Biological Control Agents

生物防治剂
  • 文章类型: Journal Article
    <b>背景和目标:</b>油棕研究的优先次序包括探索新型细菌分离株作为抑制<i>灵芝boninense</i>的可能药物。这项研究的目的是评估和表征根际细菌的潜力,从油棕榈植物的根际获得,就他们展示抗灵芝和灵芝活动的能力而言。<b>材料与方法:</b>本研究开始于采用双重培养技术选择敌对细菌。进行定性检测以评估抗真菌活性,以及几丁质酶和葡聚糖酶的合成,从某些分离物中。使用16S-rRNA核糖体引物对候选菌株进行分子鉴定,特别是27F和1492R引物。&lt;b&gt;结果:&lt;/b&gt;研究结果表明,与其他地点相比,政府种植园在重氮菌和土著细菌种群之间的比例最高。在九十种细菌分离物中,21个分离株的一个子集证明了阻碍<i>G.发展的能力。boninense</i>,如使用双重培养实验所确定的。发现21种细菌菌株具有抗真菌活性。根据序列分析发现了9种可能的细菌。这些细菌包括<i>伯克霍尔德氏菌</i>(RK2,RP2,RP3,RP5),<i>Burkholderiastagnalis</i>(RK3),<i>伯克霍尔德氏菌</i>(RP1),<i>粘质沙雷氏菌</i>(RP13)和<i>多菌根瘤菌</i>(RU4).<b>结论:</b>研究结果表明,相当比例的细菌种群表现出进行固氮的能力,吲哚-3-乙酸(IAA)生产和磷酸盐溶解。然而,值得注意的是,<i>多菌根瘤菌</i>RU4没有证明磷酸盐溶解的能力,而<i>B.领土</i>RK2没有展示IAA生产。
    <b>Background and Objective:</b> The prioritisation of oil palm studies involves the exploration of novel bacterial isolates as possible agents for suppressing <i>Ganoderma boninense</i>. The objective of this study was to evaluate and characterise the potential of rhizospheric bacteria, obtained from the rhizosphere of oil palm plants, in terms of their ability to demonstrate anti-<i>Ganoderma </i>activity. <b>Materials and Methods:</b> The study began by employing a dual culture technique to select hostile bacteria. Qualitative detection was performed to assess the antifungal activity, as well as the synthesis of chitinase and glucanase, from certain isolates. The candidate strains were molecularly identified using 16S-rRNA ribosomal primers, specifically the 27F and 1492R primers. <b>Results:</b> The findings of the study indicated that the governmental plantation exhibited the highest ratio between diazotroph and indigenous bacterial populations in comparison to the other sites. Out of a pool of ninety bacterial isolates, a subset of twenty-one isolates demonstrated the ability to impede the development of <i>G. boninense</i>, as determined using a dual culture experiment. Twenty-one bacterial strains were found to exhibit antifungal activity. Nine possible bacteria were found based on the sequence analysis. These bacteria include <i>Burkholderia territorii</i> (RK2, RP2, RP3, RP5), <i>Burkholderia stagnalis</i> (RK3), <i>Burkholderia cenocepacia</i> (RP1), <i>Serratia marcescens</i> (RP13) and <i>Rhizobium multihospitium</i> (RU4). <b>Conclusion:</b> The findings of the study revealed that a significant proportion of the bacterial population exhibited the ability to perform nitrogen fixation, indole-3-acetic acid (IAA) production and phosphate solubilization. However, it is worth noting that <i>Rhizobium multihospitium</i> RU4 did not demonstrate the capacity for phosphate solubilization, while <i>B. territory</i> RK2 did not exhibit IAA production.
