丛枝菌根结构与功能研究进展

丛枝菌根(arbuscular mycorrhiza,AM)是陆地生态系统中分布最广泛、最重要的互惠共生体之一,对提高植物抗逆性、修复污染生境、保持生态系统稳定与可持续生产力的作用显著.AM结构特征是判断菌根形成的主要指标,与其功能密切相关.本文总结了AM丛枝结构、泡囊结构、菌丝结构和侵入点结构等发育特征;分析了A型丛枝结构、P型丛枝结构、泡囊结构和根外菌丝结构与促进寄主植物养分吸收和生长、提高植物抗旱性、耐涝性、耐盐性、抗高温、拮抗病原物、提高植物抗病性、抗重金属毒性、分解有毒有机物、修复污染与退化土壤等功能的关系,及其所发挥的重要作用;探讨了影响AM结构与功能的因子,以及基于AM不同结构所发挥功能的作用机制.旨在为系统研究AM真菌发育特征、AM真菌效能机制,以及评价和筛选AM真菌高效菌种提供依据.     

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。     

AM真菌对重金属污染土壤生物修复的应用与机理

土壤重金属污染威胁人类健康和整个生态系统,而高效、低耗、安全的生物修复技术显示出了极大的应用潜力,特别是利用植物-微生物共生体增强生物修复效应的应用.丛枝菌根(Arbuscular Mycorrhizae,AM)真菌是一类广泛分布于土壤生态系统中的有益微生物,能与90％以上的陆生高等植物形成共生体.研究发现,AM真菌能够增强宿主植物对土壤中重金属胁迫的耐受性.当前,利用AM真菌开展重金属污染土壤的生物修复已经引起环境学家和生态学家的广泛关注.基于此,围绕AM真菌在重金属污染土壤生物修复作用中的最新研究进展,从物理性防御体系的形成、对植物生理代谢的调控、生化拮抗物质的产生、基因表达的调控等角度探究AM真菌在重金属污染土壤生物修复中的作用机理,以期为利用AM真菌开展重金属污染的生物修复提供理论依据,并对本领域未来的发展和应用前景进行了展望.     

同位素示踪技术在丛枝菌根真菌生态学研究中的应用

丛枝菌根(arbuscular mycorrhizal,AM)真菌是生态系统中重要的土壤微生物之一。AM真菌菌丝体网络是由AM真菌菌丝体在土壤生态系统中连接两株或两株以上植物根系所形成的菌丝体网络。随着菌根学研究的深入,如何直观的揭示AM真菌的生态学功能已经成为相关领域关注的热点问题。研究发现,利用同位素示踪技术可以开展AM真菌与宿主植物对土壤矿质营养的吸收、转运等方面的研究,以及菌丝体网络对不同宿主植物之间营养物质的分配研究和AM真菌在生态系统生态学中的功能研究。基于此,为了阐明同位素示踪技术在AM真菌研究中的价值,围绕菌根学最新研究进展,系统回顾了利用同位素示踪技术探究AM共生体对不同元素吸收和转运的机制、同位素示踪技术在AM真菌菌丝体网络研究中的价值和利用同位素示踪技术研究AM真菌在生态系统中的功能,为AM真菌生态学功能的研究提供理论基础,并对本领域未来的研究方向和应用前景进行展望。     

丛枝菌根真菌与植食性昆虫的相互作用

丛枝菌根(arbuscular mycorrhizal AM)真菌与昆虫均是陆地生态系统中的重要组分,同植物关系密切,对植物的影响和作用是巨大的。生态系统中则以AM真菌-植物-昆虫互作体系参预食物网与生态过程。早在20世纪80年代,人们已开始研究AM真菌对昆虫的影响。进入21世纪人们越来越重视AM真菌与昆虫的相互作用。总结了AM真菌对昆虫取食偏好、生长、繁殖和对植物危害等方面的影响、以及昆虫对AM真菌侵染、扩展和产孢的影响;分析了植物营养状况、昆虫性别、昆虫龄期和AM真菌种类等对AM真菌与昆虫相互作用的影响特点;探讨了AM真菌与昆虫相互作用的机制;展望了利用AM真菌抑制植食性害虫、及促进天敌昆虫和部分传粉昆虫作用的可能性,旨在丰富菌根学研究内容、促进AM真菌与昆虫互作领域的深入研究、为探索生物防控农林业害虫的新途径提供依据。     

