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1.
Muscodor albus and its biological promise   总被引:1,自引:0,他引:1  
We have found a novel fungal genus that produces extremely bioactive volatile organic compounds (VOCs). This fungal isolate was initially discovered as an endophyte in Cinnamomum zeylanicum in a botanical garden in Honduras. This endophytic fungus, Muscodor albus, produces a mixture of VOCs that are lethal to a wide variety of plant and human pathogenic fungi and bacteria. It is also effective against nematodes and certain insects. The mixture of VOCs has been analyzed using GC/MS and consists primarily of various alcohols, acids, esters, ketones, and lipids. Final verification of the identity of the VOCs was carried out by using artificial mixtures of the putatively identified compounds and showing that the artificial mixture possessed the identical retention times and mass spectral qualities as those of the fungal derived substances. Artificial mixtures of the VOCs nicely mimicked the biological effects of the fungal VOCs when tested against a wide range of fungal and bacterial pathogens. Potential applications for “mycofumigation” by M. albus are currently being investigated and include uses for treating various plant parts, and human wastes. Another promising option includes its use to replace methyl bromide fumigation as a means to control soil-borne plant diseases.  相似文献   

2.
Endophytic fungi are broadly dispersed residing inside plant tissues and have been demonstrated as a treasure for bioactive natural products. Unexplored harsh and heavy metal contaminant habitat of Avicennia marina may have diverse and potential fungal association. Therefore, this work aimed to isolate the culturable fungal endophytes associated with leaves of A. marina and to evaluate their medical potentialities. Seventeen isolates of endophyte fungi were isolated from healthy leaves and their antimicrobial activities were evaluated. Results showed that isolates had activity against micro-organisms in addition to their antioxidant activity produced a variety of phenolic compounds, besides exhibited a lowest cytotoxicity against ATCC-CCL-81 cell line. Consequently, selected endophytic fungal isolates were identified genetically as Chaetomium sp., Chaetomium madrasense, Chaetomium sp., Chaetomium globosum, Aspergillus hiratsukae, Aspergillus ochraceus, Alternaria tenuissima and Curvularia lunata with gene bank accession numbers MT089951, MT089952, MT089953, MT089954, MT089955, MT089956, MT089957 and MT089958 respectively. The most potent fungus extract was analysed using Gas chromatography–mass spectrometry which verified the presence of numerous bioactive compounds. These findings confirmed that new endophytic fungal strains derived from A. marina thrive in harsh ecosystem produce bioactive metabolites which can be recommended as a novel source for drug discovery.  相似文献   

3.
A study was conducted for isolation, identification and antibacterial potential of fungal endophytes of Adenocalymma alliaceum Miers., (Bignoniaceae), a medicinal shrub vine plant which has long history for its usages in curing various disorders. A total of 149 isolates of endophytic fungi representing 17 fungal taxa were obtained from 270 segments (90 from each stem, leaf and petiole) of this plant. Hyphomycetes (77.85%) were the most prevalent, followed by Ascomycetes (8.05%) and Coelomycetes (4.03%) respectively. A considerable amount of fungal isolates was kept under (10.07%) Mycelia-Sterilia (MS). Leaf harboured maximum colonization of endophytic fungi (72.22%) which was greater than stem (67.78%) and petiole (25.54%). The Jc similarity index was maximum (0.619) between stem vs leaf followed by leaf vs petiole (0.571) and stem vs petiole (0.428). The dominant endophytic fungi were Alternaria alternata, Aspergillus niger, Stenella agalis, Fusarium oxysporum, Curvularia lunata and Fusarium roseum. Among twelve endophytic fungi tested for antibacterial activity, crude extracts of nine endophytic fungi (75%), showed antibacterial potential against one or more clinical human pathogens. Alternaria alternata, Curvularia lunata, Penicillium sp. and Chaetomium globosum exhibited significant antibacterial activity against 4 of 5 tested pathogens, showing broad spectrum activity. This investigation explains the value of sampling from different tissues of a host plant for the greater species diversity, and additionally, the antibacterial screening of some endophytic fungi from this specific medicinal plant may represent a unique source for many of the useful antibacterial compounds.  相似文献   