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  • 文章类型: Journal Article
    在实验室和温室条件下评估了黄瓜中反式肉桂醛和柠檬烯的降解。两种商业生物农药,一种基于肉桂提取物和其他来自橙油,被利用。使用与四极杆高分辨率质量分析仪(Q-Orbitrap)偶联的气相色谱(GC)和超高效液相色谱(UHPLC)监测化合物降解。在两项研究中,反式肉桂醛遵循二级降解动力学,而柠檬烯遵循一级动力学。反式肉桂醛的半衰期值(DT50或t1/2)为2.02-2.49h,而柠檬烯的该值范围为0.49至6.17h。非靶向分析(可疑和未知模式)允许检测反式肉桂醛和柠檬烯代谢物。苯甲醇,肉桂醇,肉桂酸,对甲苯乙酸和4-羟基肉桂酸被初步鉴定为反式肉桂醛代谢产物。虽然三种柠檬烯代谢物,Carvone,柠檬烯-1,2-环氧化物,和紫苏醇,暂时确定。温室研究没有发现这些化合物的任何代谢物,因为母体化合物降解更快。
    Degradation of trans-cinnamaldehyde and limonene in cucumber was evaluated under laboratory and greenhouse conditions. Two commercial biopesticides, one based on cinnamon extract and other from orange oil, were utilized. Compound degradation was monitored using gas chromatography (GC) and ultra-high-performance liquid chromatography (UHPLC) coupled to a quadrupole-high-resolution mass analyzer (Q-Orbitrap). In both studies, trans-cinnamaldehyde followed a second-order degradation kinetics, whereas limonene followed a first-order kinetics. The half-life values (DT50 or t1/2) for trans-cinnamaldehyde ranged from 2.02 to 2.49 h, while for limonene this value ranged from 0.49 to 6.17 h. Non-targeted analysis (suspect and unknown modes) allowed for the detection of trans-cinnamaldehyde and limonene metabolites. Benzyl alcohol, cinnamyl alcohol, cinnamic acid, p-tolylacetic acid and 4-hydoxycinnamic acid were tentatively identified as trans-cinnamaldehyde metabolites. While three limonene metabolites, carvone, limonene-1,2-epoxide, and perillyl alcohol, were tentatively identified. Greenhouse studies have not revealed any metabolites of these compounds because the parent compounds degrade more quickly.
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  • 文章类型: Journal Article
    杆状病毒是感染不同物种的鳞翅目的病毒病原体,双翅目,和膜翅目,全球分布。由于它们的生物学特性和来自这些实体的生物技术应用,杆状病毒科是自然科学中研究和操纵的重要课题。随着RNA干扰机制的出现,已经描述了杆状病毒基因的存在,这些基因不编码蛋白质,而是产生类似于microRNAs(miRNAs)的转录本。这些miRNA在功能上与基因表达的调节相关,病毒和宿主序列。本文对miRNA的生物发生进行了全面的综述,函数,和一般的表征,特别关注杆状病毒中鉴定的那些。此外,它深入研究了杆状病毒miRNAs在调节病毒和宿主基因中的特定作用,并提出了结构和热力学稳定性研究,这些研究可用于检测具有预测性实用性的共同特征。这篇综述旨在扩大我们对杆状病毒miRNAome的理解,有助于改善基于杆状病毒的生物农药的生产,害虫抗性现象的管理,增强重组蛋白生产系统,以及开发多样化和改良的BacMam载体以满足生物医学需求。
    Baculoviruses are viral pathogens that infect different species of Lepidoptera, Diptera, and Hymenoptera, with a global distribution. Due to their biological characteristics and the biotechnological applications derived from these entities, the Baculoviridae family is an important subject of study and manipulation in the natural sciences. With the advent of RNA interference mechanisms, the presence of baculoviral genes that do not code for proteins but instead generate transcripts similar to microRNAs (miRNAs) has been described. These miRNAs are functionally associated with the regulation of gene expression, both in viral and host sequences. This article provides a comprehensive review of miRNA biogenesis, function, and characterization in general, with a specific focus on those identified in baculoviruses. Furthermore, it delves into the specific roles of baculoviral miRNAs in regulating viral and host genes and presents structural and thermodynamic stability studies that are useful for detecting shared characteristics with predictive utility. This review aims to expand our understanding of the baculoviral miRNAome, contributing to improvements in the production of baculovirus-based biopesticides, management of resistance phenomena in pests, enhancement of recombinant protein production systems, and development of diverse and improved BacMam vectors to meet biomedical demands.
