Suppression of clubroot by Clonostachys rosea via antibiosis and induced host resistance

The mechanism of the biofungicide Prestop^® (Clonostachys rosea) was investigated for control of clubroot (Plasmodiophora brassicae) on canola. The key product components were partitioned and assessed for their effect on pathogen resting spores, root hair infection (RHI) and disease development using light microscopy, quantitative PCR and different application treatments during infection. The whole product of Prestop was consistently more effective than the C. rosea conidial suspension or product filtrate alone in reducing RHI and clubroot development. This biofungicide showed little effect on germination or viability of resting spores. Two‐application treatments at seeding and 7–14 days after seeding achieved greater clubroot control than a single application of the biofungicide at either seeding or post‐seeding stage. This may indicate the need to maintain a high biofungicide dose in the soil during primary and secondary infection. This biocontrol fungus colonized the rhizosphere and interior of canola roots extensively, and possibly induced plant resistance based on up‐regulation of the genes that are involved in jasmonic acid (BnOPR2), ethylene (BnACO) and phenylpropanoid (BnOPCL, BnCCR) biosynthetic pathways. It is concluded that the biofungicide Prestop suppressed clubroot on canola at least via root colonization and induced systemic resistance (ISR), and the latter may be through the modulation of phenylpropanoid and jasmonic acid/ethylene metabolic pathways elicited by the fungus.     

贵州省某规模化猪场猪瘟、猪伪狂犬病和大肠杆菌病混合感染的诊断

为了解贵州省某规模化猪场猪只发病原因,课题组成员采用流行病学调查、临床症状观察、病理剖检诊断、酶联免疫吸附试验(ELISA)、PCR/RT-PCR检测、细菌分离鉴定等方法对送检的发病猪病料进行诊断.结果表明,该猪场猪只为猪瘟病病毒(CSFV)、伪狂犬病病毒(PRV)和大肠杆菌混合感染.建议该猪场根据诊断结果及时做出处理.     

Changes in plant diversity,biomass and soil C,in alpine meadows at different degradation stages in the headwater region of three rivers,China

Field surveys and experiment analyses were applied to detect the relationships between plant diversity, community biomass and soil resources at different degradation successional stages in the headwater region of three rivers in an alpine meadow. The chronosequence approach (space‐for‐time substitution) is a viable tool for obtaining integrated information within successional studies. The experimental plots were located in the Guoluo area, which is part of the source region for the Yangtze and Yellow Rivers. The results showed not only that the quantities of roots and soil that are ‘carriers’ for cultivating soil roots were altered not only by disturbance (including overgrazing) and environmental factors but also that the proportion of the rhizome to soil at the 0–10 cm soil layer was enhanced by disturbance in heavy degradation. The plant community composition changed, and the number of plant species and the proportions of fine forage decreased. Moreover, soil fertility levels decreased remarkably, and the soil was degenerated. Plant community biomass levels at different degradation successional stages affected the soil microbial biomass carbon, soil organic carbon and also affected soil fertility conditions. Soil organic carbon and soil total nitrogen declined with grassland degeneration, and the distribution of soil organic carbon was influenced greatly. The alpine species Kobresia pygmaea was at different degradation successional stages, and the plant community biomass was significantly related to soil nutrients. In the positive successional series, the composition of plant functional groups became complex gradually, plant species richness was gradually enhanced, and the change in the composition of each plant functional group also reflected the restoration degree plant community structure. Copyright © 2008 John Wiley & Sons, Ltd.     

本生烟病程相关蛋白PR-10的原核表达及抗血清制备

病程相关蛋白(Pathogenesis-related proteins,PRs)是植物受生物或非生物胁迫后诱导并积累的一类蛋白质,具有抗病抗逆的多种功能。为检测本生烟病程相关蛋白10(Nicotiana benthamiana Pathogenesis-related protein 10,NbPR10)的表达,制备其抗血清,并用以探究其可能的特性和功能。将已有的NbPR10基因构建到原核表达载体p GEX-KG中获得重组质粒p GEXKG-NbPR10,转化大肠杆菌BL21(DE3),经0.2 m M IPTG诱导表达分子量约44 k Da的融合蛋白(含GST标签),用GST亲和柱纯化获得纯化的融合蛋白。以纯化的融合蛋白为抗原免疫家兔制备NbPR10蛋白的抗血清,经Western blot测定抗血清效价达1∶10 000,能至多检测到稀释比例为1∶320的转基因本生烟叶片中的PR10蛋白或1 ng原核表达的蛋白,且能检测到本生烟根和茎中的PR10蛋白,证明PR10在本生烟根和茎中表达量较在叶部高,为进一步研究NbPR10蛋白的功能提供参考。     

