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1.
Endohyphal organisms of endophytic fungi can induce, or promote, beneficial effects of their respective host fungi to the host plant that harbours them. The Cupressaceae plant family (Coniferales) hosts highly bioactive endophytic fungi. Here, we show that a fraction of such endophytic fungi harbours bioactive endohyphal bacteria with a non‐obligatory symbiotic lifestyle. Indeed, 5 of 16 (31.25%) endophytic fungi of Cupressus sempervirens harboured endofungal bacterial strains of Bacillaceae (G+, Bacilli) and Sphingomonadaceae (G?, α‐Proteobacteria), that is Bacillus pumilus (from the fungi Leptosphaeria CSE211 and Pyrenochaeta CSE134), Bacillus subtilis (from the fungi Leptosphaeria CSE212 and Ascorhizoctonia CSE148) and Sphingomonas paucimobilis (from the fungus Ascorhizoctonia CSE195). Notably, each endophytic fungal species contained only one endofungal bacterial species that was stably maintained in symbiosis over several rounds of subculturing. Moreover, we investigated whether cypress endofungal bacteria (CEB) could benefit their host fungus competing with other fungi and bacteria or the host plant against the invading microorganisms. In vitro assays indicated that CEB possessed antagonistic activity against cypress endophytic and pathogenic microbiome. Also, CEB metabolites and volatile compounds (VOCs) exhibited antifungal and antibacterial activity against the target microbiome. Bioactivity of CEB was less than that of the endophytic microbiome of Cupressaceae, on which we reported earlier. In conclusion, our work is the first to document endohyphal bacteria of fungal endophytes of C. sempervirens and the bioactivity of such endohyphal symbionts. These findings implicate a complicated interrelationship among host plant, endophytic microbiome and endofungal bacteria, which might be of high importance for evolutionary, as well as environmental and agricultural studies. Eventually, endohyphal bacteria may be introduced as a novel source for lead molecule discovery.  相似文献   

2.
ABSTRACT

Plantation forests play a critical role in forest management due to their high productivity and large contribution to carbon sequestration (CSE). The purpose of this study was to assess the CSE of plantations containing four important conifer species distributed across Taiwan, namely, the China fir (Cunninghamia lanceolata), Japanese cedar (Cryptomeria japonica), Taiwania (Taiwania cryptomerioides) and Taiwan red cypress (Chamaecyparis formosensis). Data regarding the plantations were obtained from a survey of permanent sample plots (PSPs). We used these data to calculate the CSE in each PSP and adopted CSEmean and CSEperiod as indicators to assess the CSE of the four conifers. According to the CSEmean obtained from analysis of variance and the least significant difference method, two groups were identified among these four conifers: the Japanese cedar (4.03 Mg ha?1 yr?1) and Taiwania (3.52 Mg ha?1 yr?1) yielded higher CSEmean values and the China fir (1.79 Mg ha?1 yr?1) and Taiwan red cypress (2.36 Mg ha?1 yr?1) yielded lower CSEmean values. The same patterns were observed in the CSEperiod values; however, no significant difference in CSEperiod was observed between Taiwan red cypress and either of the two groups. Therefore, Japanese cedar and Taiwania have high CSE potential among conifers.  相似文献   

3.
[目的]为获得高效拮抗3种兰花病原真菌胶孢炭疽菌、尖孢镰孢菌和腐皮镰孢菌的菌株。[方法]使用平板对峙法筛选拮抗菌株,结合形态特征观察、生理生化试验和16S rRNA基因序列分析的方法对目的菌株进行鉴定。[结果]筛选获得5株同时拮抗三种病原菌的菌株,其中菌株GT312拮抗效果明显。16S rRNA基因序列分析显示,该菌株与Bacillus amyloliquefaciens(模式菌株FZB42T)相似性最高,为99.93%。菌株形态特征观察、生理生化试验结果与B.amyloliquefaciens描述一致。[结论]菌株GT312可同时拮抗3种兰花病原真菌,鉴定为解淀粉芽孢杆菌,为兰花病害的生物防治提供了菌株资源。  相似文献   