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  • 文章类型: Journal Article
    在巴西,种植者专门为自己使用生产有益微生物是一种被称为“农场生产”的做法。关于农场生物杀虫剂,它们最初在1970年代被部署用于多年生和半多年生作物的害虫,但是,自2013年以来,它们的使用已经扩展到玉米等一年生作物的害虫,棉花,和大豆。目前正在用这些农场制剂处理数百万公顷的土地。本地生产降低了成本,满足当地需求,减少对环境有害的化学农药的投入,促进建立更可持续的农业生态系统。批评者认为,如果不实施严格的质量控制措施,农场制剂存在以下风险:(1)被可能包括人类病原体的微生物污染或(2)含有很少的活性成分,影响田间功效。细菌杀虫剂的农场发酵占主导地位,特别是针对鳞翅目害虫的苏云金芽孢杆菌。然而,在过去的5年里,昆虫病原真菌的产量快速增长,主要用于控制吸汁昆虫,例如粉虱(烟粉虱(Gennadius))和玉米叶斗(Dalbulusmaidis(DeLong和Wolcott))。相比之下,昆虫病毒的农场生产增长有限。大多数CA。巴西有500万农村生产者拥有中小型房地产,尽管绝大多数仍然没有进行生物农药的农场生产,这个话题引起了他们的兴趣。许多采用这种做法的种植者通常使用非无菌容器作为发酵罐,导致制剂质量差,并且已经报告了失败的案例。另一方面,一些非正式报告表明,即使受到污染,农场准备工作也可能有效,什么可以解释,至少部分地,由液体培养基中微生物池分泌的杀虫次生代谢产物。的确,关于这些微生物生物农药的功效和作用方式的信息不足。通常是大型农场,一些拥有超过20,000公顷的连续耕地,产生污染程度低的生物农药,因为他们中的许多人拥有先进的生产设施,并有机会获得专业知识和训练有素的员工。农场生物农药的吸收预计将继续,但采用率将取决于诸如选择安全,和实施良好的质量控制措施(符合巴西新兴法规和国际标准)。介绍和讨论了农场生物杀虫剂的挑战和机遇。
    In Brazil, the production of beneficial microorganisms by growers exclusively for their own use is a practice known as \"on-farm production\". Regarding on-farm bioinsecticides, they were initially deployed for pests of perennial and semi-perennial crops in the 1970s but, since 2013, their use has extended to pests of annual crops such as maize, cotton, and soybean. Millions of hectares are currently being treated with these on-farm preparations. Local production reduces costs, meets local needs, and reduces inputs of environmentally damaging chemical pesticides, facilitating establishment of more sustainable agroecosystems. Critics argue that without implementation of stringent quality control measures there is the risk that the on-farm preparations: (1) are contaminated with microbes which may include human pathogens or (2) contain very little active ingredient, impacting on field efficacy. The on-farm fermentation of bacterial insecticides predominates, especially that of Bacillus thuringiensis targeting lepidopteran pests. However, there has been a rapid growth in the past 5 years in the production of entomopathogenic fungi, mostly for the control of sap-sucking insects such as whitefly (Bemisia tabaci (Gennadius)) and the corn leafhopper (Dalbulus maidis (DeLong and Wolcott)). In contrast, on-farm production of insect viruses has seen limited growth. Most of the ca. 5 million rural producers in Brazil own small or medium size properties and, although the vast majority still do not practice on-farm production of biopesticides, the topic has aroused interest among them. Many growers who adopt this practice usually use non-sterile containers as fermenters, resulting in poor-quality preparations, and cases of failure have been reported. On the other hand, some informal reports suggest on-farm preparations may be efficacious even when contaminated, what could be explained, at least partially, by the insecticidal secondary metabolites secreted by the pool of microorganisms in the liquid culture media. Indeed, there is insufficient information on efficacy and mode of action of these microbial biopesticides. It is usually the large farms, some with > 20,000 ha of continuous cultivated lands, that produce biopesticides with low levels of contamination, as many of them possess advanced production facilities and have access to specialized knowledge and trained staff. Uptake of on-farm biopesticides is expected to continue but the rate of adoption will depend on factors such as the selection of safe, virulent microbial strains and implementation of sound quality control measures (compliance with emerging Brazilian regulations and international standards). The challenges and opportunities of on-farm bioinsecticides are presented and discussed.
