丛枝菌根(arbuscular mycorrhizal,AM)真菌为球囊菌亚门Glomeromycotina活体植物专性共生真菌(Spatafora et al. 2016),约占土壤微生物总生物量的50% (Prasad et al. 2017)。化石证据和DNA序列分析推断AM真菌起源于4.0-4.6亿年前,与第一批陆生植物同时出现在地球上(Simon et al. 1993)。自1894年Frank第一次提出菌根概念以来,大量研究表明AM真菌能与80%的陆生植物形成共生关系(Smith & Read 2008;Schüßler & Walker 2011;Prasad et al. 2020)。
AM真菌孢子在植物所分泌信号物质的诱导下萌发并侵入植物根系,并在根系皮层细胞内形成丛枝(arbuscule)、泡囊(vesicle)和胞间菌丝等结构。丛枝是AM真菌与植物交换光合产物和矿质养分的界面,由植物激素(如独脚金内酯)刺激产生(Akiyama et al. 2005;Morgan & Connolly 2013)。AM真菌通过庞大的菌丝网络将植物根际以外的水分和矿质养分通过无隔菌丝中的原生质流传递给宿主植物,宿主植物则将高达20%的光合产物提供给AM真菌(Karandashov & Bucher 2005)。AM真菌共生不仅能促进宿主植物生长和对土壤中矿质养分的吸收(Marschner & Dell 1994;陈梅梅等 2009;Zavalloni et al. 2012;Chen et al. 2020;Jiang et al. 2021);还能缓解干旱(Nouri et al. 2020;Liu et al. 2021)、盐分(Porcel et al. 2012;Navarro et al. 2014;Krishnamoorthy et al. 2016)、病虫害(刘润进和陈应龙 2007;Bagy et al. 2019)和重金属(王发园和林先贵 2007;Riaz et al. 2021)等环境胁迫对宿主植物的影响,而且对植被恢复、群落生物多样性和稳定性的维持起重要作用(Zavalloni et al. 2012;Wang et al. 2017;Chen et al. 2020)。
国际上AM真菌研究大致经历3个阶段。19世纪初到20世纪初,研究集中于AM真菌的分离鉴定、分类系统的初步建立和接种效应评价;20世纪初到21世纪初,研究逐渐转向AM真菌与植物共生机理,依据形态特征建立的分类系统也日趋成熟;21世纪以来,分子生物学技术的发展与渗透,使AM真菌分类概念和分类方法有了长足发展,同时也产生一些分歧,至今仍未形成统一的分类系统。研究方向由AM真菌单一类群向多类群菌种(例如根瘤菌、解磷细菌等促生细菌)互作发展(龙伟文等 2000;Sharma & Sharma 2016;Hidri et al. 2019)。研究主题逐渐向各领域渗透,其中包括农业领域中菌肥的开发利用(Rocha et al. 2019;Paskovic et al. 2021)以及菌根植物对高盐(Porcel et al. 2012;Navarro et al. 2014;Krishnamoorthy et al. 2016)、干旱(Subramanian et al. 2006;Chitarra et al. 2016;Liu et al. 2021)等胁迫环境的耐受;环境学领域中AM真菌对重金属等污染物质的吸收转化(陈保冬 2002;Wang et al. 2017)。AM真菌对宿主专一性不高的特性也引发了AM真菌对不同植物(包括入侵植物和本地植物)种间关系的研究(Ren et al. 2017;Cheng et al. 2019;Li et al. 2019;Dong et al. 2021)。国内AM真菌研究起步较晚,但近30年来发展迅速,已形成一些特色研究体系。
本研究运用文献数据可视化应用软件CiteSpace对1990-2020年中国知识基础设施工程(China National Knowledge Infrastructure,CNKI)核心数据库收录的中文文献和Web of Science (WOS)核心集收录的英文文献进行统计分析。利用图形学、信息科学等学科理论与计量学引文、共现分析等研究方法,结合可视化图谱展现30年来国内外AM真菌研究概况。从研究发展趋势、关键词聚类、研究区域和机构分布、核心作者和期刊发表情况等方面分析了中英文文献对AM真菌领域的研究。
1 数据来源与统计方法
1.1 数据来源
本文基于AM真菌研究视角,选取WOS与CNKI分别作为英文和中文文献研究数据。根据SCI论文中关于“丛枝菌根真菌”这个主题词的常用英文书写,编制检索式：TS=(“Arbuscular mycorrhizal fung*” OR AMF OR “AM fungi” OR “mycorrhizal network*” OR “arbuscular mycorrhiza” OR “vesicular-arbuscular mycorrhiza” OR “V-A mycorrhizal fung*”) OR TI= (“Arbuscular mycorrhizal fung*” OR AMF OR “AM fungi” OR “mycorrhizal network*” OR “arbuscular mycorrhiza” OR “vesicular-arbuscular mycorrhiza” OR “V-A mycorrhizal fung*”) OR AB=(“Arbuscular mycorrhizal fung*” OR AMF OR “AM fungi” OR “mycorrhizal network*” OR “arbuscular mycorrhiza” OR “vesicular-arbuscular mycorrhiza” OR “V-A mycorrhizal fung*”)。文献类型选择“Article”和“Review”,共检索1990-2020年AM真菌研究领域发表的文献16 141篇(检索时间为2021年5月20日)。通过CiteSpace自带的文献去重功能结合手动剔除无关文献的方法,对文献进行精炼,共得到关键文献13 531篇。由于CNKI中数据来源期刊众多,层次不一,为高质量展示AM真菌研究进展,将期刊范围缩小至北大核心期刊与中国科学引文数据库(CSCD)来源期刊,依据AM真菌在CNKI中的不同关键词,在专业检索框中设定检索式为：SU=‘丛枝菌根真菌’OR SU=‘丛枝菌根’OR SU=‘AM真菌’OR SU=‘AMF’OR SU=‘VA菌根真菌’OR SU=‘泡囊-丛枝菌根真菌’OR AB=‘丛枝菌根真菌’OR AB=‘丛枝菌根’OR AB=‘AM真菌’OR AB=‘AMF’OR AB=‘VA菌根真菌’OR AB=‘泡囊-丛枝菌根真菌’OR AB=‘丛枝菌根真菌’OR KY=‘丛枝菌根’OR KY=‘AM真菌’OR KY=‘AMF’OR KY=‘VA菌根真菌’OR KY=‘泡囊-丛枝菌根真菌’。时间跨度1990-2020年,精确检索结果2 705个。对检索结果去重,删除无关条目,最终得到中文文献2 234篇。
1.2 研究方法