4.
In this study, a total of 68 endophytic bacteria were isolated from different tissues of walnut trees. About 55% and 22% of the strains had the ability to produce indole acetic acid and gibberellic acid, respectively. The capability of isolates to solubilize phosphate, growth on N‐free medium, siderophore, protease and lipase production was varied. Based on phenotypic grouping and plant growth promotion properties, twelve isolates were selected and 16S rRNA gene‐based phylogenetic analysis revealed that strains showed 99%–100% similarity to Pseudomonas, Bacillus, Arthrobacter, Roseomonas and Streptomyces genera. Amongst the selected strains, PS12, KS54, JS66 and KS74 showed root and shoot growth enhancement of poplar cutting. NS70, KS54 and PL36 strains showed antagonistic activity against Pseudomonas syringae pv. syringae;RR47, KS74 and NR69 strains had inhibition effects against Brenneria nigrifluens; and JS66 and RR26 strains had antagonistic activity against both phytopathogens under in vitro conditions. This is the first reported study to elucidate the endophytic bacterial diversity associated with walnut trees with beneficial attributes.  相似文献   

5.
Six endophytic bacterial strains from wheat roots, selected from extensive screening tests, were studied in greenhouse pot experiments against take-all disease of wheat, caused by Gaeumannomyces graminis var. tritici (Ggt). For comparison, the fungicide triadimefon was included. All six bacterial strains and triadimefon significantly reduced take-all in wheat plants between 39.4 and 57.3% compared to the inoculated control. Treatment with the bacterial strains also significantly increased growth parameters of roots (e.g., average length, fresh, and dry weight) in comparison with the inoculated control. One of the endophytic bacterial strains, designated EDR4, which proved to be most consistent in further greenhouse tests, was also examined in field trials against take-all in wheat. In the field experiment 2006/2007, height of wheat plants in Ggt inoculated plots was significantly reduced compared to the non-inoculated treatments. Yield parameters such as kernels per head and thousand kernel weight (TKW) in the inoculated control were lower compared to other treatments. In the inoculated plots, individual treatments with the strain EDR4 increased yield compared to the inoculated control. In the field trial 2007/2008 treatments with strain EDR4 as well as the fungicide triadimefon reduced take-all by 49.6 and 61.9%, respectively, compared to the inoculated control. At harvest, in the inoculated control plant height, seeds per head and TKW were significantly lower compared to the other treatments. Treatments with EDR4 eliminated the detrimental effects of take-all on grain yield to a similar degree as triadimefon application. The strain EDR4 distinctly inhibited growth of Ggt in vitro and was identified as Bacillus subtilis on the basis of its morphology and 16S rRNA sequence analysis as well as physiological and biochemical characteristics. These results indicate that the strain EDR4 has potential in directly controlling take-all disease of wheat.  相似文献   

6.
The essential oils of eighteen Egyptian plants were extracted by hydrodistillation and their chemical compositions were analyzed by GC-MS. The antifungal activity of the isolated oils was evaluated against two wood decay fungi Hexagonia apiaria and Ganoderma lucidum in vitro. The essential oil of Artemisia monosperma showed the highest inhibitory effect against H. apiaria (EC50 = 31 mg L?1) and G. lucidum (EC50 = 53 mg L?1). The results of in vitro tests indicated that the essential oils of Cupressus sempervirens, Citrus limon, Thuja occidentalis, Schinus molle, A. monosperma and Pelargonium graveolens were the most potent inhibitors against both fungi. These six oils caused significant reduction of wood mass loss of Scots pine sapwood after 6 weeks of fungal exposure. The oil of C. limon revealed the highest reduction of wood mass loss caused by H. apiaria, while A. monosperma oil displayed the highest reduction of wood loss caused by G. lucidum. These results support the potential use of essential oils for wood protection against decay fungi.  相似文献   

