丛枝菌根真菌与深色有隔内生真菌对姜瘟病的防效及抗病机理初探

【背景】青枯劳尔氏菌(Ralstonia solanacearum,R.S)引发的姜瘟病是生姜产业发展的瓶颈问题。丛枝菌根真菌(arbuscular mycorrhiza fungi, AMF)与深色有隔内生真菌(dark septate endophytes,DSE)是两类重要的共生微生物。【目的】前期研究发现,AMF与DSE可提高生姜对姜瘟病的抗性,但其抗病机制尚不清楚,极大地限制了利用这两类共生真菌对该病的防治。【方法】在温室条件下做盆栽试验,以生姜组培苗为材料,设立接种AMF、DSE和不接种AMF、DSE的对照(CK)处理,并在上述处理下的植物生长4周后淋入病原菌液,病原菌接种1周后,通过测定菌根侵染率、发病率、叶绿素含量、光合指标、磷(P)含量、防御性酶活性及丙二醛(malondialdehyde, MDA)含量,研究AMF和DSE互作对病原菌侵染后生姜生长和生理生化指标的影响。【结果】AMF和DSE分别使姜瘟病发病率降低了45.27%和52.04%(P<0.05)。AMF+DSE组合处理抑病效果更好,发病率较对照降低60.87%(P<0.05)。AMF、DSE及...     

内生真菌与宿主植物协同调控砷胁迫作用机制研究进展

丛枝菌根真菌(arbuscular mycorrhizal fungi,AMF)和深色有隔内生真菌(dark septate endophytes, DSE)是植物根系中最主要的两大类内生真菌,均可与植物根系形成菌根共生体,在促进植物生长,提高重金属等胁迫抗性方面发挥着重要作用。砷(arsenic, As)及砷化合物具有较强的毒性,可在植物中富集,造成生物链毒害。本团队一直致力于内生真菌与药用植物生长、活性物质合成,砷吸收、积累关系的研究,并取得了一定的进展。结合团队现有研究和前人研究成果,本文分析归纳了砷胁迫条件下,AMF定殖对宿主植物生长和砷吸收、积累的影响;详细阐述了砷胁迫条件下,宿主植物生理活动、抗氧化系统、激素水平、转录水平响应AMF调控的变化。其后,从宿主植物细胞内、外两个方面总结内生真菌与宿主植物协同调控砷胁迫的作用机制,归纳为“生长稀释效应”“菌丝隔离”“螯合过滤”“菌根固定化(mycorrhizal immobilization)”“转运体抑制效应”“生物转化作用”和“保宿主、降氧化”等7项作用机制,并绘制了不同机制之间的作用关系图。DSE-宿主植物调控砷胁迫的研究相...     

荒漠北沙柳根系丛枝菌根真菌和黑隔内生真菌定殖状况

为利用土壤共生真菌资源促进荒漠植被恢复和生态重建, 分别于2013年6月、8月和10月, 从内蒙古元上都地区采集北沙柳(Salix psammophila)根围0-10、10-20、20-30、30-40和40-50 cm共5个土层的土壤样品, 系统研究了丛枝菌根真菌(AMF)和黑隔内生真菌(DSE)的时空分布及其与土壤因子的相关性。结果表明: AMF和DSE的平均定殖率分别为77%和84%, 说明北沙柳根系能与这两类真菌形成良好的共生关系。AMF和DSE的分布和定殖具有明显的时空异质性, 并与土壤因子密切相关。AMF和DSE的平均定殖率均表现为10月> 8月> 6月。土壤深度对AMF和DSE的定殖率有显著影响, AMF和DSE定殖率的最大值分别在0-20 cm和0-10 cm土层。双因子方差分析表明, 月份和土层对AMF和DSE的定殖率以及土壤因子具有显著的交互效应。主成分分析表明, 土壤湿度、pH值、碱性磷酸酶、易提取球囊霉素是内蒙古荒漠环境中AMF和DSE定殖的主要影响因子。     

