Diversity and host association of the tropical tree endophyte Lasiodiplodia theobromae revealed using simple sequence repeat markers

Lasiodiplodia theobromae is a cosmopolitan fungus with a worldwide distribution in the tropics and subtropics, where it causes shoot blight and dieback of trees and shrubs and imparts blue stain in timber. In this study, eight simple sequence repeat (SSR) markers were used to evaluate the genetic diversity and gene flow between populations of L. theobromae. The relationships between isolates from different hosts were considered using three populations from different tree species in Venezuela (VEN) and the relationships between isolates from different geographical origins included populations from VEN, South Africa (RSA) and Mexico (MEX). A small number of predominant genotypes were encountered in the VEN and RSA populations and thus genotypic diversity was low. There was no evidence of host specificity for isolates of L. theobromae and there was very high gene flow between populations from different hosts. Geographical isolation existed between populations of the pathogen from different regions, with unique alleles fixed in the different populations. Gene flow was, however, less restricted between isolates from MEX and the other populations, consistent with MEX as a common source of seed in both VEN and RSA. Genetic analysis suggested predominantly clonal reproduction with some genotypes widely distributed within a region. The broad host range of L. theobromae and the lack of evidence for host specialization, coupled with its endophytic nature and the common appearance of symptoms only after harvest, is likely to hinder disease management strategies.     

柏科植物组织培养研究现状与展望

柏科植物组织培养困难,但经过多年的探索取得了很大进展。文中综述20世纪70年代以来柏科植物组织培养中外植体选择、培养基制备、诱导分化、试管苗生根、组培苗移栽等关键环节的研究进展及存在的主要问题,提出研究展望,为深入开展柏科植物组织培养研究提供参考。     

澳门青洲山假柿木姜子群落特征及多样性研究

以1 100 m2样地为研究基础,分析澳门青洲山假柿木姜子群落的种类组成、区系成分、外貌特征、群落结构以及多样性特征。结果表明,本群落有维管束植物47种,隶属于27科42属,热带分布种占绝对优势。群落外貌主要由单叶、中型叶,全缘的常绿高位芽植物决定。优势种径级显示:群落目前保持以假柿木姜子为优势种,翻白叶树与假苹婆为增长种群的格局。这3种主要种群呈集聚分布。整个群落M agarlef指数为4.907 2,Shannon-W iener指数0.874 2,S impson指数1.164 1和P ielou均匀度指数0.302 4。多样性比较显示,该群落的物种多样性低于香港黄桐群落、鼎湖山厚壳桂群落及深圳南山区鸭脚木群落,可能与该地的岛屿性、优势种显著、外来种入侵等因素有关,应加强保护维持该群落的物种多样性。     

几种柏科植物挥发物质及抗肿瘤活性初步研究

用Alamar blue法对提取的5种柏树叶挥发油进行了抗人肺癌细胞实验,结果表明,刺柏、圆柏、龙柏、日本扁柏和绒柏5种树叶挥发油对肺癌细胞NCI-H460抑制率分别为36.93%、78.4%、73.77%、81.22%和56.53%,其中日本扁柏挥发油对肺癌细胞NCI-H460抑制活性最大。采用气-质联用法对6种柏树叶挥发油的化学成分进行了研究,刺柏、圆柏、龙柏、日本扁柏和绒柏5种柏类含有的挥发物质种类分别为32、36、48、22和27种。     

世界柏科彩叶植物种质资源

柏科植物共有22个属,其中10个属拥有彩叶植物44个种、183个变种。在刺柏属、柏木属和扁柏属中的彩叶植物种数较多,而在扁柏属、刺柏属、崖柏属和柏木属中彩叶植物变种数较多。从柏科植物彩叶种或变种叶色来看,呈黄色的种或变种数最多,达100个,蓝色种或变种60个,白色种或变种16个,灰绿色种或变种3个,紫叶种或变种3个,红棕色种或变种1个。文中介绍了柏科彩叶植物种类、叶色特征,提出了我国繁育和推广利用建议。     

