多功能木霉的筛选及鉴定

测定了60株分离自土壤的木霉菌株的解磷解钾、拮抗和对有机磷农药毒死蜱的耐受、降解等功能。结果表明,5株木霉具有很好的解磷能力,其中木霉T-404的解磷效果最好,为109.22 mg·L-1。6株木霉具有明显的解钾透明圈,但是液体培养后测定发现木霉的解钾能力不强。木霉具有不同程度的拮抗作用,其中6株木霉的拮抗能力很好。大部分木霉可以耐受高浓度的毒死蜱,但是不能降解该农药。对5株具多功能潜力的优势木霉菌株进行形态学和分子生物学鉴定表明：T-403、T-404、T-440为Trichoderma koningiopsis,T-400、T-450为Trichoderma koningii。     

武夷菌素防治大豆菌核病的作用机制

武夷菌素是一种核苷类农用抗生素,具有高效、广谱、低毒等优点,对大豆菌核病具有良好的防治效果。武夷菌素防治大豆菌核病包括抑制核盘菌和诱导大豆抗病性两方面的作用。本文分别从核盘菌生长发育、生理毒性和基因表达三个层面介绍了武夷菌素抑制核盘菌的作用机制,同时,从植物防御过程中的胼胝质沉积、防御相关酶活变化和激素信号传导途径三方面综述了武夷菌素诱导大豆抗病的作用机制。此外,本文分析并展望了今后深入研究武夷菌素防治大豆菌核病作用机制的工作重点。     

哈茨木霉C184菌株对喀麦隆香蕉及大蕉根部病原菌的体外拮抗作用(英文)

体外测定了新近分离自喀麦隆香蕉及大蕉田间的哈茨木霉(Trichoderma harzianum)菌株C 184对香蕉和大蕉根部病原菌柱枝孢(Cylindrocladium pteridis)及茄镰孢(Fusarium solani),尖镰孢(Fusarium oxysporum)和曲霉 (Aspergillus sp.) 的拮抗作用. 在对峙培养中上述病原菌菌丝生长均受到明显抑制;在赛咯酚分层培养中木霉菌株对上述病原菌菌丝生长的抑制率为67%～88%;木霉菌株培养滤液对上述病原菌菌丝生长的抑制率为52%～87% .电镜下观察到木霉菌株对柱枝孢及镰孢霉的寄生过程,认为这可能是主要拮抗机制之一; 此外木霉菌株在液体培养中产生的抗生素及细胞壁降解酶也可能是抑制病原菌菌丝生长的主要原因.     

提高耐盐红螺菌拮抗能力的发酵条件初探

以光合细菌培养基为基础,初步探讨提高耐盐红螺菌拮抗能力的培养基组分等发酵条件,结果表明培养基的最佳碳源为葡萄糖,最佳氮源为磷酸氢二铵,并在培养基中应缺省硫酸锰和氯化钙。以优化后的培养基培养耐盐红螺菌,最低抑菌浓度达32 AU.mL-1,较原光合细菌基础培养基提高了大约1倍。添加聚乙二醇400、D-山梨醇表面活性剂不能提高该菌的拮抗能力。     

杨树林土壤微生物及优势菌对小穴壳菌抑制作用的研究

本文对毛白杨树林土壤内主要微生物的数量及种类进行了分析。并在实验室条件下通过琼脂培养、孢子萌发及杨树枝条接种等实验,筛选出对杨树水泡溃疡病病原小穴壳菌(Dothiorellagregaria)有拮抗作用的微生物为链霉菌和芽孢杆菌。为杨树溃疡病的微生物防治提供了菌剂生产的菌种。     

In vitro antagonistic activities of Lactobacillus spp. against Brachyspira hyodysenteriae and Brachyspira pilosicoli

The sensitivity of Brachyspira hyodysenteriae and Brachyspira pilosicoli, respectively the causative agents of Swine Dysentery and Porcine Intestinal Spirochaetosis to two probiotic Lactobacillus strains, L. rhamnosus CNCM-I-3698 and L. farciminis CNCM-I-3699 was studied through viability, motility and coaggregation assays. The cell-free supernatant of these lactobacilli contains lactic acid, that is stressful for Brachyspira (leading to the formation of spherical bodies), and lethal. It was demonstrated for the first time the in vitro coaggregation properties of two probiotic Lactobacillus strains (active or heat-treated) with two pathogenic strains of Brachyspira, leading to (1) trapping of spirochaetal cells in a physical network as demonstrated by SEM; (2) inhibition of the motility of Brachyspira. Such in vitro studies should encourage in vivo studies in animal model to evaluate the potential of the use of probiotic lactobacilli through a feeding strategy for the prevention of B. hyodysenteriae and B. pilosicoli.     

