AM真菌与西瓜枯萎病关系初探

 在温室盆栽条件下研究了丛枝菌根(Arbuscular Mycorrhiza,AM)真菌Gigaspora rosea Nicol.& Schenck、Glomusmosseae(Nicol.& Gerd.) Gerdemann & Trappe和Glomus versiforme(Karsten) Berch与西瓜枯萎病菌(Fusariumoxysporum f. sp. niveum)的关系。结果表明,接种AM真菌能促进西瓜植株的生长发育,增加植株干重;显著减少根内和根围土壤中镰刀菌群体数量及其对根系的侵染率;降低枯萎病发病率和病情指数,从而减轻西瓜枯萎病的危害。接种F.oxysporum f. sp. niveum能降低AM真菌对西瓜的侵染率,并且AM真菌与镰刀菌的不同接种时间和顺序影响西瓜枯萎病的发生发展,证实AM真菌与镰刀菌存在竞争关系。另外,AM真菌对西瓜高感枯萎病品种的防治效果优于抗病品种,说明高感品种对菌根的依赖性较大。     

接种丛枝菌根对玉米生长与抗旱性的影响

采用盆栽试验,研究了水分胁迫下接种丛枝菌根真菌对玉米生长及其抗旱性的影响。结果表明:玉米与丛枝菌根可形成良好的共生关系,接种丛枝菌根显著提高了玉米生物量、株高、地径。与未接菌相比,接菌提高了植株水分利用效率,水分胁迫和正常供水条件下,较对照分别提高117%和24.6%。接菌后玉米叶片SPAD值和可溶性蛋白含量增加,叶片过氧化氢酶活性增强。同时,接种菌根显著降低了植株叶片脯氨酸、丙二醛含量,干旱胁迫和正常供水条件下,较未接菌处理分别降低了14.1%、18.9%和59%、69%。由此可见,接种丛枝菌根真菌能够促进玉米的生长,缓解干旱胁迫对玉米生长造成的不利影响,提高了玉米的抗旱性。     

禾草内生真菌与丛枝菌根互作对多年生黑麦草生长及叶斑病的影响

为明确禾草内生真菌和丛枝菌根真菌(arbuscular mycorrhizal fungi,AMF)互作对多年生黑麦草Lolium perenne生长发育及叶斑病的影响,设置禾草内生真菌处理(由带有和不带禾草内生真菌种子建立)、AMF(幼套球囊霉Claroideoglomus etunicatum和根内球囊霉Rhizophagus intraradices)单独接种和混合接种处理及不接菌处理(对照),并在植物生长6周后接种或不接种多年生黑麦草叶斑病病原菌根腐离蠕孢Bipolaris sorokiniana,测定各处理多年生黑麦草的发病率、叶绿素含量、净光合速率、水分利用效率、AMF侵染率、P含量和生物量。结果表明:接种病原菌2周后,多年生黑麦草叶斑病的发病率为25.00%～38.75%,禾草内生真菌和幼套球囊霉均在一定程度上降低了多年生黑麦草的发病率,二者共同作用时发病率显著降低了35.48%。禾草内生真菌与AMF互作能在一定程度上提高植物叶绿素含量,促进光合作用,并促进P吸收和植物生长,二者的互作效应因禾草内生真菌与AMF组合而异,但均优于二者单独使用时的效应,其中禾草内生真菌与幼套球囊霉互作对多年生黑麦草生长及叶斑病防治的效果最好。     

荒漠生态系统中丛枝菌根真菌多样性

到目前为止,在全球荒漠生态系统中,共报道了69个科389种丛枝菌根真菌的寄主植物,其中,Compositae,Gramineae和Leguminosae 3个科的植物为荒漠生态系统中丛枝菌根真菌寄主植物的优势类群;共发表了7个属的89种丛枝菌根真菌,其中,Acaulospora和Glomus 属的真菌为荒漠生态系统中的优势类群.在此基础上,分析了荒漠生态系统中AM真菌多样性研究中存在的问题,并探讨了荒漠生态系统中AM真菌的研究方向.     

