根际微生态调控白菜根肿病发生的机制研究进展

白菜根肿病是由芸薹根肿菌(Plasmodiophora brassicae Woron)引起的一种常见土传病害,主要危害白菜的根部。根际是土壤-植物-微生物相互作用最活跃的关键微域,根际微生态系统中的微生物失衡是导致土传病害的重要因素,深入探究根际微生态与土传病害互作机制,有利于从根际微生物、抑病物质和功能代谢等方面挖掘防控土传病害安全高效的方法。本文综述了根际微生态与白菜根肿病的发生机制关系,从该病害的危害、发生的根际微生态机制及生防菌防治研究等方面综合分析了根际微生物调控白菜根肿病发生的机制,以期为白菜根肿病防控、促进土壤健康和维持根际微生态系统稳定提供理论依据。     

烟草青枯病的病原特性及流行预警

烟草青枯病是当前烟草生产中发生面积大、危害严重、防控困难的土传病害,也是烟草病虫害绿色防控最为关键的流行性病害.作为一种典型的维管束细菌性病害,植株感病属于系统性侵染,条件合适时会突然暴发危害,因此,监测预警十分重要.本文总结了烟草青枯病病原特性、发病症状及病害侵染循环的特点,介绍了影响青枯病发生的关键因子,提出了青枯病的调查与监测预警方法,旨在为烟草青枯病的基础理论研究及有效推进绿色防控提供有力支撑.     

植原体黄化病的检疫及其防控技术研究进展

植物黄化病是一种常见的而且危害严重的病害.近年来,外来有害生物的入侵给我国造成了巨额经济损失,并且对我国农林业生产安全和生态环境造成了严重的威胁,对植物检疫工作提出了新挑战.对几种由植原体引起的植物黄化病的症状、病原分类及其检疫技术和综合防控措施进行综述.     

根际真菌对黄瓜土传病害的抑制作用

为了了解根际真菌对黄瓜土传病害的影响,通过平板对峙试验和温室人工接种盆栽试验,对分离自根际土的16株真菌开展了对土传病原真菌的拮抗作用和黄瓜土传病害的抑制作用研究.结果表明: 有4株真菌对一种或多种供试病原真菌表现有拮抗作用,其中经鉴定为土曲霉的菌株JCL143对黄瓜枯萎病菌、立枯病菌和菌核病菌3种供试病原真菌均有较强的拮抗作用.在温室盆栽试验中,接种菌株JCL143对黄瓜3种病害的相对防效均在74%以上;而在不灭菌育苗基质的盆栽试验中,接种菌株JCL143对立枯病和菌核病的防效均在85%以上.在用自然土进行的温室盆栽试验中,接种菌株JCL143对伸蔓期黄瓜枯萎病的相对防效平均达84.1%.菌株JCL143的发酵液对3种供试病原真菌菌落生长都有不同程度的抑制作用,对菌核病菌的菌落生长抑菌率达63.3%.发酵液的抑菌活性随处理温度的升高而下降,对碱性pH值比酸性pH值敏感,而对蛋白酶处理不敏感.说明土曲霉是土壤中抑制植物土传病害的重要因素,菌株JCL143的抑病效果稳定,具有潜在的生防应用价值.     

小麦黄花叶病毒和小麦梭条斑花叶病毒的生物学和分子生物学研究

线状土传小麦花叶病毒病在欧洲、亚洲和北美洲等地均有发生。这类病毒由根肿菌纲的禾谷多粘菌(Ｐｏｌｙｍｙｘａｇｒａｍｉｎｉｓ)传播,并归类于马铃薯Ｙ病毒科(Ｐｏｔｙｖｉｒｉｄａｅ)的大麦黄花叶病毒属(Ｂｙｍｏｖｉｒｕｓ)。日本的Ｓａｗａｄａ(1927)[1]首次发现并描述小麦花叶病害,随后的研究表明病原是土传的。Ｉｎｏｕｙｅ(1969)[2]证明该病害的病原是小麦黄花叶病毒(ｗｈｅａｔｙｅｌｌｏｗｍｏｓａｉｃｖｉｒｕｓ,ＷＹＭＶ)。Ｓｌｙｋｈｕｉｓ(1960)[3]首次在加拿大安大略省的冬小麦上发现并描述小麦梭条斑花叶病害。Ｓｌｙｋｈｕ…     

