【作者】 白丽艳；

【导师】 郭庆元；

【作者基本信息】 新疆农业大学 ， 植物病理学， 2009， 硕士

【摘要】 大豆根腐病是大豆种植区发生比较普遍的病害,在主要种植区均造成不同程度经济损失。大豆感染根腐病后,引起地上部分叶片逐渐变黄,感病植株矮化,结荚少;地下部侧根的根尖先受到侵染,继而主根下半部出现褐色条斑,表皮及皮层变黑,严重时主根下半部分全部腐烂,造成植株死亡,直接影响大豆产量。在大豆的不同生育期从新疆大豆根腐病危害最重的布尔津县采集田间根腐病株302株,对每个单株进行病部分割后采用不同选择性培养基进行选择性分离,共分离获得425株分离物,其中镰孢霉(Fusarium )分离物307个,丝核菌(Rhizoctonia )分离物84个,腐霉菌(Pythium ) 21个,其分离比率分别为72.2 %、19.8 %、4.9 %。分离过程中未见有疫霉菌(Phytophthona )出现。据此初步说明当地大豆根腐病主要为镰孢霉根腐病,其主要病原种类包括镰孢霉、丝核菌和腐霉菌。对307个镰孢霉单孢分离菌株进行的种的鉴定结果表明:分属于5个种和1个变种,分别为尖孢镰孢霉(Fusarium.oxysporum Schlecht )、茄腐镰孢霉(Fusarium.solani (Mart.) Sacc.)、禾谷镰孢霉(Fusarium.graminearum.Schwabel )、茄腐镰孢霉蓝色变种(Fusarium.solani var.coeruleum (sacc.) Booth )、燕麦镰孢霉(Fusarium.avenum (Corda&Fr.)Sacc.)和节状镰孢霉(Fusarium.merismoidescorda Corda )。其中以尖孢镰孢霉的出现频率最高,茄腐镰孢霉次之,节状镰孢霉出现频率最低。对84个丝核菌属菌株进行的种的鉴定和融合群判定结果表明:分离所获丝核菌属菌株均为立枯丝核菌,其种内融合群分别是AG1、AG2、AG4。在这3个融合群中,以AG4出现的频率最高,AG1出现频率次于AG2,AG1出现频率最低。对不同融合群的代表菌株进行测序后比较其亲缘性结果表明:不同融合群之间相似性有差异,同一融合群中相似性也有差异。21株腐霉属菌株经鉴定均为瓜果腐霉(Pythium aphanidermatum (Eds.) Fitzp )。对6种镰孢霉和立枯丝核菌及瓜果腐霉菌进行的回接证病及致病性测定结果表明:致病力以立枯丝核菌(Rhizoctonia solani )最强,镰孢霉(Fusarium )以尖孢镰孢霉致病性最强;茄腐镰孢霉次之,腐霉菌(Pythium )也有一定的致病性。利用rDNA ITS-RFLP技术对病原菌属及分离过程中出现的三个属的非致病菌进行ITS区段的限制性酶切分析,建立了尖孢镰孢霉、立枯丝核菌及瓜果腐霉3种致病菌的分子标记,并对分离鉴定出的镰孢霉种进行了分子检测技术研究,为建立大豆根腐病病原种类的分子检测方法奠定了一定的基础。更多还原

【Abstract】 Soybean root rot, a common disease occurring in soybean growing areas has caused economic losses in the main growing areas. After infected by soybean root rot pathogen, the leaves gradually turned yellow, susceptible plants dwarfed,pods reduced, the tips of lateral root of the under-ground part were infected firstly and then brown stripe fleck appeared on the underside of taproot, the darkening at the epidermis and cortex, the under part of taproot entirely rot, and the whole plant death gradually, directly affected on the soybean yield.Four hundred and twenty five isolates were identified by different selective culture medium cultivating diseased-partition,cut and divided from 302 samples collected from fields of Burjin County in Xinjiang during different growth stages, and the Fusarium were 307 strains, Rhizoctonia were 84 strains, Pythium were 21 strains, the separation ratio are 72.2 %, 19.8% and 4.9%, respectively. Phytophthora was not found in these isolates. This result preliminarily shows that soybean root rot in this region is Fusarium.root rot, and the main types of pathogens include Fusarium, Rhizoctonia and Pythium.By single-spore isolating of 307 Fusarium strains, the results of species identification showed that: these Fusarium belonged to five species and a variation, their respectively is: F.oxysporum Schlecht, F.solani (Mart.) Sacc, F.graminearum.Schwabel, F.solani var.coeruleum (Sacc.) Booth, F.avenum(Corda&Fr.)Sacc. and F.merismoidescorda Corda.The isolation frequence is as the following: the highest occurence frequency of F.oxysporum Schlecht, F.solani (Mart.) Sacc followed by the second, F.merismoidescorda Corda were the lowest.The discriminate result of species and anastomosis groups (AGs) shows that all of these 84 isolates of Rhizoctonia DC. were identified as Rhizoctonia solani and these isolates can be categorized as follows:AG1, AG2 and AG4.Three anastomosis groups,isolation frequence is as the following:AG4, AG2, AG1. Compared the Affinity of different groups there are differences between the same similarity group and the different groups. 21 Pythium isolates were identified as Pythium aphanidermatum.Based on the pathogenicity Comparison of Fusarium, Rhizoctonia solani and Pythium aphanidermatum, the results showed that: Rhizoctonia solani had most virulence; Fusarium oxysporum had most virulence in Fusarium.spp and the Fusarium solani followed by the second, Pythium has some pathogenic.Use of rDNA ITS-RFLP technology to analysis the pathogenic bacteria and the three non-pathogenic bacteria,s ITS restriction endonuclease analysis, established the molecular markers of Fusarium oxysporum, Rhizoctonia solani and Pythium, and studied on the molecular detection techniques of Fusarium species, and to lay a foundation of established the molecular detection methods of soybean root rot pathogen.更多还原