海南霸王岭热带雨林常见植物丛枝菌根真菌调查

对海南霸王岭热带雨林的12科16种常见植物的丛枝菌根状况进行了调查,用碱解离-酸性品红染色法进行了真菌鉴定。结果表明,13种植物形成典型的丛枝菌根,占所调查植物的81%;3种植物没有形成丛枝菌根,占所调查植物的19%。用湿筛沉淀法从这些植物根际土壤中共分离鉴定出了3属11种丛枝菌根真菌(AMF),即无梗囊霉属(Acaulos-pora)3种,球囊霉属(Glomus)7种,巨孢囊霉属(Gigaspora)1种;其中,球囊霉属是样地的优势属。在AMF中,孔窝无梗囊霉(A.foveata)分离频率最高,在14种植物的根际土中都有发现;此外,大果球囊霉(G.macrocarpum)的相对多度最大,为59%,具有最强的产孢能力。同时,在11种植物的根中发现了深色有隔内生真菌(DSE),占调查植物的69%;其中,11种植物同时被DSE和AMF感染。     

不同程度铅锌污染区丛枝菌根真菌和深色有隔内生真菌侵染特征

对陕西凤县铅硐山铅锌矿区4个不同程度铅锌污染样地植物根系的丛枝菌根真菌(AMF)和深色有隔内生真菌(DSE)进行了资源和分布调查。结果表明:(1)无铅锌污染的矿山上调查的15种植物中除黄连木没有检测到AMF侵染、栓皮栎和酸模不能被DSE侵染外,其他植物均能与AMF和DSE共生,但平均侵染率较低,仅分别为32.3%和25.9%;铅锌轻度污染的尾矿荒地和铅中度污染、锌重度污染的尾矿坝植物根系内AMF和DSE侵染率明显提高,AMF的平均侵染率分别为53.3%和68.3%,DSE的平均侵染率分别为38.6%和54.2%;铅锌重度污染的废弃冶炼厂样地植物AMF侵染率明显下降,平均只有17.6%,而DSE的侵染没有受重金属污染的抑制,仍达到60.3%。(2)4个样地植物根际土壤中AMF孢子分布不均匀,每克土的孢子密度在0.08～6.84个,平均为1.5个。对4个样地均有分布的狼牙刺、博落回、山蒿和秦岭风毛菊的AMF、DSE侵染状况调查发现,轻度和中度的铅锌污染能促进AMF与宿主共生关系的建立,而重度污染则显著抑制AMF侵染;AMF孢子密度没有呈现一定的规律性,且与AMF侵染率之间没有显著相关性;DSE侵染率与土壤锌含量存在显著正相关关系(r=0.505,P<0.05),而与土壤铅含量没有显著相关性。可见,AMF和DSE能够广泛存在于铅硐山铅锌矿区,尤其是DSE表现出较强的耐受性和适应性。     

丛枝菌根真菌应用技术研究进展

丛枝菌根(AM)共生体系能够改善植物营养状况,增强植物对各种逆境胁迫的耐受性,其在农业和生态环境方面的应用得到广泛关注.近年来,在AM真菌(AMF)应用技术和田间试验方面取得了许多重要成果.本文在介绍AMF种质资源库、商业化菌剂生产及相关专利申报情况的基础上,结合实例从菌剂生产、接种技术、接种效应影响因素等方面综述了AMF应用技术的理论与实践,包括国内外近年来菌根技术在农业、园艺、生态修复等方面的应用,最后提出尚待系统深入研究的 AMF应用领域中的关键科学和技术问题,旨在为菌根技术的发展和推广应用提供参考.     

丛枝菌根真菌与植物共生对植物水分关系的影响及机理

自1885年Frank首次提到菌根(mykorhiza)概念以来,大量的试验证实了丛枝菌根真菌(AMF)与植物根系之间形成具有一定结构和功能的共生体,促进植物生长并提高干旱耐受能力,在干旱生态系统中发挥重要的作用。该研究多集中在对宿主植物生理生态的影响及其机制方面,然而菌根共生对宿主植物水分吸收和信号产生、传递的影响研究少而分散,缺少系统总结。综述了最近四十多年丛枝菌根真菌与植物共生体对宿主植物干旱适应性影响研究进展,讨论了菌根共生对植物根冠通讯的影响及机理。干旱胁迫下AMF与植物共生,通过影响宿主植物一系列生理生态过程,提高宿主植物横向根压和纵向蒸腾拉力。经典的Ohm吸水模型是该方向最有代表性的研究成果,该模型揭示了菌根共生的根外菌丝具有不同于根细胞的细胞结构和水分运输性能,这为宿主植物提供一种特殊的快速吸水方式,可提高植物对土壤水分的吸收和运输能力。研究表明,AMF会影响宿主植物根冠通讯过程,如诱发信号级联反应,诱导根系尽早感知水分胁迫并产生非水力根源信号,提高宿主对干旱的耐受性。讨论了AMF在根冠通讯分子机制研究方面存在的问题及可能的解决途径,展望了AMF在干旱农业生产中的应用潜力。     