丛枝菌根真菌对植物根腐病的抑制效应及其机制

根腐病是一类危害严重的土传病害,常常导致作物产量和品质降低。丛枝菌根(AM)真菌是一类重要的土壤微生物,通过与植物根系建立共生体而发挥重要的生理生态功能。研究表明,AM真菌通过调节宿主植物一系列生理生化响应,诱导植物增强根腐病抗性。当前,利用AM真菌开展根腐病等土传病害的生物防治是植物与微生物互作领域的研究热点。本文全面梳理了AM真菌对宿主植物根腐病病原物的抑制效应,系统总结了AM真菌改变宿主植物根系形态结构、改善植物营养水平、与病原物竞争生态位点、激活植物防御体系、调节根系分泌物等方面的研究结果,分析了AM真菌抑制根腐病危害的作用机制,展望了AM真菌抑制根腐病危害的潜在机制和AM真菌高效利用面临的现实问题,旨在为利用AM真菌开展植物根腐病的生物防治提供理论依据。     

马尾松苗叶枯病与防治

松苗叶枯病是危害马尾松苗木和幼树的主要叶部病害,对苗期和幼林生长影响较大。由于回归种植松树对苗木的需求,当前在苗圃生长过程中出现的叶枯病比较普遍。本文观察该病害的为害情况、症状、病原、发生情况、防治方法,与相似的病虫害区别等进行探讨,以培育健康苗木供造林需要。     

西瓜枯萎病及抗性育种研究进展

西瓜枯萎病是一种毁灭性的土传真菌病害,给西瓜生产造成了严重的经济损失,选育抗性新品种是防治西瓜枯萎病的一种有效手段.主要对西瓜枯萎病的症状、病原、侵染途径、抗性机制及抗性育种等方面进行了综述,并对西瓜枯萎病及抗性育种研究进行展望.     

红托鬼笔黄水病病原鬼笔复膜孢酵母侵染过程的组织学观察

红托鬼笔黄水病是一种由鬼笔复膜孢酵母引起的致灾性土传病害,极难防治。本研究通过探索获得高质量红托鬼笔组织石蜡切片技术的基础上,对幼担子果生长期病原接种后第8、16、24、32、40、48和72 h进行组织取样,利用Van-clear透明剂制备石蜡切片,观察病原的侵染过程,以健康的幼担子果做对照。结果表明：健康的红托鬼笔包被表面菌丝呈管状,与包被中部菌丝结构无明显差异。而接种病原后第8 h时,即可观察到病原细胞和假丝形成,包被表面菌丝萎缩、褐变,病原细胞通过菌丝间隙向内扩散和侵染,侵染速度18.14 μm/h。接种后32 h包被表面菌丝大量降解,主要是病原细胞和假丝存在,此时病原可以侵染至包被中部菌丝组织。接种后40 h幼担子果表面分泌黄色渗出物液滴,包被表面开始溃烂,病原侵染至幼担子果包被胶质层,并不断向内侵染。本研究采用石蜡切片法对黄水病病原的侵染过程进行了组织学观察,为其致病机制和病害综合防治研究提供借鉴。     

土传真菌病害拮抗菌的筛选及其生防效果研究

为了获得对主要粮食作物水稻、小麦和经济作物大豆常见土传病害具有防治效果的生防菌,本研究从土壤中筛选到一株对所选6种病原真菌均有较好拮抗效果的菌株。基于形态学、生理生化特性及16S rDNA序列分析进行菌种鉴定,利用菌丝生长速率法对其无菌滤液和挥发性气体的抑菌效果进行验证,同时研究了其无菌滤液的热稳定性、酸碱稳定性和对蛋白酶K的稳定性。结果表明:本研究筛选到一株贝莱斯芽孢杆菌Bacillus velezensis CX-2,其无菌滤液对6种病原真菌的抑菌率在71%~95%之间,对小麦纹枯病菌、小麦全蚀病菌的抑菌率分别高达90.13%、94.34%;挥发性气体对6种病原菌的抑菌率在45%~80%之间;无菌滤液中的抗菌活性物质具有较强的热稳定性和对蛋白酶K的稳定性;无菌滤液pH在5~9之间时具有稳定的抑菌活性。该菌株可作为作物土传真菌病害生防菌剂较为理想的功能菌株。     

