共查询到20条相似文献，搜索用时 703 毫秒
1.
MYB转录因子蛋白普遍存在于植物中,广泛参与植物的生长发育和代谢调控。为研究GhMYB9基因对棉纤维的调控机制,使用PCR方法,从棉花中克隆1个R2R3-MYB基因GhMYB9(Gen Bank登录号:AF336286.1);利用生物信息学方法分析其氨基酸序列;构建酵母表达载体。结果表明,该基因c DNA全长1 145 bp,开放阅读框长795 bp,编码264个氨基酸,预测其蛋白分子量约为29.624 k D,等电点为9.13。推测的氨基酸序列中含有2个高度保守的SANT结构域。GhMYB9基因组包含2个外显子和1个内含子。进化树分析表明,GhMYB9和Gh MYB聚在同一分支(HQ234875.1)。酵母单杂交试验结果表明,GhMYB9转录因子能够特异结合AC顺式作用元件。本研究结果为进一步阐明GhMYB9的生物学功能奠定了基础。 相似文献
2.
MYB是真核生物中一类重要的转录因子,参与调控植物生长发育、初生次生代谢和生物或非生物胁迫响应。为全面解析甘薯基因组MYB转录因子信息,本研究基于甘薯二倍体近缘野生种三裂叶薯的全基因组测序数据,利用多种生物学软件和在线工具对三裂叶薯MYB转录因子的结构域、基因结构、保守基序、染色体定位和系统进化等进行鉴定和分析。利用qRT-PCR检测其中10个R2R3-MYB基因在干旱和盐胁迫下的表达情况。结果表明,在三裂叶薯的全基因组中共鉴定出不均匀分布于15条染色体的160个Itb MYB基因,其中第7号染色体上分布最多(21个基因),第8号染色体上分布最少(6个基因)。根据MYB结构域所含MYB重复个数,160个Itb MYB家族转录因子被分为4类,其中1R类包含36个基因、R2R3类120个基因、3R类4个基因、4R类1个基因。系统进化分析显示,160个Itb MYB聚为18个亚家族,且同一亚家族的Itb MYB转录因子的motif类型和数目相似,但所含外显子和内含子的数目不同。根据拟南芥R2R3-MYB转录因子的分类标准,进一步将三裂叶薯R2R3-MYB类分为30个亚类。qRT-PCR检测结果表明,R2R3-MYB响应干旱和盐胁迫,且不同胁迫时间下不同组织中的表达量存在差异。本试验为进一步研究甘薯MYB转录因子的功能奠定了一定的理论基础。 相似文献
3.
甘蔗R2R3-MYB类似基因Sc2RMyb1的克隆及表达特性分析 总被引：2，自引：0，他引：2
R2R3-MYB是MYB转录因子基因家族的主要成员,已被证明在次生代谢和非生物逆境胁迫应答中起重要作用。为获得甘蔗(Saccharum complex)R2R3-MYB转录因子基因序列信息及其在不同非生物因子胁迫下的表达情况,本研究通过对甘蔗EST数据的分析,运用电子克隆获得一个甘蔗R2R3-MYB类似基因序列,进而采用PCR方法从甘蔗中克隆了该基因的基因组DNA和cDNA序列,基因命名为Sc2RMyb1(GenBank序列号:JQ823165)。Sc2RMyb1的基因组DNA全长1807bp,由3个外显子和2个内含子构成,编码区长度为1284bp,编码427个氨基酸。构建含有Sc2RMyb1基因的原核表达载体并转入大肠杆菌(Escherichia coli),经IPTG诱导产生的重组蛋白相对分子量约为52kD。在NaCl胁迫的LB培养基上,重组菌生长明显优于对照菌。实时荧光定量PCR分析表明,甘蔗中Sc2RMyb1基因的表达受H2O2和NaCl抑制而下调,推测该基因作为负调节因子参与了NaCl胁迫应答相关基因的调控过程。本研究结果为后续该类转录因子基因在甘蔗抗逆相关机理研究和抗逆育种中的应用提供了基础资料。 相似文献
4.
