西瓜蔓枯病研究 Ⅰ.症状及病原

本文详细报道了西瓜蔓枯病的症状和病原菌的形态特点,并鉴定其有性阶段为Mycosphaerellamelonis(Pass)Chiu et Walker,无性阶段为Ascochyta-cucumis Fautr et Roum.此外,还在其他瓜类作物上作了病原菌的致病性试验.     

Prepenetration stages in infection of clematis by Phoma clematidina

A detailed study of conidial germination, germ-tube growth and the formation of infection structures in Phoma clematidina , the causal agent of clematis wilt, is described for two clematis varieties differing in disease resistance. On both the resistant and susceptible varieties, the fungus entered leaves and stems by direct penetration of the cuticle, often, but not always, following the formation of infection structures. More germ tubes per conidium were formed on the susceptible host, but these germ tubes were on average shorter than on the resistant host. Although germ tubes regularly entered the plant via trichomes, stomata were not found to be sites of entry. Following penetration of the cuticle of resistant plants, germ-tube growth was sometimes restricted to the subcuticular region, and halo formation occurred at the sites where penetration was attempted. Subcuticular growth and halo formation were not observed on susceptible plants. These observations may partly explain the resistance of small-flowered clematis varieties to P. clematidina .     

克萎星对棉花黄萎病的防治效果

克萎星可溶性粉剂是河南省濮阳农业科学研究所研制生产的防治棉花黄萎病的新农药，田间药效试验结果表明：克萎星防治棉花黄萎病，发病初期叶面喷施，防效71．7％～100％，最佳施用浓度500～1000倍液，间隔期7～10d,棉花安全。     

Identification and use of a wild plant with antimicrobial activity against Ralstonia solanacearum, the cause of bacterial wilt of potato

Fresh aerial tissue and roots of 14 wild plants in Okinawa prefecture were investigated for their antimicrobial activity against Ralstonia solanacearum , which causes bacterial wilt of potato. A 70% aqueous ethanol extract of fresh aerial tissue of Geranium carolinianum L. showed strong antimicrobial activity against R. solanacearum . This extract also showed antimicrobial activity against the pathogens causing common scab of potato and soil rot of sweet potato. The antimicrobial substance could be extracted with hot water, and was effective against R. solanacearum in soil. In the field test, a treatment combining incorporation of dried aerial tissue into the soil and solarization was highly effective for control of bacterial wilt of potato. These findings suggest that G. carolinianum L. could be used as a biological agent for the control of bacterial wilt of potato.     

SUPEROXIDE DISMUTASE FAMILY GENES IN WATERMELON AND THEIR RESPONSES TO DIFFERENT ABIOTIC STRESSES

• A total of 8 SOD genes from watermelon were identified and bioinformatically analyzed. • The SOD proteins from watermelon and other different plant species can be classified into five groups consistent with their metal cofactors. • ClSOD genes exhibited distinctive tissue-specific and abiotic stress responsive expression patterns. Superoxide dismutase (SOD) is an important enzyme in the antioxidant system of plants and plays a vital role in stress responses by maintaining the dynamic balance of reactive oxygen species (ROS) concentrations. Genome-wide analysis of the SOD gene family in various plant species has been conducted but little is known about this gene family in watermelon (Citrullus lanatus). Here, eight SOD genes were identified in the watermelon genome and are designated ClCSD1-5, ClFSD1-2 and ClMSD according to their metal cofactors. Phylogenetic analysis shows that SOD proteins from various plant species can be classified into five groups and members in the same group possess the same metal cofactor and similar subcellular localizations. Expression analysis of the ClSOD genes indicates that they had tissue-specific expression patterns with high expression in different tissues including the leaves, flowers and fruit. In addition, the expression of ClSOD genes differed appreciably under salinity, drought and abscisic acid (ABA) treatments, indicating that they may be involved in ROS scavenging under different abiotic stresses via an ABA-dependent signaling pathway. These results lay the foundation for elucidating the function of ClSOD genes in stress tolerance and fruit development in watermelon.     

西瓜抗枯萎病基因同源序列的克隆与分析

本研究根据已克隆的抗枯萎病基因的NBS保守结构域设计了22条上游简并引物和17条下游简并引物,以西瓜抗枯萎病种质PI296341-FR和感枯萎病品种97103为材料,获得了7条来自基因组DNA的RGA序列（GenBank登录号：DQ156558-DQ156564）,均含有NBS保守区的P-环、kinase-2或kinase-3等抗病基因的特征序列结构,所编码的氨基酸序列与已知抗枯萎病基因Fom-2、I2C-1、I2C-2和I2等编码的氨基酸序列表现出11%～72%的同源性,其中来自PI296341-FR的RGA序列175R1与甜瓜抗枯萎病基因Fom-2的同源性最高,为72%。来自PI296341-FR与97103的RGA序列之间同源性较高（73%～97%）,证明了抗病基因在进化上的保守性。     

中国松材线虫病专题文献分析

以1989-2005年《中国期刊全文数据库》、《中文科技期刊数据库》收录的松材线虫病研究文献为依据,采用文献计量学的方法,对松材线虫病研究文献的数量、主要文献源及文献来源期刊的类别、文献主题类型、文献内容等方面进行统计分析和讨论．从一个侧面反映我国松材线虫病研究的现状和发展趋势。     

不同向日葵品种对黄萎病的抗性*

采用浸根接种法鉴定不同向日葵种质资源对黄萎病的抗性差异。结果表明：40份供试向日葵品种依据抗性划分标准共分为3类,其中中抗品种有5份如：‘118’、‘新葵杂5号’等;低抗品种有8份如‘767’、‘KJ003’等;其余27份供试材料均呈现感病;没有鉴定出免疫和高抗的向日葵品种。     

几种药剂防治烟草青枯病田间药效试验

7种药剂防治烟草青枯病进行了田间药效试验,结果表明,7种药荆均能推迟青枯病的发病高峰期,减轻发病程度,其中荧光假单胞菌3 000亿个/克粉剂和农用链霉素的防效最好,药效稳定,持续时间长,对烟草青枯病的防治效果分别达到74.92%、74.48%.此外,罗建新菌肥和活性菌肥对烟草青枯病也具有较好的防治效果,防效分别为66.27%和69.39%.     

甲基营养型芽胞杆菌AL7对棉花黄萎病的盆栽防治效果及定殖能力

为了探明甲基营养型芽胞杆菌AL7对棉花黄萎病的防治效果及其定殖能力,本文利用盆栽接种试验研究了菌株AL7对棉花黄萎病的防治效果;将带四环素抗性的pGFP78质粒转入到菌株AL7中,分析了菌株AL7在棉花根围土壤中、根部组织内的定殖情况。结果表明,菌株AL7对棉花黄萎病的盆栽防治效果为77.1%。pGFP78质粒转入后对菌株AL7的生长没有明显影响,仍具有游动性和产生物膜。定殖检测结果表明,菌株AL7能够在棉花根围土壤中及根系组织内长期定殖,接种5 d时定殖数量最高,达6×10~6cfu/g土,接种80 d后根围土壤中的定殖数量仍维持在2×10~6 cfu/g,根系组织内的定殖量为6×10~4 cfu/g。利用激光共聚焦显微镜观察验证,接种7 d后菌株AL7已经进入到棉花根部的中柱鞘细胞,能够在棉花根内大量定殖。