AM真菌在草原生态系统中的功能

AM真菌是土壤生态系统中重要的微生物类群,能与陆地生态系统中80%以上的高等植物建立共生体系。目前,AM真菌在维持草原生态系统稳定性中的功能已经成为生态学研究的热点问题之一。基于此,从植物个体、种群、群落和生态系统等不同层次探究AM真菌在维持植物群落多样性和草原生态系统稳定性中的功能。分析发现在个体水平上,AM真菌对宿主植物具有促生效应、抑制效应或中性效应。在种群水平上,分析AM真菌对不同宿主植物吸收土壤矿质营养的分配和调控策略,围绕构成草原植被的两大组成成分:牧草和有毒植物,论述AM真菌对植物种群增长和衰败的调控机制,并从草原植物群落的物种多样性和稳定性角度,探讨AM真菌与植物群落之间的相关性。在生态系统水平上,围绕AM真菌对草原生态系统的演替和退化草原的修复等展开论述,以期为利用AM真菌开展草原生态系统保护和恢复治理提供理论依据,并对草原菌根生态学领域未来的研究进行展望。     

丛枝菌根真菌提高植物抗病性的作用机制*

近年来, 人们越来越重视丛枝菌根（AM）真菌对植物病原物的影响和提高植物抗病性的效应。当前建立在分子生物学、免疫学和组织化学技术上的基础研究, 可以从分子水平上深入了解AM真菌提高植物抗病性的作用机制。本文主要探讨AM真菌拮抗植物土传病原物、提高抗病性的可能机制和研究途径。1 AM真菌对植物土传病原物的拮抗作用自然条件下,绝大多数植物都能形成菌根。菌根围（Mycorrhizosphere）内的主要成员：根系、细菌、真菌、线虫等之间往往通过协同和/或拮抗作用达到动态平衡。其中植物—植物间、植物—微生物间、微生物—微生物间、…     

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。     

丛枝菌根网络的生态学功能研究进展

丛枝菌根(AM)真菌是陆地生态系统中重要的土壤微生物之一.其在土壤生态系统中延伸出的根外菌丝,可以通过菌丝融合的方式形成丛枝菌根网络(AMN).AMN在土壤生态系统中发挥着重要功能：一方面,AMN可以改变土壤的理化性质,其根外菌丝分泌物可以影响土壤微生物生存的微环境,进而改变土壤微生物的群落组成;另一方面,AM真菌的根外菌丝可以吸收土壤养分,并通过AMN将吸收的营养物质在宿主植物间进行分配,调节植物物种之间的竞争关系.为了全面阐述AMN在生态系统中的功能,本文围绕最新的AMN研究成果,探究AM真菌根外菌丝在土壤中相互融合的机制、AMN影响土壤微生物的数量和组成、调节植物群落的生态学机理,以及AMN调节地下资源、植物种内和种间竞争、影响植物群落的多样性和丰富度等生态系统功能.阐述在全球变化过程中AMN与大气氮沉降、CO₂浓度升高以及温度升高的相关性,探究其在维持生态系统稳定性中的作用,并对本领域未来的发展方向和应用前景进行展望.     