8种柏科植物的精气成分及其生理功效分析

植物的器官和组织在自然状态下释放出的气态有机物称为植物精气。1997~2007年间,测量了湖南、云南、新疆等地的日本扁柏、干香柏、柏木、西藏柏木、侧柏、圆柏、叉子圆柏的精气成分及相对含量;2008年测量了重庆城口崖柏的精气成分及相对含量,并在珠三角地区调查了崖柏精气的医疗保健效果。结果表明:柏木的叶片、木材和林分中均富含对人体有益的萜类化合物,这些化合物有显著的医疗保健功效;同科不同种的柏树精气成分及相对含量不同,各树种由高到低,依次是崖柏45种、圆柏32种、日本扁柏31种、柏木29种、叉子圆柏25种、侧柏24种、干香柏22种、西藏柏木11种;各种成分的相对含量不同,单萜变化范围46.10%~94.49%,倍半萜变化范围1.21%~87.83%,其它萜类0.47%~52.71%。崖柏是世界级的极危物种,叶片含有31种萜类、木材含有35种萜类,崖柏根雕及木屑储藏室的空气中含有33种萜类。柏树精气的医疗保健功能已得到世界公认。     

中国引种的柏科树种概况

自２０世纪以来我国先后从国外引进柏科树种大约５属５２种１１变种，至今保存２属５２种４变种。表现最好且在生产上有较大栽培面积的主要是柏木属、扁柏属和圆柏属的１０余个种：日本扁柏和日本花柏已成为长江中下游各省（区）中高山地带的优良造林树种；墨西哥柏和绿柏已成为我国中亚热带中、低山地区的优良造林树种；铅笔柏在北亚热带和暖温带湿润地区栽培较广；欧洲刺柏和辅地柏在北方一些城市广泛用作园林树种；铅笔柏在北亚热     

Diversity of the endophytic filamentous fungal leaf community at different development stages of eucalyptus

Fungal endophytic species inhabiting the leaves of eucalypts are capable of utilising leaf sugars and can influence both plant growth and health. Endophytic fungal symbionts can use simple soluble sugars in leaves as their main carbon source. This study set out to determine the diversity and distribution of the endophytic filamentous fungal leaf community in the hybrid Eucalyptus urograndis due to its economic importance. The fungal leaf community was characterised using denaturing gradient electrophoresis (DGGE) and correlated with levels of leaf nutrients and sugars throughout plant development. Sequencing of DGGE bands revealed the presence of Basidiomycota and Ascomycota phyla. Fourteen species and three genera of filamentous fungi were identified, and the population structure was affected by the plant developmental stage. Levels of K, Cu, N and Mn influenced communities from the clonal garden, whereas leaves in the field had higher glucose, fructose and sucrose. Many fungi were found to be specific to a certain development stages: Diplomitoporus crustulinus, Podosphaera tridactyla and Aspergillus restrictus to the clonal garden stage;Chaetomella acutiseta and Ascotricha chartarum to the shading stage;Erratomyces patelii and Saxomyces sp. to the shading output stage;Lepidostroma sp. and Saxomyces sp. to the dispatch stage;and Mycosphaerella populicola to the field stage. Teratosphaeria toledana and Teratosphaeria acidotherma were found at more than one developmental stage. Cladosporium sp. and Rhodosporidium fluviale colonized and persisted in plants at the dispatch and field stages. This is the first report of P. tridactyla, A. restrictus, E. patelii, Saxomyces and Lepidostroma sp. as endophytes in eucalipt.     

7种松柏科植物粗提物对黄栌枯萎病菌的抑制效果

本研究利用带毒平板法测定了4种松科(Pinaceae)植物和3种柏科(Cupressaceae)植物的针叶或鳞叶粗提物对黄栌(Cotinus coggygria)枯萎病菌(Verticillium dahliae)的抑制效果。结果表明,在供试7种植物中,砂地柏(Juniperus sabina)鳞叶提取物的抑菌效果最强,其抑菌率达到85.83%;其次为雪松(Cedrus deodara)针叶提取物,其抑菌率为60.53%;白皮松(Pinus bungeana)针叶、华山松(Pinus armandii)针叶、油松(Pinus tabuliformis)针叶和侧柏(Platycladus orientalis)鳞叶提取物的抑菌率分别为32.71%、28.89%、25.84%和11.21%。桧柏(Juniperuschinensis)鳞叶提取物的抑菌率仅为5.35%,与对照无显著差异,而其他6种植物提取物的抑菌率与对照间差异均达到极显著水平。     

Diversity and community structure of wood-inhabiting fungi found in Japanese wooden houses analyzed by the next-generation sequencing