保护地黄瓜根内和土壤中丛枝菌根真菌和深色有隔内生真菌多样性研究（英文）

对于野生植物根内定殖的丛枝菌根真菌(AMF)和暗隔内生真菌(DSE)多样性及其生态功能现已进行了众多的调查研究。然而,对于同时定殖于栽培作物同一根系的这两种真菌的物种多样性和功能了解甚少。本研究旨在采用传统的形态学方法和PCR‐DGGE技术探究保护地栽培的黄瓜Cucumis sativus Linn.根内AMF和DSE的物种多样性。PCR‐DGGE结果显示共有7种AMF,包括Funneliformis mosseae,Glomus fasciculatum,Glomus indicum,Scutellospora dipurpurescens,Gigaspora margarita以及2个未培养的Archaeospora;而以黄瓜植株根段作为接种物加富培养后,依据其所产生的孢子形态特征进行分类鉴定,则只分离获得3种,即F.mosseae,G.indicum和Gi.Margarita;同时,采用常规分离纯化的方法从黄瓜根内分离得到DSE 6个菌株,其中1株经分子生物学鉴定为Phoma leveillei。从保护地根区土壤中分离AMF孢子并通过形态学分类鉴定,获得了9属20种。研究结果表明,Glomus是保护地栽培黄瓜根系内的优势属,针对数量,相对于传统形态鉴定技术,分子技术可以检测到根内更多的AMF。     

菌根真菌是唱响生物共生交响曲的主角——菌根真菌专辑序言

地球上任何生物都不是单独进行生命活动和进化的,即生物之间更多的是依靠密切联合、共生互助、需求互补和共同发展。其中,陆地生态系统中的强大分解者真菌和强大生产者植物关系密切,特别是以菌根真菌(mycorrhizal fungi)为代表的植物共生真菌自始至终与植物共生,这一强-强共生联合在维持生态平衡、保存生态系统可持续生产力与生态系统综合服务功能体系中,其分布之广、作用之多、功能之强和贡献之大,可谓名副其实的生物共生体系中的主导者。近年来,中国在真菌与植物共生研究领域成绩斐然,占据世界重要地位。本期《菌物学报》"菌根真菌专刊"刊登了2篇综述和20篇研究报告。综述分别对丛枝菌根(AM)真菌在煤矿区生态修复应用研究和兰科植物与菌根真菌的营养关系进行了总结和热点论述;研究报告分别对菌物界球囊菌门AM真菌全球公认种的中文学名给予了全面规范正确的描述、对中国部分林区红桦外生菌根真菌多样性、华山松印度块菌菌根中的块菌交配型基因、AM真菌对枳吸收磷和分泌磷酸酶的影响、转Bt基因棉叶片腐熟物抑制AM真菌定殖及菌根对磷的吸收、低pH影响AM真菌丛枝发育和磷的吸收、接种AM真菌与间作对红壤上玉米和大豆种间氮素竞争的影响、AM真菌及其菌种组合对植物根结线虫病害的影响以及接种AM真菌和施加铁可协同降低水稻砷累积等方面进行了研究。本期内容基本体现了中国菌根真菌分类、物种多样性、生理学、生态学、生理生态效应与作用机制研究的最新进展,对当前和今后开展植物共生真菌的研究具有重要的引领作用。     

