AM真菌与非菌根植物的相互作用关系

丛枝菌根(AM)真菌作为一类在全球分布广泛的土壤微生物,能够与陆地上大多数的维管植物形成专性共生关系,对于植物营养吸收和生态系统功能具有重要作用.而较少量的维管植物如苋科、黎科、石竹科、十字花科等植物被认为是非菌根植物.目前,对于这些非菌根植物与AM真菌之间的相互作用关系研究少且分散,缺乏系统总结.本文综述了非菌根植物的类型以及低侵染的原因,邻体植物形成的菌丝网络对AM真菌侵染非菌根植物的影响,并探讨AM真菌和非菌根植物之间可能存在的相互作用,以及植物-AM真菌之间的物质交换及可能存在的生态功能,旨在为进一步发挥非菌根植物在脆弱生态系统的功能潜力提供新思路.     

Systemic inhibition of arbuscular mycorrhiza development by root exudates of cucumber plants colonized by<Emphasis Type="Italic"> Glomus mosseae</Emphasis>

The arbuscular mycorrhizal (AM) non-host plants mustard, sugar beet, lupin and the AM host plant cucumber were used as test plants. Cucumber plants were grown either in the absence of the AM fungus (AMF) Glomus mosseae or in a split-root system, with one side mycorrhizal and one side non-mycorrhizal. Root exudates of the AM non-host plants, the non-mycorrhizal cucumber plants and the mycorrhizal and the non-mycorrhizal side of the split-root system of mycorrhizal cucumber plants were collected and applied to cucumber plants inoculated with the AMF. Root exudates of non-mycorrhizal cucumber plants showed a significant stimulatory effect on root colonization, whereas root exudates from the mycorrhizal and the non-mycorrhizal sides of a split-root system of a mycorrhizal cucumber plant did not show this stimulatory effect and were even slightly inhibitory. Root exudates of the two AM non-host plants mustard and sugar beet significantly reduced root colonization in cucumber plants, whereas no such effect was observed when root exudates of the AM non-host plant lupin were applied.     

Inoculation of field-established mulberry and papaya with arbuscular mycorrhizal fungi and a mycorrhiza helper bacterium

The effects of soil inoculation with arbuscular mycorrhizal (AM) fungi and a mycorrhiza helper bacterium (MHB) were investigated on mulberry and papaya plants already established in the field. Ten-year-old mulberry plants (var. M5) were inoculated with Glomus fasciculatum and 1.5-year-old papaya plants (var. Solo) were inoculated with a mixed culture of G. mosseae and G. caledonium with or without Bacillus coagulans at two levels of P fertilizer. Growth, P uptake, yield and AM colonization levels were monitored. Leaf yield in mulberry and fruit yield in papaya were minimal in uninoculated plants given 50% recommended P. However, crop yields of both mulberry and papaya inoculated with AM fungi alone or together with the bacterium and given 50% recommended P were statistically on a par with that of uninoculated plants given 100% recommended P. As inoculation of B. coagulans increased mycorrhiza levels in AM fungal-inoculated plants, this may be included in the class of MHB. Thus, mulberry and papaya already established in the field may respond to AM inoculation and MHB may increase symbiosis development by efficient AM fungi.     

西双版纳热带雨林中丛枝菌根真菌的初步研究*

对西双版纳热带雨林中30个科的42种植物根系的丛枝菌根真菌定居情况进行了调查,并从这些植物的根际土壤中分离鉴定了分属于无梗囊霉属(Acaulospora)、球囊霉属(Glomus)和硬囊霉属(Sclerocystis)的25种丛枝菌根真菌。对热带雨林土壤中丛枝菌根真菌的孢子密度（spore density）、物种丰富度（species richness）以及已鉴定种的出现频率进行统计分析发现：热带雨林土壤中丛枝菌根真菌的孢子密度在每100g土壤116~1560个之间,平均478个;物种丰富度在2~7之间,平均为4.5;无梗囊霉属和球囊霉属真菌是热带雨林土壤中丛枝菌根真菌的优势类群。     

Non-host plants: Are they mycorrhizal networks players?