CiteSpace知识图谱是由美国德雷塞尔大学教授陈超美开发,用来分析、挖掘科学文献中蕴含的潜在知识,并在科学计量学、数据和信息可视化背景下逐渐发展起来的一款多元、分时、动态的引文可视化分析软件(李杰和陈超美 2016;宋洁和刘学录 2019)。该软件不仅能直观展示每个节点在知识网络中的位置与大小,还可通过不同的功能选择,分析相关领域研究文献的来源地区、研究学者、研究热点及其演变情况,是当前应用最广的知识图谱绘制工具之一(祝薇等 2018;宋洁和刘学录 2019)。本文借助 CiteSpace 5.8.R3版本软件的合作网络共现及共被引分析等功能,对AM真菌研究领域内1990-2020年的文献进行分析并绘制相应知识图谱来探究研究前沿及热点问题。
1.3 数据处理
运用Origin 8.0分别绘制年发表文献量随时间变化柱状图。运用CiteSpace软件分析数据,时间跨度选择1990-2020年,时间切片为1年,节点分别选择国家、机构、共被引期刊、领域作者、共被引文献及关键词,阈值设置为Top N=50 per slice,即提取每个时间切片中排名前50的对象。并通过寻径网络算法(pathfinder network scaling)对网络进行合并与修剪。根据研究需要分别选择聚类视图(cluster view)或共现视图(co-occurrence view)。聚类视图采用对数似然算法(LLR)进行聚类命名。生成并保存图谱后,通过图谱节点数量和年轮、频次、突现强度、中心度(centrality)和同质性(silhouette)等指标对知识图谱进行解读,把握AM真菌研究领域的发展规律。其中中心度指经过某个节点连接另外两个节点的最短路径线占这两个节点之间最短路径线之比,体现文献在网络结构中的重要性,通常把中心度>0.1的节点称为关键节点(项国鹏等 2016)。同质性代表聚类集群的相似度。S值在0-1之间,S越接近1说明类群内部相似程度越大,聚类的主题越明确,研究者关注这个问题越集中。一般认为S>0.5表明聚类合理(陈悦等 2015)。突现强度用于识别研究的新趋势,体现关键词在研究时段内出现频次的骤增程度,突现强度越高,研究主题越热门(宋洁和刘学录 2019)。
2 结果与分析
2.1 发文量变化趋势
1990-2020年间,AM真菌研究领域的英文发文量总体呈快速上升趋势(图1)。依据文献波动情况可分为平稳发展阶段(1990-2006年)和快速发展阶段(2007-2020年)。1990-2006年年发文量变化范围为43-348篇,该时期研究集中于植物侵染状况调查、菌种分离、接种及宿主植物对矿物质养分(以磷为主)的吸收。2007年以后该领域研究呈快速增长趋势,2019和2020年发文量分别高达1 209和1 237篇。这主要得益于3个方面：一是植物-土壤反馈理论的逐步完善使研究人员对AM真菌重要作用的认识越来越深刻;二是国际性和地区性AM真菌种质资源库的建立使AM真菌菌种的获得变得快捷容易,研究人员不再需要自己耗费时间精力专门分离菌种;三是AM真菌专用引物的不断发表、高通量测序及磷脂脂肪酸检测技术的发展使得其他学科的研究人员可以将AM真菌纳入其研究体系。
图1
图1
1990-2020年丛枝菌根真菌研究文献年发表量时间分布
Fig. 1
Temporal distribution of annual publications on AM fungi from 1990 to 2020. CNKI: China National Knowledge Infrastructure; WOS: Web of Science.
中文文献在这方面增长表现为3个阶段：发展期(1990-2000)、增长期(2001-2009)和波动期(2010-2020)。在发展期,中国AM真菌研究从1990年以前的起步阶段进入发展阶段,年发文量从0篇增加到24篇,年平均发文量10篇。研究集中于菌种资源调查以及果蔬等经济作物和林地AM真菌的应用,少量研究开始探索AM真菌对植物养分吸收的机制。2001年开始,该领域发文进入增长期,年发文量从29篇增加到119篇,平均发文量65篇。该时期对AM真菌接种研究的范围逐步扩展,对逆境胁迫抵抗的研究开始出现。2010年以后进入波动期。年发文量108-177篇,这一时期对AM真菌与宿主植物抗逆性(例如重金属、盐、干旱和温度等胁迫)关系的研究大量涌现。对中国特定区域和环境(例如喀斯特地貌区、内蒙古风沙区、内蒙古草原、金属和煤矿采矿区等)的AM真菌调查及应用研究逐渐增加,同时在各研究机构和高校形成特色研究方向。
2.2 研究热点及趋势
2.2.1 突现词趋势分析
用CiteSpace中依据探测频率突增的算法,运用突现性检测(burst detection)功能,对研究主题在短期内突然呈现急速增长的状态进行检测,以识别新的研究趋势。将时间切片设置为1年,将同义词合并分别得到41和31个英文和中文文献突现词(表1)。
表1 突现词信息表
Table 1
| 关键词 Keywords | 突现强度 Burst strength | 持续时间 Duration | 关键词 Keywords | 突现强度 Burst strength | 持续时间 Duration |
|---|---|---|---|---|---|
| Germination | 22.73 | 1990-1999 | 球囊霉属 | 7.23 | 1994-2003 |
| Infection | 207.73 | 1990-2004 | 新记录种 | 6.63 | 1994-2007 |
| Gigaspora margarita | 30.41 | 1991-2004 | 接种效应 | 3.98 | 1998-2007 |
| Spores | 57.24 | 1991-2005 | 矿质营养 | 4.91 | 1999-2006 |
| Nitrogen fixation | 13.48 | 1991-2006 | 孢子密度 | 4.45 | 2005-2010 |
| Growth response | 12.07 | 1991-2007 | 油蒿 | 3.67 | 2007-2009 |
| Phosphate | 41.76 | 1991-2008 | 时空分布 | 4.54 | 2007-2011 |
| Nodulation | 20.30 | 1991-2008 | 生长效应 | 4.31 | 2007-2011 |
| Morphology | 20.30 | 1992-2003 | 施氮量 | 3.81 | 2008-2012 |
| Glomus | 42.84 | 1992-2007 | 葡萄 | 5.29 | 2009-2010 |
| Classification | 9.62 | 1993-1997 | 丛枝菌根真菌 | 4.93 | 2009-2010 |
| Trifolium subterraneum | 22.19 | 1993-2005 | 产量 | 3.7 | 2009-2011 |
| External hyphae | 97.73 | 1993-2006 | 烤烟 | 4.59 | 2010-2014 |
| In vitro | 32.78 | 1993-2007 | 连作 | 3.71 | 2013-2016 |
| Phosphorus | 30.68 | 1993-2007 | 根系形态 | 4.64 | 2013-2017 |