盐碱胁迫对染内生菌和不染菌苇状羊茅根系丛枝菌根真菌群落多样性和组成的影响

香柱菌属Epichloë内生真菌存在于宿主植物地上部组织,不仅能提高宿主植物对生物与非生物逆境的抗性,而且能对周围环境中的微生物产生影响。该研究以染内生菌(endophyte-infected,EI)和不染菌(endophyte-free,EF)苇状羊茅Festuca arundinacea为实验材料,探究内生真菌和不同水平盐碱胁迫处理对宿主根系丛枝菌根真菌(arbuscular mycorrhizal fungi,AMF)群落多样性和组成的影响。结果表明,内生真菌和盐碱胁迫处理对苇状羊茅根系AMF多样性影响存在交互作用。EF苇状羊茅根系AMF多样性随盐碱胁迫处理水平的增加而降低,内生真菌的存在缓解了这一效应,在200和400 mmol/L盐碱胁迫处理下,内生真菌感染增加了苇状羊茅根系AMF多样性;此外,内生真菌感染改变了苇状羊茅根系AMF群落组成,降低了优势属Funneliformis相对多度,增加了Claroideoglomus、Glomus和unclassified AMF相对多度。结构方程模型结果表明,内生真菌通过间接增加土壤总磷浓度对苇状羊茅根系AMF多样性产生影响。本研究为筛选盐碱污染区生态修复的植物-微生物共生体提供基础。     

AMF和DSE组合菌剂促生防线虫病效应

本试验旨在探究丛枝菌根真菌（AMF）和暗隔内生真菌（DSE）组合菌剂对南方根结线虫Meloidogyne incognita发育、侵染、黄瓜根结线虫病以及黄瓜生长发育的影响,为进一步探索AMF和DSE协同发挥生理生态效应的作用机制奠定基础。试验对“津优35号”黄瓜接种南方根结线虫、Phoma leveillei（DSE）、Funneliformis mosseae（AMF）、Glomus versiforme（AMF）、Acaulospora laevis（AMF）和/或Scutellospora aurigloba（AMF）。结果表明,供试AMF与DSE 能促进黄瓜生长、提高产量和增强抗病性。AMF+DSE组合处理的菌根和DSE的定殖数量、株高、茎粗、地上部和根系干重、单株产量等显著优于单接种AMF或单接种DSE处理。以F. mosseae + P. leveillei组合抑制南方根结线虫的发育、降低线虫繁殖数量、根内定殖数量、发病率和根结指数的效果最好。     

Wetland dicots and monocots differ in colonization by arbuscular mycorrhizal fungi and dark septate endophytes

As an initial step towards evaluating whether mycorrhizas influence composition and diversity in calcareous fen plant communities, we surveyed root colonization by arbuscular mycorrhizal fungi (AMF) and dark septate endophytic fungi (DSE) in 67 plant species in three different fens in central New York State (USA). We found colonization by AMF and DSE in most plant species at all three sites, with the type and extent of colonization differing between monocots and dicots. On average, AMF colonization was higher in dicots (58±3%, mean±SE) than in monocots (13±4%) but DSE colonization followed the opposite trend (24±3% in monocots and 9±1% in dicots). In sedges and cattails, two monocot families that are often abundant in fens and other wetlands, AMF colonization was usually very low (<10%) in five species and completely absent in seven others. However, DSE colonization in these species was frequently observed. Responses of wetland plants to AMF and DSE are poorly understood, but in the fen communities surveyed, dicots appear to be in a better position to respond to AMF than many of these more abundant monocots (e.g., sedges and cattails). In contrast, these monocots may be more likely to respond to DSE. Future work directed towards understanding the response of these wetland plants to AMF and DSE should provide insight into the roles these fungal symbionts play in influencing diversity in fen plant communities.     

Fungal root endophyte associations of plants endemic to the Pamir Alay Mountains of Central Asia

The fungal root endophyte associations of 16 species from 12 families of plants endemic to the Pamir Alay Mountains of Central Asia are presented. The plants and soil samples were collected in Zeravshan and Hissar ranges within the central Pamir Alay mountain system. Colonization by arbuscular mycorrhizal fungi (AMF) was found in 15 plant species; in 8 species it was of the Arum type and in 4 of the Paris type, while 3 taxa revealed intermediate arbuscular mycorrhiza (AM) morphology. AMF colonization was found to be absent only in Matthiola integrifolia, the representative of the Brassicaceae family. The AM status and morphology are reported for the first time for all the species analyzed and for the genera Asyneuma, Clementsia, and Eremostachys. Mycelia of dark septate endophytes (DSE) accompanied the AMF colonization in ten plant species. The frequency of DSE occurrence in the roots was low in all the plants, with the exception of Spiraea baldschuanica. However, in the case of both low and higher occurrence, the percentage of DSE root colonization was low. Moreover, the sporangia of Olpidium spp. were sporadically found inside the root epidermal cells of three plant species. Seven AMF species (Glomeromycota) found in the trap cultures established with soils surrounding roots of the plants being studied were reported for the first time from this region of Asia. Our results provide information that might well be of use to the conservation and restoration programmes of these valuable plant species. The potential application of beneficial root-inhabiting fungi in active plant protection projects of rare, endemic and endangered plants is discussed.     