Common mycorrhizal networks (CMNs) that connect individual plants of the same or different species together play important roles in nutrient and signal transportation, and plant community organization. However, about 10% of land plants are non-mycorrhizal species with roots that do not form any well-recognized types of mycorrhizas; and each mycorrhizal fungus can only colonize a limited number of plant species, resulting in numerous non-host plants that could not establish typical mycorrhizal symbiosis with a specific mycorrhizal fungus. If and how non-mycorrhizal or non-host plants are able to involve in CMNs remains unclear. Here we summarize studies focusing on mycorrhizal-mediated host and non-host plant interaction. Evidence has showed that some host-supported both arbuscular mycorrhizal (AM) and ectomycorrhizal (EM) hyphae can access to non-host plant roots without forming typical mycorrhizal structures, while such non-typical mycorrhizal colonization often inhibits the growth but enhances the induced system resistance of non-host plants. Meanwhile, the host growth is also differentially affected, depending on plant and fungi species. Molecular analyses suggested that the AMF colonization to non-hosts is different from pathogenic and endophytic fungi colonization, and the hyphae in non-host roots may be alive and have some unknown functions. Thus we propose that non-host plants are also important CMNs players. Using non-mycorrhizal model species Arabidopsis, tripartite culture system and new technologies such as nanoscale secondary ion mass spectrometry and multi-omics, to study nutrient and signal transportation between host and non-host plants via CMNs may provide new insights into the mechanisms underlying benefits of intercropping and agro-forestry systems, as well as plant community establishment and stability.     

我国北方农田土壤中AM真菌的多样性

AM真菌是农业生态系中一类重要的土壤微生物,它在农田土壤中的发生和分布受多种环境因素的影响。为深入了解我国北方农田土壤中AM真菌的多样性规律,于2000年在河北、山东的农田土壤中采集有代表性的土样127个。通过进一步扩繁、纯化,从中分离出AM真菌5属22种,鉴定了20个种,包括一个国内新记录种沾屑球囊霉(Glomus spurcum)。分析AM真菌的多样性特点及其影响因素发现,农田土壤中以球囊霉属(Glomus)的频度最高,其次为无梗囊霉属(Acaulospora);优势种类为幼套球囊霉(Glomus etunicatum)和摩西球囊霉(Glomus mosseae).土壤速效磷含量、pH状况主要对孢子密度产生影响,对种群分布影响不大。宿主植物类型对AM真菌的侵染状况和多样性影响较大;比较玉米(Zea mays)、甘薯(Ipomoea batatas)根区AM真菌的种群组成后发现两者有所不同,但优势种一致.     

龙脑香科植物对丛枝菌根真菌的影响

在天然林地和温室盆栽条件下,比较研究了龙脑香科植物对丛枝菌根(Arbuscular mycorrhizas,AM)真菌孢子密度、相对多度、频度、属的组成、丰度和侵染状况等方面的影响.结果表明,用坡垒作盆栽寄主加富培养后,菌根侵染率、泡囊、丛枝和侵入点都低于原采样植物,以原坡垒土壤中栽植苗木的侵染率为最高,可达20.3%;而以望天树根围土壤栽植的苗木为最低,仅为10.6%;坡垒还不同程度地改变了原采样植物根围土壤中AM真菌孢子的密度、相对多度、频度、属的组成、丰度等.在4种土壤中,栽植坡垒苗木后,AM真菌的孢子密度都有不同程度的增长.采用与原采样相同种类的植物作为AM真菌加富培养的寄主更有利于促进AM真菌的生长发育、保持AM的多样性.     

Xyloglucanases in the interaction between saprobe fungi and the arbuscular mycorrhizal fungus Glomus mosseae

We studied the production of xyloglucanase enzymes of pea and lettuce roots in the presence of saprobe and arbuscular mycorrhizal (AM) fungi. The AM fungus Glomus mosseae and the saprobe fungi Fusarium graminearum, Fusarium oxysporum-126, Trichoderma harzianum, Penicillium chrysogenum, Pleurotus ostreatus and Aspergillus niger were used. G. mosseae increased the shoot and root dry weight of pea but not of lettuce. Most of the saprobe fungi increased the level of mycorrhization of pea and lettuce, but only P. chrysogenum and T. harzianum inoculated together with G. mosseae increased the dry weight of pea and lettuce respectively. The AM and saprobe fungi increased the production of xyloglucanases by plant roots. The level of xyloglucanase activities and the number of xyloglucanolytic isozymes in plants inoculated with G. mosseae and most of the saprobe fungi tested were higher than when both microorganisms were inoculated separately. The possible relationship between xylogucanase activities and the ability of AM and saprobe fungi to improve the dry weight and AM root colonization of plants was discussed.     