| Glomus mosseae | 37.05 | 1994-2010 | 球囊霉素 | 4.85 | 2013-2020 |
| Zea may | 13.98 | 1995-2000 | 玉米 | 8.3 | 2016-2017 |
| Transport | 42.89 | 1996-2008 | 群落结构 | 9.6 | 2016-2020 |
| Glomale | 32.07 | 1997-2010 | 间作 | 7.47 | 2016-2020 |
| Medicago truncatula | 5.45 | 2005-2020 | 多样性 | 7.42 | 2016-2020 |
| Tomato | 17.68 | 2007-2011 | 滇重楼 | 7.22 | 2016-2020 |
| Community structure | 16.19 | 2008-2015 | 干旱胁迫 | 6.4 | 2016-2020 |
| Field | 16.69 | 2009-2012 | 抗氧化酶 | 5.75 | 2016-2020 |
| Ecosystem | 21.69 | 2009-2018 | 土壤养分 | 5.59 | 2016-2020 |
| Glomus intraradices | 16.28 | 2010-2014 | 喀斯特 | 5.35 | 2016-2020 |
| Grassland | 21.03 | 2011-2015 | 光合作用 | 4.45 | 2016-2020 |
| Wheat | 13.41 | 2012-2013 | 根际土壤 | 3.52 | 2016-2020 |
| Functional diversity | 16.77 | 2012-2014 | 紫花苜蓿 | 6.72 | 2017-2020 |
| Nutrition | 17.56 | 2012-2017 | 植物修复 | 4.58 | 2017-2020 |
| Gene expression | 23.40 | 2012-2020 | 盐胁迫 | 4.74 | 2018-2020 |
| Glomeromycota | 21.01 | 2014-2015 | 生物量 | 4.23 | 2018-2020 |
| Molecular diversity | 20.15 | 2014-2016 | |||
| Stress | 51.05 | 2015-2018 | |||
| Fertilization | 32.87 | 2015-2020 | |||
| Land use | 23.52 | 2016-2017 | |||
| Yield | 70.82 | 2016-2020 | |||
| Microbial community | 42.54 | 2016-2020 | |||
| Forest | 19.39 | 2016-2020 | |||
| Drought | 18.39 | 2016-2020 | |||
| Heavy metal | 32.25 | 2017-2020 | |||
| Management | 18.78 | 2017-2020 |
英文文献根据突现词主题大致经历了：调查与描述、培养与机理和功能与应用3个依次出现又互相交叉的阶段：调查与描述阶段主要为1990-2005年,该时期研究集中于不同环境和宿主中AM真菌形态学分类调查及基本功能描述。菌根侵染率是大多数调查的基本指标,而孢子是形态学分类的对象,因而infection (侵染)和spores (孢子)具有最高的突现强度和较长的持续时间。早期基本功能的探究集中于对土壤中磷酸盐的利用,因而phosphate (磷酸盐)也具有较高的突现强度。这个阶段早期,对豆科固氮植物接种AM真菌的研究大量出现;到后期,研究逐渐转向宿主植物与AM真菌间信号分子的识别,对菌根形成信号途径的研究表明其与豆科植物共享固氮过程中的结瘤信号部分途径,因此nitrogen fixation (氮固定)和nodulation (结瘤)成为这段时间的突现词。期间所用菌种以Gigaspora margarita为主,所用宿主以豆科植物Trifolium subterraneum为主。该时期形态分类相关的词,例如morphology (形态学),classification (分类)和Glomale (球囊霉目)等出现较多,其中球囊霉属Glomus突现强度最高,且一直持续到2007年,这与Glomus属在1845年被提出后,形态学鉴定的大多数AM真菌被归入该属有关(王幼珊等 2012)。内囊霉科Endogonaceae突现强度较高,但是只持续到2000年,这是因为1989年设立球囊霉科Glomaceae后,Endogonaceae的使用逐渐减少和停用(王幼珊等 2012)。培养体系与机理研究发展阶段主要为1993-2010年,此时多种培养体系建立(Brundrett et al. 1996)。除传统盆栽培养外,较多研究开始运用离体培养技术和分室隔网培养体系研究菌丝在养分传输过程中的作用,因而in vitro (离体),external hyphae (外生菌丝),transport (转运),phosphorus (磷)等成为该阶段突现词。这些培养体系的改进为AM真菌与宿主共生机理的研究提供了基础手段(Cassells et al. 1996;Declerck et al. 1998)。该阶段使用频率较高的菌种Glomus mosseae具有较高的突现强度和较长的持续时间,这与该菌种容易扩繁且功能强大有关。功能与应用阶段主要开始于2010年,该阶段突现强度较高的词有yield (产量)、stress (胁迫)、heavy metal (重金属)、land use (土地利用)和fertilization (施肥),说明该阶段研究方向已从AM真菌本身及对养分的利用转向提高宿主产量和对胁迫环境(特别是重金属)的抵抗。而研究范围也从宿主植物和AM真菌向整个土壤微生物群落转变,因此microbial community (微生物群落)也成为这个阶段的突现词。对近3年的突现词单独分析发现,随着越来越多的菌种实现基因组测序和多组学分析,Glomus intraradices、Medicago truncatula和Gene expression (基因表达)成为突现词,表明该领域菌种和宿主植物集中于上述两个物种,研究内容深入分子领域,既包括宿主植物基因表达的研究,也包括AM真菌作用的分子机理 (Wang et al. 2017;Xue & Wang 2020)。