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  • 文章类型: Journal Article
    农业低碳技术应用与农户收益的关系和作用机制尚不明确,尤其是发展中国家缺乏证据。本文以江西省农业大户为研究对象,中国,以2019年至2020年为研究对象,并从实地调研中获取相关数据,探讨农业低碳技术应用对规模化农户收益的内在影响。在相关理论分析的基础上,提出了农业低碳技术的划分维度,农业低碳技术根据六个维度细分为十种特定的低碳技术:耕作系统,育种,受精,灌溉,医学应用,和废物处理。设计并研究了相关问题,以获取低碳技术在农业中的应用现状和大规模农户的收入成本状况的数据。在理论分析的基础上,提出了研究假设,并根据获得的大型农户数据进行了实证分析。七项低碳技术在农业中的应用:保护性耕作系统,直接播种技术,选择复合肥/有机肥/控释肥,土壤配方施肥技术,深层施肥/灌溉施肥,喷头/滴灌/湿灌/间歇灌溉,秸秆资源化显著提高了规模农民的收入水平。此外,生物可降解农业膜的应用,生物农药,新的农药控释技术对规模农民的收入水平没有显着影响,由于它们的低应用和渗透率。根据本文的研究结果,政府应加强农业低碳技术的推广和补贴,特别是那些对大规模农民收入没有重大影响的技术,如可生物降解的农业膜,生物农药,和新的农药控释技术,从而实现减少碳排放和增加农民收入的双赢。
    The relationship and mechanism between agricultural low-carbon technology application and farm household returns are not yet clear, especially the lack of evidence from developing countries. This paper takes large-scale farming households in Jiangxi Province, China, from 2019 to 2020 as the research object, and obtains relevant data from field research to explore the intrinsic impact of agricultural low-carbon technology application on the returns of large-scale farming households. Based on the relevant theoretical analysis, the division dimensions of agricultural low-carbon technologies were proposed, and agricultural low-carbon technologies were subdivided into ten specific low-carbon technologies according to six dimensions: tillage system, breeding, fertilization, irrigation, medicine application, and waste treatment. Relevant questions were designed and researched to obtain data on the application status of low-carbon technologies in agriculture and the income cost status of large-scale farmers. Based on the theoretical analysis, the research hypotheses were proposed, and an empirical analysis was conducted based on the obtained data from large-scale farmers. The application of seven low-carbon technologies in agriculture: conservation tillage system, direct sowing technology, selection of compound fertilizer/organic fertilizer/controlled-release fertilizer, soil formula fertilization technology, deep fertilization/irrigation fertilization, sprinkler/drip irrigation/wet irrigation/intermittent irrigation, and straw resourceization significantly improved the income level of large-scale farmers. Furthermore, the application of biodegradable agricultural membranes, biopesticides, and new pesticide-controlled release technologies did not have significant effects on the income level of large-scale farmers, due to their low application and penetration rate. Based on the findings of the paper, the government should strengthen the promotion and subsidies of agricultural low-carbon technologies, especially those technologies that have no significant impact on large-scale farmers\' income, such as biodegradable agricultural membranes, biopesticides, and new pesticide controlled-release technologies, so as to achieve a win-win situation of reducing carbon emissions and increasing farmers\' income.
