为明确广东省金边露兜(Pandanus pygmaeus)叶斑病病原菌及其生物学特性,采用组织分离法从罹病叶片获得菌株t1.通过致病性测定、菌株形态观察和分子生物学测定,对其进行了种类鉴定和生物学特性研究.结果表明,引起金边露兜叶斑病的致病菌为暹罗炭疽菌(Colletotrichum siamense).病原菌株t1生长最佳条件为:温度28℃,pH 7,可利用各种碳源和氮源;产孢的最适条件为:温度28℃,pH 10,连续光照,碳源和氮源分别为纤维素和蛋白胨.黑暗条件下24 h有利于菌丝生长,连续光照24 h时产孢量最大.病原菌菌丝致死温度为55℃、10 min.这是国内首次报道暹罗炭疽菌引起的金边露兜叶斑病的研究,这将有助于了解该病害生物学特性,为其防治提供参考.

草地贪夜蛾Spodoptera furgiperda(J.E.Smith)是一种新的入侵害虫,目前已侵入我国多个省区,严重危害玉米.本研究调查了广州地区草地贪夜蛾僵虫的自然发生率,并分离出具有较高致病性的白僵菌,测定了其对草地贪夜蛾3龄幼虫的致病性.结果表明:广州地区草地贪夜蛾幼虫僵虫发生普遍,田间僵虫率最高为20.99％,累积僵虫率达43.21％;结合僵虫、致病菌菌落、显微超微等形态和分子生物学分析,以及致病性测定,确定从草地贪夜蛾幼虫上分离的真菌为球孢白僵菌Beauveria bassiana;分离培养的分生孢子和僵虫体表洗脱的分子孢子对幼虫致病力相近,有效致死浓度为1 ×107 cfu/mL,幼虫累积校正死亡率达78.57％.研究结果表明,该白僵菌菌株对草地贪夜蛾幼虫具有较高的致病性,可作为生防真菌进一步的研究.

为筛选新的具有抑菌活性的放线菌,采用稀释平板法从深圳赤坳水库保护林地芒箕土壤中分离筛选得到1株放线菌A50,并对A50进行初步鉴定以及抑菌活性测定。根据形态学特征、生理生化特性和基于16SrDNA序列及系统发育分析等方面的研究结果 ,菌株A50鉴定为Streptomyceyes nodosus。采用对峙平板法测定A50的抑菌活性,结果表明,放线菌菌株A50对5种供试植物病原真菌菌丝生长均有不同程度的抑制作用,其中以对玉米小斑病（Bipolaris maydis）的抑菌效果最好,抑菌带宽度达1.5cm。A50发酵液原液浸泡处理花生白绢病菌核,处理后72h抑制率达68%,稀释20倍后仍有9%的抑制率。放线菌A50是一株具有良好开发应用前景的生防菌株。

[目的]研究毛壳菌(Chaetomium sp.YMF1.00843)产胞外几丁质酶的酶学性质及抑菌活性,为几丁质酶的抑菌作用机理研究提供依据.[方法]利用蛋白活性电泳方法纯化几丁质酶液,测定几丁质酶的酶学性质,并用酶液浸泡病原菌菌块,研究酶液的抑菌活性.[结果]用蛋白活性电泳方法得到几丁质酶的纯酶液,经检测为电泳纯条带,分子质量为43 ku.毛壳菌几丁质酶的最适反应温度为40℃,最适pH为6,40℃以下保温30 min均能保持其初始活性,在pH 5～9保温30 min仍旧具有较高的活性,Ca2+和Zn2+能明显增强几丁质酶的活性,其纯酶液能抑制立枯丝核菌和烟草赤星病菌的菌丝生长.[结论]毛壳菌几丁质酶在比较温和的条件下能保持一定的活性,纯酶液对部分病原真菌有较强的抑制作用.

The teaching reform on General Plant Pathology was discussed from aspects of teaching content and teaching method,in order to culture high quality talents.

A causal agent of bacterial leaf spot of Euphorbia pulcherrima was isolated and identified,which occurred in Guangzhou,Guangdong Province in recent years.The pathogenicity test,physiological and biochemical characteristics tests,16S rDNA sequence analysis were undertaken to elucidate the precise position of the causal bacterium.The results indicated that the pathogen showed Gram's negative reaction and aerobic growth and yellow colony.The pathogen produced fluorescent pigment and could grow well at the temperature of 33 ℃.16S rDNA sequence identity between the isolated pathogenic strain YPH1(GenBank accession No.KC841470) and 8 strains of Xanthomonas axonopodis was more than 99.7%.By construction of their phylogenetic tree using neighbor-joining method in MEGA 4.0 software based on 16S rDNA sequence,the YPH1 strain and the other 7 strains of X.axonopodis belonged to a clade.The isolated pathogen was primarily identified as a X.axonopodis.