对中文文献突现词分析发现,1994年才开始出现突现词。与英文文献类似,研究早期也以AM真菌分类为主,因此球囊霉属和新记录种具有最高的突现强度,且新记录种一词一直持续到2007年,说明这个阶段在国内不断有新记录种发表。国内对AM真菌接种效应的研究集中于1998-2007年,因而接种效应和矿质营养为该阶段突现词。从2005年开始,AM真菌野外分布调查大量出现,而孢子密度是反映AM真菌丰度最常见的指标。因此,2005-2011这个时间段孢子密度和时空分布两个词表现出较高的突现强度。对AM真菌在不同经济作物方面的应用的研究集中于2009-2015年,该阶段有多种作物,例如葡萄、烤烟和玉米成为突现词,同时反映接种效应的指标(产量)也成为这个时期的突现词。这与2003年中国“丛枝菌根真菌种质资源库”(Bank of Glomeromycota in China,BGC)的建立有关,该资源库不断分离培养并为中国各研究机构提供菌种。从2011年起,研究开始关注不同环境条件下AM真菌对宿主植物胁迫抵抗的作用。该时期代表环境条件的干旱胁迫、盐胁迫、间作、连作和植物修复等成为突现词,且大部分突现词一直持续至今。2016年以来,高通量测序的发展和测序成本的降低,以及AM真菌涉及领域的拓展,使对不同生境条件下AM群落及相关微生物群落的研究爆发式增长,因而群落结构和多样性呈现较高的突现强度。
2.2.2 关键词聚类分析
图2
表2 英文文献关键词聚类一览表
Table 2
| 编号 ID | 聚类大小 Size | 同质性 Silhouette | 年份 Year | 聚类标签 Label (LLR) |
|---|---|---|---|---|
| #0 | 52 | 0.660 | 1999 | Diversity; am fungi; nitrogen; community; carbon; bacteria; identification; bioma; dynamics; organic matter |
| #1 | 39 | 0.627 | 1992 | Gigaspora margarita; host; Glomus; photosynthesis; nitrogen fixation; germination; in vitro; vegetation; clover; soil disturbance |
| #2 | 38 | 0.523 | 2000 | Medicago truncatula; symbiosis; Glomus intraradices; tolerance; accumulation; Glomus mosseae; stress; resistance; heavy metal; gene expression |
| #3 | 37 | 0.671 | 1993 | Phosphorus; growth; colonization; inoculation; response; plant growth; nutrient uptake; maize; yield; field |
| #4 | 28 | 0.811 | 1992 | Plant; external hyphae; system; Endogonaceae; endophyte; Glomus fasciculatum; in vitro; classification; tillage; taxonomic concept |
| #5 | 21 | 0.744 | 1993 | Arbuscular mycorrhizal fungi; transport; Trifolium subterraneum; nodulation; morphology; water relation; Zea may; citrus; nitrate; phosphorus nutrition |
| #6 | 19 | 0.801 | 1992 | Rhizosphere; microorganism; population variation; quantification; enrichment; biosynthesis; salinity; calcium oxalate; abscisic acid; hydraulic conductivity |
| #7 | 8 | 0.939 | 1990 | N15; fixation; natural vegetation system; n transfer; ryegrass; sand dune; florida coalwaste |
| #8 | 6 | 0.984 | 1990 | Root; forest; ecology; Agropyron; environment; functional relationship |
表3 中文文献关键词聚类一览表
Table 3
| 编号 ID | 聚类大小 Size | 同质性 Silhouette | 年份 Year | 聚类标签 Label (LLR) |
|---|---|---|---|---|
| #0 | 134 | 0.865 | 2005 | 丛枝菌根真菌;养分;紫色土;根际;互作;旱稻;信号转导;胁迫;信号物质;抑制效应 |
| #1 | 93 | 0.815 | 2006 | 生长量;抗旱性;干旱胁迫;水分胁迫;柑橘;群落结构;矿质元素;抗氧化酶;渗透调节;耐盐性 |
| #2 | 89 | 0.858 | 2008 | 生长;盐胁迫;黄瓜;光合作用;间作;产量;光合特性;烤烟;品质;养分吸收 |
| #3 | 80 | 0.828 | 2006 | 多样性;根际土壤;土壤养分;孢子;生物修复;微生物;西藏高原;群落组成;环境因子;功能 |
| #4 | 71 | 0.920 | 2007 | 土壤因子;球囊霉素;空间分布;时空分布;土壤酶;生态分布;药用植物;油蒿;刺槐;红壤 |
| #5 | 71 | 0.869 | 2006 | 重金属;土壤;紫花苜蓿;植物修复;接种效应;黑麦草;菌根修复;土壤污染;多环芳烃;土壤修复 |
| #6 | 70 | 0.880 | 2006 | 番茄;矿质营养;生长效应;生长发育;葡萄;基质;抗性;相互作用;抗病性;磷水平 |
| #7 | 68 | 0.879 | 2004 | 侵染率;菌丝;孢子萌发;孢子数;菌丝生长;菌丝量;侵染强度;类黄酮;am菌剂;氮磷比 |
| #8 | 68 | 0.817 | 2006 | 玉米;低温胁迫;棉花;生理指标;有机磷;菌根菌;竞争;黄顶菊;黄萎病;解磷细菌 |
| #9 | 59 | 0.869 | 2007 | 孢子密度;入侵植物;频度;菌根类型;牡丹;盐碱土;感染率;聚类分析;季节动态;湿地植物 |
| #10 | 46 | 0.905 | 2007 | 降解;植物;抗逆性;氮沉降;精氨酸;接种;共生;矿区;土壤呼吸;气候变化 |
| #11 | 44 | 0.896 | 2003 | 球囊霉属;新记录种;原囊霉属;黄檗;相对多度;孢子壁;形态;硬囊霉属;资源调查;优势种 |
| #12 | 34 | 0.962 | 2004 | 宿主植物;羊草;构树;pH;光合速率;接种势;林木;磷添加;气孔导度;有机质 |
| #13 | 33 | 0.849 | 2006 | 根瘤菌;大豆;白三叶草;双接种;植被重建;矿区复垦;生态效应;磷肥;氮吸收;镉胁迫 |
| #14 | 32 | 0.921 | 2008 | 生物量;滇重楼;苜蓿;喜树幼苗;指纹图谱;次生代谢;喜树碱;可溶性糖;MDA;甾体皂苷 |
| #15 | 29 | 0.969 | 2005 | 菌根;应用;生物防治;菌剂;高温胁迫;植物营养;土传病害;高粱;污染土壤;机制 |
| #16 | 25 | 0.959 | 2004 | 丛枝;小麦;内生真菌;果树;泡囊;藏北高原;外生菌丝;生物胁迫;高寒草原;海拔梯度 |