利用丛枝菌根真菌提高植物抗病性研究进展

本文就近年来国内外有关丛枝菌根真菌对植物土传病害的防效及其抗性机制进行了阐述,同时展望了丛枝菌根真菌资源在设施蔬菜生产中的广阔应用前景。     

抗黄瓜枯萎病丛枝菌根真菌与根围促生细菌组合菌剂的筛选

 丛枝菌根真菌(AMF)和植物根围促生细菌(PGPR)同时接种具有促生防病的作用。本试验旨在评价AMF与PGPR组合菌剂防治黄瓜枯萎病(Fusarium oxysporum f. sp. cucumerinum )的效果,以获得高效生防菌剂。于温室盆栽条件下将AMF Funneliformis mosseae(Fm)、Glomus intraradices(Gi)和 Glomus versiforme(Gv)与PGPR菌株(PR2-1、PS1-3、PS1-5、PS2-6和PS3-2)不同组合菌剂处理黄瓜(Cucumis sativus, 品种:香翠16号),测定各处理对黄瓜植株生长量、枯萎病防治效果和黄瓜产量的影响。供试AMF+PGPR各组合菌剂处理能不同程度的增加黄瓜根系AMF侵染率和根围细菌的定殖数量、促进黄瓜生长发育和降低枯萎病危害程度。其中,以Fm+PS3-2和 Gv+PS2-6组合菌剂促生和增产效果最好, 以Fm+PS1-5、Fm+PS3-2和Gv+PS2-6组合菌剂防治枯萎病效果最好。综合评价筛选获得高效组合为Fm+PS3-2和Gv+PS2-6。这两个处理可使黄瓜枯萎病病情指数分别下降50.0%和58.4%,防效达到54.5%和63.7%,具有一定的田间应用潜力。     

茉莉酸介导的丛枝菌根真菌诱导植物抗病性研究进展

丛枝菌根（arbuscular mycorrhizal, AM）真菌能与植物根系建立共生体提高植物抗病性。植物激素茉莉酸（jasmonic acid,JA）参与AM的形成,介导AM真菌诱导的植物抗病性。目前,关于AM真菌诱导的植物抗病性内容较为丰富,但是关于JA介导的AM真菌诱导的植物抗病性却有待进一步研究。本文首先总结了JA对AM形成和AM对植物内源JA积累的影响;其次介绍了AM真菌对植物抗病性影响及诱导机制;最后从诱导形成防御结构、提高酶活性及合成防御蛋白、诱导次生代谢物质合成、诱导调控信号分子、JA与其他激素相互作用五个方面探讨了JA在AM真菌诱导抗病性中的作用,并对本领域的研究方向进行展望,以期为植物病害防治和菌根研究提供可借鉴的思路。     

丛枝菌根真菌与小麦孢囊线虫的相互作用

 近年来, 小麦孢囊线虫(cereal cyst nematodes, CCN:主要病原为燕麦孢囊线虫Heterodera avenae)对小麦(Triticum aestivum)的危害日益严重, 亟待探索新的生防途径。丛枝菌根真菌(arbuscular mycorrhizal fungi, AMF)作为环境功能生物, 对寄主植物具有生物药肥双重作用, 不仅能促进植物吸收利用养分, 而且能拮抗土传病原物、提高植物抗病性。本研究以AMF与CCN相互作用为切入点, 试图明确AMF与CCN相互作用关系, 并科学评价不同AMF抑制CCN、降低病害的效应。试验于温室盆栽条件下进行, 设接种AMF Gigaspora margarita(Gi.m)、Glomus mosseae(G.m)、Glomus intraradices(G.i)、Glomus versiforme(G.v)、Gi.m +G.m+G.i+G.v、CCN、CCN+Gi.m、CCN+G.m、CCN+G.i、CCN+G.v、CCN+Gi.m+G.m+ G.i+G.v和不接种对照(CK)共12个处理。结果表明, 接种AMF各处理均能降低小麦孢囊线虫侵染率、土壤中孢囊数和根内J2数量, 其中Gi.m处理抑制效果最大;CCN不同程度减少AMF侵入点数和产孢数量。Gi.m 和CCN+Gi.m处理的根内丛枝着生数量最多, 而后者根内的超氧化物歧化酶、苯丙氨酸解氨酶和过氧化氢酶活性显著高于其他处理、丙二醛含量则显著低于其他CCN+AM真菌处理。Gi.m和G.i处理的小麦株高、地上部干重高于其他处理;Gi.m 和CCN+Gi.m的处理的单穗重和单株产量均高于其他处理。表明AMF能不同程度拮抗CCN、促进小麦生长和提高产量, 其中, Gi.m是高效菌种。结论认为, AMF与CCN之间存在一定相互抑制作用, AMF能通过诱导植株防御反应拮抗CCN。     