入侵植物与丛枝菌根真菌的相互作用

入侵植物的入侵改变了入侵地生物群落的结构,导致生物多样性的丧失.丛枝菌根真菌(AMF)作为陆地生态系统中土壤微生物普遍的组成部分,它的种类和组成能够影响入侵植物的生长表现.这种真菌与寄主(入侵植物)特殊的关系也暗示了AMF能够影响入侵植物的入侵.反之,入侵植物的入侵同样也会影响AMF的群落结构和功能.本文在简要总结我国入侵植物种类及其危害的基础上,着重探讨了AMF与入侵植物入侵之间的关系,即AMF对入侵植物入侵过程中的作用、入侵植物入侵后如何影响AMF以及两者之间的相互作用机制.     

Suppression of the root-knot nematode [Meloidogyne incognita (Kofoid & White) Chitwood] on tomato by dual inoculation with arbuscular mycorrhizal fungi and plant growth-promoting rhizobacteria

Arbuscular mycorrhizal (AM) fungi and plant growth-promoting rhizobacteria (PGPR) have potential for the biocontrol of soil-borne diseases. The objectives of this study were to quantify the interactions between AM fungi [Glomus versiforme (Karsten) Berch and Glomus mosseae (Nicol. & Gerd.) Gerdemann & Trappe] and PGPR [Bacillus polymyxa (Prazmowski) Mace and Bacillus sp.] during colonization of roots and rhizosphere of tomato (Lycopersicon esculentum Mill) plants (cultivar Jinguan), and to determine their combined effects on the root-knot nematode, Meloidogyne incognita, and on tomato growth. Three greenhouse experiments were conducted. PGPR increased colonization of roots by AM fungi, and AM fungi increased numbers of PGPR in the rhizosphere. Dual inoculations of AM fungi plus PGPR provided greater control of M. incognita and greater promotion of plant growth than single inoculations, and the best combination was G. mosseae plus Bacillus sp. The results indicate that specific AM fungi and PGPR can stimulate each other and that specific combinations of AM fungi and PGPR can interact to suppress M. incognita and disease development.     

Influence of arbuscular-mycorrhizal fungi, Rhizobium meliloti strains and PGPR inoculation on the growth of Medicago arborea used as model legume for re-vegetation and biological reactivation in a semi-arid mediterranean area

Medicago arborea can be used for re-vegetationpurposes under semiarid conditions. These woody legumes have the ability toforman association with arbuscular mycorrhizal (AM) fungi and rhizobial bacteria,which can be maximised by microorganisms producing certain stimulatingmetabolites acting as plant growth promoting rhizobacteria (PGPR). The effectsof single and combined inoculations using microorganisms with different andinteractive metabolic capacities, namely three Glomusspecies, two Rhizobium meliloti strains (a wild type, WTand its genetically modified derivative GM) and a plant growth promotingrhizobacterium, (PGPR), were evaluated. All three inoculated AM fungi affectedMedicago growth in different ways. Differences weremaintained when soil was co-inoculated with each of the rhizobial strains (WTorGM) and the PGPR. Mycorrhizal fungi were effective in all cases, but the PGPRonly affected plant growth specific microbial situations. PGPR increased growthof G. mosseae-colonised plants associated withRhizobium WT strain by 36% and those infected byG. deserticola when associated with the rhizobial GMstrainby 40%. The most efficient microbial treatments involved mycorrhizalinoculation, which was an indication of the AM dependency of this plantspecies.Moreover, PGPR inoculation was only effective when associated with specificmycorrhizal endophytes (G. mosseae plus WT andG.deserticola plus GM rhizobial strain). The reduced root/shoot (R/S)ratio resulting from PGPR inoculation, was an indication of more effective rootfunction in treated plants. AM colonisation and nodule formation wereunaffectedby the type of AM fungus or bacteria (rhizobial strain and/or PGPR). AM fromnatural soil were less infective and effective than those from the collection.The results supported the existence of selective microbial interactionsaffecting plant performance. The indigenous AM fungi appeared to be ineffectiveand M. arborea behaved as though it was highly dependentonAM colonisation, which implied that it must have a mycorrhizal association toreach maximum growth in the stressed conditions tested. Optimum growth ofmycorrhizal M. arborea plants was associated with specificmicrobial groups, accounting for a 355% increase in growth overnodulatedcontrol plants. The beneficial effect of PGPR in increasing the growth of awoody legume, such as M. arborea under stress, was onlyobserved with co-inoculation of specific AM endophytes. As a result of theinteraction, only shoot biomass was enhanced, but not as a consequence ofenhancing of the colonising abilities of the endophytes. The growthstimulation,occurring as a consequence of selected microbial groups, may be critical anddecisive for the successful establishment of plants under Mediterraneanclimaticand soil conditions.     