中华鳖六株病原菌的分类鉴定及其中草药拮抗研究

为提高养殖质量、达到无公害中华鳖的生产,本研究对来源于不同地域的中华鳖常见疾病的六株致病菌(WG985、TL97427、FS954、JS967、SG978、SS978)菌株进行了分类鉴定与中草药抑菌敏感性测试.结果表明4株为温和气单胞菌,2株分别为嗜水气单胞菌和豚鼠气单胞菌,6菌株对健康中华鳖均有较强毒力.药敏测定显示各菌株对中草药的拮抗作用基本一致,对大多数药物均表现不敏感,仅就地锦草、五倍子等个别药物敏感,但彼此间仍存有一定差异.     

苏南典型区农田土壤硒-镉拮抗作用研究

以苏南典型区2027套稻米-土壤样品的Se、Cd含量及其相关的元素地球化学调查数据为基础,通过元素相关性统计分析及生物富集系数(BCF)等分布特征研究,本文探讨了农田土壤中Se与Cd的拮抗作用及其控制因素。结果表明：1)土壤中Se和Cd分布共消长特征明显,两者之间具有显著正相关性、相关系数R最高可达0.87；2)有关岩石、陶瓷原料、河泥等均可成为农田富集Se、Cd的物质来源,且多为富Cd强于富Se,只有源于富硒岩石的富硒土壤可排除Cd污染干扰、其开发利用价值最高；3)稻米Se与Cd的生物富集系数多介于0.1～0.8之间,土壤偏碱性有利于稻籽吸收Se、偏酸性则有助于稻籽吸收Cd,受土壤Se、Cd同富集之影响,富硒米与镉超标大米可能同时出现；4)土壤富Se抑制稻米Cd吸收是有条件的,当土壤Se大于0.4mg/kg、总有机碳大于1.5%时,稻米Cd与土壤Se、Cd生物富集系数与土壤Se之间均存在显著负相关性,相关系数R分别为-0.74、-0.56；5)pH与Cd生物富集系数、TOC与Se生物富集系数之间也有显著负相关性,其相关系数R分别为-0.79、-0.65。     

河南省白灵侧耳菌株遗传多样性分析

采用拮抗反应和基因间隔区2(intergenic spacer 2,IGS2)分析方法对河南省32个白灵侧耳(Pleurotus tuoliensis)菌株的遗传多样性进行分析。结果:除菌株Pt1、Pt5和Pt22外,绝大多数菌株间存在拮抗反应;应用Hpa Ⅱ、Rsa Ⅰ和Hae Ⅲ等3个限制性内切酶,对IGS2扩增产物进行酶切和电泳分析,不同菌株电泳后产生多样性丰富的图谱。根据聚类分析结果将所有菌株分为3个大类,3个大类遗传关系相对较远,最终将32个菌株鉴定为3组,可为今后白灵侧耳新品种杂交选育亲本的选择提供参考。     

A review of biocontrol agents in controlling late blight of potatoes and tomatoes caused by Phytophthora infestans and the underlying mechanisms

Phytophthora infestans causes late blight on potatoes and tomatoes, which has a significant economic impact on agriculture. The management of late blight has been largely dependent on the application of synthetic fungicides, which is not an ultimate solution for sustainable agriculture and environmental safety. Biocontrol strategies are expected to be alternative methods to the conventional chemicals in controlling plant diseases in the integrated pest management (IPM) programs. Well-studied biocontrol agents against Phytophthora infestans include fungi, oomycetes, bacteria, and compounds produced by these antagonists, in addition to certain bioactive metabolites produced by plants. Laboratory and glasshouse experiments suggest a potential for using biocontrol in practical late blight disease management. However, the transition of biocontrol to field applications is problematic for the moment, due to low and variable efficacies. In this review, we provide a comprehensive summary on these biocontrol strategies and the underlying corresponding mechanisms. To give a more intuitive understanding of the promising biocontrol agents against Phytophthora infestans in agricultural systems, we discuss the utilizations, modes of action and future potentials of these antagonists based on their taxonomic classifications. To achieve a goal of best possible results produced by biocontrol agents, it is suggested to work on field trials, strain modifications, formulations, regulations, and optimizations of application. Combined biocontrol agents having different modes of action or biological adaptation traits may be used to strengthen the biocontrol efficacy. More importantly, biological control agents should be applied in the coordination of other existing and forthcoming methods in the IPM programs. © 2023 Society of Chemical Industry.