Design and development of a DNA array for rapid detection and identification of multiple tomato vascular wilt pathogens

Fusarium wilt, caused by Fusarium oxysporum f. sp. lycopersici, and Verticillium wilt, caused by either Verticillium albo-atrum or Verticillium dahliae, are devastating diseases of tomato (Lycopersicon esculentum) found worldwide. Monitoring is the cornerstone of integrated pest management of any disease. The lack of rapid, accurate, and reliable means by which plant pathogens can be detected and identified is one of the main limitations in integrated disease management. In this paper, we describe the development of a molecular detection system, based on DNA array technology, for rapid and efficient detection of these vascular wilt pathogens. We show the utility of this array for the sensitive detection of these pathogens from complex substrates like soil, plant tissues and irrigation water, and samples that are collected by tomato growers in their greenhouses.     

Managing soilborne diseases of vegetable crops with a pre-plant soil or substrate amendment of a corn distillation product

The efficacy of condensed distiller's solubles (CDS), a co-product of ethanol production from corn, rich in organic matter, and high in carbon to nitrogen ratio, was tested as a pre-plant amendment against Verticillium wilt of eggplant and potato scab in potato soils from commercial fields and against damping-off diseases of radish and cucumber seedlings in a peat-based mix and muck soil. Eggplants grown in a potato soil amended with CDS (1% mass/mass) showed less Verticillium wilt and increased fresh (37-54%) and dry (31-45%) plant biomass compared to the control in the greenhouse. In a potato soil with medium levels of disease, CDS (1 or 2%) increased the percentage of marketable tubers by 116% under greenhouse, 119% under micro-plot and 75% under field conditions. In the growth room, CDS (1, 2, and 4%) amendment to a peat-based mix infested with Rhizoctonia solani 1 week before planting seeds improved the percentage of healthy radish seedlings (22-72% healthy seedlings compared to 2% in the control). Levels of disease suppression increased with the incubation time prior to planting. Disease control effect of CDS was not consistent between different batches of peat-based mix. In a non-suppressive batch of peat-based mix, disease suppression by CDS was enhanced by a bio-control agent, Trichoderma hamatum 382. In muck soil from a commercial field naturally-infested with Pythium spp., CDS (0.25, 0.5, and 1%) provided protection of cucumber seedlings from damping-off immediately after incorporation, but the maximum protection was seen after 1 week with all three rates. The number of total bacteria was enhanced in the CDS-amended muck soil. In the micro-plots, CDS (0.5 and 1%) as an amendment to muck soil 2 weeks before planting improved the percentage of healthy cucumber seedlings and fresh plant weight compared to the control. CDS is not toxic to the pathogens and disease suppression is believed to be due to biological activity stimulated by CDS in the substrate.     

Overexpression of potato miR482e enhanced plant sensitivity to Verticillium dahliae infection

Verticillium wilt of potato is caused by the fungus pathogen Verticillium dahliae. Present sRNA sequencing data revealed that miR482 was in response to V. dahliae infection, but the function in potato is elusive. Here, we characterized potato miR482 family and its putative role resistance to Verticillium wilt. Members of the potato miR482 superfamily are variable in sequence, but all variants target a class of disease‐resistance proteins with nucleotide binding site (NBS) and leucine‐rich repeat (LRR) motifs. When potato plantlets were infected with V. dahliae, the expression level of miR482e was downregulated, and that of several NBS‐LRR targets of miR482e were upregulated. Transgenic potato plantlets overexpressing miR482e showed hypersensitivity to V. dahliae infection. Using sRNA and degradome datasets, we validated that miR482e targets mRNAs of NBS‐LRR disease‐resistance proteins and triggers the production of trans‐acting (ta)‐siRNAs, most of which target mRNAs of defense‐related proteins. Thus, the hypersensitivity of transgenic potato could be explained by enhanced miR482e and miR482e‐derived ta‐siRNA‐mediated silencing on NBS‐LRR‐disease‐resistance proteins. It is speculated that a miR482‐mediated silencing cascade mechanism is involved in regulating potato resistance against V. dahliae infection and could be a counter defense action of plant in response to pathogen infection.     