| #17 | 23 | 0.921 | 2003 | 三叶草;烟苗;菌丝桥;有效磷;增殖技术;肥力;生长状况;氮磷营养;营养传递;侵染能力 |
| #18 | 22 | 0.948 | 2011 | 干旱;石漠化;耐旱性;桑树;生态修复;营养;光合参数;岩溶;双重胁迫;抗旱基因 |
中文关键词中,聚类#0 包括的研究范围较广,是一个综合性较强的聚类。聚类#1、#5、#13、#15和#18以胁迫环境条件下的生态修复为主,研究较多的胁迫包括干旱、水分、盐分、重金属、多环芳烃和高温中的一种或两种;接种方式涉及AM真菌单接种及与根瘤菌双接种;研究方向较多的有矿区重金属污染修复和石漠化及岩溶地区的生态修复。聚类#2、#6和#8主要涉及接种对经济作物生长生理和抗病性的影响,其中对黄瓜、烤烟、番茄、葡萄、玉米和棉花的研究较多,研究的指标包括生长效应、光合作用、养分吸收和抗病性等。聚类#3、#4、#9、#11和#16的关键词侧重于野外调查研究,其中#3以群落多样性与环境的关系为主,包含多样性、土壤养分、孢子和环境因子等。#4以土壤因子及球囊霉素调查为主,包括土壤因子、空间分布、土壤酶等。#11的关键词以野外调查过程中的形态学分类为主,出现次数较多的有球囊霉属、新记录种和原囊霉属等。#9和#16侧重于不同生境中AM真菌与宿主共生状况调查,其中包括盐碱土、藏北高原和高寒草原等主要生境,牡丹、小麦和果树等宿主植物,以及孢子密度、频度、感染率和丛枝等测定指标。聚类#7和#17主要利用室内培养装置研究养分传输机理。常用的宿主植物有三叶草和烟草,主要通过分室培养装置等研究菌丝桥在养分传递中的作用。
2.3 研究主体力量分析
2.3.1 地域和机构分布
图3
图4
表4 中文和英文主要研究机构中心度和发文量
Table 4
| 英文文献机构 Publishing institution of English articles | 国家 Country | 中心度 (发文量) Centrality (NP) | 中文文献机构 Publishing institution of Chinese articles | 中心度 (发文量) Centrality (NP) |
|---|---|---|---|---|
| 西班牙高等学术研究委员会 CSIC | 西班牙 Spain | 0.12 (458) | 中国农业大学资源与环境学院 College of Resources and Environment, China Agricultural University | 0.16 (57) |
| 美国农业部农业研究所 USDA ARS | 美国 USA | 0.10 (178) | 北京市农林科学院植物营养与资源研究所 Institute of Plant Nutrition and Resources, Beijing Academy of Agriculture and Forestry Sciences | 0.16 (45) |
| 法国国家农业研究院 INRA | 法国 France | 0.10 (166) | 青岛农业大学菌根生物技术研究所 Institute of Mycorrhizal Biotechnology, Qingdao Agricultural University | 0.11 (87) |
| 西澳大利亚大学 Univ Western Australia | 澳大利亚 Australia | 0.05 (197) | 中国科学院大学 University of Chinese Academy of Sciences | 0.11 (52) |
| 都灵理工大学 Univ Turin | 意大利 Italy | 0.05 (150) | 西南大学资源环境学院 School of Resources and Environment, Southwest University | 0.11 (48) |
| 圭尔夫大学 Univ Guelph | 加拿大 Canada | 0.04 (153) | 中国科学院研究生院 Graduate School of Chinese Academy of Sciences | 0.11 (21) |
| 意大利国家研究委员会 CNR | 意大利 Italy | 0.04 (135) | 中国科学院南京土壤研究所 Nanjing Institute of Soil Sciences, Chinese Academy of Sciences | 0.09 (30) |
| 阿德莱德大学 Univ Adelaide | 澳大利亚 Australia | 0.04 (132) | 西南大学园艺园林学院 School of Horticulture and Landscape Architecture, Southwest University | 0.08 (37) |
| 巴塞尔大学 Univ Basel | 瑞士 Switzerland | 0.04 (108) | 河南科技大学农学院 College of Agriculture, Henan University of Science and Technology | 0.07 (26) |
| 隆德大学 Lund Univ | 瑞典 Sweden | 0.04 (96) | 西北农林科技大学林学院 College of Forestry, Northwest A&F University | 0.06 (49) |
| 加州大学戴维斯分校 Univ Calif Davis | 美国 USA | 0.04 (95) | 内蒙古农业大学林学院 College of Forestry, Inner Mongolia Agricultural University | 0.06 (18) |
| 中国科学院 Chinese Acad Sci | 中国 China | 0.03 (585) | 中国矿业大学(北京)地球科学与测绘工程学院 School of Geoscience and Surveying Engineering, China University of Mining and Technology (Beijing) | 0.05 (33) |
| 捷克共和国科学院 Acad Sci Czech Republ | 捷克 Czech Republic | 0.03 (157) | 中国科学院生态环境研究中心 Research Center for Eco-Environment, Chinese Academy of Sciences | 0.05 (26) |
| 加拿大农业及农业食品部 Agr & Agri Food Canada | 加拿大 Canada | 0.03 (125) | 云南农业大学资源与环境学院 College of Resources and Environment, Yunnan Agricultural University | 0.05 (24) |
| 约克大学 Univ York | 英国 UK | 0.03 (92) | 河北大学生命科学学院 College of Life Sciences, Hebei University | 0.04 (139) |
NP: Number of published papers, the same below.