7.
Several wood-based sandwich panels with low-density fiberboard core were developed for structural insulated walls and floors, with different face material, panel thickness, and core density. The elastic moduli with and without shear effect (E L, E 0) and shear modulus (Gb) were evaluated in four-point bending. Generally, the stiffer face, thicker panel, and higher core density were advantageous in flexural and shear rigidity for structural use, but the weight control was critical for insulation. Therefore, optimum designs of some virtual sandwich structures were analyzed for bending stiffness in relation to weight for fixed core densities, considering the manufactured-panel designs. As a result, the plywood-faced sandwich panel with a panel thickness of 95 mm (PSW-T100), with insulation performance that had been previously confirmed, was most advantageous at a panel density of 430 kg/m3, showing the highest flexural rigidity (E L I = 13 × 10−6 GNm2) among these panels, where E L, E 0, and G b were 3.5, 5.5, and 0.038 GN/m2, respectively. The panel was found to be closest to the optimum design, which meant that its core and face thickness were optimum for stiffness with minimum density. The panel also provided enough internal bond strength and an excellent dimensional stability. The panel was the most feasible for structural insulation use with the weight-saving structure.  相似文献   

8.
采集人工种植2年的铁皮石斛,将根、茎和叶研磨为粉末,采用NA培养基分离纯化其内生细菌,酶切去除冗余,利用16S rRNA基因序列同源性分析,对铁皮石斛根、茎和叶中分离得到的49株内生细菌进行分离鉴定。结果表明,获得的49株内生细菌在根、茎、叶中分别有24株、15株和10株,分别属于芽孢杆菌属的5个种、假单孢杆菌属的1个种和沙雷氏菌属的1个种。分离出的内生细菌表现出一定程度的细菌区系相似性,也表现出细菌区系的器官特异性。铁皮石斛内生细菌在石斛根部分布的属、种数量明显比茎、叶多,土壤可能是铁皮石斛内生细菌的主要来源;铁皮石斛不同部位内生细菌群落结构存在一定差异,群落种数根＞茎＞叶。研究获得荧光假单胞杆菌20株,占总内生细菌数量的40.82％,判断其可能为优势菌株。  相似文献   

9.
Samples of roots, leaves and stems of healthy oak trees were collected from various locations in the Baneh and Marivan regions, Iran. In total, 63 endophytic bacteria were isolated and grouped according to phenotypic properties. Seven selected isolates were further identified by partial sequencing of the 16S rRNA gene. Isolates Pp54, Pp88, Pp95 and Pp177 were Pseudomonas spp., isolates Sm59 and Sm79 were Stenotrophomonas spp., and isolate Bf 172 was a Bacillus sp. The ability of these isolates for plant hormone production such as auxin and gibberellin was evaluated, along with siderophore production, phosphate solubilization, atmospheric nitrogen fixation, protease and hydrogen cyanide production. All strains produced auxin and gibberellin in different amounts. Atmospheric nitrogen fixation ability was positive for strains Sm79, Pp54, Pp88 and Pp95. All strains except Sm79 solubilized phosphate. Strains Sm59, SM79, Pp88, Pp177 and Bf172 produced protease. Pp88, Pp95, Bf172 and Pp177 were able to produce siderophore. Strains Sm79 and Pp95 released low concentrations of hydrogen cyanide. Amongst the strains tested, Pp95, Pp88, Pp177 and Sm79 had different inhibitory effects on the bacterial plant pathogen, Pseudomonas syringae pv. syringae under in vitro conditions. This is the first reported case of endophytic Bacillus, Pseudomonas and Stenotrophomonas strains from oak trees in Iran.  相似文献   

10.
Interactions between the pine wood nematode (PWN), Bursaphelenchus xylophilus, and bacteria of the genus Pseudomonas were examined by cultivating axenic PWN and bacterial strains using callus of Pinus thunbergii. Ten (Pseudomonas fluorescens, Pseudomonas putida, Pseudomonas cepacia and Pseudomonas spp.) of the 29 bacterial strains tested, significantly increased the reproduction of PWN. The rest of the bacteria (19 strains of 10 species) inhibited the reproduction of PWN completely. The growth of 18 of the 29 bacterial strains tested, including the 10 strains promoting PWN reproduction, was significantly increased by the presence of PWN. It indicated a mutualistic symbiotic relationship between PWN and the 10 bacterial strains in the genus Pseudomonas. The bacterial mutualistic symbionts are organisms, which may have co‐evolved with PWN rather than being accidentally associated. The finding provides further evidence for our hypothesis that pine wilt disease is complex, induced by both PWN and associated phytotoxin‐producing bacteria.  相似文献   