西双版纳地区龙脑香科植物AM真菌的初步研究

 对云南省西双版纳地区17种龙脑香科树种根系丛枝菌根（Arbuscular mycorrhiza, AM）真菌的定居情况进行了调查,并对根围土壤中AM真菌进行了分离和鉴定。结果表明,调查根样均有不同程度的菌根感染,感染率最高可达40%,调查揭示了西双版纳地区龙脑香科植物在自然条件下可形成丛枝菌根。初步从龙脑香科植物根际土壤中分离、鉴定出32种AM真菌,隶属于无梗囊霉属（Acaulospora）、球囊霉属（Glomus）、原囊霉属（Achaeospora）、拟球囊霉属（Paraglomus）和盾巨孢囊霉属（Scutellospora）,其中,无梗囊霉属和球囊霉属真菌为西双版纳地区龙脑香科植物AM真菌优势类群。     

The host range of Plasmodiophora brassicae and its relationship to endogenous glucosinolate content

The host range of the soilborne obligate biotroph, Plasmodiophora brassicae was investigated. Evidence is presented that infection by P. brassicae might occur in non- Brassica species, leading to the potential formation of resting spores. Structures resembling P. brassicae were found in the root cortex of Tropaeolum majus , Carica papaya , Reseda alba and Beta vulgaris as demonstrated by scanning electron microscopy. Inoculation of Brassica rapa roots with spores extracted from either T. majus or B. vulgaris roots which had been previously inoculated with P. brassicae led to development of clubroot in the roots of B. rapa . It was also shown that the development of the symptom might be correlated with glucosinolate content, although other host factors are implicated in the B. vulgaris interaction with P. brassicae . In the glucosinolate-containing non-Brassicas, T. majus and C. papaya , the concentrations of benzylglucosinolate increased markedly in roots inoculated with P. brassicae , compared with the controls. There were also increases in concentrations of benzylglucosinolate in leaves of T. majus after P. brassicae infection. However, in R. alba roots, the total glucosinolate content decreased after inoculation with P. brassicae compared with the controls. High root concentrations of 2-OH-2-phenylethylglucosinolate (glucobarbarin) compared with low root indole glucosinolates in this species might limit P. brassicae infection and development. The importance of our investigations in relation to cultivation of non- Brassica species on fields infested with P. brassicae is discussed.     

Interspecific differences in the response of arbuscular mycorrhizal fungi to Artemisia tridentata grown under elevated atmospheric CO2

Arbuscular mycorrhizal (AM) fungi form mutualistic symbioses with the root systems of most plant species. These mutualisms regulate nutrient exchange in the plant–soil interface and might influence the way in which plants respond to increasing atmospheric CO₂. In other experiments, mycorrhizal responses to elevated CO₂ have been variable, so in this study we test the hypothesis that different genera of AM fungi differ in their response, and in turn alter the plant's response, to elevated CO₂. Four species from three genera of AM fungi were tested. Artemisia tridentata Nutt. seedlings were inoculated with either Glomus intraradices Schenck & Smith, Glomus etunicatum Becker & Gerdemann, Acaulospora sp. or Scutellospora calospora (Nicol. & Gerd.) Walker & Sanders and grown at either ambient CO₂ (350 ppm) or elevated CO₂ (700 ppm). Several significant inter-specific responses were detected. Elevated CO₂ caused percent arbuscular and hyphal colonization to increase for the two Glomus species, but not for Acaulospora sp. or S. calospora . Vesicular colonization was not affected by elevated CO₂ for any fungal species. In the extra-radical phase, the two Glomus species produced a significantly higher number of spores in response to elevated CO₂, whereas Acaulospora sp. and S. calospora developed significantly higher hyphal lengths. These data show that AM fungal taxa differ in their growth allocation strategies and in their responses to elevated CO₂, and that mycorrhizal diversity should not be overlooked in global change research.     

接种AM真菌对玉米和油菜种间竞争及土壤无机磷组分的影响

在温室盆栽条件下,分别模拟单作、间作和尼龙网分隔种植,比较接种丛枝菌根(arbuscular mycorrhizal, AM)真菌Glomus intraradices和Glomus mosseae对菌根植物玉米和非菌根植物油菜生长和磷吸收状况的影响,并分析土壤中各无机磷组分的变化。结果发现,接种AM真菌可以促进土壤中难溶性磷(Ca₁₀-P和O-P)向有效态磷转化,并显著降低总无机磷含量 (P<0.05),显著提高菌根植物玉米的生物量和磷吸收量(P<0.05),特别是在间作体系中使玉米的磷营养竞争比率显著提高了45.0%-104.1% (P<0.05),显著降低了油菜的生物量和磷吸收量(P<0.05),从而增强了了菌根植物的竞争优势,降低了非菌根植物与菌根植物的共存能力。揭示了石灰性土壤中AM真菌对植物物种多样性的影响,有助于更加全面地理解AM真菌在农业生态系统中的作用。     