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  • 文章类型: Journal Article
    尖孢镰刀菌f.sp.cubense(Foc)热带种族4(TR4)由于其传播的增加而威胁着香蕉的生产。生物控制方法已得到广泛研究,并构成了综合疾病管理策略的有趣补充措施。它们主要基于单一生物防治剂(BCA)的使用。在这项研究中,我们通过设计合成微生物群落(SynCom)来控制香蕉枯萎病(FWB)向前迈出了一步。假单胞菌属的96个分离株。,芽孢杆菌。,链霉菌属。,和木霉属。从香蕉根际获得,并在体外选择对FocTR4的拮抗作用。在盆栽实验中,SynCom1.0(44个具有中等至高拮抗活性的分离株)等大型群体或SynCom1.1(7个高效分离株)等小型群体提供了相似的疾病控制(症状严重程度降低35%).对SynCom1.1分离株之间以及它们与Foc之间的相互作用的体外研究表明,有益微生物不仅拮抗病原体,而且还拮抗某些SynCom成分。此外,Foc通过对抗有益的微生物来捍卫自己。我们还证明了,镰刀酸,镰刀菌属的次生代谢产物之一,可能参与了这样的互动。有了这些知识,然后用三种分离物设计了SynCom1.2:绿鱼假单胞菌亚种。pisciumPS5、BBN8.2和绿木霉T2C1.4。这些分离物的非同时土壤施用(以减少交叉抑制)会随着时间的推移延迟FWB进展,发病率和严重程度显着降低。SynCom1.2的表现也优于两个商业BCA,BioPak®和T-Gro。最终,对SynCom1.2分离株的几种生物控制性状进行了表征,并对其基因组进行了测序。我们的数据表明,组装用于生物防治的SynCom并非易事。仅仅是拮抗剂的混合物(例如,SynCom1.0和1.1)可能提供有效的生物控制,但需要对有益微生物之间的相互作用进行准确的调查以改善结果(例如,SynCom1.2)。SynCom1.2是进一步开发用于FWB生物控制的有价值的工具。
    Fusarium oxysporum f. sp. cubense (Foc) tropical race 4 (TR4) is threatening banana production because of its increasing spread. Biological control approaches have been widely studied and constitute interesting complementary measures to integrated disease management strategies. They have been based mainly on the use of single biological control agents (BCAs). In this study, we moved a step forward by designing a synthetic microbial community (SynCom) for the control of Fusarium wilt of banana (FWB). Ninety-six isolates of Pseudomonas spp., Bacillus spp., Streptomyces spp., and Trichoderma spp. were obtained from the banana rhizosphere and selected in vitro for the antagonism against Foc TR4. In pot experiments, a large community such as SynCom 1.0 (44 isolates with moderate to high antagonistic activity) or a small one such as SynCom 1.1 (seven highly effective isolates) provided similar disease control (35% symptom severity reduction). An in vitro study of the interactions among SynCom 1.1 isolates and between them and Foc revealed that beneficial microorganisms not only antagonized the pathogen but also some of the SynCom constituents. Furthermore, Foc defended itself by antagonizing the beneficial microbes. We also demonstrated that fusaric acid, known as one of the secondary metabolites of Fusarium species, might be involved in such an interaction. With this knowledge, SynCom 1.2 was then designed with three isolates: Pseudomonas chlororaphis subsp. piscium PS5, Bacillus velezensis BN8.2, and Trichoderma virens T2C1.4. A non-simultaneous soil application of these isolates (to diminish cross-inhibition) delayed FWB progress over time, with significant reductions in incidence and severity. SynCom 1.2 also performed better than two commercial BCAs, BioPak® and T-Gro. Eventually, SynCom 1.2 isolates were characterized for several biocontrol traits and their genome was sequenced. Our data showed that assembling a SynCom for biocontrol is not an easy task. The mere mixtures of antagonists (e.g., SynCom 1.0 and 1.1) might provide effective biocontrol, but an accurate investigation of the interactions among beneficial microorganisms is needed to improve the results (e.g., SynCom 1.2). SynCom 1.2 is a valuable tool to be further developed for the biological control of FWB.