Arbuscular mycorrhizal fungi and nitrogen uptake

Nitrogen (N) is among the most important macro-nutrients significantly affecting plant growth and yield production. Accordingly, N must be supplied adequately so that optimum amounts of yield are resulted. There are different ways of supplying N to the plant including the use of chemical and biological fertilization. The chemical properties of N make it very mobile, especially under humid conditions. Hence, N must not be overfertilized with respect to the economical and environmental points of view. N Biological fertilization includes the use of plant growth-promoting rhizobacteria (PGPR) including the N-fixing bacteria, rhizobium. There are also arbuscular mycorrhizal (AM) fungi in the soil, which are symbiotic to most terrestrial plants enhancing plant growth and yield production through increasing the uptake of water and nutrients by the host plant. Numerous experiments have indicated the important role of AM fungi in enhancing P uptake by plant. However, it is yet a matter of debate that how AM fungi may affect soil N dynamic and hence plant N uptake. Some of the most important and recent aspects regarding such effects by AM fungi are highlighted, which can be of significance to health and productivity of the ecosystem.     

The role of mycorrhizae and plant growth promoting rhizobacteria (PGPR) in improving crop productivity under stressful environments

Both biotic and abiotic stresses are major constrains to agricultural production. Under stress conditions, plant growth is affected by a number of factors such as hormonal and nutritional imbalance, ion toxicity, physiological disorders, susceptibility to diseases, etc. Plant growth under stress conditions may be enhanced by the application of microbial inoculation including plant growth promoting rhizobacteria (PGPR) and mycorrhizal fungi. These microbes can promote plant growth by regulating nutritional and hormonal balance, producing plant growth regulators, solubilizing nutrients and inducing resistance against plant pathogens. In addition to their interactions with plants, these microbes also show synergistic as well as antagonistic interactions with other microbes in the soil environment. These interactions may be vital for sustainable agriculture because they mainly depend on biological processes rather than on agrochemicals to maintain plant growth and development as well as proper soil health under stress conditions. A number of research articles can be deciphered from the literature, which shows the role of rhizobacteria and mycorrhizae alone and/or in combination in enhancing plant growth under stress conditions. However, in contrast, a few review papers are available which discuss the synergistic interactions between rhizobacteria and mycorrhizae for enhancing plant growth under normal (non-stress) or stressful environments. Biological interactions between PGPR and mycorrhizal fungi are believed to cause a cumulative effect on all rhizosphere components, and these interactions are also affected by environmental factors such as soil type, nutrition, moisture and temperature. The present review comprehensively discusses recent developments on the effectiveness of PGPR and mycorrhizal fungi for enhancing plant growth under stressful environments. The key mechanisms involved in plant stress tolerance and the effectiveness of microbial inoculation for enhancing plant growth under stress conditions have been discussed at length in this review. Growth promotion by single and dual inoculation of PGPR and mycorrhizal fungi under stress conditions have also been discussed and reviewed comprehensively.     

