Molecular Characterization of a Triticum durum-Haynaldia villosa Amphiploid and Its Derivatives for Resistance to Gaeumannomyces graminis var. tritici

Take-all is a serious disease found in wheat across the world. Haynaldia villosa is considered to be resistant to take-all at a high level. TH3 was an amphiploid （2n =42, AABBVV） between Triticum durum and Haynaldia viUosa with significant resistance to take-all fungus isolated from China. In greenhouse experiment, the derivatives of the hybrid between wheat and TH3 showed better resistance to take-all than that of the wheat control. One of the derivatives named HW918-5 was selected for further analysis. Cytological and genomic in situ hybridization （GISH） analysis indicated that a monotelosome originated from H. villosa existed in the genome of the offspring of the line HW918-5. The monotelosome with promising resistant gene for take-all was located on the 3V chromosome of H. villosa in the further PCR-based molecular analysis.

转TiERF1-RC7双价基因小麦的鉴定及其全蚀病抗性

为探讨TiERF1和RC7基因对小麦抗全蚀病的防御反应,本研究对转TiERF1-RC7双价基因小麦进行了分子检测以及全蚀病抗性的室内和田间鉴定。结果表明,转入的TiERF1和RC7基因在转基因小麦中可以遗传和转录;与受体扬麦18相比,5个转TiERF1-RC7小麦株系在整个生育期抗病性显著提高,苗期的全蚀病严重度在10%以下,成熟期的白穗率在13%以下,而扬麦18的严重度为62.98%,白穗率为26.09%。电子显微镜观察结果表明抗病转基因小麦根表的全蚀病原菌菌丝数量及生长势明显低于感病材料。上述结果说明,转入的TiERF1和RC7基因抑制了全蚀病原菌的侵染及在转基因小麦中繁殖,进而提高了转基因小麦对全蚀病的抗性。

草坪斑枯病病原菌及其近缘种属的系统发育及基因宏阵列检测

夏季草坪斑枯病是由子囊菌纲巨座壳科真菌Magnaporthe poae在夏季高温高湿环境下引起的一种草坪病害。对来源不同的24个Magnaporthe及其近缘种属Gaeumannomyces菌株的ITS1-5.8S-ITS2测序序列进行比较及系统发育分析。结果表明：M.poae及其近缘种属真菌可分为A和B 2个群：A群由M.oryzae和Pyricularia oryzae菌种组成并形成2个分支,二者亲缘关系较近,且具有侵染寄主植物根部和地上部分的能力。B群由M.salvinii、M.poae、M.rhizophila、G.incrustans和G.graminis种内的2个变种（G.graminis var.graminis和G.graminis var.tritici）组成,B群真菌除M.salvinii外均有侵染寄主根部能力。在草坪环境中,B群真菌种内检测鉴定较A群困难。本研究根据真菌ITS基因的种内序列高度保守,种间差异明显的特点,分别设计了基因宏阵列单体（20~24 bp）、二聚体（40~48 bp）和单体加20个“A”（30~34 bp）3种寡核苷酸基因宏阵列检测探针来快速检测鉴定B群病原真菌。基因宏阵列检测结果表明：设计的检测探针均能准确、特异地检测鉴定B群的3种真菌,检测灵敏度从高到低依次为：二聚体探针、单体加20个“A”探针、单体探针。结论：在草坪土壤环境中,二聚体基因宏阵列检测探针（40~48 bp）对于Magnaporthe及其近缘种属菌株的检测较传统的单体检测探针更为灵敏与准确。

木霉菌制剂对禾谷全蚀病的防治作用(英文)

木霉菌是对多种植物病原真菌有作用的拮抗体,包括Gaeumannomycesgraminisvar.tritici(Ggt),Pythiumspp.,Rhizoctoniasolani以及Fusariumspp.木霉菌能产生抑制植物病原真菌生长与活力的抗菌物质,是理想的植物病害生物防治菌。有效的生物防治方法可为农民提供低风险而又灵活的病害防治措施,特别是在需要减缓病原菌对化学杀菌剂产生抗药性的情况下。本文综合介绍了在南澳大利亚田间进行的利用康宁木霉菌(T.koningii)防治禾谷类根部病害的结果,并重点介绍澳大利亚在商品化开发方面的工作进展。在病害发生严重的情况下,康宁木霉菌可降低小麦全蚀病和丝核菌根腐病发病程度分别达24%和48%。小麦产量增加7%,也能降低大麦丝核菌根腐病发病程度达59%。康宁木霉菌也能够防治由Ceratocystisparadoxa引起的甘蔗凤梨病。

药剂处理对小麦全蚀病防效及其产量因素的影响

研究结果表明,采用药剂土壤处理和药剂拌种对小麦全蚀病[Gaeumannomyces graminis(Sacc.)ArX&Olivier var.tritici J.Walker]均表现出较好防效,对小麦产量也有明显影响。不同药剂土壤处理与对照相比,次生根受害症状表现推迟8～10 d,剑蚀消、70%甲基托布津和50%多菌灵防效分别为57.4%、32.9%和21.8%,后期枯穗率与对照枯穗率(0.75%)相比,防效分别为72.0%、66.6%和56.0%;产量与对照相比,分别增产31.1%、22.3%和18.6%。不同药剂拌种处理与对照相比,健禾保根部受害症状表现推迟12 d,其他处理推迟16～18 d;通过次生根受害程度调查,综合处理区平均防效达90.6%,3%敌萎丹、2.5%适乐时、12.5%全蚀净、3%敌萎丹+2.5%适乐时、6%立克莠和健禾保等处理平均防效分别为75.7%、51.2%、83.3%、66.4%、81.7%和57.4%;后期枯穗率与对照相比,平均防效依次分别达到85.3%、80.0%、97.3%、78.6%、84.0%和52.0%;产量表现以2.5%适乐时药剂拌种小麦产量最高,12.5%全蚀净处理小麦产量偏低。

Resistance of oat to ‘take-all' causing fungus (Gaeumanno-myces graminis var.tritici)

Evaluation with the pot assay at seedling stage in greenhouse showed that oat (Arena saliva) was highly resistant to take-all disease to which, however, wheat (Triticum aestivum) was extremely susceptible. The oat roots were shown to be inhibitory to the invasion and spread of take-all causing fungus G. graminis var. tritici by the following criteria: (i) less infection sites were observed (about 1/7 of those in wheat); (ii) the ectotrophic growth of G. graminis var. tritici on oat roots was much slower than that on those of wheat, and the runner hyphae appeared as kidney- or fork-shaped hyphopodia on the surface of oat roots which could not be discerned on that of wheat roots; (iii) the period from inoculation to penetration into the epidermis of oat roots was about 2.9 times as long as that of wheat; (iv) the infection hyphae were hindered substantially when it was about to penetrate into the epidermis of oat roots with the mycelium deformed; and (v) the cortical layer of oat roots was revealed to be