Potential for control of seedling blight of wheat caused by Fusarium graminearum and related species using the bacterial endophyte Bacillus mojavensis

Fusarium-infected wheat seed decreases germination, seedling emergence, and causes post emergence seedling death, and can contribute to wheat scab and ear rot of maize, with consequent production of mycotoxins such as deoxynivalenol and zearalenone. Current seed treatments have proved ineffective in controlling seedling blight and scab. A patented endophytic bacterial strain, Bacillus mojavensis RRC 101, and several other strains of this species were studied to determine in vitro antagonism to some Fusarium species and to assess the potential of this bacterium to serve as an endophytic biocontrol for seedling blight of wheat produced by species within the F. graminearum complex, as well as other species of Fusarium. Seedling emergence and seed germination were two tests used as indicators of seedling blight. These tests were conducted in growth rooms with two wheat cultivars highly susceptible to scab, Norm and Pioneer 2552, and other cultivars with varying resistance to scab. The results indicated that all strains of this bacterium were antagonistic in vitro to the strains of F. graminearum and its seven related species, as well as four strains of F. pseudograminearum and the two strains of F. verticillioides. Germination of the highly scab susceptible cultivar 2552 was increased from 77 to 97% when planted in soil containing a mixed inoculum of F. graminearum and related species. Seedling emergence in the very susceptible wheat cultivar Norm increased from 20 to 82% when treated with the bacterium. The data indicated that inoculating wheat kernels with B. mojavensis reduced seedling blight of wheat produced by F. graminearum and related Fusarium species indicating the potential for this bacterium as a biocontrol under field condition.     

极小种群濒危植物广西火桐、丹霞梧桐的叶绿体基因组特征

广西火桐(Firmiana kwangsiensis)和丹霞梧桐(F. danxiaensis)是我国南方特有物种, 其分布范围狭窄, 种群数量少。为了解其叶绿体基因组结构及系统发生关系, 本文通过高通量测序方法获得广西火桐和丹霞梧桐的浅层基因组数据, 通过生物信息学方法对叶绿体全基因组进行组装, 并对其结构特征进行分析。结果表明: 广西火桐和丹霞梧桐的叶绿体基因组大小分别为160,836 bp和161,253 bp, 具有典型被子植物叶绿体基因组环状四分体结构, 包含长度分别为89,700 bp、90,142 bp的大单拷贝区(large single copy, LSC), 长度分别为19,970 bp、20,067 bp的小单拷贝区(small single copy, SSC)及长度分别为25,583 bp、25,522 bp的2个反向重复序列区(inverted repeat sequence, IR)。两个物种的叶绿体基因组共注释得到131个基因, 包括86个蛋白编码基因、37个tRNA基因和8个rRNA基因。广西火桐的叶绿体基因组中共检测出26个正向重复序列、2个反向重复序列、21个回文重复序列、21个串联重复序列和98个简单重复序列; 丹霞梧桐叶绿体基因组中共检测出23个正向重复序列、5个反向重复序列、21个回文重复序列、30个串联重复序列和107个简单重复序列。系统发生分析结果表明5种梧桐属(Firmiana)植物构成两个强烈支持的分支(支持率100%), 一个分支为广西火桐、美丽火桐(F. pulcherrima)和火桐(F. colorata), 其中广西火桐与美丽火桐构成姐妹群; 另一分支是互为姐妹群的丹霞梧桐和云南梧桐(F. major)。综上所述, 广西火桐和丹霞梧桐的叶绿体基因组结构、基因排列及重复序列具有较高的相似性, 系统进化树将5种梧桐属物种分为两个分支, 其中广西火桐和美丽火桐最近; 而丹霞梧桐与云南梧桐关系最近。本研究鉴定的SSR位点可为梧桐属物种系统发生、进化关系的研究提供遗传信息。     