丛枝菌根真菌和氮磷钾复合肥对砖瓦场破坏地土壤肥力的影响

将砖瓦声场采土后破坏的土壤装入盆内,每盆加NPK往复和合肥（10：5：10）0,50μg.g^-1和100μg.g^-1,并接种丛枝菌根真菌（AMF）Gigaspora albida,Gigaspora sp1,Glomus mosseae 109,Glomus versiforme,Scutellospora calospor和Scuteospora verrucosa接种物（孢子和感染菌根的根段）0和20000接种势单位／盆,然后播种三叶草（Trifolium repens).植株生长5个月以后收割并翻压入土壤中、第2年于此土壤中重复一试验。当植株在土壤中完全腐烂后,测定土壤PH值和矿质元素含量,结果表明接种AMF能显著增加植株的干、鲜重及 体内N,P,K,Zn和Cu的含量,及土壤中有铲P,Zn,Cu和总N的含量。Glomus mosseae,Glomus versiforme,Gigaspora albida和Scutellospora calospora比其他菌种更有效。接种和施肥能改变根围土PH值。接种AMF并配和施肥处理的效应比单一接种或施肥效果好,施NPK复合肥也能改善土肥肥力,但降低土训中AMF的孢子数量。     

AM真菌和镰刀菌对西瓜根系膜脂过氧化作用和膜透性的影响

 在温室盆栽条件下研究了丛枝菌根(arbuscular mycorrhiza,AM)真菌Glomus versiforme (Karsten) Berch和西瓜枯萎镰刀菌(Fusarium oxysporum f. sp. niveum)对西瓜根系中膜脂过氧化产物丙二醛(MDA)含量和细胞膜透性的影响。结果表明,接种AM真菌的西瓜根系中MDA含量、组织自动氧化速率和膜透性均低于对照,先接种G. versiforme,后接种F. oxysporum f. sp. niveum处理的MDA含量、组织自动氧化速率和细胞膜透性均低于只接种F. oxysporum f. sp. niveum的处理。接种G. versiforme感枯萎病西瓜品种"郑杂5号"MDA含量、组织自动氧化速率和膜透性降低幅度大于抗病品种"京欣1号"的接种处理,说明G. versiforme可降低感病西瓜品种的膜透性和MDA的产生,从而有效地保护细胞膜系统,减轻F. oxysporum f. sp. niveum对西瓜的为害程度。     

Effect of native and allochthonous arbuscular mycorrhizal fungi on Casuarina equisetifolia growth and its root bacterial community

Exotic trees are often planted to recover degraded lands. Inoculation with mycorrhizal fungi can improve their survival. Plant growth is partly dependent on the strain used, but little attention has been paid to the selection of mycorrhizal fungi. The aim of this study was to determine whether the growth of Casuarina equisetifolia L. (Johnson) is affected by two different mycorrhizal inocula generated using fungal spores retrieved from an Australian site (allochthonous soil) and a Senegalese site (native soil) under C. equisetifolia trees. Comparative experiments were conducted with plants in a Senegalese soil, previously sterilized or not, and grown in a greenhouse. At harvest, parameters related to plant growth and mycorrhization were evaluated and soil bacterial communities were compared. Tree growth was significantly influenced by both types of inoculants. In unsterilized soil, plants inoculated with the native inoculant were taller than plants inoculated with the allochthonous inoculant and control plants. The frequency of mycorrhization with both inoculants was higher in unsterilized soil. The strongest effects of the mycorhizosphere on the soil microbiome were obtained with the allochthonous inoculum, and analysis of the taxonomic composition revealed mycorrhizal communities specific to each inoculum. These results suggest that the development of C. equisetifolia and its root bacterial community are dependent on the composition of the mycorrhizal inoculum. The functional consequences of this rhizosphere effect in terms of soil fertility should be further studied to better guide reforestation operations.     

