【作者】 郭玉杰；

【导师】 邓晖；

【作者基本信息】 中国农业科学院 ， 微生物学， 2016， 硕士

【摘要】 平脐蠕孢属(Bipolaris Shoemaker)和弯孢属(Curvularia Boedijn)真菌能造成多种禾本科植物的病害,是重要的植物病原菌。近几年,此两属真菌分子系统学研究取得了较大进展,对一些种的模式菌株进行多基因系统发育分析,将平脐蠕孢属的多个种组合到弯孢属,并对平脐蠕孢属进行了系统的整理。本研究以实验室采集分离获得和中国农业微生物菌种保藏中心(ACCC)保藏的此两属真菌菌株为研究材料,包含平脐蠕孢属255株和弯孢属188株真菌。通过对此两属真菌的rDNA ITS序列测定和分析,选取代表性菌株进行了甘油醛-3-磷酸脱氢酶(GPDH)和延伸因子(EF-1α)基因的序列测定,分别构建了单基因的系统发育树和多基因组合的系统发育树。研究表明,251株平脐蠕孢属真菌属于Bipolaris bicolor、B.coffeana、B.cookei、B.heveae、B.heliconiae、B.maydis、B.oryzae、B.peregianensis、B.pluriseptata、B.secalis、B.setariae、B.sorokiniana、B.victoriae、B.yamadae、B.zeae和B.zeicola这16个已知种。其中B.coffeana、B.heliconiae、B.pluriseptata和B.secalis这4个种为中国新记录种。通过构建单基因的系统发育树和多基因组合的系统发育树,ACCC 38217、ACCC 38219、ACCC 38221和ACCC 38224这4株菌在一个稳定的独立分支上,并且与已发表平脐蠕孢属种的分支相距较远。通过形态观察发现,它们与已发表种存在较大差异,将其作为疑似新种。对平脐蠕孢属的每个种选择代表性菌株进行一致培养条件下的形态学观察和描述,产孢的种类与已报道的形态特征描述相一致。本研究中平脐蠕孢属真菌种的分子系统学研究结果支持了形态学种。同时发现平脐蠕孢属多数种的寄主为禾本科的多种植物;麦根腐平脐蠕孢B.sorokiniana的寄主范围包含禾本科、茄科、豆科、菊科、亚麻科、蔷薇科、锦葵科、大麻科、榆科和木兰科等10个科的多种寄主。通过分析188株弯孢属真菌的rDNA ITS序列,我们选取了36株弯孢属菌株也进行了多基因序列分析。结果表明它们分别属于弯孢属19个已知种,包括Curvularia akaiiensis、C.alcornii、C.bannonii、C.geniculata、C.gladioli、C.hawaiiensis、C.heteropogonicola、C.homomorpha、C.inaequalis、C.intermedia、C.lunata、C.nicotiae、C.nodulosa、C.papendorfii、C.robusta、C.spicifera、C.trifolii、C.tuberculata和C.verruculosa。其中C.akaiiensis和C.alcornii为中国新记录种。通过构建单基因的系统发育树和多基因组合的系统发育树,我们发现其中有三个独立分支未能与参照菌株聚类到一起。菌株ACCC 36558和ACCC 36653聚类到一个独立分支上;菌株ACCC38398、ACCC 38411、ACCC 38423、ACCC 38427、ACCC 38413、ACCC 38482和ACCC 36353聚类到一起;ACCC 36570、ACCC36685、ACCC 38337、ACCC 38399和ACCC 38318聚类到一起;将其定为弯孢属的3个疑似新种。本研究采用分子系统学的方法对我国平脐蠕孢属和弯孢属真菌菌株进行研究,研究结果有助于了解我国此两属真菌资源的种类和多样性,为此类群真菌资源的进一步研究和利用提供了基础。更多还原

【Abstract】 The genera Bipolaris Shoemaker and Curvularia Boedijn are important plant pathogenic fungi, which can cause diseases of plants in Gramineae. Molecular phylogenetic studies of the two genera were reported during recent years. According to the multi-genes phylogenetic analysis, some species of Bipolaris were treated as the new combinations of the genus Curvularia and the species of Bipolaris were systematically studied.In this study, 255 strains of Bipolaris and 188 strains of Curvularia in our lab isolated from the specimens in China and preserved in Agricultural Culture Collection of China(ACCC) were used as materials. Ribosomal DNA ITS sequencing and analysis of the strains of the two genera were done. More than 80 strains with rDNA ITS sequence difference were selected to sequencing the GPDH and EF-1α genes, and the phylogenetic reconstructions of concatenated and individual gene trees were performed.The results show that 251 strains of Bipolaris belong to 16 published species, including B. bicolor、B. coffeana、B. cookei、B. heveae、B. heliconiae、B. maydis、B. oryzae、B. peregianensis、B. pluriseptata、B. secalis、B. setariae、B. sorokiniana、B. victoriae、B. yamadae、B. zeae and B. zeicola. Among them, the four species B. coffeana、B. heliconiae、B. pluriseptata and B. secalis are new records in China.Phylogenetic reconstructions of concatenated and individual gene trees indicate that the four strains ACCC 38217, ACCC 38219, ACCC 38221 and ACCC 38224 do not belong to either Bipolaris species. Based on multilocus sequence analysis and morphology, the four strains are assigned to a possible new species of Bipolaris.The morphological characters of the representative strain from each species were described in detail, which were grown on the same condition. In this study, most species of Bipolaris were isolated from different hosts’ species in Gramineae, while B. sorokiniana were found on Gramineae, Asteraceae, Cannabaceae, Linaceae, Leguminosae, Magnoliaceae, Malvaceae, Rosaceae, Solanaceae, Ulmaceae 10 families of plants in China.After analysis of 188 rDNA ITS sequences of Curvularia, 36 strains were selected to study the phylogenetic relationship with multi-locus. The phylogenetic trees show that the strains of Curvularia in this study belong to 19 published species, including Curvularia akaiiensis, C. alcornii, C. bannonii, C. geniculata, C. gladioli, C. hawaiiensis, C. heteropogonicola, C. homomorpha, C. inaequalis, C. intermedia, C. lunata, C. nicotiae, C. nodulosa, C. papendorfii, C. robusta, C. spicifera, C. trifolii, C. tuberculata and C. verruculosa. Among them, two species Curvularia akaiiensis and C. alcornii are first reported in China.The individual and multi-genes combined phylogenetic trees show that 3 groups of strains are phylogenetically distinct from published Curvularia species. Three possible new species are found in Curvularia, in which ACCC 36558 and ACCC 36653 are assigned as Curvualaria sp.1, ACCC 38398, ACCC 38411, ACCC 38423, ACCC 38427, ACCC 38413, ACCC 38482 and ACCC 36353 are assigned as Curvualaria sp.2, while ACCC 36570, ACCC36685, ACCC 38337, ACCC 38399 and ACCC 38318 are assigned as Curvualaria sp.3.Molecular phylogenetic relationship of Bipolaris and Curvularia strains were studied in this study, the results will add the knowledge of the species and diversity of the two genera fungi resources in China, and applied the basis of the further research and utilization of these fungi.更多还原