11.
The aim of this study was to describe endophytic fungal communities residing in five mangrove species (Sonneratia caseolaris, Sonneratia hainanensis, Sonneratia ovata, Sonneratia Paracaseolaris, Sonneratia apetala) collected at the south coast of China. The colonization frequency (CF) of endophytes in roots, stems and leaves was measured and the structures of endophytic communities were investigated, using endophytic fungal diversity indices and similarity coefficients. We found high biodiversity and tissue specificity of endophytic fungi. A total of 391 fungal isolates were identified using morphological and molecular methods. We recovered a total of 39 distinct endophytic species, of which Cytospora, Diaporthe, Fusarium, Glomerella, Mycosphaerella, Phoma, Phomopsis and Stemphylium were the dominant fungal taxa. Most recovered species were found on more than one host species but the dominant species differed according to host and tissue type.  相似文献   

12.
Leyland cypress (×Cupressocyparis leylandii) has been regarded as an intergeneric hybrid between Monterey cypress (Cupressus macrocarpa) and Alaska cypress (Chamaecyparis nootkatensis) in the Cupressaceae. Each partial sequence of the 18S-rDNA from nuclear and therbcL from chloroplast DNA genomes was determined using above three species. At the 59th site from the 5′ end of the 152 bp of the determined 18S-rDNA sequence, one base difference was identified between Monterey cypress (T) and Alaska cypress (A). However, Leyland cypress showed either nucleotide A or T at this site. Since nuclear DNA is inherited by biparental mode, this result shows genetic evidence that the nucleic genome of Leyland cypress originates from Monterey cypress and Alaska cypress and that this species is of hybrid origin.  相似文献   

13.
Tree biomass plays a key role in sustainable management by providing different aspects of ecosystem. Estimation of above ground biomass by non-destructive means requires the development of allometric equations. Most researchers used DBH (diameter at breast height) and TH (total height) to develop allometric equation for a tree. Very few species-specific allometric equations are currently available for shrubs to estimate of biomass from measured plant attributes. Therefore, we used some of readily measurable variables to develop allometric equations such as girth at collar-height (GCH) and height of girth measuring point (GMH) with total height (TH) for A. rotundifolia, a mangrove species of Sundarbans of Bangladesh, as it is too dwarf to take DBH and too irregular in base to take Girth at a fixed height. Linear, non-linear and logarithmic regression techniques were tried to determine the best regression model to estimate the above-ground biomass of stem, branch and leaf. A total of 186 regression equations were generated from the combination of independent variables. Best fit regression equations were determined by examining co-efficient of determination (R2), co-efficient of variation (CV), mean-square of the error (MSerror), residual mean error (Rsme), and F-value. Multiple linear regression models showed more efficient over other types of regression equation. The performance of regression equations was increased by inclusion of GMH as an independent variable along with total height and GCH.  相似文献   

14.
Ramets of the Cupressus sempervirens clone Bolgheri were raised in three CO2 concentrations in a naturally CO2‐enriched environment [360 (control), 680 and 1670 μmol mol–1 CO2]. Bolgheri is patented as resistant to Seiridium cardinale. The ramets were artificially inoculated using a virulent isolate of S. cardinale. Healing of the resulting cankers was visually assessed over 6 years. Six months after inoculation, cankers on trees grown at 680 μmol mol–1 were significantly larger than the controls. However, no significant trend was recorded at later dates. In conclusion, the Bolgheri clone maintained its resistance to S. cardinale and could be used to control cypress canker even in increasing atmospheric CO2 concentrations.  相似文献   

15.
A general regression model for large areas may have poor statistical properties for smaller sub-regions. In this study, we test the local indicators of spatial association (LISA) in the selection of localization areas of a general regression model. We present four different LISAs: Moran’s I i , Geary’s c i , G i , and G i *. These indices show if there is a cluster of similar values in the data (Moran’s I i and Geary’s c i ) or if there is a cluster of positive or negative values (G i and G i *). The material is NFI9 (9th National Forest Inventory) sample tree (Pinus sylvestris) data from Southern Finland. LISAs were calculated from the residuals of a form height regression model, which was fitted to the original data. We detected statistically significant clustering of similar values with both global indices Moran’s I and Geary’s c. This means that local indices may show statistically significant clustering of similar values only because the surrounding of an observation happens to have high values. Therefore we use G i *-index in selection of sub-areas. We tested the localization in three sub-areas: (1) one where the G i *-index was positive, (2) one where the index was negative, and (3) one where the index was both positive and negative and zero. In particular, localization removed the local bias of the global model. The effect of localization on variances was minor. The effect of localization on residuals in Areas 1 and 2 correspond to a level correction of the global model. The G i *-index (and G i -index) seem to be useful for selecting localization areas, even though there is still need for future studies.  相似文献   