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  • 文章类型: Journal Article
    食品工业仍在寻找新的解决方案,以有效确保食品的微生物安全,特别是新鲜和最低限度加工的食品。如今,在微生物食品安全和保存中使用噬菌体作为潜在的生物防治剂是一个有前途的策略。该研究的目的是分离和全面表征新型噬菌体,该噬菌体具有针对最低限度加工的植物食品的腐生细菌菌群的裂解活性,如混合叶沙拉。从城市污水中分离出的43只噬菌体,四个噬菌体,即肠杆菌噬菌体KKP3263,柠檬酸杆菌噬菌体KKP3664,肠杆菌噬菌体KKP3262和沙雷氏菌噬菌体KKP3264对路德维吉肠杆菌KKP3083,弗氏柠檬酸杆菌KKP3655,阴沟肠杆菌KKP3082和沙雷氏菌KKP3084菌株具有裂解活性,分别。透射电子显微镜(TEM)和全基因组测序(WGS)将肠杆菌噬菌体KKP3263鉴定为自拟病毒科,和柠檬酸杆菌噬菌体KKP3664,肠杆菌噬菌体KKP3262和沙雷氏菌噬菌体KKP3264作为Myoviridae家族的成员。基因组测序显示,这些噬菌体具有线性双链DNA(dsDNA),大小为39,418bp(KKP3263),61,608bp(KKP3664),84,075bp(KKP3262),和148,182bp(KKP3264)。没有抗生素抗性基因,毒力因子,整合酶,重组酶,或阻遏物,它们是溶源病毒的主要标记,在噬菌体基因组中进行了注释。沙雷氏菌噬菌体KKP3264对鸡沙雷氏菌KKP3084菌株的生长抑制最大。使用MOI1.0导致特定增长率系数的值降低了近5倍。噬菌体在宽范围的温度(-20°C至50°C)和活性酸度值(pH从4至11)中保持其裂解活性。所有噬菌体在60°C下保留至少70%的裂解活性在80°C时,未观察到针对测试细菌菌株的裂解活性。沙雷氏菌噬菌体KKP3264对化学因子的抗性最强,通过在3至11的更宽pH范围内保持高裂解活性。结果表明,这些噬菌体可能是针对最低限度加工的植物性食品的腐生细菌菌群的潜在生物防治剂。
    The food industry is still searching for novel solutions to effectively ensure the microbiological safety of food, especially fresh and minimally processed food products. Nowadays, the use of bacteriophages as potential biological control agents in microbiological food safety and preservation is a promising strategy. The aim of the study was the isolation and comprehensive characterization of novel bacteriophages with lytic activity against saprophytic bacterial microflora of minimally processed plant-based food products, such as mixed leaf salads. From 43 phages isolated from municipal sewage, four phages, namely Enterobacter phage KKP 3263, Citrobacter phage KKP 3664, Enterobacter phage KKP 3262, and Serratia phage KKP 3264 have lytic activity against Enterobacter ludwigii KKP 3083, Citrobacter freundii KKP 3655, Enterobacter cloacae KKP 3082, and Serratia fonticola KKP 3084 bacterial strains, respectively. Transmission electron microscopy (TEM) and whole-genome sequencing (WGS) identified Enterobacter phage KKP 3263 as an Autographiviridae, and Citrobacter phage KKP 3664, Enterobacter phage KKP 3262, and Serratia phage KKP 3264 as members of the Myoviridae family. Genome sequencing revealed that these phages have linear double-stranded DNA (dsDNA) with sizes of 39,418 bp (KKP 3263), 61,608 bp (KKP 3664), 84,075 bp (KKP 3262), and 148,182 bp (KKP 3264). No antibiotic resistance genes, virulence factors, integrase, recombinase, or repressors, which are the main markers of lysogenic viruses, were annotated in phage genomes. Serratia phage KKP 3264 showed the greatest growth inhibition of Serratia fonticola KKP 3084 strain. The use of MOI 1.0 caused an almost 5-fold decrease in the value of the specific growth rate coefficient. The phages retained their lytic activity in a wide range of temperatures (from -20 °C to 50 °C) and active acidity values (pH from 4 to 11). All phages retained at least 70% of lytic activity at 60 °C. At 80 °C, no lytic activity against tested bacterial strains was observed. Serratia phage KKP 3264 was the most resistant to chemical factors, by maintaining high lytic activity across a broader range of pH from 3 to 11. The results indicated that these phages could be a potential biological control agent against saprophytic bacterial microflora of minimally processed plant-based food products.