Interactions between Lotus japonicus genotypes and arbuscular mycorrhizal fungi

Abstract

Interactions between three genotypes (Ljsym 71-1, Ljsym 71-2 and Ljsym 72) of Lotus japoicus and one isolate from each of four species of arbuscular mycorrhizal fungi (Glomus sp. R-10, Glomus intraradices, Glomus etunicatum, and Gigaspora margarita) were investigated and compared with the wild-type ‘Gifu’ B-129. All the three genotypes showed no or defective internal colonization after inoculation with these AM fungi. In Ljsym72 mutant, the AM fungi produced deformed appressoria on the root surface, but failed to form any internal structures (internal hyphae, arbuscules and vesicles) except only in Glomus intraradices. The Ljsym71-1 and Ljsym71-2 mutants had more deformed appressoria and occasionally formed internal hyphae, arbuscules and vesicles, depending on AM fungi used. Wild-type ‘Gifu’ (nod⁺myc⁺) plants had typical colonization. The colonization of mutants by several fungi varied and provides a basis for studying recognition and compatibility between plants and mycorrhizal fungal species. These mutants also will be useful in studies of the genetics of the symbiosis between plant species and AM fungi.     

不同pH水平下两种菌根真菌对紫云英生长的影响及其相互作用

设计在不同pH水平（4.3、5.1、5.8、6.8）下两种VA菌根真菌Glomus mosseae和Gigaspora margarita对紫云英Astragalus sinicus进行单接种、混合接种及无接种对照的盆栽实验。对紫云英地上和地下部分生物量、根部侵染率、SDH和ALP酶活进行了检测。实验结果表明：紫云英的生长效应与VA菌根真菌的侵染率及两种酶活成明显相关性。土壤pH升高,单接种Glomus mosseae和混合接种的侵染率也随之升高,而单接种Gigaspora margarita的侵染率呈现     

Arbuscular Mycorrhizal Fungi Promote the Growth of Ceratocarpus arenarius (Chenopodiaceae) with No Enhancement of Phosphorus Nutrition

The mycorrhizal status of plants in the Chenopodiaceae is not well studied with a few controversial reports. This study examined arbuscular mycorrhizal (AM) colonization and growth response of Ceratocarpus arenarius in the field and a greenhouse inoculation trial. The colonization rate of AM fungi in C. arenarius in in-growth field cores was low (around 15%). Vesicles and intraradical hyphae were present during all growth stages, but no arbuscules were observed. Sequencing analysis of the large ribosomal rDNA subunit detected four culturable Glomus species, G. intraradices, G. mosseae, G. etunicatum and G. microaggregatum together with eight unculturable species belong to the Glomeromycota in the root system of C. arenarius collected from the field. These results establish the mycotrophic status of C. arenarius. Both in the field and in the greenhouse inoculation trial, the growth of C. arenarius was stimulated by the indigenous AM fungal community and the inoculated AM fungal isolates, respectively, but the P uptake and concentration of the mycorrhizal plants did not increase significantly over the controls in both experiments. Furthermore, the AM fungi significantly increased seed production. Our results suggest that an alternative reciprocal benefit to carbon-phosphorus trade-off between AM fungi and the chenopod plant might exist in the extremely arid environment.     

Effects of metal phytoextraction practices on the indigenous community of arbuscular mycorrhizal fungi at a metal-contaminated landfill

Phytoextraction involves use of plants to remove toxic metals from soil. We examined the effects of phytoextraction practices with three plant species (Silene vulgaris, Thlaspi caerulescens, and Zea mays) and a factorial variation of soil amendments (either an ammonium or nitrate source of nitrogen and the presence or absence of an elemental sulfur supplement) on arbuscular mycorrhizal (AM) fungi (Glomales, Zygomycetes) at a moderately metal-contaminated landfill located in St. Paul, Minn. Specifically, we tested whether the applied treatments affected the density of glomalean spores and AM root colonization in maize. Glomalean fungi from the landfill were grouped into two morphotypes characterized by either light-colored spores (LCS) or dark-colored spores (DCS). Dominant species of the LCS morphotype were Glomus mosseae and an unidentified Glomus sp., whereas the DCS morphotype was dominated by Glomus constrictum. The density of spores of the LCS morphotype from the phytoremediated area was lower than the density of these spores in the untreated landfill soil. Within the experimental area, spore density of the LCS morphotype in the rhizosphere of mycorrhizal maize was significantly higher than in rhizospheres of nonmycorrhizal S. vulgaris or T. caerulescens. Sulfur supplement increased vesicular root colonization in maize and exerted a negative effect on spore density in maize rhizosphere. We conclude that phytoextraction practices, e.g., the choice of plant species and soil amendments, may have a great impact on the quantity and species composition of glomalean propagules as well as on mycorrhiza functioning during long-term metal-remediation treatments.     