以抗白粉病华东葡萄（Vitis pseudoreticulata W.T.Wang）株系白河-35-1为材料,在经葡萄白粉病病原菌（Uncinula necator（Schw.）Burr.）诱导后获得的EST序列的基础上,本研究通过RACE技术克隆了一个具有转录域的转录因子全长1324bpcDNA序列,其阅读框为1053bp,编码350个氨基酸,命名为VpRFL1（GenBank登录号：FJ356672）。应用PCR技术,进一步获得了转录因子VpRFL1基因的DNA序列,其序列全长1599bp,VpRFL1基因包含3个外显子,2个内含子。生物信息学分析表明,华东葡萄白河-35-1VpRFL1基因编码的氨基酸序列在N端含有核定位信号,C端含有C4C4型RING锌指结构域。VpRFL1/PBI221-GFP在洋葱（Alliumcepa）表皮细胞中的瞬时表达分析表明,该转录因子主要定位于细胞核内。VpRFL1的序列特征与定位分析结果初步表明该转录因子基因在核内起作用,并可能参与了抗逆反应的相关途径。 相似文献
5.
棉花转录因子基因(GhMYB11)的克隆与表达分析 总被引：1，自引：0，他引：1
MYB基因家族在植物应对外界生物和非生物胁迫的过程中有重要的调控作用.本研究利用二倍体雷蒙德氏棉(Gossypium raimondii)基因组数据库,从陆地棉(G.hirsutum)品种鲁棉研32号中克隆到一个新的MYB转录因子GhMYB111(GenBank登录号:HQ234875.1),Cdna全长1 001 bp,开放阅读框828bp.通过与模式植物拟南芥(Arabidopsis thaliana)和主要作物小麦(Triticum aestivum L.)、玉米(Zea mays L.)、水稻(Oryza sativa L.) MYB蛋白的氨基酸序列比对发现,GhMYB 11蛋白与拟南芥中脱落酸(abscisic acid,ABA)合成和信号传导的重要基因AtMYB13/14编码的蛋白高度相似(E值分别为7e-83和1e-90),含两个高度保守的MYB结构域R2R3及一个转录激活结构域.实时定量PCR分析发现,GhMYB 11基因在黄萎病菌(Verticillium dahliae)侵染、干旱、盐和氧化胁迫处理后的棉花幼苗叶片中表达显著上调.GhMYB11基因可能在棉花生物和非生物胁迫反应中起重要调控作用,是陆地棉品种抗逆性遗传改良的重要候选基因.本研究为利用基因工程手段提高棉花抗逆性提供了基础材料 相似文献
6.
MYB转录因子在植物响应盐胁迫过程中起着重要的调控作用。为明确MYB类转录因子RcWER-like生物学功能,本研究以月季月月粉为材料,利用生物信息学分析及实时荧光定量PCR技术研究RcWER-like基因在盐处理、激素处理、盐与激素综合处理下不同组织不同时间点的表达特性。结果表明,依据转录组测序获得的序列信息和月季全基因组信息克隆得到了RcWER-like,该基因全长为882 bp,开放阅读框(ORF)为669 bp,编码223个氨基酸。序列比对发现,RcWER-like在N端具有保守的R2R3-MYB结构域。系统进化树分析结果显示,RcWER-like与桃PpWER-like、梅花PmWER-like、苹果MdWER-like处于同一分支,属于R2R3-MYB类转录因子。实时荧光定量PCR结果表明,RcWER-like基因在盐胁迫处理24 h后表达明显上调,且外施水杨酸和茉莉酸甲酯均可诱导RcWER-like的表达;在盐胁迫下,外施水杨酸和茉莉酸甲酯可诱导RcWER-like的表达,且均高于单独盐或激素处理。此外,月季RcWER-like在盐处理、激素处理、盐与激素综合处理下不同组织不同时间点的表达模式存在显著差异,R2R3-MYB类转录因子RcWER-like参与了月季盐胁迫响应和对水杨酸和茉莉酸甲酯的应答过程,可能在月季高盐胁迫应答中具有重要的作用。本研究结果为月季耐盐分子育种提供了候选基因资源和理论依据。 相似文献
7.