基于ITS和ndhF-rpl32序列的荞麦种间亲缘关系分析

荞麦起源于我国, 演化形成了丰富的物种和遗传多样性。为了有效研究和利用荞麦及其野生种资源, 以从四川、甘肃、贵州等地采集的荞麦属(Fagopyrum)10个种(含变种、亚种和复合体种)共71份材料为对象, 通过ITS和叶绿体ndhF-rpl32序列分析, 利用MEGA5.0构建系统进化树, 探讨了荞麦种内及种间亲缘关系。结果表明, 在ITS序列矩阵中, 序列长度为725 bp, 信息位点为150个, 占序列总长度的20.7%; 在ndhF-rpl32序列矩阵中, 序列长度为940 bp, 信息位点为158个, 占序列总长度的16.8%。由ITS序列和ndhF-rpl32序列构建的两个进化树都可以将71份材料分为大粒荞麦种组和小粒荞麦种组; 其中, 大粒荞麦种组包括栽培苦荞和米苦荞(F. tataricum)、金荞复合体(F. cymosum complex)、栽培甜荞(F. esculentum)和野生甜荞(F. esculentum ssp. ancestralis); 小粒荞麦种组包括齿翅野荞(F. gracilipes var. odontopterum)、疏穗小野荞(F. leptopodum var. grossii)、小野荞(F. leptopodum)、密毛野荞(F. densovillosum)、细柄野荞(F. gracilipes)和硬枝万年荞(F. urophyllum)。而ndhF-rpl32序列构建的系统发育树还能区分栽培甜荞和野生甜荞, 具有更好的聚类效果。另外, 与栽培甜荞相比, 金荞复合体与栽培苦荞的亲缘关系更近。该研究为荞麦属种的分类和条形码研究提供了一定的科学依据。     

小麦响应禾谷镰刀菌侵染的转录组学研究进展

由禾谷镰刀菌引起的小麦赤霉病直接为害作物穗部,不仅严重影响小麦产量,还可因为毒素污染问题威胁人畜健康。近年来对小麦与禾谷镰刀菌互作的转录组学研究带来了很多新见解,概述了小麦响应禾谷镰刀菌侵染的转录组学研究进展,主要比较了不同抗性品种、不同器官、不同籽粒发育时期的小麦穗部在禾谷镰刀菌侵染时的基因表达特征,总结了赤霉病感染时小麦的激素响应、信号传导、转录调控和防卫相关基因的表达规律,以期促进研究者对小麦响应禾谷镰刀菌侵染规律的理解。     

野生柳生金针菇和金针菇的分离、生物学特性及驯化栽培

采自滇西北地区的2份野生大型真菌标本,通过形态学及内转录间隔区(ITS)序列的分子系统发育分析鉴定为柳生金针菇Flammulina rossica和金针菇F.filiformis.以分离纯化保藏的菌株Mdr-02和Mdr-09作为实验材料,进行生物学特性和驯化栽培研究,采用碳源、氮源、无机盐、pH和温度5个因素进行单因...     

Population genetic structure of the giant panda staple food bamboo (Fargesia spathacea complex) and its taxonomic implications

The taxonomy of woody bamboo presents many difficulties due to its long blooming interval and complex morphological variation. Whether the current taxonomy reflects genuine species divergence within woody bamboo is an intriguing question. The Fargesia spathacea Franch. complex comprises 15 closely related species with a sympatric distribution in China. Their classification has long been controversial because only a handful of vegetative traits are available, providing a good opportunity to explore the evolutionary relationships and genetic differentiation in woody bamboo. Here, we present a study involving 750 individuals from 39 representative populations in the F. spathacea complex using 14 simple sequence repeat markers. We found varying degrees of genetic diversity across populations of the F. spathacea complex (He = 0.07–0.81) and largely negative F-values at the population level, implying an excess of heterozygotes in the populations. Phylogenetic analyses revealed that all populations were divided into two major groups (clusters A and B), with the majority of the 15 species representing distinct genetic lineages. Based on population genetic analysis along with morphological evidence, we confirmed the identity of three species (F. decurvata J. L. Lu, F. spathacea, and F. murielae Gamble) and suggested the invalidation of four other species (F. scabrida T. P. Yi, F. robusta T. P. Yi, F. denudata T. P. Yi F. murielae (Gamble) T. P. Yi, and F. nitida (Mitford) Keng f. ex T. P. Yi). The delimitation of the remaining eight species has yet to be explored. The analysis of ecological factors and spatial autocorrelation suggested that altitudinal differences might account for the distinct genetic divergence between the two major groups.     