4.
Agrobacterium tumefaciens has the ability to transfer its T-DNA to plants, yeast, filamentous fungi, and human cells and integrate it into their genome. Conidia of the maize pathogen Helminthosporium turcicum were transformed to hygromycin B resistance by a Agrobacterium-tumefaciens-mediated transformation system using a binary plasmid vector containing the hygromycin B phosphotransferase (hph) and the enhanced green fluorescent protein (EGFP) genes controlled by the gpd promoter from Agaricus bisporus and the CaMV 35S terminator. Agrobacterium-tumefaciens-mediated transformation yielded stable transformants capable of growing on increased concentrations of hygromycin B. The presence of hph in the transformants was confirmed by PCR, and integration of the T-DNA at random sites in the genome was demonstrated by Southern blot analysis. Agrobacterium-tumefaciens-mediated transformation of Helminthosporium turcicum provides an opportunity for advancing studies of the molecular genetics of the fungus and of the molecular basis of its pathogenicity on maize.  相似文献   

5.
Particle bombardment and Agrobacterium-mediated transformation are two popular methods currently used for producing transgenic maize. Agrobacterium-mediated transformation is expected to produce transformants carrying fewer copies of the transgene and a more predictable pattern of integration. These putative advantages, however, tradeoff with transformation efficiency in maize when a standard binary vector transformation system is used. Using Southern, northern, real-time PCR, and real-time RT-PCR techniques, we compared transgene copy numbers and RNA expression levels in R1 and R2 generations of transgenic maize events generated using the above two gene delivery methods. Our results demonstrated that the Agrobacterium-derived maize transformants have lower transgene copies, and higher and more stable gene expression than their bombardment-derived counterparts. In addition, we showed that more than 70% of transgenic events produced from Agrobacterium-mediated transformation contained various lengths of the bacterial plasmid backbone DNA sequence, indicating that the Agrobacterium-mediated transformation was not as precise as previously perceived, using the current binary vector system.  相似文献   

6.
Calotropis procera has many important medicinal properties with proven pharmacological potential. Some of these properties may be mediated by its fungal endophytes. This study analyzed, for the first time, the community of endophytic fungi of C. procera outside its region of origin. A total of 156 fungal isolates distributed across 19 taxa were obtained from 468 fragments of C. procera leaves at different stages of maturation. The rate of endophyte colonization increased with the leaf age/development. The dominant species of endophytic fungi of C. procera introduced in Northeast Brazil were different from those found in studies on the same species and other species of the same genus in native regions. The dominant endophyte was Phaeoramularia calotropidis (63.5 %), followed by Guignardia bidwellii (21.1 %). Six isolates of endophytic fungi showed antimicrobial activity against human pathogenic micro-organisms and one plant pathogenic fungus. The antibacterial activity was more intense than the antifungal activity. The endophytic Curvularia pallescens (URM 6048) stood out inhibited Gram-positive bacteria, Staphylococcus aureus, Streptococcus pyogenes, the plant pathogenic fungus Colletotrichum dematium. Ecological and biotechnological aspects of endophytic mycota are discussed.  相似文献   

7.
Summary Since the success of Agrobacterium-mediated transformation of rice in the early 1990s, significant advances in Agrobacterium-mediated transformation of monocotyledonous plant species have been achieved. Transgenic plants obtained via Agrobacterium-mediated transformation have been regenerated in more than a dozen monocotyledonous species, ranging from the most important cereal crops to ornamental plant species. Efficient transformation protocols for agronomically important cereal crops such as rice, wheat, maize, barley, and sorghum have been developed and transformation for some of these species has become routine. Many factors influencing Agrobacterium-mediated transformation of monocotyledonous plants have been investigated and elucidated. These factors include plant genotype, explant type, Agrobacterium strain, and binary vector. In addition, a wide variety of inoculation and co-culture conditions have been shown to be important for the transformation of monocots. For example, antinecrotic treatments using antioxidants and bactericides, osmotic treatments, desiccation of explants before or after Agrobacterium infection, and inoculation and co-culture medium compositions have influenced the ability to recover transgenic monocols. The plant selectable markers used and the promoters driving these marker genes have also been recognized as important factors influencing stable transformation frequency. Extension of transformation protocols to elite genotypes and to more readily available explants in agronomically important crop species will be the challenge of the future. Further evaluation of genes stimulating plant cell division or T-DNA integration, and genes increasing competency of plant cells to Agrobacterium, may increase transformation efficiency in various systems. Understanding mechanisms by which treatments such as desiccation and antioxidants impact T-DNA delivery and stable transformation will facilitate development of efficient transformation systems.  相似文献   