Host plant species effects on arbuscular mycorrhizal fungal communities in tallgrass prairie

Symbiotic associations between plants and arbuscular mycorrhizal (AM) fungi are ubiquitous in many herbaceous plant communities and can have large effects on these communities and ecosystem processes. The extent of species-specificity between these plant and fungal symbionts in nature is poorly known, yet reciprocal effects of the composition of plant and soil microbe communities is an important assumption of recent theoretical models of plant community structure. In grassland ecosystems, host plant species may have an important role in determining development and sporulation of AM fungi and patterns of fungal species composition and diversity. In this study, the effects of five different host plant species [Poa pratensis L., Sporobolus heterolepis (A. Gray) A. Gray, Panicum virgatum L., Baptisia bracteata Muhl. ex Ell., Solidago missouriensis Nutt.] on spore communities of AM fungi in tallgrass prairie were examined. Spore abundances and species composition of fungal communities of soil samples collected from patches within tallgrass prairie were significantly influenced by the host plant species that dominated the patch. The AM fungal spore community associated with B. bracteata showed the highest species diversity and the fungi associated with Pa. virgatum showed the lowest diversity. Results from sorghum trap cultures using soil collected from under different host plant species showed differential sporulations of AM fungal species. In addition, a greenhouse study was conducted in which different host plant species were grown in similar tallgrass prairie soil. After 4 months of growth, AM fungal species composition was significantly different beneath each host species. These results strongly suggest that AM fungi show some degree of host-specificity and are not randomly distributed in tallgrass prairie. The demonstration that host plant species composition influences AM fungal species composition provides support for current feedback models predicting strong regulatory effects of soil communities on plant community structure. Differential responses of AM fungi to host plant species may also play an important role in the regulation of species composition and diversity in AM fungal communities. Received: 29 January 1999 / Accepted: 20 October 1999     

Extracellular polysaccharides are involved in the attachment of Azospirillum brasilense and Rhizobium leguminosarum to arbuscular mycorrhizal structures.

Arbuscular mycorrhizal (AM) fungi, one of the most important component of the soil microbial community, establish physical interactions with naturally occurring and genetically modified bacterial biofertilizers and biopesticides, commonly referred to as plant growth-promoting rhizobacteria (PGPR). We have used a genetic approach to investigate the bacterial components possibly involved in the attachment of two PGPR (Azospirillum and Rhizobium) to AM roots and AM fungal structures. Mutants affected in extracellular polysaccharides (EPS) have been tested in in vitro adhesion assays and shown to be strongly impaired in the attachment to both types of surfaces as well as to quartz fibers. Anchoring of rhizobacteria to AM fungal structures may have special ecological and biotechnological significance because it may facilitate colonisation of new rhizospheres by the bacteria, and may be an essential trait for the development of mixed inocula.     

Cellular interactions between arbuscular mycorrhizal fungi and rhizosphere bacteria

Summary We have investigated whether direct physical interactions occur between arbuscular mycorrhizal (AM) fungi and plant growth promoting rhizobacteria (PGPRs), some of which are used as biocontrol agents. Attachment of rhizobia and pseudomonads to the spores and fungal mycelium ofGigaspora margarita has been assessed in vitro and visualized by a combination of electron and confocal microscopy. The results showed that both rhizobia and pseudomonads adhere to spores and hyphae of AM fungi germinated under sterile conditions, although the degree of attachment depended upon the strain.Pseudomonas fluorescens strain WCS 365 andRhizobium leguminosarum strains B556 and 3841 were the most effective colonizers. Extracellular material of bacterial origin containing cellulose produced around the attached bacteria may mediate fungal/bacterial interactions. These results suggest that antagonistic and synergistic interactions between AM fungi and rhizosphere bacteria may be mediated by soluble factors or physical contact. They also support the view that AM fungi are a vehicle for the colonization of plant roots by soil rhizobacteria.Abbreviations AM arbuscular mycorrhiza - PGPR plant growth promoting rhizobacteria - CBH cellobiohydrolase - DAPG 2,4-(diacetyl-phloroglucinol - TY triptone-yeast - LB Lauria-Bertani Dedicated to Prof. Dr. Dr. h.c. Eberhard Schnepf on the occasion of his retirement     

Specific interactions between arbuscular mycorrhizal fungi and plant growth-promoting bacteria: as revealed by different combinations