瓜类枯萎病菌遗传多样性和亲缘关系的SRAP分析

尖孢镰刀菌可造成不同瓜类的枯萎病.为明确不同寄主、不同地区的瓜类枯萎病菌菌株间的遗传多样性及亲缘关系,采用相关序列扩增多态性(SRAP)分子标记技术,对来源于不同地区、不同寄主的95株尖孢镰刀菌的基因组DNA进行多态性扩增.以筛选出的19对引物共扩增出238条带,多态性比率为100%,平均每对引物扩增出12.5个位点和12.5个多态性位点;尖孢镰刀菌苦瓜专化型共扩增出166条带,其中145条为多态性条带,多态性比率为87.4%,平均每对引物扩增出8.7个位点和7.7个多态性位点,说明尖孢镰刀菌的遗传变异较为广泛.瓜类枯萎病菌株间的遗传相似系数范围为0.68～0.99,样品间的平均Nei遗传多样性指数和Shannon指数分别为0.2390和0.3718.在遗传相似系数为0.74时,可将供试的95株尖孢镰刀菌划分为苦瓜、黄瓜、西瓜、甜瓜4个专化群.在SRAP聚类树中,同一寄主的尖孢镰刀菌聚在一个分支上,其中尖孢镰刀菌苦瓜专化型菌株间的遗传相似系数范围为0.78～0.99,Nei遗传多样性指数为0.1811,平均Shannon指数为0.2750,表明尖孢镰刀菌苦瓜专化型的遗传变异较大,且菌株的聚群与地理来源存在相关性.     

Potential of fungal antagonists for biocontrol of Fusarium spp. in wheat and maize through competition in crop debris

Pathogenic Fusarium spp. cause head blight in wheat or ear rot in maize leading to yield losses and also a reduction in quality due to mycotoxin contamination of the grain. Infected crop residues are the main inoculum source for epidemics. Saprophytic fungi, obtained from cereal tissues or necrotic tissues of other crops, were screened for their ability to colonise wheat straw and maize stalks and to suppress sporulation of pathogenic Fusarium spp. Results of bio-assays conducted under controlled conditions were variable among Fusarium spp. and host substrates for most antagonists tested, such as yeasts, Trichoderma spp. and non-pathogenic Fusarium spp. Isolates of Clonostachys rosea consistently suppressed sporulation of F. culmorum and F. graminearum on wheat straw, and of F. culmorum, F. graminearum, F. proliferatum and F. verticillioides on maize stalks. Isolates of C. rosea, C. cladosporioides and F. equiseti were applied to pieces of maize stalks or flowering ears in preliminary experiments conducted under field conditions. The colonisation of stalk pieces by pathogenic Fusarium spp. was assessed after 9 months. Colonisation of stalk pieces by pathogenic Fusarium spp. was significantly reduced at several sampling dates. However, results obtained with the antagonists were not consistent for all sampling dates and between experiments.     

Field Evaluation of Fungal Competitors of Fusarium culmorum and F. graminearum, Causal Agents of Ear Blight of Winter Wheat, for the Control of Mycotoxin Production in Grain

Thirty-seven antagonists, from a collection of 113 pre-screened microorganisms, were tested in field experiments on winter wheat for their ability to control ear blight and production of mycotoxins, particularly deoxynivalenol (DON), in grain by Fusarium culmorum and F. graminearum. Ears were spray-inoculated during anthesis with spore suspensions, first of test fungi and then of the pathogen. Isolates of F. equiseti were the most effective treatments. A strain of F. equiseti (G9) decreased DON consistently on wheat inoculated with F. culmorum, compared with the control, often by more than 70%. It performed well under severe disease pressure (F. culmorum at 10⁵ conidia mL^-1) and similarly to a standard fungicide, tebuconazole. Percentages of diseased grains and amounts of DON corresponded well. Small quantities of nivalenol (NIV) occurred in grain samples after treatment with some F. equiseti strains. On wheat inoculated with F. graminearum, F. equisti G2 decreased the percentage diseased grains by 92% and DON by 94%. One strain of F. equiseti (G2) was found to produce small amounts of NIV in pure culture.     

东北红豆杉—无花果复合种植对两种植物生长和土壤酶活性影响

设计了室内控制条件下的东北红豆杉和无花果的复合种植实验，并与单一种植东北红豆杉和单一种植无花果的模式进行了比较。分别考察了上述3种模式下，东北红豆杉和无花果的生长指标、光合作用以及土壤酶活性差异。结果表明：①在生长量方面，复合种植3个月的东北红豆杉的株高增长率为152.6%，是单一种植的东北红豆杉株高增长率的1.56倍；复合种植3个月的无花果，其当年生枝的生长量为68.4 cm³，比单一种植的无花果高36.3%。②在光合作用指标方面，在800 μmol·m^-2·s^-1光照强度下，复合种植3个月的东北红豆杉和无花果净光合速率与相应的单一种植相比，分别提高了19.0%和5.3%。③在土壤酶活性方面，在7月份，复合种植模式下的土壤蔗糖酶、脲酶和酸性磷酸酶活性比单一种植东北红豆杉土壤相应酶活性分别提高51.6%、58.5%和50.8%，比单一种植物无花果土壤相应酶活性分别提高85.5%、47.5%和71.9%；土壤多酚氧化酶活性在不同种植模式之间无显著差异（P>0.01）。综上，东北红豆杉-无花果复合种植可以提高土壤蔗糖酶、脲酶和酸性磷酸酶活性，对两种植物生长均具有促进作用。上述结果可为在生产实践上进行东北红豆杉-无花果复合经营提供参考。     