8.
We examined interactions between host plants, endophytic fungi, and leaf-mining moths (Phyllonorycter sp.) in an oak (Quercus grisea x Q. gambelii) hybrid zone. The community of endophytic fungi and two common endophyte species examined responded to host plant hybridization. Total fungal frequency (TFF) and frequency of Gnomonia cerastis were lowest on hosts resembling Q. grisea, and increased linearly towards those resembling Q. gambelii. In contrast, Coccochorella quercicola was most frequently isolated from Q. grisea-like hosts and decreased in frequency across hybrids towards Q. gambelii. Frequency of G. cerastis and TFF covaried with Phyllonorycter density across the hybrid zone, but direct effects of endophytes on Phyllonorycter density were not detected. Associations between endophytes and unexplained mortality of Phyllonorycter varied according to endophyte species and state of Phyllonorycter development. In the sap-feeding stage, unexplained mortality was negatively associated with TFF and frequencies of Hormonema sp. and Preussia funiculata; whereas, in the tissue-feeding stage, unexplained Phyllonorycter mortality was positively associated with G. cerastis frequency. Three-way interactions between plant hybridization, endophytic fungi, and the insect herbivore were not significant.  相似文献   

9.
Although the terrestrial and temperate orchids–fungal biology have been largely explored, knowledge of tropical epiphytic orchids–fungus relationships, especially on the ecological roles imparted by non-mycorrhizal fungal endophytes, is less known. Exploitation of the endophytic fungal mycobiota residing in epiphytic orchid plants may be of great importance to further elucidate the fungal ecology in this special habitat as well as developing new approaches for orchid conversations. The composition of fungal endophytes associated with leaves, stems and roots of an epiphytic orchid (Dendrobium nobile), a famous Chinese traditional medicinal plant, was investigated. Microscopic imaging, culture-dependant method and molecular phylogeny were used to estimate their entity and diversity. Totally, there were 172 isolates, at least 14 fungal genera and 33 different morphospecies recovered from 288 samples. Ascomycetes, coelomycetes and hyphomycetes were three major fungal groups. There were higher overall colonization and isolation rates of endophytic fungi from leaves than from other tissues. Guignardia mangiferae was the dominant fungal species within leaves; while the endophytic Xylariaceae were frequently observed in all plant tissues; Colletotrichum, Phomopsis and Fusarium were also frequently observed. Phylogenetic analysis based on ITS gene revealed the high diversity of Xylariacea fungi and relatively diverse of non-Xylariacea fungi. Some potentially promising beneficial fungi such as Clonostachys rosea and Trichoderma chlorosporum were found in roots. This is the first report concerning above-ground and below-ground endophytic fungi community of an epiphytic medicinal orchid, suggesting the ubiquitous distribution of non-mycorrhizal fungal endophytes in orchid plants together with heterogeneity and tissue specificity of the endophyte assemblage. Possible physiological functions played by these fungal endophytes and their potential applications are also discussed briefly. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.  相似文献   

10.
Muscodor albus MOW12, an endophytic fungus isolated from Piper nigrum in Mawlong, Meghalaya, India, resembles some cultural and hyphal characteristics of previous isolates of Muscodor sp. In addition, it possesses about 99 % similarity in its ITS rDNA with other M. albus isolates and thus is nicely centered within the genetic tree to other Muscodor spp. This xylariaceae fungus effectively inhibits and kills certain plant pathogenic fungi by virtue of a mixture of volatile compounds that it produces. The majority of these compounds were identified by gas chromatography/mass spectrometry as small molecular weight esters, alcohols, and acids. The main ester components of this isolate of M. albus in its volatile mixture are acetic acid, ethyl ester; propanoic acid, 2-methyl-, methyl ester and acetic acid, 2-methylpropyl ester. This appears to be the first report of any M. albus strain from India.  相似文献   