2.3.2 主要期刊分布
1990年以来,AM真菌相关研究共发表于300余个期刊,其中共被引次数较高的有Mycorrhiza、New Phytologist和Plant and Soil等(表5)。New Phytologist共被引次数和影响因子最高,菌根研究专刊Mycorrhiza发文量最高。由于AM真菌是土壤微生物的重要组成,且与植物关系密切,因此土壤生物界重要期刊Soil Biology & Biochemistry以及植物土壤相互关系领域期刊Plant and Soil的共被引次数较高。中文文献主要发表于《生态学报》《菌物学报》和《应用生态学报》等。其中微生物领域期刊只有菌物学报与微生物学通报,这说明中文文献主要集中于生态学科方面的研究。
表5 AM真菌研究发文量前十的期刊
Table 5
| 序号 No. | 英文期刊 English journals | 发文量 Records | 共被引次数 Total cited frequency | 影响因子 IF in 2020 | 中文期刊 Chinese journals | 发文量 Records |
|---|---|---|---|---|---|---|
| 1 | Mycorrhiza | 846 | 7 618 | 3.069 | 生态学报 Acta Ecologica Sinica | 141 |
| 2 | New Phytologist | 692 | 10 662 | 8.512 | 菌物学报 Mycosystema | 115 |
| 3 | Plant and Soil | 635 | 8 829 | 3.299 | 应用生态学报 Chinese Journal of Applied Ecology | 84 |
| 4 | Soil Biology & Biochemistry | 462 | 6 459 | 5.795 | 北方园艺 Northern Horticulture | 68 |
| 5 | Applied Soil Ecology | 395 | 3 855 | 3.187 | 植物营养与肥料学报 Journal of Plant Nutrition and Fertilizer | 50 |
| 6 | Biology and Fertility of Soils | 227 | 3 908 | 5.521 | 生态学杂志 Chinese Journal of Ecology | 50 |
| 7 | Frontiers in Plant Science | 202 | 1 308 | 4.402 | 微生物学通报 Microbiology | 42 |
| 8 | PLoS One | 205 | 2 534 | 2.740 | 西北植物学报 Acta Botanica Boreali-Occidentalia Sinica | 42 |
| 9 | Symbiosis | 190 | 768 | 1.780 | 草业学报 Acta Prataculturae Sinica | 37 |
| 10 | Journal of Plant Nutrition | 156 | 1 096 | 1.132 | 草业科学 Pratacultural Science | 37 |
2.3.3 主要作者分析
通过综合考虑发文量和中心度客观反映作者对AM真菌研究领域的贡献。在英文文献发文量≥25的作者中,选取中心度≥0.02的14位作者以及中心度为0.01中发文量最高的1位作者;中文文献列出中心度≥0.03中发文量位于前15的作者(表6)。英文文献发文量和中心度均位居第一的是德国的土壤生物学家Matthias C. Rillig;瑞士联邦政府农业、食品和环境研究组织的Fritz Oehl也具有较高的发文量和中心度;来自中国的作者有2位,分别是Qiangsheng Wu和Baodong Chen,这两位作者在中文文献中也排在前15位,在中英文AM真菌研究中均发挥重要作用。英文文献中,中国长江大学的Qiangsheng Wu发文量较高,排名第3。在中文文献中,河北大学的贺学礼发文量最高,青岛农业大学的刘润进和中国农业大学的李晓林分别排名第2和第3,且具有较高的中心度(表6)。
表6 主要作者的发文量和中心度
Table 6
| 序号 No. | 作者 Author | 国家 Country | 发文量 NP | 中心度 Centrality | 作者 Author | 发文量 NP | 中心度 Centrality |
|---|---|---|---|---|---|---|---|
| 1 | Matthias C. Rillig | 德国 Germany | 121 | 0.05 | 贺学礼 He XL | 142 | 0.11 |
| 2 | Fritz Oehl | 瑞士Switzerland | 107 | 0.03 | 刘润进Liu RJ | 116 | 0.29 |
| 3 | Qiangsheng Wu | 中国China | 102 | 0.01 | 李晓林Li XL | 69 | 0.33 |
| 4 | Iver Jakobsen | 丹麦Denmark | 68 | 0.04 | 毕银丽Bi YL | 59 | 0.07 |
| 5 | José-Miguel Barea | 西班牙Spain | 66 | 0.02 | 冯固Feng G | 53 | 0.06 |
| 6 | Silvio Gianinazzi | 法国France | 51 | 0.03 | 唐明Tang M | 52 | 0.07 |
| 7 | Baodong Chen | 中国China | 48 | 0.02 | 赵丽莉Zhao LL | 48 | 0.03 |
| 8 | Paola Bonfante | 意大利Italy | 44 | 0.02 | 王幼珊Wang YS | 43 | 0.15 |
| 9 | Horst Vierheilig | 澳大利亚 Australia | 39 | 0.03 | 林先贵 Lin XG | 40 | 0.11 |
| 10 | Yves Piché | 加拿大Canada | 37 | 0.02 | 吴强盛Wu QS | 37 | 0.04 |
| 11 | Concepcion Azcón-Aguilar | 西班牙 Spain | 36 | 0.04 | 姚青 Yao Q | 34 | 0.09 |
| 12 | Joseph B. Morton | 美国 USA | 29 | 0.03 | 陈保冬 Chen BD | 32 | 0.10 |
| 13 | John C. Dodd | 英国UK | 25 | 0.02 | 王发园Wang FY | 26 | 0.03 |
| 14 | Pål Axel Olsson | 瑞典Sweden | 23 | 0.02 | 张美庆Zhang MQ | 25 | 0.04 |
| 15 | Ian R. Sanders | 瑞士 Switzerland | 18 | 0.02 | 赵斌 Zhao B | 24 | 0.09 |
2.3.4 核心文献分析
对中心度≥0.2的文献按共被引频次排序发现,排名前10位的文献有4篇来自AM真菌发文量较高的10个期刊,其余主要来自国际顶级期刊Science、Nature以及综述类期刊Annual Review of Plant Biology和Nature Reviews Microbiology,还有一篇来自菌根学专刊Mycological Research (表7)。从文献内容看,其中有5篇与AM真菌分类学和系统发育关系有关,这与AM真菌分类学地位及其科属种的频繁变化有关。近年来,随着分子生物学技术的发展和AM真菌特异引物的不断出现,研究结果不断冲击传统的形态特征结果,使得AM真菌的系统发育关系不断被修正。其余几篇主要集中于AM真菌与植物共生机理的研究、AM真菌对宿主植物的作用以及对AM真菌多样性的关注。
表7 WOS数据库中AM真菌研究文献共被引频次表
Table 7
| 作者 Author | 期刊 Journal | 年份 Year | 文献 Title | 被引频次 Cited frequency |
|---|---|---|---|---|
| Krüger M | New Phytologist | 2012 | Phylogenetic reference data for systematics and phylotaxonomy of arbuscular mycorrhizal fungi from phylum to species level | 210 |
| Davison J | Science | 2015 | Global assessment of arbuscular mycorrhizal fungus diversity reveals very low endemism | 197 |
| Kiers ET | Science | 2011 | Reciprocal rewards stabilize cooperation in the mycorrhizal symbiosis | 193 |
| Spatafora JW | Mycologia | 2016 | A phylum-level phylogenetic classification of zygomycete fungi based on genome-scale data | 189 |
| Redecker D | Mycorrhiza | 2013 | An evidence-based consensus for the classification of arbuscular mycorrhizal fungi (Glomeromycota) | 154 |
| Parniske M | Nature Reviews Microbiology | 2008 | Arbuscular mycorrhiza: the mother of plant root endosymbioses | 141 |
| Smith SE | Annual Review of Plant Biology | 2011 | Roles of arbuscular mycorrhizas in plant nutrition and growth: new paradigms from cellular to ecosystem scales | 136 |
| van der Heijden MGA | Nature | 1998 | Mycorrhizal fungal diversity determines plant biodiversity, ecosystem variability and productivity | 135 |