长白山阔叶红松林5种主要树种水分利用效率与叶片养分特征

以长白山阔叶红松林中5种优势树种(红松、水曲柳、色木槭、蒙古栎、紫椴)为研究对象,利用稳定碳同位素技术分析了植物的水分利用效率(WUE),测定了叶片碳(C)、氮(N)、磷(P)3种营养元素的含量用以分析植物对养分的利用特征,并综合分析了植物WUE与叶片养分含量之间的关系.结果 表明:冠层不同位置微气象因子的差异导致WU...     

黄顶菊凋落物分解对节肢动物群落结构的影响

选择黄顶菊(Flaveria bidentis)入侵的林地、农田、荒地、沟渠等4种生境作为调查样地, 比较黄顶菊与本地植物凋落物的分解速率及凋落物分解对节肢动物群落结构的影响。于2014年10月凋落物高峰期在各样地内分别搜集黄顶菊与本地植物的凋落物, 每种凋落物称取20 g装入尼龙网分解袋中, 放入各生境。2015年的每个月将不同生境不同处理凋落袋各取回10袋, 用Tullgren法分离节肢动物。 4种生境共捕获17,466头, 隶属8纲18目, 4种生境的优势类群皆为蜱螨目和啮目。其中, 林地、农田、荒地、沟渠4种生境处理组中节肢动物数量分别为1,698头, 1,838头, 2,631头, 3,413头, 分别比对照组高18%, 53%, 22%, 11%。多数月份黄顶菊凋落物中的节肢动物丰富度及多样性指数高于同生境对照组, 并且在黄顶菊生长盛期差异显著; 黄顶菊凋落物的分解速率高于对照植物分解速率, 且各月份凋落物分解速率动态与节肢动物数量变化动态呈显著相关。黄顶菊凋落物对节肢动物的影响与人为干扰程度有关, 这种影响在人为干扰较小的荒地与沟渠生境中更为明显。综上所述, 黄顶菊凋落物的分解改变了节肢动物群落结构, 并引起节肢动物多样性的升高。     

Mechanical resistance of wheat straw after incubation in cultures of ruminal cellulolytic microorganisms

The mechanical properties of wheat straw fragments were measured using tensile and shear tests before and after incubation in pure cultures of the rumen fungus Neocallimastix frontalis MCH3, in pure cultures of the rumen cellulolytic bacteria Fibrobacter succinogenes S85 and Ruminococcus flavefaciens 007 and in co-cultures associating the fungus with each of the two bacterial species.

N. frontalis considerably reduced the tensile strength of the straw; on the contrary R. flavefaciens increased it and F. succinogenes did not affect it. In co-cultures, F. succinogenes and N. frontalis interacted synergistically to weaken straw resistance, whereas R. flavefaciens inhibited the fungal action. The shear test also revealed that physical and mechanical properties were strongly affected by the action of the three microorganisms. After six days of incubation the straws resistance to shearing was lower after incubation with N. frontalis or R. flavefaciens than in the presence of F. succinogenes. No synergism or antagonism between microorganisms was observed in the shear test.

These results thus clearly demonstrate a specific action of the three rumen microorganisms in physical degradation of plant material.     