为探究桃MADS转录因子基因的序列特征、表达模式及其对类胡萝卜素合成的调控作用,本研究从桃果实中克隆得到一个MADS-box家族基因,命名为PpMADS1。结果表明,PpMADS1的开放阅读框(ORF)为732 bp,编码243个氨基酸,蛋白具有亲水性,稳定性较差,其二级结构以α-螺旋为主要构成元件,且与三级结构相似。亚细胞定位预测显示PpMADS1蛋白定位于细胞核。氨基酸序列分析及系统进化分析结果表明,PpMADS1属于MADS-box转录因子AG亚族,与乌梅亲缘关系最近。实时荧光定量PCR结果表明,PpMADS1基因在芽和叶中几乎不表达,在花和果实中大量表达,黄肉桃品种金丽果实成熟后期PpMADS1表达量显著高于白肉桃品种湖景果实。双荧光素酶试验结果表明,PpMADS1转录因子对PpPSY和PpCHYB启动子具有转录激活作用。因此推测PpMADS1可能通过调控PpPSY和PpCHYB基因表达促进桃果实类胡萝卜素合成。本研究为桃MADS-box转录因子的进一步功能分析奠定了理论基础。 相似文献
8.
沪油15中两个AP2/ERF-B1亚族转录因子的克隆与分析 总被引：1，自引：1，他引：0
利用油菜EST数据库,以拟南芥ERF-B1亚族转录因子序列为探针,电子克隆拼接得到2个cDNA序列（BnaERFB1-1和BnaERFB1-2）,通过PCR和RT-PCR方法分别从甘蓝型油菜沪油15的DNA和cDNA中克隆了上述基因。克隆转录因子BnaERFB1-1-Hy15和BnaERFB1-2-Hy15与电子克隆的序列差异很小,分别只有2个和6个氨基酸位点不同,且都没有内含子。从cDNA序列、氨基酸序列的相似性、组成成分、理化性质、疏水性/亲水性、进化树、序列比对、功能域、二级和三级结构等方面进行了分析,结果显示,BnaERFB1-1-Hy15和BnaERFB1-2-Hy15转录因子属于AP2/ERF家族中的ERF-B1亚族,是亲水性蛋白,在蛋白质的三级结构上与拟南芥atERF7相似。EST丰度分析显示,BnaERFB1-1的表达主要集中在种子中,而BnaERFB1-2的表达则主要集中在分生组织中。 相似文献
9.
棉花转录因子GhWRKY11的克隆及功能分析 总被引：1，自引：0，他引：1
短季棉(Gossypium hirsutum)的早熟往往伴随着早衰,挖掘和鉴定衰老相关基因对于选育早熟不早衰棉花新品种具有重要意义,而WRKY转录因子广泛参与调控植物衰老过程.本研究克隆了陆地棉WRKY转录因子GhWRKY11(GenBank accession No.JN604988),cDNA全长1 055 bp,包含1 008 bp开放阅读框(open reading frame,ORE),编码335个氨基酸,属于WRKY转录因子Ⅱd亚组.蛋白序列系统进化分析表明,GhWRKY11与拟南芥(Arabidopsis thaliana)AtWRKY11的相似度较高.基因结构分析表明,Gh WRKY11基因有3个外显子和2个内含子.亚细胞定位结果表明,GhWRKY11蛋白定位在洋葱(Allium cepa)表皮的细胞核.qRT-PCR结果分析表明,Gh WRKY11在盛花期的棉花叶片中优势表达,在子叶衰老过程中表达下调.