| Schussler A | Mycological Research | 2001 | A new fungal phylum, the Glomeromycota: phylogeny and evolution | 135 |
| Opik M | New Phytologist | 2010 | The online database MaarjAM reveals global and ecosystemic distribution patterns in arbuscular mycorrhizal fungi (Glomeromycota) | 125 |
3 总结与展望
尽管AM真菌在土壤中广泛分布,但其与植物专性共生且难以纯培养的特性,使得相关研究起步较晚(Declerck et al. 1998;李晓林和冯固 2001)。本文运用文献计量学的方法,利用CiteSpace分别对WOS和CNKI数据库中1990-2020年中英文文献进行统计和可视化分析,展示了AM真菌研究领域的文献数量年变化、研究热点和发展趋势、国家和机构合作网络、核心机构分布、主要作者和核心期刊分析。英文文献在年发文量和增长速度方面均远超过中文文献。美国较高的发文量和中心度表明其在该领域的重要贡献。西班牙、德国、英国和澳大利亚等国家发表的文献也具有较高的中心度。中国的英文文献发文量仅次于美国,但是中心度较低,说明中国在英文文献的总体质量上还有待提高。对核心文献和关键词突现综合分析发现,AM真菌研究已有的重要方向包括：分类及系统发育关系(Schüβler et al. 2001;Krüger et al. 2012)、与宿主植物共生和养分交换机理(Zavalloni et al. 2012;Chen et al. 2020;Jiang et al. 2021)、农林业生产方面对不良环境(干旱、重金属、盐分和病害等)的抵抗(王发园和林先贵 2007;Wang 2017;Nouri et al. 2020;Liu et al. 2021)以及与其他生物的相互作用(Sharma & Sharma 2016;Hidri et al. 2019;Wang et al. 2021)。这些研究方向仍然值得进行更深入的研究：
1) 对菌种测序及基因谱系的研究。目前只有不到10种AM真菌实现基因组测序,样本的有限性使得对该真菌进化、共生及功能相关基因还不能形成规律性认识。对更多菌种基因组的测序不仅能为AM真菌的进化地位和不同菌种谱系关系的分析提供更可靠的依据;同一菌种不同菌株的测序还可为揭示AM真菌繁殖方式提供证据。
2) 农业和生态修复方面的机理研究及运用。在加快农业可持续发展和提高污染环境的生态修复方面,AM真菌的运用可以依次从以下3方面开展：①通过传统盆栽培养法结合水培、培养基培养等方法分离与扩繁功能菌种;②通过分子生物学方法对菌种特定功能(例如元素吸收和转运)作用机理深入分析;③通过控制实验探究和绘制功能菌种对环境因子(养分浓度、干旱水平和重金属含量等)的适应谱,为农业开发和运用提供切实可行的指导。
3) 从地下微生物系统的角度出发研究AM真菌与其他微生物相互关系。该研究方向可以从3个层次开展：①AM真菌与其他菌根真菌(例如深色有隔内生真菌)的相互关系及对根内和根际资源的竞争,这方面研究可以在多种菌根真菌共存的物种中开展;②AM真菌与其他微生物(例如AM内共生菌、菌丝际微生物)的直接关系和对宿主养分吸收利用的协同作用;③AM真菌-宿主-其他微生物三者分泌物之间的相互作用及其调控。
致谢
感谢华东师范大学博士生杨扬对Web of Science数据库中较早年份文献信息的搜索和导出。
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Arbuscular mycorrhizal (AM) fungi, which form symbioses with the roots of the most important crop species, are usually considered biofertilizers, whose exploitation could represent a promising avenue for the development in the future of a more sustainable next-generation agriculture. The best understood function in symbiosis is an improvement in plant mineral nutrient acquisition, as exchange for carbon compounds derived from the photosynthetic process: this can enhance host growth and tolerance to environmental stresses, such as water stress (WS). However, physiological and molecular mechanisms occurring in arbuscular mycorrhiza-colonized plants and directly involved in the mitigation of WS effects need to be further investigated. The main goal of this work is to verify the potential impact of AM symbiosis on the plant response to WS To this aim, the effect of two AM fungi (Funneliformis mosseae and Rhizophagus intraradices) on tomato (Solanum lycopersicum) under the WS condition was studied. A combined approach, involving ecophysiological, morphometric, biochemical, and molecular analyses, has been used to highlight the mechanisms involved in plant response to WS during AM symbiosis. Gene expression analyses focused on a set of target genes putatively involved in the plant response to drought, and in parallel, we considered the expression changes induced by the imposed stress on a group of fungal genes playing a key role in the water-transport process. Taken together, the results show that AM symbiosis positively affects the tolerance to WS in tomato, with a different plant response depending on the AM fungi species involved.© 2016 American Society of Plant Biologists. All Rights Reserved.
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The role of abscisic acid (ABA) during the establishment of the arbuscular mycorrhiza (AM) was studied using ABA sitiens tomato (Lycopersicon esculentum) mutants with reduced ABA concentrations. Sitiens plants and wild-type (WT) plants were colonized by Glomus intraradices. Trypan blue and alkaline phosphatase histochemical staining procedures were used to determine both root colonization and fungal efficiency. Exogenous ABA and silver thiosulfate (STS) were applied to establish the role of ABA and putative antagonistic cross-talk between ABA and ethylene during AM formation, respectively. Sitiens plants were less susceptible to the AM fungus than WT plants. Microscopic observations and arbuscule quantification showed differences in arbuscule morphology between WT and sitiens plants. Both ABA and STS increased susceptibility to the AM fungus in WT and sitiens plants. Fungal alkaline phosphate activity in sitiens mutants was completely restored by ABA application. * The results demonstrate that ABA contributes to the susceptibility of tomato to infection by AM fungi, and that it seems to play an important role in the development of the complete arbuscule and its functionality. Ethylene perception is crucial to AM regulation, and the impairment of mycorrhiza development in ABA-deficient plants is at least partly attributable to ethylene.