11.
This study was conducted to explore fungal endophyte communities inhabiting a toxic weed (Stellera chamaejasme L.) from meadows of northwestern China. The effects of plant tissue and growth stage on endophyte assemblages were characterized. Endophytes were recovered from 50 % of the samples, with a total of 714 isolates. 41 operational taxonomical units (OTUs) were identified, consisting of 40 OTUs belonging primarily to Ascomycota and 1 OTU belonging to Basidiomycota. Pleosporales and Hypocreales were the orders contributing the most species to the endophytic assemblages. The total colonization frequency and species richness of endophytic fungi were higher in roots than in leaves and stems. In addition, for the plant tissues, the structure of fungal communities differed significantly by growth stages of leaf emergence and dormancy; for the plant growth stages, the structure of fungal communities differed significantly by plant tissues. This study demonstrates that S. chamaejasme serves as a reservoir for a wide variety of fungal endophytes that can be isolated from various plant tissues.  相似文献   

12.
Endophytic fungi play an important role in terrestrial ecosystem, while little is known about those in hemi-parasitic plants, a group of special plants which absorb nutrients from its hosts by haustoria. The relationship of the endophytes in the two parts of the bipartite systems (hemiparasites together with their hosts) is also poorly understood. Endophytic fungi of a hemi-parasitic plant Macrosolen tricolor, and its host plant Camellia oleifera were investigated and compared in this study. M. tricolor contained rich and diversified endophytic fungi (H′ = 2.829), which consisted mainly of ascomycetes, distributed in more than ten orders of four classes (Sordariomycetes, Dothideomycetes, Leotiomycetes and Eurotiomycetes) besides Incertae sedis strains (23.2 % of total). In addition, 2.2 % of isolates were identified to be Basidiomycota, all of which belonged to Agaricomycetes. Obvious differences were observed between the endophytic fungal assembles in the leaves and those in the branches of M. tricolor. The endophytic fungi isolated from C. oleifera distributed in nearly same orders of the four classes of Ascomycota and one class (Agaricomycetes) of Basidiomycota as those from M. tricolor with similar proportion. For both M. tricolor and C. oleifera, Valsa sp. was the dominant endophyte species in the leaves, Torula sp. 1 and Fusarium sp. 1 were the dominant endophytic fungi in the branches. The similarity coefficient of the endophyte assembles in the two host was 64.4 %. Canonical correspondence analysis showed that the endophyte assembles of M. tricolor and C. oleifera were significantly different (p < 0.01).  相似文献   

13.
Development of in vitro plant regeneration method from Brassica explants via organogenesis and somatic embryogenesis is influenced by many factors such as culture environment, culture medium composition, explant sources, and genotypes which are reviewed in this study. An efficient in vitro regeneration system to allow genetic transformation of Brassica is a crucial tool for improving its economical value. Methods to optimize transformation protocols for the efficient introduction of desirable traits, and a comparative analysis of these methods are also reviewed. Hence, binary vectors, selectable marker genes, minimum inhibitory concentration of selection agents, reporter marker genes, preculture media, Agrobacterium concentration and regeneration ability of putative transformants for improvement of Agrobacterium-mediated transformation of Brassica are discussed.  相似文献   