赤霉素(gibberellin,GA3)处理棉花幼苗后,GhWRKY11在2、4、8和12h的表达显著(P＜0.05)或极显著(P＜0.01)上调;水杨酸(salicylic acid,SA)处理后,GhWRKY11的表达量随处理时间的增加而逐渐升高,并且在2、4、8和12h的表达极显著(P＜0.01)上调;同时,GhWRKY11可以在某些时间点被脱落酸(abscisic acid,ABA)、乙烯(ethylene,ET)、H2O2和茉莉酸(jasmonic acid,JA)诱导表达上调.GhWRKY11在受到低温(12℃)胁迫处理时表达上调,且在2、8和12h达极显著(P＜0.01);盐胁迫(200 mmol/L NaCl)处理后,GhWRKY11在2、4、8和12 h的表达显著(P＜0.05)或极显著(P＜0.01)上调;15％聚乙二醇6000(polyethylene glycol 6000,PEG6000)处理后,在12h的表达量极显著(P＜0.01)上调;损伤处理对该基因的表达没有显著影响.播种45 d后,与野生型拟南芥相比,GhWRKY11拟南芥过表达植株衰老延缓,由此推断,GhWRKY11可以延缓植株衰老,初步鉴定GhWRKY11是衰老的负调控因子.该基因的克隆和功能的初步分析为创制转基因抗早衰棉花材料提供基础资料. 相似文献
11.
【目的】以富士（Fuji）、 秦冠（Qinguan）嫁接在平邑甜茶（Malus hupehensis Rehd.）上的当年生盆栽苗为试验材料,采用砂培方法,研究了缺氮胁迫和干旱对富士和秦冠生长情况、 光合参数、 植株各部位氮磷钾含量及氮素利用效率的影响,分析比较了低氮干旱条件下富士和秦冠生长及氮素利用的差异,以期为果树生产高效肥水利用提供理论指导。【方法】试验共设四个处理: 正常氮正常水（ZZ）、 低氮正常水（DZ）、 正常氮干旱（ZG）、 低氮干旱（DG）。氮素和水分均设置两个水平,分别为正常氮（6 mmol/L NO-3-N）、 低氮（0.3 mmol/LNO-3-N）、 正常供水（保持盆中砂子相对含水量为饱和含水量的80%~85%）、 干旱处理（保持盆中砂子相对含水量为饱和含水量的60%~65%）。【结果】富士和秦冠的生物量（茎和叶）、 株高茎粗等生长指标以及光合速率、 气孔导度、 蒸腾速率均为正常氮正常水（ZZ）＞低氮正常水（DZ）＞正常氮干旱（ZG）＞低氮干旱（DG）,并且相对应处理下秦冠的以上指标均高于富士;正常供水下,缺氮处理使富士、 秦冠的根冠比比正常氮处理均有所增加,富士提高了2.05%,秦冠提高了22.40%。富士和秦冠的氮、 磷、 钾含量均表现出正常氮正常水（ZZ）＞低氮正常水（DZ）＞正常氮干旱（ZG）＞低氮干旱（DG）; 氮、 钾元素含量在植株各部位的分布顺序依次是叶＞根＞茎,磷元素则是根＞叶＞茎;光合氮素利用效率（PNUE）和氮素利用效率表现为秦冠处理之间差异极显著,富士处理之间差异不显著;秦冠的PNUE和NUE明显高于富士,在低氮正常水（DZ）处理下,秦冠氮肥利用率比富士高42.07%,在低氮干旱（DG）处理下高64.14%;低氮胁迫下富士和秦冠的NUE显著提高,并且秦冠提高的幅度高于富士。【结论】施用氮肥能够显著提高富士与秦冠的干物质量,同等水肥条件下,秦冠生长优于富士;水分亏缺会减少叶片对氮的吸收,干旱条件下适度增施氮肥,可提高果树的抗旱能力;低氮干旱胁迫下秦冠的生长指标、 光合指标及氮素利用效率指标均优于富士,表现出较强的抗低氮干旱胁迫的能力。 相似文献
12.