不同pH水平下两种菌根真菌对紫云英生长的影响及其相互作用

设计在不同pH水平(4.3、5.1、5.8、6.8)下两种VA菌根真菌Glomus mosseae和Gigaspora margarita对紫云英Astragalus sinicus进行单接种、混合接种及无接种对照的盆栽实验.对紫云英地上和地下部分生物量、根部侵染率、SDH和ALP酶活进行了检测.实验结果表明:紫云英的生长效应与VA菌根真菌的侵染率及两种酶活成明显相关性.土壤pH升高,单接种Glomus mosseae和混合接种的侵染率也随之升高,而单接种Gigaspora margarita的侵染率呈现出先上升后下降的趋势.本实验设计了特异性扩增Glomus mosseae和Gigaspora margarita的引物gml和gigl,在混合接种实验中,nested PCR扩增结果显示:在低pH水平下(4.3-5.1)大多数根段为Gigaspora margarita所侵染,在高pH水平下(5.8-6.8)Glomusmosseae表现出较强的竞争力,但并没有检测到两种VA真菌存在于同一条侵染根段;对比单接种实验,在低pH水平下,Glomus mosseae显著抑制了Gigaspora margarita的侵染,而在高pH水平下Gigasporamargarita明显促进Glomus mosseae的侵染.     

AM真菌在煤矿废弃物中生态适应性的初步研究

以粉煤灰、草炭、蛭石、河沙为培养基质,分别对4种不同AM真菌:Glomus mosseae,G.diaphanum,G.intraradices和G.versiforme的生态适应性进行研究。结果表明,菌根的侵染率、孢子密度和菌丝长度分别与菌根真菌种类、培养基质状况及寄主植物种类有关。4种基质的扩繁效果顺序为:河沙>粉煤灰>草炭>蛭石。G.mosseae和G.diaphanum在基质中的产孢量和菌丝长度优于G.intraradices和G.versiforme,可作为优势菌株。4种菌根真菌在粉煤灰中对寄主的侵染率均达到60%以上,粉煤灰作为菌根真菌培养基质具有更大潜力和实际应用价值。     

福建漳州常见药用植物根围的丛枝菌根真菌

为了解闽南地区药用植物根围丛枝菌根真菌多样性分布,作者调查了福建省漳州市20种常见药用植物根围的AM真菌。从福建省漳州市小溪镇、国强乡等地共分离出无梗囊霉属Acaulospora 12种、原囊霉属Archaeospora 1种、巨孢囊霉属Gigaspora 2种、球囊霉属Glomus 42种、盾巨孢囊霉属Scutellospora 9种,其中沙生球囊霉Glomus arenarium、金黄球囊霉Glomus aureum和厚皮球囊霉Glomus callosum等3种为我国新记录种。     

Selection of appropriate host plants used in trap culture of arbuscular mycorrhizal fungi

Arbuscular mycorrhizal (AM) fungi in coalmine spoil, island forest and saline soils were enriched in pot culture with maize (Zea mays L.), tobacco (Nicotiana tabacum L.), white clover (Trifolium repens Linn.) and silverweed cinquefoil (Potentilla anserina L.). Based on spores, there were more species of AM fungi in the coalmine spoil (15 species, 3 genera), than in the forest soil (11 species, 4 genera) and the saline soil (5 species, 2 genera). In the trap cultures, the total of 28 species in Acaulospora, Gigaspora, Glomus, and Sclerocystis detected in the original soils were all recovered with at least one of the four trap plants. The highest spore and species numbers were recovered in trap cultures of T. repens inoculated with coalmine spoil. Glomus constrictum and Glomus multicaule were the dominant species associated with N. tabacum grown in saline soil and forest soil. The dominant species of AM fungi on the four hosts was Acaulospora mellea, which had over 90% of the spore incidence in pot trap culture in coalmine spoil. It is suggested that there be selectivity between host plants and AM fungi. The number of species of AM fungi detected was influenced by host plants under certain conditions and white clover was generally the optimal host plant to detect diversity of AM fungi.