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  • 文章类型: Journal Article
    挥发性有机化合物(VOCs)在生物体间的交流中起着重要作用,包括植物,有益或致病微生物,和害虫。体外,我们观察到,测试的八种担子菌中的七种的生长被生物防治剂假单胞菌蛋白菌株CHA0的VOC抑制。在子囊门中,只有一些物种是敏感的(例如,菌核病,灰葡萄孢菌,等。),但其他人具有抗性(例如,尖孢镰刀菌f.sp.立方体,大丽花黄萎病菌,等。).我们进一步发现,CHA0以及其他十种有益的或植物病原性的细菌菌株都能够抑制异位菌。在这项研究中被用作模型物种。此外,只有当细菌在含有蛋白胨或胰蛋白胨等消化蛋白的培养基上生长时,这种抑制作用才会发生(例如,Luria-Bertani琼脂或LBA)。此外,抑制与真菌生长的琼脂培养基的pH增加同时发生。因此,据推测,源自细菌降解蛋白质的生物氨在真菌抑制中起主要作用。的确,当作为合成化合物测试时,它对H.abietinum具有高度毒性(有效浓度50%或EC50=1.18M;最低抑制浓度或MIC=2.14M)。使用气相色谱与质谱联用(GC/MS),与在马铃薯葡萄糖琼脂(PDA)上生长的细菌相比,在LBA上生长的CHA0发现了8种VOC。其中,两种化合物对H.abietinum的毒性甚至比氨更大:二甲基三硫的EC50=0.02M和MIC=0.2M,和2-乙基己醇的EC50=0.33M和MIC=0.77M。真菌生长抑制是菌丝的严重细胞和亚细胞改变的结果,早在暴露于VOC15分钟时就发生了,透射和扫描电子显微镜观察证明。CHA0的VOCs诱导的阿比菌的转录组重编程指出,当细胞试图通过激活防御机制进行反应时,对核糖体和蛋白质合成产生不利影响。这需要从成长和发展中转移大量的能量(健身成本)。
    Volatile organic compounds (VOCs) play an important role in the communication among organisms, including plants, beneficial or pathogenic microbes, and pests. In vitro, we observed that the growth of seven out of eight Basidiomycete species tested was inhibited by the VOCs of the biocontrol agent Pseudomonas protegens strain CHA0. In the Ascomycota phylum, only some species were sensitive (e.g., Sclerotinia sclerotiorum, Botrytis cinerea, etc.) but others were resistant (e.g., Fusarium oxysporum f. sp. cubense, Verticillium dahliae, etc.). We further discovered that CHA0 as well as other ten beneficial or phytopathogenic bacterial strains were all able to inhibit Heterobasidion abietinum, which was used in this research as a model species. Moreover, such an inhibition occurred only when bacteria grew on media containing digested proteins like peptone or tryptone (e.g., Luria-Bertani agar or LBA). Also, the inhibition co-occurred with a pH increase of the agar medium where the fungus grew. Therefore, biogenic ammonia originating from protein degradation by bacteria was hypothesized to play a major role in fungus inhibition. Indeed, when tested as a synthetic compound, it was highly toxic to H. abietinum (effective concentration 50% or EC50 = 1.18 M; minimum inhibitory concentration or MIC = 2.14 M). Using gas chromatography coupled to mass spectrometry (GC/MS), eight VOCs were found specifically emitted by CHA0 grown on LBA compared to the bacterium grown on potato dextrose agar (PDA). Among them, two compounds were even more toxic than ammonia against H. abietinum: dimethyl trisulfide had EC50 = 0.02 M and MIC = 0.2 M, and 2-ethylhexanol had EC50 = 0.33 M and MIC = 0.77 M. The fungus growth inhibition was the result of severe cellular and sub-cellular alterations of hyphae occurring as early as 15 min of exposure to VOCs, as evidenced by transmission and scanning electron microscopy observations. Transcriptome reprogramming of H. abietinum induced by CHA0\'s VOCs pointed out that detrimental effects occurred on ribosomes and protein synthesis while the cells tried to react by activating defense mechanisms, which required a lot of energy diverted from the growth and development (fitness cost).