Kyle Devey Michael Mucalo Gordon Rajendram Joseph Lane 《Communications in Soil Science and Plant Analysis》2015,46(4):72-80
Laser-induced breakdown spectroscopy (LIBS) is a new technique for the analysis of plant material. This study investigates the application of LIBS to pasture-based plant samples. The LIBS measurements were obtained from pelletized pasture samples (100 samples) that had been also analyzed by inductively coupled plasma–optical emission spectroscopy (ICP-OES) following microwave digestion for calibration and comparison purposes. Comparisons for elements sodium (Na), potassium (K), magnesium (Mg), calcium (Ca), manganese (Mn), iron (Fe), copper (Cu), zinc (Zn), boron (B), phosphorus (P), and sulfur (S) showed that LIBS could be used for almost all the standard profile total elements with concentrations down to low mg/kg levels (observed error of Na: 0.024 percent, K: 0.18 percent, Mg: 0.016 percent, Ca: 0.073 percent, P: 0.017 percent, Mn: 31 mg/kg, Fe: 150 mg/kg, Zn: 6.6 mg/kg, and B: 1.1 mg/kg). Elemental analysis at less than mg/kg levels was not possible using LIBS. The elements S and Cu were particularly difficult to analyze with reliability using LIBS at the concentration levels found in the plant samples. Replacing microwave digestion and subsequent ICP analysis with a direct analysis of dried plant samples using LIBS has the potential to improve the productivity and reduce the cost of testing. 相似文献
13.
《中国生态农业学报》2014,(8)
正The Center for Agricultural Resources Research(CARR),the Institute of Genetics and Developmental Biology(IGDB),Chinese Academy of Sciences,invites applicants for several research group leader positions.CARR is one of the research organizations in Chinese Academy of Sciences(CAS).We seek nominations and applications from individuals who have expertise and a record of accomplishment in research areas related to ecology,agro-hydrology, 相似文献
14.
M.A. Callaham Jr. J.M. BlairT.C. Todd D.J. KitchenM.R. Whiles 《Soil biology & biochemistry》2003,35(8):1079-1093
The responses of tallgrass prairie plant communities and ecosystem processes to fire and grazing are well characterized. However, responses of invertebrate consumer groups, and particularly soil-dwelling organisms, to these disturbances are not well known. At Konza Prairie Biological Station, we sampled soil macroinvertebrates in 1994 and 1999 as part of a long-term experiment designed to examine the effects and interactions of annual fire, mowing, and fertilization (N and P) on prairie soil communities and processes. For nearly all taxa, in both years, responses were characterized by significant treatment interactions, but some general patterns were evident. Introduced European earthworms (Aporrectodea spp. and Octolasion spp.) were most abundant in plots where fire was excluded, and the proportion of the total earthworm community consisting of introduced earthworms was greater in unburned, unmowed, and fertilized plots. Nymphs of two Cicada genera were collected (Cicadetta spp. and Tibicen spp.). Cicadetta nymphs were more abundant in burned plots, but mowing reduced their abundance. Tibicen nymphs were collected almost exclusively from unburned plots. Treatment effects on herbivorous beetle larvae (Scarabaeidae, Elateridae, and Curculionidae) were variable, but nutrient additions (N or P) usually resulted in greater densities, whereas mowing usually resulted in lower densities. Our results suggest that departures from historical disturbance regimes (i.e. frequent fire and grazing) may render soils more susceptible to increased numbers of European earthworms, and that interactions between fire, aboveground biomass removal, and vegetation responses affect the structure and composition of invertebrate communities in tallgrass prairie soils. 相似文献
15.
