玉米大斑病菌Ht－毒素的硅胶G柱层析分析

通过硅胶Ｇ柱层析（２７×６７０ｍｍ）对玉米大斑病菌Ｈｔ－毒素进行了分离、纯化。试验结果表明，用丙酮（１／３）氯仿（２／３）混合为洗脱液，以１６．７ｍＬ／ｈ的洗脱速度可获得单一的Ｈｔ－毒素组分Ｉ，经气相色谱分析证实分离得到的组分Ｉ确为纯品。     

我国玉米大斑病菌生理小种组成变异研究

采用常规鉴别寄主鉴定技术,分析采自2005年和2006年我国10省份的100份玉米大斑病病菌分离物的致病性变异。鉴定结果表明,共鉴定出15个类型的生理小种,0、1、2、3、N、12、13、1N、23、2N、3N、12N、123N、123、23N;我国玉米大斑病菌的小种组成在继续变化之中,在全国范围内已无优势小种的存在;1、0号生理小种虽然是主要小种类群,但所占比例也仅有约20%,生理小种组成趋于多元化;北方地区小种的毒力组成较南方地区复杂,且毒力更强,不仅有能够克服单抗性基因的小种,而且有能够克服4个抗性基因几乎所有组合类型的小种。     

玉米大斑病菌Ht－毒素的硅胶G柱层析分析

通过硅胶Ｇ柱层析（２７×６７０ｍｍ）对玉米大斑病菌Ｈｔ－毒素进行了分离、纯化。试验结果表明，用丙酮（１／３）氯仿（２／３）混合为洗脱液，以１６．７ｍＬ／ｈ的洗脱速度可获得单一的Ｈｔ－毒素组分Ｉ，经气相色谱分析证实分离得到的组分Ｉ确为纯品。     

感染斑病菌后玉米抗感近等基因系丁布含量变化的比较研究

本文比较了玉米抗、感大斑病菌近等基因系丁布含量及其在感病过程中的动态变化。结果发现，在未受病菌侵染的情况下，Ht1Ht1、Ht2Ht2和HtNHtN3种抗病系以及htht感病系间丁布含量没有明显差异。接种大斑病菌后，各种抗病系在病菌侵染初期丁布含量迅速大幅度上升，在整个病程中始终明显高于感病系。感染大斑病菌最终导致罹病植     

尖角突脐孢菌在温室环境下侵染稗草的致病体系研究

稗属（Echinochloa）杂草是全世界水稻等作物生产中的一类恶性杂草。人工除稗安全但费时费力，化学除稗高效但伴随农产品安全和环境相融友好方面的潜在风险。因此，寻求安全高效的除稗活性成分和施药技术成为国际上除稗剂发展的重要方向之一。在研究和开发生物除稗剂的技术体系中，满足高通量筛选安全、高效的除稗生防因子的温室检测体系是极为重要的支持平台，同样，生物除稗剂的田间科学施药技术亦应依据生防因子在稗草上致病和致害所需的最佳条件来制定。基于此，亟需探明生防因子侵染稗草致病的相关条件并建立快速有效的生防因子除稗效果温室检测体系和田间施药技术。本文系统研究了影响尖角突脐孢菌侵染稗草的相关因子，建立了稳定的温室环境下尖角突脐孢菌侵染稗草的致病体系。     

Effect of planting density of maize on the progress and spread of northern leaf blight fromExserohilum turcicum infested residue source

Effect of plant density (37,037, 44,444 and 55,555 plants/ha) on the increase of northern leaf blight in time and space on two maize cultivars planted at spacings of 90, 75 and 60 between rows and 30 cm within rows was investigated.Exserohilum turcicum infested maize residue was used as an inoculum source. Maize density did not significantly affect the disease indices, but significantly influenced the grain yield of the two cultivars. In contrast, the two cultivars differed significantly (P0.01) in disease severity, but not grain yield. Higher disease severities and grain yields were associated with higher plant densities, whereas the apparent infection rate was lower in higher plant density. Distance from the maize residue (inoculum source) significantly influenced disease severity. The percentage leaf area blighted, area under disease progress curve and disease progress curve intercept decreased with distance from the maize residue area, but the apparent infection rate on EV8429-SR appeared to increase with distance. Disease gradients (b) were higher in closely planted maize and flattened with time in one location only.     