Verticillium wilt of olive: a case study to implement an integrated strategy to control a soil-borne pathogen

Olive (Olea europaea L.) is one of the first domesticated and cultivated tree species and has historical, social and economical relevance. However, its future as a strategic commodity in Mediterranean agriculture is threatened by diverse biotic (traditional and new/emerging pests and diseases) and abiotic (erosion, climate change) menaces. These problems could also be of relevance for new geographical areas where olive cultivation is not traditional but is increasingly spreading (i.e., South America, Australia, etc). One of the major constraints for olive cultivation is Verticillium wilt, a vascular disease caused by the soil-borne fungus Verticillium dahliae Kleb. In this review we describe how Verticillium wilt of olive (VWO) has become a major problem for olive cultivation during the last two decades. Similar to other vascular diseases, VWO is difficult to manage and single control measure are mostly ineffective. Therefore, an integrated disease management strategy that fits modern sustainable agriculture criteria must be implemented. Multidisciplinary research efforts and advances to understand this pathosystem and to develop appropriate control measures are summarized. The main conclusion is that a holistic approach is the best strategy to effectively control VWO, integrating biological, chemical, physical, and cultural approaches.     

The Arabidopsis thaliana DNA-binding protein AHL19 mediates verticillium wilt resistance

Verticillium spp. are destructive soilborne fungal pathogens that cause vascular wilt diseases in a wide range of plant species. Verticillium wilts are particularly notorious, and genetic resistance in crop plants is the most favorable means of disease control. In a gain-of-function screen using an activation-tagged Arabidopsis mutant collection, we identified four mutants, A1 to A4, which displayed enhanced resistance toward the vascular wilt species Verticillium dahliae, V. albo-atrum and V. longisporum but not to Fusarium oxysporum f. sp. raphani. Further testing revealed that mutant A2 displayed enhanced Ralstonia solanacearum resistance, while mutants A1 and A3 were more susceptible toward Pseudomonas syringae pv. tomato. Identification of the activation tag insertion site in the A1 mutant revealed an insertion in close proximity to the gene encoding AHL19, which was constitutively expressed in the mutant. AHL19 knock-out alleles were found to display enhanced Verticillium susceptibility whereas overexpression of AHL19 resulted in enhanced Verticillium resistance, showing that AHL19 acts as a positive regulator of plant defense.     

松褐天牛天敌微生物的研究进展

系统总结了国内外在松褐天牛MonochamusalternatusHope天敌微生物方面的研究进展。概述了松褐天牛天敌微生物的种类组成、致病力、应用技术、控制作用和应用前景 ,并简要分析了松褐天牛的危害性和防治现状。天敌微生物特别是病原真菌在松褐天牛的综合治理中有着广阔的应用前景。     

棉花黄萎病及其抗病育种的研究

就棉花黄萎病菌的致病机理、棉花的抗黄萎病机制、抗黄萎病的遗传方式以及抗黄萎病棉花育种等方面的研究进行了综述。     

陆地棉品种和骨干品系黄萎病抗性鉴定

选育和推广抗病品种是防治陆地棉黄萎病的主要措施,为了早日实现多类型、多区域大面积抗病品种的应用,本研究选取107份遗传背景差异较大的种质,利用河北省农林科学院棉花研究所小安舍试验站黄萎病病圃进行了3年黄萎病抗性重复鉴定。鉴定得到抗病品系8个,占7.5%;耐病品种(系)20个,占18.7%。本研究表明,当前被作为育种亲本的抗病品系还太少,需要深入开展抗病遗传机制,以及与其他经济性状协同改良的关系,为陆地棉抗病育种提供理论指导;达到抗病或接近抗病水平的大部分品种(系)来自于海陆野远缘后代,具有外源基因血统,证明了远缘杂交是陆地棉黄萎病抗性改良的有效手段。