14.
Fungal endophytic communities and potential host preference of root-inhabiting fungi of boreal forest understory plants are poorly known. The objective of this study was to find out whether two neighboring plant species, Deschampsia flexuosa (Poaceae) and Trientalis europaea (Primulaceae), share similar root fungal endophytic communities and whether the communities differ between two sites. The study was carried out by analysis of pure culture isolates and root fungal colonization percentages. A total of 84 isolates from D. flexuosa and 27 isolates from T. europaea were obtained. The roots of D. flexuosa harbored 16 different isolate types based on macromorphological characteristics, whereas only 4 isolate types were found in T. europaea. The root colonization by dark septate and hyaline septate hyphae correlated with isolate numbers being higher in D. flexuosa compared to T. europaea. The different isolate types were further identified on the basis of internal transcribed spacer sequence and phylogenetic analysis. An isolate type identified as dark septate endophyte Phialocephala fortinii colonized 50 % of the T. europaea and 21 % of the D. flexuosa specimens. In addition, Meliniomyces variabilis, Phialocephala sphaeroides, and Umbelopsis isabellina were found colonizing the grass, D. flexuosa, for the first time and Mycena sp. was confirmed as an endophyte of D. flexuosa. Site-specific differences were observed in the abundance and diversity of endophytic fungi in the roots of both study plants, but the differences were not as predominant as those between plant species. It is concluded that D. flexuosa harbors both higher amount and more diverse community of endophytic fungi in its roots compared to T. europaea.  相似文献   

15.
从蔓草虫豆(Atylosia scarabaeoides)、余甘子(Phyllanthus emblica)和黄花稔(Sida acuta)等5种云南元江干热河谷植物的525个组织块中,共分离得到内生真菌371株,内生真菌的分离频率在0.61~0.92之间,且所有植物叶内生真菌的分离频率都明显高于茎(P<0.05)。经形态学鉴定,内生真菌分属于拟茎点霉属(Phomopsis sp.)、离蠕孢属(Bipolaris sp.)和交链孢属(Alternaria sp.)等32个分类单元。拟茎点霉属为干热河谷植物优势内生真菌属,从所有被调查植物的茎叶中都分离得到该属真菌,且相对分离频率高达12.90%~50.54%。内生真菌群落组成的多样性和相似性分析结果表明,云南元江干热河谷植物内生真菌多样性偏低、宿主专一性较小。  相似文献   

16.
As carnivorous plants acquire substantial amounts of nutrients from the digestion of their prey, mycorrhizal associations are considered to be redundant; however, fungal root endophytes have rarely been examined. As endophytic fungi can have profound impacts on plant communities, we aim to determine the extent of fungal root colonisation of the carnivorous plant Drosera rotundifolia at two points in the growing season (spring and summer). We have used a culture-dependent method to isolate fungal endophytes and diagnostic polymerase chain reaction methods to determine arbuscular mycorrhizal fungi colonisation. All of the roots sampled contained culturable fungal root endophytes; additionally, we have provided molecular evidence that they also host arbuscular mycorrhizal fungi. Colonisation showed seasonal differences: Roots in the spring were colonised by Articulospora tetracladia, two isolates of uncultured ectomycorrhizal fungi, an unidentified species of fungal endophyte and Trichoderma viride, which was present in every plant sampled. In contrast, roots in the summer were colonised by Alatospora acuminata, an uncultured ectomycorrhizal fungus, Penicillium pinophilum and an uncultured fungal clone. Although the functional roles of fungal endophytes of D. rotundifolia are unknown, colonisation may (a) confer abiotic stress tolerance, (b) facilitate the acquisition of scarce nutrients particularly at the beginning of the growing season or (c) play a role in nutrient signalling between root and shoot.  相似文献   

17.
Tartary buckwheat (Fagopyrum tataricum) is a potentially important source of rutin, a natural bioactive flavonoid with antihyperglycemic, antioxidative, antihypertensive, and anti-inflammatory properties. This study examines the effects of endophytic fungi on rutin production in the hairy root cultures of F. tataricum. Without obvious changes in the appearance of the hairy roots, the exogenous fungal mycelia elicitors efficiently stimulated the hairy root growth and rutin biosynthesis, and the stimulation effect was mainly dependent on the mycelia elicitor species, as well as its treatment dose. Two endophytic fungal isolates Fat9 (Fusarium oxysporum) and Fat15 (Alternaria sp.) were screened as promising candidates for promoting F. tataricum hairy root growth and rutin production. With application of polysaccharide (PS) of endophyte Fat9 (200 mg/L), and PS of endophyte Fat15 (100 mg/L) to the hairy root cultures on day 25, the rutin yield was increased to 45.9 mg/L and 47.2 mg/L, respectively. That was about 3.1- to 3.2-fold in comparison with the control level of 14.6 mg/L. Moreover, the present study revealed that the accumulation of rutin resulted from the stimulation of the phenylpropanoid pathway by mycelia PS treatments. This may be an efficient strategy for enhancing rutin production in F. tataricum hairy root culture provided with its endophytic mycelia elicitors.  相似文献   