The co-existence between DSE and AMF symbionts affects plant P pools through P mineralization and solubilization processes

The capacity of dark septate endophytes (DSE; Phialocephala turiciensis, Acephala applanata, P. glacialis and Phaeomollisia piceae) to solubilize inorganic phosphate (P) and to mineralize the organic form was studied. We analysed the effect of DSE strains on P uptake by Trifolium repens in the presence or absence of arbuscular mycorrhizal fungi (AMF). Phosphatases were observed both in the absence of the host plant and the organic resource, showing that the P mineralization process is not induced by the enzyme substrate or the host. DSE were more efficient at mineralizing organic P. Independently of the presence of AMF, DSE increased the pool of P in the soil, with significant differences being found in P levels among the different DSE. In contrast, plant P uptake was increased by AMF. The P content of plants increased with the co-inoculation of AMF and P. turiciensis or P. piceae. We hypothesize a close relationship between DSE and AMF in relation to P availability and uptake in plants. Whereas DSE increase the pool of P in the rhizosphere, AMF are responsible for P transfer to the host, with co-colonization of plants by DSE and AMF showing a synergistic outcome.     

Medicinal plants as hosts of arbuscular mycorrhizal fungi and dark septate endophytes

Arbuscular mycorrhizal and dark septate endophyte associations of 31 medicinal plant species collected from the Garden of Medicinal Plants of the Faculty of Pharmacy, Jagiellonian University, Collegium Medicum in Kraków were investigated. Arbuscular mycorrhiza (AM) was found in 30 species; 23 were of the Arum-type, 5—Paris and 2 taxa revealed intermediate morphology. Many plants were strongly colonized by arbuscular mycorrhizal fungi (AMF). The mycelium of dark septate endophytes (DSE) was observed in 21 taxa. However, the percentage of root colonization by these fungi was low. Spores of 15 species of AMF (Glomeromycota) were found in the rhizosphere of the investigated plants. Our results are the first detailed report of both AMF and DSE associations of these plant species. The use of AMF and DSE during the process of medicinal plant cultivation for pharmaceutical purposes is discussed.     

Root fungal symbionts interact with mammalian herbivory, soil nutrient availability and specific habitat conditions

Herbivory, competition and soil fertility interactively shape plant communities and exhibit an important role in modifying conditions for host-dependent fungal symbionts. However, field studies on the combined impacts of natural herbivory, competition and soil fertility on root fungal symbionts are rare. We asked how mammalian herbivory, fertilization, liming and plant–plant competition affect the root colonization of arbuscular mycorrhizal fungi (AMF) and dark septate endophytic (DSE) fungi of the dicot herb, Solidago virgaurea. The 2-year full-factorial experiment was conducted in two contrasting habitats: non-acidic and acidic mountain tundra. We found that herbivory increased arbuscular colonization (i.e. the site of resource exchange) at fertile non-acidic sites, where vegetation was rich in species having AMF symbionts, whereas at infertile acidic sites, where plants having AMF symbiont are scarce, the response was the opposite. Herbivory of the host plant negatively affected DSE hyphal and sclerotial colonization in unfertilized plots, possibly due to reduced carbon flow from the host plant while there was no effect of herbivory in fertilized plots. DSE colonization was highest in unfertilized exclosures where soil nutrient concentrations were also lowest. Liming had a negative effect on DSE hyphal colonization, and its effect also interacted with herbivory and the habitat. Biomass removal of the neighboring plants did not affect the root colonization percent of either arbuscules or DSE. Our results show that the impacts of aboveground mammalian herbivory, soil nutrient availability and specific habitat conditions on belowground root fungal symbionts are highly dependent on each other. Arbuscule response to herbivory appeared to be regulated by specific habitat conditions possibly caused by differences in the AMF availability in the soil while DSE response was associated with availability of host-derived carbon. Our result of the relationship between herbivory and soil nutrients suggests an important role of DSE in ecosystem processes.     