AM真菌诱导的番茄信号物质及其对根结线虫的 抑制 效应

丛枝菌根(AM)真菌能诱导植物合成一些信号物质,如茉莉酸(JA)、水杨酸(SA)、一氧化氮(NO)、H2O2等,这些信号在AM真菌与植物识别、共生体建立和激活植物防御系统过程中发挥着重要作用[1].     

Dynamics of arbuscular mycorrhizal fungi associated with desert ephemeral plants in Gurbantunggut Desert

Previous studies documented that most desert plants can be colonized by arbuscular mycorrhizal (AM) fungi,however,little is known about how the dynamics of AM fungi are related to ephemerals in desert ecosystems.The dynamics of AM fungi with desert ephemerals were examined to determine the effects of host plant life stages on the development of AM fungi.Mean colonization of ephemeral annual plants was 45% lower than that of ephemeral perennial plants.The colonizations were much higher in the early part of the growing season than in later parts,peaking at flowering times.The phenology of AM fungi in root systems varied among different ephemerals.The density of AM fungal spores increased with the development of ephemeral annual plants,reached its maximum at flowering times,and then plateaued about 20 days after the aboveground senescence.A significant positive correlation was found between AM fungi spore density and biomass of ephemeral annual plants.The life cycles of AM fungi associated with desert ephemerals were very short,being about 60-70 days.Soil temperature and water content had no direct influence on the development of AM fungal spores.We concluded that the development of AM fungi was in response to desert ephemeral phenology and life history strategy.     

Effectiveness of arbuscular mycorrhizal fungi in the protection of date palm (Phoenix dactylifera L.) against bayoud disease

In the present study, arbuscular mycorrhizal fungi (AMF) (Glomus monosporus, Glomus deserticola, Glomus clarum and a complex of native AMF coming from the Aoufous date palm grove in the south of Morocco) have been shown to protect date palm seedlings against bayoud disease. Treatment with AMF reduced disease severity by 8–77% depending on the AMF isolate used. In addition, all mycorrhizal fungi stimulate significantly shoot height and biomass and increase the number of leaves per plant. The plants associated with Aoufous complex present the best improvement of plant growth and great effectiveness in reducing bayoud disease incidence. Moreover, the AMF induce change in activities of two defence-related enzymes (peroxidases and polyphenoloxidases). The potential involvement of this induced biochemical defence reaction in protecting date palm against bayoud is discussed.     

AMF+PGPR组合提高黄瓜抗枯萎病的作用机制

对黄瓜(Cucumis sativus)品种香翠16接种尖孢镰刀菌黄瓜专化型(Fusarium oxysporum f.sp.cucumerinum,Foc)、丛枝菌根真菌(AMF)Funneliformis mosseae(Fm)+Foc、丛枝菌根真菌Glomus versiforme(Gv)+Foc、根围促生细菌(PGPR)PS2-6+Foc、PS3-2+Foc、Fm+PS3-2+Foc以及Gv+PS2-6+Foc,以不接种处理作为对照。结果表明,接种Foc条件下,Fm+PS3-2和Gv+PS2-6组合处理的抗病效果显著优于单接种AMF或PGPR处理;镜检观测到靠近AMF菌丝的Foc菌丝纤细,生长不良。AMF菌丝能缠绕Foc菌丝,并阻挡其侵入根系;AMF侵染率与其防效均呈正相关(P0.05);Fm+PS3-2+Foc和Gv+PS2-6+Foc处理的根系活力是单接种Foc的4.6倍;与不接种对照相比,Fm+PS3-2+Foc和Gv+PS2-6+Foc处理的黄瓜叶片中吲哚乙酸(IAA)含量分别提高了205%和166%,赤霉素(GA3)提高了33%和22%,玉米素核甘(ZR)提高了100%和80%,JA平均提高了65%,ABA降低23%和17%;而与单接种Foc处理相比,IAA提高了667%和568%,GA3提高了223%和196%,ZR提高了254%和219%,茉莉酸(JA)含量平均提高了215%,而脱落酸(ABA)含量只有单接种Foc处理的53%;Fm+PS3-2+Foc和Gv+PS2-6+Foc处理显著提高了黄瓜叶内苯丙氨酸解氨酶(PAL)防御酶活性和PAL基因表达量。综上推断AMF+PGPR组合是通过拮抗病原物、促进合成抗病信号物质、上调防御基因表达、提高防御酶活性和降低植株体内有毒物质等机制降低病害和改善植物抗病性。