禾谷镰孢菌β2微管蛋白与苯并咪唑类杀菌剂互作研究

小麦赤霉病是小麦上的主要病害之一,在全世界范围内引起该病害的致病菌主要是禾谷镰孢菌Fusarium graminearum。目前,使用杀菌剂是生产上防治小麦赤霉病发生和危害的主要手段,常用的杀菌剂主要有苯并咪唑类杀菌剂(benzimidazoles)等,苯并咪唑类杀菌剂的作用靶标是β2微管蛋白。本研究旨在探究小麦赤霉病菌中β2微管蛋白与苯并咪唑类杀菌剂的互作机制,通过同源建模的方法获得了禾谷镰孢菌β2微管蛋白的三维结构,并在此基础上将β2微管蛋白与4种苯并咪唑类杀菌剂(多菌灵、苯菌灵、噻菌灵、甲基硫菌灵)进行分子对接。分子对接结果显示β2微管蛋白第198位苯丙氨酸和第236位缬氨酸与4种苯并咪唑类杀菌剂直接互作形成氢键,第50、134、165、167、198、200、236、237、239、240、250、253、257、314位氨基酸形成药剂结合口袋。通过比较β2微管蛋白与4种苯并咪唑类杀菌剂结合自由能,发现与其他3种杀菌剂相比,β2微管蛋白与多菌灵的结合自由能最小(-5.72 kcal/mol),说明其与多菌灵互作亲和力更强。采用菌丝生长速率法测定了禾谷镰孢菌对4种苯并咪唑类杀菌剂的EC₅₀值,禾谷镰孢菌对多菌灵、苯菌灵、噻菌灵、甲基硫菌灵的EC₅₀值分别为0.772、0.862、1.088、13.266 mg/L,该结果表明禾谷镰孢菌对多菌灵的敏感性强于其他3种杀菌剂,与分子对接结果相吻合。     

Tilletia vankyi, a new species of reticulate-spored bunt fungus with non-conjugating basidiospores infecting species of Festuca and Lolium

A bunt fungus, exhibiting a spore germination pattern unique to known reticulate-spored species of Tilletia was found infecting plants in seed production fields of Festuca rubra ssp. rubra (red fescue) and F. rubra ssp. fallax (Chewing's fescue) in Oregon, and in seed lots of Lolium perenne (perennial ryegrass) from Australia and Germany. Teliospores germinated to form 20–40 uninucleate, non-conjugating basidiospores, and colonies derived from single basidiospores produced teliospores in culture. In inoculation studies using single basidiospore colonies, perennial ryegrass and L. perenne ssp. multiflorum (Italian or annual ryegrass) were infected. A phylogenetic analysis, based on ITS region rDNA, eukaryotic translation elongation factor 1 alpha, and the second largest subunit of RNA polymerase II demonstrated that the fescue and ryegrass bunts are conspecific, and distinct from known species of Tilletia.     

Ideal phenotypes and mismatching haplotypes – errors of mtDNA treeing in ants (Hymenoptera: Formicidae) detected by standardized morphometry

A total of 401 nest samples of Formica lugubris Zetterstedt, F. pratensis Retzius, F. aquilonia Yarrow, F. rufa Linnaeus, and F. polyctena Förster, covering the entire Palaearctic range of these species and including 2100 individual workers, was phenotypically investigated by a system of standardized morphometry, pairwise removal of allometric variance, and canonical discriminant functions. A mitochondrial DNA fragment including the cytochrome b gene was sequenced in 148 samples from basically the same range. In the more difficult F. pratensis vs. F. lugubris case, the phenotypic system correctly determined 99.6% of all nest samples, and 95.1% with p<0.05. In all other pairwise species discriminations any nest sample was correctly determined with p<0.01, and three samples with hybrids F. rufa×lugubris were identified. At four localities in the Pyrenees and the Urals, 9 samples with F. pratensis phenotypes (7 of them ideal) but F. lugubris mtDNA haplotypes could be identified, resulting in 14.5% of phenotype/haplotype mismatches. A local dominance of this mismatch combination was observed at one Pyrenean and one Ural locality. There was no indication of an F. pratensis haplotype associated with an F. lugubris phenotype. One ideal F. polyctena phenotype was associated with an F. aquilonia haplotype in a sample from the Urals, and one ideal F. aquilonia phenotype was combined with an F. lugubris haplotype in a sample from central Siberia, resulting in overall phenotype/haplotype mismatch frequencies of 12.5% and 11.1%, respectively. We conclude that all these samples cannot represent actual F₁ hybrids but are the result of hybridizations in the past followed by unidirectional purging of the nuclear genome. Whether this process of purging worked very fast or over longer periods of population history, and whether or not it was complete or incomplete, cannot be assessed from the available information. These facts of hybridizing in two thirds of the W Palaearctic wood ant species, of extreme regional hybrid frequencies (up to 26%), of unidirectional purging of nDNA associated with mismatching mtDNA haplotypes, and of occasional achievement of local dominance of these mismatch combinations, may serve as urgent warning not to perform isolated mtDNA phylogenetic studies without a geographically and locally wide sampling basis and without control by nDNA information or reliable phenotypic determination. The latter two systems definitely have superior significance when conflicts with mtDNA indications arise.     