丛枝菌根真菌提高盐胁迫植物抗氧化机制的研究进展

土地盐渍化是在自然环境和人为活动的双重作用下形成的全球性的重要生态问题,其会对植物造成渗透失衡、离子胁迫、氧化损伤等危害,导致植物生长缓慢、生物量减少甚至是绝产。丛枝菌根真菌(AMF)是一种普遍存在于土壤中的有益微生物,能够与大多数植物根系形成共生关系,其共生关系在多种逆境生态系统中均具有重要生态意义。AMF-植物共生体具有高效抗氧化系统,能够提高植物在盐胁迫下的抗氧化反应进而增强耐盐性。本文从氧化损伤、渗透调节、抗氧化机制和生物活性分子等角度,系统地阐述了丛枝菌根真菌提高植物抗氧化机制的研究进展,并提出了研究展望,以期为利用菌根生物技术提高植物耐盐性提供理论参考。     

Contrasting impacts of defoliation on root colonization by arbuscular mycorrhizal and dark septate endophytic fungi of Medicago sativa

Individual plants typically interact with multiple mutualists and enemies simultaneously. Plant roots encounter both arbuscular mycorrhizal (AM) and dark septate endophytic (DSE) fungi, while the leaves are exposed to herbivores. AMF are usually beneficial symbionts, while the functional role of DSE is largely unknown. Leaf herbivory may have a negative effect on root symbiotic fungi due to decreased carbon availability. However, evidence for this is ambiguous and no inoculation-based experiment on joint effects of herbivory on AM and DSE has been done to date. We investigated how artificial defoliation impacts root colonization by AM (Glomus intraradices) and DSE (Phialocephala fortinii) fungi and growth of Medicago sativa host in a factorial laboratory experiment. Defoliation affected fungi differentially, causing a decrease in arbuscular colonization and a slight increase in DSE-type colonization. However, the presence of one fungal species had no effect on colonization by the other or on plant growth. Defoliation reduced plant biomass, with this effect independent of the fungal treatments. Inoculation by either fungal species reduced root/shoot ratios, with this effect independent of the defoliation treatments. These results suggest AM colonization is limited by host carbon availability, while DSE may benefit from root dieback or exudation associated with defoliation. Reductions in root allocation associated with fungal inoculation combined with a lack of effect of fungi on plant biomass suggest DSE and AMF may be functional equivalent to the plant within this study. Combined, our results indicate different controls of colonization, but no apparent functional consequences between AM and DSE association in plant roots in this experimental setup.     

Coexistence of arbuscular mycorrhizae and dark septate endophytic fungi in an undisturbed and a disturbed site of an arid ecosystem

Effect of disturbance on root colonization and vertical distribution of arbuscular mycorrhizal fungi (AMF) and dark septate endophytes (DSE) was investigated at two adjacent sites of Lal Suhanra Biosphere Reserve, Pakistan. Disturbance clearly affected AMF and DSE colonization, vertical distribution of AMF and plant community structure. Mean colonization of AMF and DSE was slightly less at the disturbed site. Average spore densities, diversity and richness of AMF and DSE were higher at the undisturbed site. A study of the vertical distribution of AMF associated with the five plant species most common to each study site indicated that beside AMF and DSE colonization disturbance may affect AMF species composition. Correlation of AMF with DSE is also discussed.     

陆地农业生态系统丛枝菌根真菌物种多样性研究进展

丛枝菌根真菌(AMF)是一种古老的、在自然界中普遍存在的土壤微生物,能与大部分陆生植物形成互惠互利的菌根共生体.在这种共生关系中,AMF从植物获取自身生长所需碳源的同时,帮助宿主吸收氮、磷等营养物质.AMF在农业生态系统中具有重要作用,能够促进植物生长、改善作物品质、提高植物抗逆性、稳定土壤结构、维护生态平衡和维持农业可持续发展.本文总结了近几年来陆地农业生态系统AMF的研究进展,着重从我国陆地农业生态系统AMF物种多样性、AMF生物多样性时空分布特征及影响AMF多样性的因素等几个方面,综述了陆地农业生态系统AMF的物种多样性,并对以后的研究进行了展望.