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As one of the rhizospheric microorganisms PGPR(Plant Growth Promoting Rhizobacteria) and AMF(Arbuscular Mycorrhizal Fungi) play an important role in promoting plant growth. It is of significance to further study and elucidate the interactions between them to utilize and regulate the interactions among rhizospheric microorganisms, and promote and protecte plant growth. Many research results show that on one hand, there exists synergism between PGPR and AMF. AMF can transfer PGPR or act as a media in the process of spread of PGPR along roots, where PGPR create many beneficial conditions for the infection of AMF. Both of them can indirectly enhance the other side's colonization or infection ability through their own promoting role on plant growth. On the other hand, they compete with each other for nutrients and niches, and probably produce some secondary metabolites which cause detrimental effects on the other. However, whether these interactions are synergistic or competitive depends upon the AM fungal or PGPR species involved. So far, the research work is extensive, even in molecular level in some aspects, but not systematic and deep. It is believed however, with the development of techniques in molecular biology and the increasing application of advanced testing methods, the new breakthroughs will be gained in the study and understanding on the interactions.
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Seedlings of Cleopatra mandarin (Citrus reshni Hort. ex Tan.) and Alemow (Citrus macrophylla Wester) were inoculated with a mixture of AM fungi (Rhizophagus irregularis and Funneliformis mosseae) (+AM), or left non-inoculated (-AM). From forty-five days after fungal inoculation onwards, half of +AM or -AM plants were irrigated with nutrient solution containing 50 mM NaCl. Three months later, AM significantly increased plant growth in both Cleopatra mandarin and Alemow rootstocks. Plant growth was higher in salinized +AM plants than in non-salinized -AM plants, demonstrating that AM compensates the growth limitations imposed by salinity. Whereas AM-inoculated Cleopatra mandarin seedlings had a very good response under saline treatment, inoculation in Alemow did not alleviate the negative effect of salinity. The beneficial effect of mycorrhization is unrelated with protection against the uptake of Na or Cl and the effect of AM on these ions did not explain the different response of rootstocks. This response was related with the nutritional status since our findings confirm that AM fungi can alter host responses to salinity stress, improving more the P, K, Fe and Cu plant nutrition in Cleopatra mandarin than in Alemow plants. AM inoculation under saline treatments also increased root Mg concentration but it was higher in Cleopatra mandarin than in Alemow. This could explain why AM fungus did not completely recovered chlorophyll concentrations in Alemow and consequently it had lower photosynthesis rate than control plants. AM fungi play an essential role in citrus rootstock growth and biomass production although the intensity of this response depends on the rootstock salinity tolerance.Copyright © 2013 Elsevier GmbH. All rights reserved.
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Arbuscular mycorrhizal (AM) fungi and plant growth-promoting rhizobacteria, responsible for enhancing plant nutrition, vigour and growth, may be used to reduce dosages of chemical fertilisers. Technologies that allow an economically viable and efficient application of these beneficial microbes in large scale agriculture must be studied. Seed coating is a potential delivery system for efficiently introducing minor amounts of bioinoculants. Despite the dramatic reduction on inoculum dose per plant, inoculation of AM fungi via seed coating was as effective as conventional soil inoculation. Fertilisation and inoculation had a significant impact on maize shoots nutrient concentrations. Different fertilisation regimes did not influence mycorrhizal colonisation. Plants without fertilisation and singly inoculated with R. irregularis showed shoot nutrient concentration increments of 110, 93, 88 and 175% for nitrogen, phosphorus, potassium and zinc, respectively, comparing with non-inoculated controls. Plants singly inoculated with P. fluorescens via seed coating under full fertilisation, presented enhancements of 100, 75 and 141% for magnesium, zinc and manganese, respectively, comparing with non-inoculated controls. Seed coating is a promising tool for delivering microbial inoculants into the soil, while promoting sustainable production of maize. This technology is particularly pertinent in low input agriculture, with potential environmental profits and food quality improvements.
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PMID:26070449
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7 Evolution of the ‘plant-symbiotic’ fungal phylum, Glomeromycota
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Research progress on international studies on applied ecology based on Web of Science
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PMID:30912400
Applied ecology is one of the most important scientific and technological tools for natural resources management and environment protection. Under the current situation of natural resource shortage, serious environmental pollution, and ecosystem degradation, understanding the theoretical basis, research methods and research hotspots of international studies on applied ecology is of great significance for consolidating the knowledge base, indicating the research direction, defining the strategic position of China's studies on applied ecology. Based on the principle of bibliometrics and information visualization software (CiteSpace and Carrot), we took two document datasets as research objects which were searched from Web of Science based on different search strategies in the field of international studies on applied ecology from 1980 to 2018. We analyzed the spatial and temporal distribution of the literature, the core research forces, the evolution and frontier trend of research hotspots from three dimensions, i.e. research carrier, research strength, and research content. Our results could reveal its evolutionary trajectory, research status and development trend and provide reference for future studies on applied ecology in China.
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Zygomycete fungi were classified as a single phylum, Zygomycota, based on sexual reproduction by zygospores, frequent asexual reproduction by sporangia, absence of multicellular sporocarps, and production of coenocytic hyphae, all with some exceptions. Molecular phylogenies based on one or a few genes did not support the monophyly of the phylum, however, and the phylum was subsequently abandoned. Here we present phylogenetic analyses of a genome-scale data set for 46 taxa, including 25 zygomycetes and 192 proteins, and we demonstrate that zygomycetes comprise two major clades that form a paraphyletic grade. A formal phylogenetic classification is proposed herein and includes two phyla, six subphyla, four classes and 16 orders. On the basis of these results, the phyla Mucoromycota and Zoopagomycota are circumscribed. Zoopagomycota comprises Entomophtoromycotina, Kickxellomycotina and Zoopagomycotina; it constitutes the earliest diverging lineage of zygomycetes and contains species that are primarily parasites and pathogens of small animals (e.g. amoeba, insects, etc.) and other fungi, i.e. mycoparasites. Mucoromycota comprises Glomeromycotina, Mortierellomycotina, and Mucoromycotina and is sister to Dikarya. It is the more derived clade of zygomycetes and mainly consists of mycorrhizal fungi, root endophytes, and decomposers of plant material. Evolution of trophic modes, morphology, and analysis of genome-scale data are discussed.© 2016 by The Mycological Society of America.
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Role of a buscular mycorrhizae in phytoremediation of heavy metal-contaminated soils
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The migration footprint of industrial ecology research: visualized research based on CiteSpace Ⅱ
Arbuscular mycorrhizal associations and the major regulators
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Exposure to warming and CO2 enrichment promotes greater above-ground biomass, nitrogen, phosphorus and arbuscular mycorrhizal colonization in newly established grasslands
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Knowledge mapping analysis of ecological risk research based on CiteSpace