AM真菌摩西管柄囊霉对干旱胁迫下枳抗氧化酶基因表达的影响

测定分析了接种丛枝菌根（AM）真菌摩西管柄囊霉Funneliformis mosseae对正常供水与干旱处理的盆栽枳Poncirus trifoliata实生苗生长、活性氧代谢及抗氧化酶基因表达量的影响。结果表明,7周干旱处理显著降低了根系菌根侵染率。接种摩西管柄囊霉显著促进了干旱处理的枳植株生长,增加了根系体积和叶片相对含水量,显著降低了叶片脯氨酸含量,同时也上调了干旱处理的枳叶片精氨酸脱羧酶基因（PtADC1和PtADC2）和超氧化物歧化酶基因（PtFe-SOD和PtMn-SOD）、过氧化物酶基因（PtPOD）和过氧化氢酶基因（PtCAT1）的表达,因而维持了一个相对更低的活性氧水平（如过氧化氢）,有利于增强植株的抗旱性。     

模拟采食干扰下克隆整合对两种箭竹分株种群更新的影响

动物对植物的采食会刺激植物进行补偿性更新生长, 克隆整合效应能够通过分株之间的物质传输增强克隆植物的这种补偿生长。现今对克隆整合效应在箭竹(Fargesia)补偿更新中的作用仍未得到全面认识。2011年10月到2012年11月, 设立了糙花箭竹(Fargesia scabrida)和缺苞箭竹(F. denudata)各40个样方, 分别进行不剪除样方内分株和剪除样方内分株数量的25%、50%、75%四种模拟采食干扰处理, 并将样方四周的根状茎切断或保持连接。从2012年6月起观测并统计了箭竹分株种群的累积出笋率、总出笋率、补充率, 以及新生分株的株高、基径和单株生物量。结果表明: (1)在不剪除分株的样方, 切断根状茎连接显著增加了糙花箭竹的出笋率和补充率, 但降低了新生分株的株高和单株生物量, 也显著降低了缺苞箭竹的出笋率和补充率; (2)保持根状茎连接时, 25%的剪除强度仅仅降低了糙花箭竹新生分株的单株生物量; 同样在保持根状茎连接的条件下, 25%、50%的剪除强度使缺苞箭竹种群的补充率有所降低, 而切断根状茎后缺苞箭竹在25%的剪除强度下的分株补充率反而升高; (3) 75%的剪除强度并未影响两种箭竹新生分株数量更新, 但造成新生分株质量显著下降; 切断根状茎连接显著降低了糙花箭竹的新生分株的株高和基径, 对缺苞箭竹影响不显著。实验证明克隆整合影响了两种箭竹新生分株的萌发、存活和生长, 但不是两种箭竹进行补偿更新的主要机制, 仅在糙花箭竹分株种群受到重度采食干扰后的更新中才起到明显的促进作用; 两种箭竹均能在50%的剪除强度下通过补偿生长恢复种群的稳定, 75%的剪除强度则会造成箭竹新生分株质量的下降。     

Phenotypic analysis of adults of Fasciola hepatica, Fasciola gigantica and intermediate forms from the endemic region of Gilan, Iran

Fascioliasis is an important human and animal disease caused by Fasciola hepatica and Fasciola gigantica. In Iran, the distribution of these two species overlaps in most areas, including the northern human endemic province of Gilan where both fasciolids are simultaneously found in individual cattle and buffaloes. A phenotypic study of fasciolid adult flukes from naturally infected bovines from Gilan was carried out by means of an exhaustive morphometric analysis using traditional microscopic measurements and an allometric model. The Iranian fasciolids were compared to F. hepatica and F. gigantica standard populations, i.e. from geographical areas where both species do not co-exist (Bolivia and Burkina Faso, respectively). Although morphometric values somewhat overlapped, there were clear differences in allometric growth. The allometric function was adjusted to 25 pairs of variables. Results obtained revealed that Iranian F. hepatica-like specimens are larger than the F. hepatica standard and Iranian F. gigantica-like specimens are longer and narrower than the F. gigantica standard, but with smaller body area. Measurements which permit a specific differentiation in allopatric populations (distance between ventral sucker and posterior end of the body; ratio between body length and body width) overlap in the specimens from Gilan, thus proving the presence of intermediate forms. When compared to the standard populations, the different Iranian fasciolid morphs show greater differences in F. gigantica-like specimens than in F. hepatica-like specimens. This study shows that simple, traditional microscopic measurements may be sufficient for the morphometric characterisation of fasciolids, even in areas where intermediate forms are present.