Genetic differentiation in populations of Exserohilum turcicum from maize and sorghum in South Africa

Exserohilum turcicum is the causal agent of northern leaf blight, a devastating foliar disease of maize and sorghum. Specificity of E. turcicum to either maize or sorghum has been observed previously, but molecular evidence supporting host specialization is lacking. The aim of this study was to compare the genetic structure of E. turcicum isolates collected from adjacent maize and sorghum fields in Delmas and Greytown in South Africa. In addition, the mode of reproduction of this pathogen was investigated. Isolates from maize (N = 62) and sorghum (N = 64) were screened with 12 microsatellite markers as well as a multiplex mating type PCR assay. No shared haplotypes were observed between isolates from different hosts, although shared haplotypes were detected between isolates from maize from Delmas and Greytown. Population structure and principal coordinate analyses revealed genetic differentiation between E. turcicum isolates from maize and sorghum. Analysis of molecular variance indicated higher among‐population variation when comparing populations from different hosts, than comparing populations from different locations. Lack of shared haplotypes, high proportion of private alleles, greater among‐population variance between hosts than locations and significant pairwise population differentiation indicates genetic separation between isolates from maize and sorghum. The high haplotypic diversity in combination with unequal mating type ratios and significant linkage equilibrium indicates that both sexual and asexual reproduction contributes to the population genetic structure of E. turcicum in South Africa.     

河北省玉米大斑病菌生理小种组成研究

采用鉴别寄主鉴定技术,对2009～ 2010年采自河北省的120份玉米大斑病菌菌株进行生理小种组成及毒性分析.结果表明,共鉴定出15个生理小种致病类型,即0、1、3、N、12、13、1N、23、2N、3N、123、12N、13N、23N和123N,其中,0号和1号生理小种为优势小种,分别占总分离数的24.2％和20.8％;其次为1N和N号生理小种,分别占总分离数的10.0％和9.2％.春玉米区大斑病菌生理小种的结构较复杂,出现多个生理小种类型,夏玉米区大斑病菌生理小种的结构相对较简单.将各菌株进行毒性分析发现,河北省玉米大斑病菌对Htl和HtN基因的毒性较高,毒性频率分别为57.5％和37.5％;对Ht2和Ht3基因毒性较低.     

云南省部分地区玉米大斑病菌生理小种鉴定

 对分离于云南省部分地区的24个大斑病单孢菌株生理小种鉴定结果表明：0号生理小种仍然是云南省的优势小种,占供试菌株的41.7％;23N号生理小种占33.3％;1号、3号及23号各占供试菌株的8.3％。     

玉米中QM同源基因的克隆及其差异表达分析

利用cDNA-AFLP技术和5'' RACE技术在玉米自交系黄早四Ht2上分离并克隆了QM（编码核糖体蛋白L10）同源基因(命名为ZmQM)。其cDNA全长为967 bp, 开放阅读框为738 bp,。该基因编码245个氨基酸的ZmQM蛋白,分子量为27.78 kD, 等电点(pI)为10.69, 预测含蛋白酶C磷酸化位点、N-酰基化位点和酰胺化等位点。玉米ZmQM蛋白与包括人类等l3个物种QM蛋白的同源性比较发现, 氨基酸序列相似性为66%~92%。RT-PCR分析表明, 在接种玉米大斑病菌(Exserohilum turcicum) 1号小种12 h后, 黄早四Ht2中ZmQM基因表达量较黄早四中明显上调,推测ZmQM基因可能参与黄早四Ht2对玉米大斑病菌1号小种的抗性反应。