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  • 文章类型: Journal Article
    生物农药替代化学农药对于确保农产品质量和促进环境可持续性至关重要。本研究以稻农生物农药使用意愿和行为为研究对象。基于理性小农理论,从“农民个体和家庭特征”三个方面设计了调查问卷,“农民认知”和“外部因素”。然后对中国吉林省七个地级市的163名稻农进行了调查。采用logistic模型分析导致稻农生物农药施用行为偏离初始意愿的影响因素。利用解释结构模型(ISM)分析各影响因素之间的逻辑层次关系。结果表明:(1)45%的农户被调查,他们对生物农药施用的意愿和行为之间存在偏差;(2)在导致农民对生物农药施用的意愿和行为之间存在偏差的重要因素中,表面层面的直接因素是生物农药意识。中间层次的间接因素是农产品质量安全意识,深层次的根源是农民受教育程度。(3)农民行为偏离其意愿的主要原因是他们对生物农药的知识缺乏和生物农药的不完整市场结构。在综合分析的基础上,建议提高农民的职业化水平,加强绿色生产宣传,加快生物农药市场的制定,进一步促进生物农药的使用。
    The substitution of chemical pesticides by biopesticides is crucial to ensure the quality of agricultural products and to foster environmental sustainability. This study takes the willingness and the behaviors of rice farmers on the application of biopesticides as the research object. The survey questionnaire was designed based on the theory of rational small-scale farmers from three aspects: \"individual and family characteristics of farmers\", \"cognition of farmers\" and \"external factors\". The survey was then conducted on 163 rice farmers in seven prefecture-level cities in Jilin Province of China. The logistic model was used to analyze the influencing factors resulting in the deviation of the behaviors of the rice farmers from their initial willingness on the application of biopesticides. The explanatory structure model (ISM) was used to analyze the logical hierarchical relationship among various influencing factors. The results show that: (1) For 45% of the farmers surveyed, there\'s a deviation between their willingness and behaviors regarding the application of biopesticides; (2) Among the significant factors leading to the deviation between farmers\' willingness and behaviors concerning the application of biopesticides, the surface-level direct factor is biopesticide awareness. The mid-level indirect factors are agricultural product quality and safety awareness and the deep-level root cause is farmers\' education level. (3) The primary reason for the deviation of the farmers\' behaviors from their willingness is their lack of knowledge about biopesticides and the biopesticides\' incomplete market structure. Based on the comprehensive analysis, it is recommended to improve the professionalization of the farmers, to strengthen the publicity of green production and to accelerate the formulation of the biopesticides market to further promote the usage of biopesticides.
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  • 文章类型: Journal Article
    美国中西部可持续农业经常使用半自然田间边界。这些栖息地旨在帮助多样化其他单一文化景观,并为它们提供生态系统服务,包括生物控制。捕食性和寄生性节肢动物(即,潜在的天敌)通常在这些栖息地中蓬勃发展,并可能进入农作物以帮助控制害虫。然而,关于半自然田间边界为这些节肢动物提供越冬避难所的能力的详细信息知之甚少。在这项研究中,我们使用土壤出苗帐篷来表征潜在的天敌群落(即,捕食的甲虫,黄蜂,蜘蛛,和其他节肢动物)在栽培的有机作物田地和相邻的田地边界越冬。我们发现了更丰富的资源,物种丰富度,和独特的群落组成的掠夺性和寄生节肢动物在田间边界与耕地相比,通常不适合作为越冬栖息地。此外,潜在的天敌倾向于与forb覆盖呈正相关,与草覆盖呈负相关,这表明草丛覆盖较少的草地边界不太适合作为冬季避难所。这些结果表明,像田野边界这样的半自然栖息地可能每年都是许多天敌的来源,对于保护农业景观中的节肢动物多样性至关重要。
    Semi-natural field borders are frequently used in midwestern U.S. sustainable agriculture. These habitats are meant to help diversify otherwise monocultural landscapes and provision them with ecosystem services, including biological control. Predatory and parasitic arthropods (i.e., potential natural enemies) often flourish in these habitats and may move into crops to help control pests. However, detailed information on the capacity of semi-natural field borders for providing overwintering refuge for these arthropods is poorly understood. In this study, we used soil emergence tents to characterize potential natural enemy communities (i.e., predacious beetles, wasps, spiders, and other arthropods) overwintering in cultivated organic crop fields and adjacent field borders. We found a greater abundance, species richness, and unique community composition of predatory and parasitic arthropods in field borders compared to arable crop fields, which were generally poorly suited as overwintering habitat. Furthermore, potential natural enemies tended to be positively associated with forb cover and negatively associated with grass cover, suggesting that grassy field borders with less forb cover are less well-suited as winter refugia. These results demonstrate that semi-natural habitats like field borders may act as a source for many natural enemies on a year-to-year basis and are important for conserving arthropod diversity in agricultural landscapes.
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