玉米大斑病是世界玉米产区主要的真菌病害之一，引起该病害的真菌为玉米大斑病菌（Setosphaeria turcica），为异宗配合真菌，其无性态为玉米大斑凸脐孺孢（Exserohilum turcicum）。玉米大斑病菌分生孢子萌发后形成高度特化的侵染结构—黑化的附着胞。附着胞通过产生高膨压来穿透植物表皮，其中甘油是产生膨压的主要来源。本研究分析了附着胞侵染玉米叶片的位置，发现大多数萌发的分生孢子通过直接穿透表皮细胞进入叶片内部，无论是通过表皮细胞还是气孔侵染玉米叶片，附着胞都是侵染所必需的。为了进一步确定影响附着胞发育的关键因素，我们分析了黑色素抑制剂（三环唑，TCZ）、DNA复制抑制剂（羟基脲，HU）和自噬抑制剂（3-甲基腺嘌呤，3-MA）等对附着胞膨压和甘油含量的影响。结果表明，在对照和抑制剂处理下，附着胞膨压和甘油浓度在附着胞成熟阶段均达到最高水平，三种抑制剂在附着胞成熟阶段对附着胞膨压的影响最大，糖原和脂质体是产生甘油的主要物质。研究发现，在附着胞的发育过程中，抑制剂会影响糖原和脂质体在分生孢子、芽管和附着胞中的分布。黑色素、DNA复制和自噬通过调节甘油积累和代谢影响玉米大斑病菌附着胞的发育，该研究可为附着胞膨压和甘油含量之间的关系提供新的见解。

同源重组（homologous recombination, HR）和非同源末端连接（nonhomologous end joining, NHEJ）是真核生物两种主要的双链断裂（DSB）修复方法。通常抑制NHEJ中关键组分的活性能够提高靶基因敲除的效率或者影响真核生物的生长和发育。然而，在玉米大斑病菌（Exserohilum turcicum）有关NHEJ途径的作用了解甚少。为了研究玉米大斑病菌中编码NHEJ途径关键组分蛋白Ku80基因的功能，我们在玉米大斑病菌鉴定并分析了该基因对病菌生长发育及致病性调控作用。方法：本研究通过利用同源比对的方法，在玉米大斑病菌中鉴定到与酵母Ku80同源的基因，命名为StKU80，并对该基因进行了相关生物信息分析；利用农杆菌介导的遗传转化技术（ATMT）获得了两株稳定的StKU80基因敲除突变体，并对基因的功能进行了分析。结果：保守结构域分析表明，StKu80包含真核生物的KU70p / KU80p蛋白典型的结构域VWA，Ku78和Ku-PK-bind；进一步的系统发育分析表明，StKu80与来自小麦颖枯病菌（Parastagonospora nodorum）的Ku80（XP_001802136.1）亲缘关系较近，其次是来自红曲霉（Monascus ruber）的Ku80（AGF90044.1）；突变体与野生型（WT）菌株相比，突变体的菌丝间隔变的更长，细胞壁较薄，在细胞壁表面的物质变的变少以及细胞中线粒体的含量变多；对突变体致病相关的结构进行分析表明，突变体不产生分生孢子和成熟的附着胞，但是突变体的HT毒素活性与WT类似，表明StKU80影响了病菌了侵染过程，但并未影响病菌的致病力；对StKU80能否参与调控胁迫响应反应分析发现，突变体对由H₂O₂产生的氧化反应高度敏感，但是对紫外不敏感。结论：StKU80在调控玉米大斑病菌的生长发育、致病性及胁迫响应过程中发挥着重要的作用。

The mitogen-activated protein kinase (MAPK), a key signal transduction component in the MAPK cascade pathway, regulates a variety of physiological activities in eukaryotes.  However, little is known of the role MAPK plays in phytopathogenic fungi.  In this research, we cloned the MAPK gene STK1 from the northern corn leaf blight pathogen Setosphaeria turcica and found that the gene shared high homology with the high osmolality glycerol (HOG) MAPK gene HOG1 of Saccharomyces cerevisiae.  In addition, gene knockout technology was employed to investigate the function of STK1.  Gene knockout mutants (KOs) were found to have altered hyphae morphology and no conidiogenesis, though they did show similar radial growth rate compared to the wild-type strain (WT).  Furthermore, microscope observations indicated that STK1 KOs did not form normal appressoria at 48 h post-inoculation on a hydrophobic surface.  STK1 KOs had reduced virulence, a significantly altered Helminthosporium turcicum (HT)-toxin composition, and diminished pathogenicity on the leaves of susceptible inbred corn OH43.  Mycelium morphology appeared to be significantly swollen and the radial growth rates of STK1 KOs declined in comparison with WT under high osmotic stress.  These results suggested that STK1 affects the hyphae development, conidiogenesis, and pathogenicity of S. turcica by regulating appressorium development and HT-toxin biosynthesis.  Moreover, the gene appears to be involved in the hypertonic stress response in S. turcica.

Large amounts of Flaveria bidentis’s root culturing solution were obtained by using DFT (deep flow technique) equipment and these solution which was vacuum concentrated (10, 20 mg mL-1) can have a certain inhibition on Triticum aestivum, Cucumis sativus, Raphanus sativus, Amaranthus retroflexus, Setaria viridis, Chenopodium album, Echinochloa crusgalli and Chloris virgata. This outcome suggested some active compounds in the root exudates of Flaveria bidentis can inhibit the germination, seedling elongation and root length. The dichloromethane extract of root exudates was identificated by GC-MS, and 29 kinds of compounds, including esters, hydrocarbons, ketones, thiazole, amines, etc. were obtained and the phthalate n-octyl ester, phthalate 2-ethylhexyl ester were proved to be allelochemicals. The culturing solution of root exudates was separated through the resin column and silica gel column and a component inhibiting seedling height, root length and fresh weight of wheat was got. There were 6 kinds of organic compounds in this component including dioctyl phthalate, 1,2-phthalate, mono(2-ethylhexyl) ester by GC-MS.

Natural herbicides, or environment-friendly bioherbicides have been attracted more and more attentions. Isolation and structural identification of natural herbicide-active compounds from plant pathogens has been proved to be an effective approach for novel lead discovery of the pesticide development. In this study, the metabolites of the mutant strain PAM1, which obtained from PA1 of Pythium aphanidermatum (Eds.) Fitzp by ultraviolet radiation were separated and identified by HPLC, NMR, and IR. The results revealed that three active compounds including 4-hydroxy-3-methoxycinnamic acid and two indole derivatives, exhibited inhibition activity on the elongation of radical and coleoptile of Digtaria sanguinalis (L.) Scop.