The diversity and community structures of wood-inhabiting fungi in 16 decayed wood samples from ten wooden houses in Japan were analyzed using a next-generation sequencing (NGS) to determine the fungi responsible for wood decay. DNA of fungi in decayed wood was extracted directly, the internal transcribed spacer (ITS) region in ribosomal DNA (rDNA) was amplified by polymerase chain reaction (PCR), and then, sequences of tagged ITS fragments were analyzed by NGS. Results of sequencing indicated that 68 species of ascomycetes, 37 species of basidiomycetes, and one fungus each from Mortierellales and Mucoromycetes were detected. The fungal community structures showed diversity and included various species of ascomycetes. A microscopic examination of cell wall structure in decayed wood samples suggested that some ascomycetes were soft-rot fungi. Heat map analysis indicated that the similarity in the structures of fungal communities was influenced to a greater extent by the wood species of samples than where they were used as a component.     

西藏巨柏种群天然更新与群落特征研究

巨柏(Cupressus gigantea)为雅鲁藏布江地区分布的特有种,属国家一级保护植物。本文通过在米林-朗县雅鲁藏布江河谷13个面积为1 000 m2的巨柏林样地调查资料,按照近河谷和远河谷山坡的地理分布差异,统计分析了巨柏的种群天然更新特征;通过对群落的组成与结构的分析,初步阐述了巨柏群落的物种组成和结构特征。结果表明,雅鲁藏布江巨柏的更新情况比较差,种群年龄结构不稳定,整体上呈现了明显的种群衰退现象。通过种群的年龄结构分析,反映出了巨柏种群的失衡事件主要发生在最近几十年内,即0.6 m高度10 cm树径范围。巨柏林内物种组成结构单一,乔木层为单一巨柏种,灌木层和草本层的优势种数较少。鉴于巨柏种群环境沙化影响加剧、天然更新能力下降等因素,种群的延续面临较大威胁,需进一步加强该种群的保护和研究。     

红豆杉内生真菌代谢产物的分离与鉴定

从红豆杉树皮中分离到了一株能产生物活性化合物的青霉菌,并对该菌株的发酵产物进行了分离和分析,从中提取分离到了2种化合物。经过图谱分析和文献比对,确定这2种化合物的结构为过氧麦角甾醇和贝诺酯。过氧麦角甾醇具有抗肿瘤、抑菌等活性,贝诺酯是一种应用广泛的镇痛消炎药,本实验中产量分别为2和1.5 mg/L。其他成分经GC/MS分析主要为十三酸、十八烯酸等脂肪酸化合物。本实验是首次从植物内生真菌中分离得到贝诺酯,也是天然贝诺酯的首次报道。     

Morphological and cultural variation of Seiridium spp. from cankered Cupressaceae hosts in New Zealand

Studies of Seiridium. spp. isolated from cankered cypresses and related hosts in New Zealand indicate that only 2 species are present, namely, 5. unicorne and 5. cardinale, following sdtton, and not 3 species as proposed by boesewinkel. Apart from a difference in the presence/absence of conidial appendages, the two pathogens are similar in many biological characteristics. Isolates of S. unicorne showed a continuum of variation in conidial size and cultural morphology making it difficult to justify splitting of the species.     

Detection of the endophyte Discula umbrinella in buds and twigs of Fagus sylvatica

Endophytic fungi have been isolated from buds and twigs of beech trees collected at four different sites in Switzerland. Discula umbrinella. was recovered at high frequencies from the bud scales and the twig pieces contiguous to the buds, but was virtually absent from the rolled up leaves enclosed by the scales. In addition to infection by air-borne inoculum, thalli of D. umbrinella may grow from the twigs into the leaf tissues.     

菌剂添加对人工林土壤呼吸和有机质含量及细菌群落影响

为了解不同菌剂对广西3种人工林凋落物分解、土壤呼吸、土壤有机质含量和微生物群落组成的影响,通过室内培养试验,研究配施不同菌剂后土壤呼吸速率、土壤有机质含量、土壤微生物群落及其功能多样性的变化.结果表明,3种菌剂显著增加了土壤呼吸速率,同时增加了土壤有机含量,并且对土壤微生物群落及功能多样性有明显的促进作用.其中,益加益菌剂对凋落物分解及土壤有机质含量提升效果最佳,马尾松添加益加益处理后土壤有机质含量提升了5.48％,桉树增加了4.49％,并且马尾松和桉树处理添加益加益菌剂后,Chao1指数和Shannon指数显著上升.因此,生产实践中推荐使用益加益菌剂可以促进凋落物分解,提高广西人工林的土壤地力,维持人工林的可持续经营.     