Grete Skrede Berit Karoline Martinsen Anne-Berit Wold Stein-Erik Birkeland Kjersti Aaby 《Acta Agriculturae Scandinavica, Section B - Plant Soil Science》2013,63(3):193-208
Abstract A 3-year study was carried out to investigate quality parameters in 14 tree fruit and berry species grown in southern Norway. The species were blueberry, apple, aronia, sour cherry, sweet cherry, red raspberry, strawberry, blackcurrant, gooseberry, red currant and elderberry, harvested along with wild bilberry, cloudberry and lingonberry. Significant differences between species were identified for all quality parameters. The coefficient of variation between species was lowest for pH (12.5%), dry matter (18.9%) and soluble solids (25.3%), followed by titratable acids (59.3%), total phenolics (83.8%), antioxidant capacity FRAP (85.7%) and antiradical power by the DPPH-assay (97.8%), total monomeric anthocyanins (132%) and ascorbic acid (137%). Average coefficient of variation within species were lower and ranged from 4 (pH) to 62% (ascorbic acid). Only the FRAP values were significantly affected by harvesting year with lower levels in 2004 than in 2005 and 2006. There were significant interactions between species and harvesting year for dry matter, soluble solids, pH, ascorbic acid and FRAP. The results indicate generic ranges in composition within species independent upon growing location and climate, and the composition of the tree fruits and berries is not likely to deviate from these ranges. It is concluded that desirable composition of tree fruits and berries and their products should primarily be achieved by selection among species rather than searching fors broadened variation within individual species. 相似文献
16.
《Communications in Soil Science and Plant Analysis》2012,43(7):865-877
Potassium (K) fixation and release in soil are important factors in the long-term sustainability of a cropping system. Changes in K concentration and characteristics of K fixation and release in rhizosphere and nonrhizosphere soils in the rapeseed (Brassica napus L.)–rice (Oryza sativa L.) rotation were investigated using a rhizobox system. The concentrations of different forms of K in both rhizosphere and nonrhizosphere soils decreased with plants compared to without plants, regardless of K fertilizer application. Potassium uptake by crops mainly came from the rhizosphere soil. In the treatment without K fertilizer (–K), the main form of K supplied by the soil to the crops was 1.0 mol L?1 nitric acid (HNO3) nonextractable K, followed by nonexchangeable K, and then exchangeable K. In the treatment with K fertilizer (+K), the main K forms supplied by the soil to the crops were exchangeable K and nonexchangeable K. The amount and rate of K fixation after one cycle of the rapeseed–rice rotation was greater in rhizosphere soil than in nonrhizosphere soil. The amount and rate of K fixation of soil in the +K treatment were significantly less than in the –K treatment. The cumulative amounts of K released with 1.0 mol L?1 ammonium acetate (NH4OAc) and 1.0 mol L?1 HNO3 extraction increased with the increasing numbers of extractions, but the K-releasing power of soil by successive extraction decreased gradually and finally became almost constant. The release of K was less in rhizosphere soil than in nonrhizosphere soil. The release of K in the +K treatment was similar to that in the –K treatment in rhizosphere soil, but the K release in nonrhizosphere soil was greater with the +K than the –K treatment. Overall, the information obtained in this study will be helpful in formulating more precise K fertilizer recommendations for certain soils. 相似文献
17.
Y. Bashan J. J. Bustillos L. A. Leyva J.-P. Hernandez M. Bacilio 《Biology and Fertility of Soils》2006,42(4):279-285
Inoculation of wheat seedlings with the plant growth-promoting bacterium Azospirillum brasilense Cd was immobilized in alginate microbeads and, without applying any stress, significantly increased the quantity of several
photosynthetic pigments, such as chlorophyll a, chlorophyll b, and the auxiliary photoprotective pigments violaxanthin, zeaxanthin, antheroxanthin, lutein, neoxanthin, and β-carotene.
This resulted in greener plants with no apparent visible stress. After monitoring the quantity of photosynthetic pigments
for 4 weeks, we observed that inoculated plants had higher quantities of pigments in shoot and stem. The greatest difference
in the quantity of all pigments between inoculated and noninoculated plants occurred in the first week of growth. Regardless
of treatment, the quantity of pigments in stems was three to four times less than the quantity of these pigments in shoots.
Application of Azospirillum, either as liquid inoculant or as alginate microbeads, did not alter the positive effect of the bacteria on pigment production
or the positive response of the plants towards A. brasilense Cd inoculation. 相似文献
18.