蝴蝶兰软腐病是蝴蝶兰上最重要的病害,严重威胁着蝴蝶兰的生产和销售。本文阐述了蝴蝶兰软腐病的症状特点、病原特征、发生规律及其防治技术,为指导蝴蝶兰软腐病的防治具有重要的意义。

<正>兰花是花卉产业最重要的观赏植物之一[1],一旦感染上病毒,其观赏价值和经济价值将受到严重影响。近年来,随着兰花产业的迅速发展,兰花国际国内贸易和种质交流十分频繁,建兰花叶病毒(Cymbidium mosaic virus,CyMV)和齿兰环斑病毒(Odontoglossum ringspot virus,ORSV)是严重影响兰花生产的2种主要病毒[2-3],有必要建立这两种病毒的高效检测方法。一些研究者对这2种病毒建立了双重RT-PCR检测方法[4-6],但对其检测体系的影响因素研究不多[5]。本试验对此进行了研究,旨在为兰花进出口贸易和安全生产奠定基础。

Microbes living with interior tissues of healthy plants without causing disease symptoms are called fungal endophytes.Fungal endophytes possess high diversity.They like to play protective or mutualistic roles to the host plants they inhabit.So much research had been carried to focus on fungal endophytes.Researchers can find the more effective ways and resource to go on the next research following the clues provided by former.

Vuculic acid is a phytotoxin produced by Nimbya alternantherae,a potential biocontrol agent to alligatorweed(Alternanthera philoxeroides).Effect of vuculic acid on photosynthesis of alligatorweed leaf was investigated.The results showed that after the leaves were treated with the toxin for 5 d,net photosynthe-tic rate,stomatal conductance and transpiration rate declined but intercellular carbon dioxide concentration increased significantly,and the chloroplasts swelled,chloroplast membrane digested and lamellae distorted.The effect on photosynthesis was increased with the increase of the mass concentration of the toxin.However,the toxin had no effect on chlorophyll contents.It was deduced that the damage of chloroplast ultrastructure might be the direct cause of photosynthesis decrease.

Cymbidium mosaic virus(CyMV) and Odontoglossum ringspot virus(ORSV) were evaluated by DAS-ELISA respectively in 44 diseased orchid samples collected from Guangdong province,the results showed that CyMV and ORSV were detected in 59.1% and 36.4% respectively,mixed infections with CyMV and ORSV were detected in 22.7% of the 44 diseased orchid samples.CyMV and ORSV were evaluated by one step RT-PCR respectively in 24 diseased orchid samples collected from Guangdong province,the results showed that CyMV and ORSV were detected in 83.3% and 75% respectively,mixed infections with CyMV and ORSV were detected in 66.7% of the 24 diseased orchid samples.These results suggested that the sensitivity of RT-PCR method is higher than that of DAS-ELISA method.

By a suppression subtractive hybridization technique,a suppression subtractive hybridization cDNA library was constructed with resistant Chieh-qua cultivar Zajiao 20 leaf induced by Fusarium oxysporum f.sp.beniacasa.Detection and analysis of the library construction showed that the technique was efficient in the subtractive hybridization and a good quality SSH-cDNA library was obtained.The titers of forward-and reverse-SSH-cDNA libraries were 3.64×105 CFU / mL and 6.80× 105 CFU / mL,respectively.More than 90% clones were recombinant and the length of the insert fragments were ranging from 400～800 bp in the forward-and reverse-SSH libraries.

综述了差减cDNA文库在植物抗性研究中的应用.

This paper discussed the micro process,signal substance and biochemical basis of the interaction mechanism between Colletotrichum and host plants,so as to provide reference for the further research.

The recent progress on the molecular marker for groundnut disease resistance,inheritance of resistance,mechanism of resistance and resistance evaluation of resource were reviewed.The foreground of the molecular marker application in peanut was prospected.

In order to control papaya anthracnose with the biologically,four good Trichoderma spp.isolates T05-049,T8-R,T05-035 and T05-044 were screened from 90 strains by testing and comparing their antibiotic action,amount of spore production,mycelin growth and parasitic ability to Colletotrichum on two different media.The amount of spore production was 1.42×109,5.45×108,4.16×108,1.38×109,respectively.Trichoderma spp.T05-049,T8-R,T05-035 and T05-044 strains grew better at the present of 1.01 mg/L of Thiabendazole and at the temperature from 10 ℃ to 25 ℃);The antibiosis to Colletotrichum spp.was 3,1,1 and 5,respectively.The inhibition rate to C.gloeosporioides and C.capcisi was higher than 57.05% and 47.87%,respectively,on PDA or papaya medium at 25,20 and 15 ℃.The autoeciousness effect was better.