甘肃省四种母猪繁殖障碍性疫病抗体血清学检测

运用乳胶凝集试验(LAT)和ELISA方法对酒泉、张掖、金昌、武威、兰州、临夏、白银、定西、天水和平凉10个市州38个规模化和农村个体养猪场送检的619份血样和血清进行了PPV、PR、PRRS和JE免疫抗体检测,3年度平均阳性率PPV为80.83%、PR为60.70%、PRRS为43.39%、JE为47.57%,免疫抗体平均阳性率以PPV最高,PRRS和JE免疫抗体平均阳性率偏低。对8市州24个猪场采送的132份血清进行的PPV、PR、PRRS和JE感染抗体检测表明,PPV感染抗体平均阳性率为18.57%、PR感染抗体平均阳性率为15.28%、PRRS感染抗体平均阳性率为23.28%J、E感染抗体平均阳性率为24.14%。     

水稻纹枯病发病过程PR1和PBZ1的表达动态

 采用从福建省稻田分离纯化的纹枯病菌(Rhizoctonia solani)菌株FJ-15接种籼稻9311,分析了水稻在纹枯病菌侵染致病过程中,编码病程相关蛋白的基因表达动态,并观察了症状的变化。Northern blot分析表明:PR1在接种12 h后开始表达,在之后的4个时间段其表达量逐步增强;而PBZ1也在12 h开始表达,在48 h表达量激剧增强几乎与72 h表达量相当。组织和症状观察表明,接种12 h后叶鞘表面菌丝纵横分枝,接种36 h后出现零星病斑,接种48 h后表现典型的受害症状,接种72 h后病斑继续扩大,并可蔓延到非接种叶鞘。结果表明,PR1和PBZ1的表达与水稻和纹枯病菌亲和互作的过程存在对应关系。     

山西省晋中市规模猪场母猪伪狂犬病群流行率及感染风险因素横断面研究

为了解2018年山西省晋中市规模猪场母猪伪狂犬病血清学场群流行率,寻找猪伪狂犬病毒感染的潜在风险因素,以母猪存栏大于100头的75个规模猪场为研究目标,按照发现疫病的抽样策略,采用两阶段抽样方法,随机选取51个规模猪场,在每个养殖场随机抽取30份血清样品进行感染抗体检测,并对所有检测的规模猪场开展问卷调查。抗体检测结果显示,晋中市规模猪场母猪伪狂犬病场群流行率为40.90%(95%CI:27.3%～54.5%)。单因素分析显示,风险因素为"方圆3 km内有其他家畜养殖场、交易市场或者屠宰场",保护性因素为"引进猪只时检测伪狂犬病毒感染抗体和1年内引进公猪精液"。建立的模型拟合度较好,模型ROC曲线下面积为0.835(95%CI:0.658～1.000)。调查结果提示,新建养殖场要与其他的家畜养殖场、交易市场或者屠宰场保持安全的养殖距离,规模养殖场要坚持自繁自养,在引进种猪和公猪精液时一定要进行严格地PRV检测。     

β-氨基丁酸诱导烟草产生PR蛋白及对TMV的抑制作用

 本文研究了β-氨基丁酸(BABA)诱导系统侵染寄主烟草NC89产生PR蛋白及其对TMV的抑制作用。用5mmol/LBABA对抗性烟和非抗性烟进行叶面喷施处理均可以抑制烟草叶片中TMV的产生,平均抑制率分别达到59%和49%。BABA和SA处理均可以诱导2种烟草叶片中PR1、PR2和PR5基因的表达,其中对PR1的诱导作用相对较强。分别用BABA和SA处理非抗性烟草,在处理后的不同时间内2种药剂对PR1基因的诱导规律基本相同。用BABA和SA分别预处理非抗性烟草2d后接种TMV,2种药剂对烟草叶片中PR1基因的影响是完全不同的,其中,BABA处理后接种TMV抑制PR1基因的表达,在接种后第72h已经检测不到PR1基因的存在,SA处理后接种TMV对PR1基因的影响呈现弱-强-弱的变化趋势,在接种后第24hPR1的表达量达到最强,以后逐渐减弱。试验结果表明:BABA能够提高非抗性烟草对TMV的抗性,但是BABA诱导烟草产生抗TMV的作用机制可能是一种不同于目前普遍公认的SA的作用机制。     

玉米弯孢菌叶斑病抗性机制的初步研究

玉米弯孢菌叶斑病菌［Curvularialunata（Wakker）Boed．］侵染不同抗性品种后,寄主叶片防御酶系和PR蛋白活性的变化及叶片汁液对病菌孢子萌发有影响,研究发现：PAL,PO,SOD和β-1,3-葡聚精酶在对弯孢菌叶斑病的抗性中起到一定的作用,尤其是PR蛋白β-1,3-葡聚糖酶活性在抗性机制中发挥更为重要的作用。木质素可能是在病菌侵染初期发挥抗侵入的作用。抗病品种叶片汁液可能含有抑菌物质,病菌侵染有利于刺激这种物质抑菌作用的提高,在抗病品种中更为明显。