18.
AsAgrobacterium tumefaciens, which has long been used to transform plants, is known to transfer T-DNA to budding yeast,Saccharomyces cerevisiae, a variety of fungi were subjected to theA. tumefaciens-mediated transformation to improve their transformation frequency and feasibility. TheA. tumefaciens-mediated transformation of chestnut blight fungus,Cryphonectria parasitica, is performed in this study as the first example of transformation of a hardwood fungal pathogen. The transfer of the binary vector pBIN9-Hg, containing the bacterial hygromycin B phosphotransferase gene under the control of theAspergillus nidulans trpC promoter and terminator, as a selectable marker, led to the selection of more than 1,000 stable, hygromycin B-resistant transformants per 1×106 conidia ofC. parasitica. The putative transformants appeared to be mitotically stable. The transformation efficiency appears to depend on the bacterial strain, age of the bacteria cell culture and ratio of fungal spores to bacterial cells. PCR and Southern blot analysis indicated that the marker gene was inserted at different chromosomal sites. Moreover, three transformants out of ten showed more than two hybridizing bands, suggesting more than two copies of the inserted marker gene are not uncommon.  相似文献   

19.
Endophytic fungi were isolated from healthy, living, and symptomless tissues of inner bark, leaf, and roots of Aegle marmelos, a well-known medicinal plant, growing in different parts of India including Varanasi. A total of 79 isolates of endophytic fungi were isolated, representing 21 genera, adopting a standard isolation protocol. Members of the deuteromycotina were more prevalent than ascomycotina and others. The result was quite encouraging in terms of maximum isolates recovery from hyphomycetes (78.5%) followed by ascomycetes (8.9%) and coelomycetes (7.6%) respectively, which corroborates previous studies in same area. However, 5.1% isolates remained unidentified and were classified under Mycelia Sterilia. No isolate was obtained from either basidiomycotina or from zygomycotina. Fusarium spp. had maximum colonization frequency (8.00%) in this plant. The other dominant endophytic genera were Aspergillus spp., Alternaria sp., Drechslera sp., Rhizoctonia sp., Curvularia sp., Nigrospora sp., and Stenella sp. Only two ascomycetous members Chaetomium globosum and Emericella sp. (perfect state of Aspergillus sp.) were obtained from the bark sample. These results indicated that distribution of endophytic fungi within the A. marmelos is not even. Bark harbors more endophytic fungi than leaf and root.  相似文献   

20.
Foliar endophytic fungi are present in almost all vascular plants. The composition of endophyte communities varies among plant individuals. Likely, but understudied, sources of this variation are the species composition of the plant community and initial attacks by insect herbivores. We addressed these issues by characterizing fungal endophyte communities on leaves of chestnut (Castanea sativa) grown in pure vs. mixed stands. We used ITS metabarcoding methods to identify endophytic fungi associated with galls caused by the invasive gall wasp, Dryocosmus kuriphilus, and with surrounding chestnut leaf tissues. We found 1378 different OTUs. The richness, diversity and composition of endophyte communities differed between galls and surrounding leaf tissues but were independent of forest stand composition. Fungal endophyte richness was lower in galls than in surrounding leaf tissues. Most differences in the composition of fungal endophyte communities between galls and foliar tissues were due to OTU turnover. These results suggest that insect-induced galls provide a particular habitat condition for endophytic microorganisms, regardless of forest species composition. A better understanding of endophyte biology is important to improve their use as biocontrol agents of galling insects.  相似文献   

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