Dhritiman Ghosh Velusamy Srinivasan Olli H. Tuovinen Aaron Peacock Mark Radosevich 《Soil biology & biochemistry》2009,41(6):1331-1334
We examined the community composition of microbes that colonized atrazine-containing beads buried in agricultural soils that differed in atrazine treatment history. Bacterial abundance was 5-40-fold greater in atrazine-fortified beads. In beads containing 20 mg atrazine kg−1 buried in soil with a history of atrazine application (conditioned soil), the abundance of Actinobacteria increased approximately 80-fold whereas in control soil, Actinobacteria were enriched only 10-fold and the gamma-Proteobacteria and Planctomycetes increased by 60- and 25-fold, respectively. The gamma-Proteobacteria were enriched by 120- and 230-fold in beads containing 200 mg atrazine kg−1 in conditioned and control soil, respectively. The results demonstrate that BioSep® beads are a suitable matrix for recruiting a diverse subset of the bacterial community involved in atrazine degradation. 相似文献
19.
Pilar García Juan-Vicente Monte Carlos Casanova Consuelo Soler 《Genetic Resources and Crop Evolution》2002,49(1):103-109
Arbitrary oligonucleotides were used as primers to amplifygenomic DNA of 48 wild Spanish populations of Agropyroncristatum, Elymus hispanicus,E. caninus,E. repens,Thinopyrum curvifolium, Th.junceum and Th.intermedium. Genetic diversity was analysedusing nineteen primers. The number of amplified products ranged from8 to 18 per primer and a total of 240 markers were scored. Differentlevels of intraspecific genetic diversity were found, the allogamousspecies E. repens andTh. intermedium being themost variable. Jaccard's similarity coefficients for internalmeasure within and between populations were used to produce a clusterdiagram. The results demonstrate differences in the degree ofsimilarity between taxonomic units. Interpopulational variability andinterspecific genomic relationships of these species arediscussed. 相似文献
20.
The effects of three commonly used fungicides on the colonization and sporulation by a mixture of three arbuscular mycorrhizal (AM) fungi consisting of Glomus etunicatum (Becker & Gerd.), Glomus mosseae (Nicol. & Gerd.) Gerd. & Trappe, and Gigaspora rosea (Nicol. & Schenck) in symbiosis with pea plants and the resulting response of the host-plant were examined. Benomyl, PCNB, and captan were applied as soil drenches at a rate of 20 mg active ingredient kg-1 soil 2 weeks after transplanting pea seedlings in a silty clay-loam soil containing the mixed inocula of AM fungi (AM plants). Effects of fungicides were compared to untreated plants that were inoculated with fungi (AM control). The effect of mycorrhizal inoculation on plant growth was also examined by including nonmycorrhizal, non-fungicide-treated plants (non-AM control). Fungicides or inoculation with AM fungi had only a small effect on the final shoot weights of pea plants, but had greater effects on root length and seed yield. AM control plants had higher seed yields and lower root lengths than the corresponding non-AM plants, and the fungicide-treated AM plants had intermediate yields and root lengths. Seed N and P contents were likewise highest in AM control plants, lowest in non-AM plants, and intermediate in fungicide-treated AM plants. All three fungicides depressed the proportion (%) of root length colonized by AM fungi, but these differences did not translate to reductions in the total root length that was colonized, since roots were longer in the fungicide-treated AM plants. Pea plants apparently compensated for the reduction in AM-fungal metabolism due to fungicides by increasing root growth. Fungicides affected the population of the three fungi as determined by sporulation at the final harvest. Captan significantly reduced the number, relative abundance, and relative volume of G. rosea spores in the final population relative to the controls. The relative volume of G. etunicatum spores was greater in all the fungicide-treated soils, while G. mosseae relative volumes were only greater in the captan-treated soil. These findings show that fungicides can alter the species composition of an AM-fungal community. The results also show that AM fungi can increase seed yield without enhancing the vegetative shoot growth of host plants. 相似文献