Tree species as hosts for arbuscular mycorrhizal and dark septate endophyte fungi

A survey of 35 tree species(belonging to 28 genera in 19 families) in Aliyar,South India was carried out to ascertain their arbuscular mycorrhizal(AM) and dark septate endophyte(DSE) fungal status.All the tree species examined had AM association.AM and DSE colonization is reported for the first time in 20 and 14 species respectively.Cooccurrence of AM and DSE was observed in 14(40%) tree species.The extent of DSE colonization was inversely related to the extent of AM fungal colonization.Six tree species had Arum-type,18 had intermediatetype and 11 had typical Paris-type AM morphology.AM fungal spore morphotypes belonging to 11 species in two genera were isolated from the rhizosphere soil.AM fungal spore numbers were not related to the extent of AM colonization and Glomus dominated spore diversity.AM association individually and along with DSE were found respectively in the 63% and 44% of the economically important tree species.The occurrence of AM and DSE fungal association in economically important indigenous tree species indicates the possibility of exploiting this association in future conservation programmes of these species.     

Isolation, stability and bioactivity of Jatropha curcas phorbol esters

Jatropha curcas seed oil, which can be utilized for biodiesel production upon transesterification, is also rich in phorbol esters (PEs). In this study, PEs from J. curcas oil (Jatropha factors C₁ and C₂ (purified to homogeneity), Jatropha factors C₃ and (C₄ + C₅) (obtained as mixtures) and PE-rich extract (containing all the above stated Jatropha factors) were investigated. The concentrations of Jatropha PEs were expressed equivalent to Jatropha factor C₁. In the snail (Physa fontinalis) bioassay, the order of potency (EC₅₀, μg/L) was: PE-rich extract < factor C₃ mixture < factor C₂ < factor C₁ < factor (C₄ + C₅). In the Artemia salina bioassay, the order of potency (EC₅₀, mg/L) was: factor C₂ < factor C₃ mixture < factor C₁ < factor (C₄ + C₅) mixture. In addition, Jatropha PEs exhibited platelet aggregation (ED₅₀, μM, factor C₂ < factor C₃ mixture < factor C₁ < factor (C₄ + C₅) mixture. The stability of a PE-rich extract was evaluated and found to be low at room temperature but favourable in ethanol over a range of temperatures. By integrating the isolation methodology developed in this study in the Jatropha biodiesel industry, PEs could be obtained as value-added co-products.     

修枝对福建柏人工幼林生长的影响

在福建省大田梅林国有林场,对5年生的福建柏人工林进行修枝试验,修枝3 a后调查分析树高、胸径和枝下高的生长情况。结果表明:修枝对幼林期福建柏人工林的胸径生长无显著影响,对树高、单株立木材积和枝下高具有正向促进作用,作用由大到小为:修剪枯枝+2轮活枝>修剪枯枝>不修枝。与不修枝相比,修枝3 a后,修剪枯枝处理树高生长增加了57.61%,单株立木材积生长量提高44.86%,枝下高增长了4.43倍;修剪枯枝+2轮活枝处理树高生长量提高55.14%,单株立木材积生长量提高72.37%,枝下高增长了5.62倍。     

Detectionin situ of endophyte withinTricholoma matsutake/Pinus densiflora mycorrhizal roots

Tricholoma matsutake/Pinus densiflora mycorrhizas andP. densiflora roots were collected from beneath matureT. matsutake fruit-bodies in a Shiro in central Japan and investigated for evidence of endophytic infection.Tricholoma matsutake infection was determined microscopically on cleared, bleached and stained mycorrhizas by the presence of both a thin, discontinuous mantle and highly branched, sparingly septate Hartig net mycelium within the root cortex. Endophytic infection of Matsutake mycorrhizas was characterized by intracortical sclerotia, simple septate mycelium within the cortex and vascular cylinder and intracellular spore masses within the root cortex. This research was supported by a grant from the Bio-oriented Technology Research Advancement Institution (BRAIN).