℃ to 35℃ .The mycelium could grow in pH value range from 2.76 to 10.75 with the most appropriate pH Value range from 4.86 to 6.41. Among the carbon resourses, mannite is the best for the mycelial growth while Maltose is the worst. As for the sporula-tion, lactose is the most appropriate for the sporulation, while the sucrose is the worst. Amomg the nitrogen resourses, glycine is worst for the mycelial growth, and NaNO_3 is the best. KNO_3 is the best for sporulation, while Peptone is worst.Result of determining of the toxicity of seven fungicides to Bipolaris australiensis show that EC50 of 10% polyoxin B DP, 25% Amistar EC, 50% Carbendazim DP, 80% Mancozeb DP, 50%captan DP, 30%Armure EC, 10% Score GR is 5912.965μg/ml, 1135.283μg/ml, 21.33029μg/ml, 18.24744μg/ml, 9.6468μg/ml, 1.148368μg/ml,
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