The interactions between two plant growth-promoting rhizobacteria (PGPR, Pseudomonas fluorescens SBW25 and Paenibacillus brasilensis PB177), two arbuscular mycorrhizal (AM) fungi (Glomus mosseae and Glomus intraradices) and one pathogenic fungus (Microdochium nivale) were investigated on winter wheat (Triticum aestivum cultivar Tarso) in a greenhouse trial. PB177, but not SBW25, had strong inhibitory effects on M. nivale in dual culture plate assays. The results from the greenhouse experiment show very specific interactions; for example, the two AM fungi react differently when interacting with the same bacteria on plants. Glomus intraradices (single inoculation or together with SBW25) increased plant dry weight on M. nivale-infested plants, suggesting that the pathogenic fungus is counteracted by G. intraradices, but PB177 inhibited this positive effect. This is an example of two completely different reactions between the same AM fungus and two species of bacteria, previously known to enhance plant growth and inhibit pathogens. When searching for plant growth-promoting microorganisms, it is therefore important to test for the most suitable combination of plant, bacteria and fungi in order to achieve satisfactory plant growth benefits.     

The interactions between plant life form and fungal traits of arbuscular mycorrhizal fungi determine the symbiotic community

Arbuscular mycorrhizal (AM) fungi have traditionally been considered generalist symbionts. However, an increasing number of studies are pointing out the selectivity potential of plant hosts. Plant life form, determined by plant life history traits, seems to drive the AM fungal community composition. The AM fungi also exhibit a wide diversity of functional traits known to be responsible for their distribution in natural ecosystems. However, little is known about the role of plant and fungal traits driving the resultant symbiotic assemblages. With the aim of testing the feedback relationship between plant and fungal traits on the resulting AM fungal community, we inoculated three different plant life forms, i.e. annual herbs, perennial herbs and perennial semi-woody plants, with AM fungal communities sampled in different seasons. We hypothesized that the annual climate variation will induce changes in the mean traits of the AM fungal communities present in the soil throughout the year. Furthermore, the association of plants with different life forms with AM fungi with contrasting life history traits will show certain preferences according to reciprocal traits of the plants and fungi. We found changes in the AM fungal community throughout the year, which were differentially disrupted by disturbance and altered by plant growth form and plant biomass. Both plant and fungal traits clearly contributed to the resultant AM fungal communities. The revealed process can have implications for the functioning of ecosystems since changes in dominant plant life forms or climatic variables could influence the traits of AM fungal communities in soil and hence ecosystem processes.     

Do soil inoculants accelerate dryland restoration? A simultaneous assessment of biocrusts and mycorrhizal fungi

Biological soil crusts (biocrusts) and arbuscular mycorrhizal (AM) fungi are communities of soil organisms often targeted to assist in the achievement of multiple ecological restoration goals. In drylands, benefits conferred from biocrust and AM fungal inoculation, such as improved native plant establishment and soil stabilization, have primarily been studied separately. However, comparisons between these two types of soil inoculants and investigations into potential synergies between them, particularly at the plant community scale, are needed to inform on‐the‐ground management practices in drylands. We conducted two full‐factorial experiments—one in greenhouse mesocosms and one in field plots—to test the effects of AM fungal inoculation, biocrust inoculation, and their interaction on multiple measures of dryland restoration success. Biocrust inoculation promoted soil stabilization and plant drought tolerance, but had mixed effects on native plant diversity (positive in greenhouse, neutral in field) and productivity (negative in greenhouse, neutral in field). In greenhouse mesocosms, biocrust inoculation reduced plant biomass, which was antagonistic to % root length colonized by AM fungi. Inoculation with native or commercial AM fungi did not influence plant establishment, drought tolerance, or soil stabilization in either study, and few synergistic effects of simultaneous inoculation of AM fungi and biocrusts were observed. These results suggest that, depending on the condition of existing soil communities, inoculation with AM fungi may not be necessary to promote dryland restoration goals, while inoculation with salvaged biocrust inoculation may be beneficial in some contexts.