16.
细叶桉种源-家系综合选择的研究   总被引：9，自引：2，他引：9       下载免费PDF全文
对细叶桉14个种源的100个家系生长性状,形质性状进行源间和家系间的差异分析和遗传分析,结果表明性状间差异极显,家系遗传力大于单株遗传力,除分枝性状外,生长性状与形质性状相关极显。7年生生长最好的13659种源的平均树高,胸径和单株材积分别是最差种源13308的1．27,1．32和2．14倍,7年生最优家系是No.17号家系,其单株材积达0.06134 m^3,是最差家系No.33号的3．6倍,虽家系群体均值的1．74倍。运用指数选择法对家系进行多性状综合选择,初步选出22个优良家系,其树高,胸径,材积,枝下高,干形和分枝的遗传增益分别达到7．31％,6．39％,18．01％,13．77％,8．22％和5．36％。  相似文献   

17.
为筛选适宜鄂北岗地的造林树种,提高造林成效,采用样地调查方法对2018年鄂北岗地“精准灭荒”工程造林项目进行了调查,比较各树种造林成活率、保存率及造林第二年生长情况,结合主成分分析并聚类,综合评价各树种的造林效果。结果表明,11个造林树种间的造林成活率、保存率、盖度、新梢生长量及中心干枯死率均存在极显著差异,其中,油茶造林成活率、保存率最高（96.7%±2.0%、94.9%±2.7%）,湿地松盖度最大（0.097±0.011）,刺槐一年生梢最长（39.8 cm）,油茶、湿地松、柏木中心干枯死率低;造林指标的综合评价值（D值）由高到低排序,依次为油茶、湿地松、女贞、柏木、刺槐、栾树、桂花、重阳木、银杏、樟树、槲栎。通过聚类分析将11个造林树种分为4 个类群,最适宜的树种为油茶、湿地松和女贞,比较适宜的树种为柏木和刺槐,适宜性差的树种为栾树、桂花、重阳木、银杏、樟树,不适宜树种为槲栎。油茶、湿地松、女贞、柏木、刺槐综合表现较优,可作为鄂北岗地造林的首选树种。  相似文献   

18.
Three new polyketides named penialidins A–C (1–3), along with one known compound, citromycetin (4), were isolated from an endophytic fungus, Penicillium sp., harbored in the leaves of the Cameroonian medicinal plant Garcinia nobilis. Their structures were elucidated by means of spectroscopic and spectrometric methods (NMR and HRMSn). The antibacterial efficacies of the new compounds (1–3) were tested against the clinically-important risk group 2 (RG2) bacterial strains of Staphylococcus aureus and Escherichia coli. The ecologically imposing strains of E. coli (RG1), Bacillus subtilis and Acinetobacter sp. BD4 were also included in the assay. Compound 3 exhibited pronounced activity against the clinically-relevant S. aureus as well as against B. subtilis comparable to that of the reference standard (streptomycin). Compound 2 was also highly-active against S. aureus. By comparing the structures of the three new compounds (1–3), it was revealed that altering the substitutions at C-10 and C-2 can significantly increase the antibacterial activity of 1.  相似文献   

19.
A new disease, causing mortality of Italian cypress (Cupressus sempervirens) trees cv. ‘Totem', was observed in an Israeli nursery. Fusarium compactum was isolated from cankers, and its pathogenicity was confirmed by Koch's test. The fungus readily formed conidia and chlamydospores in PDA culture. Growth of F. compactum was fastest at 26–30°C. Artificial inoculations with F. compactum caused severe cankering of several species of each of the following coniferous genera: Cupressus, Juniperus, Tetraclinis, Thuja, Cedrus and Pinus. Canker development was significantly enhanced when extreme water stress was imposed on cypress saplings prior to inoculation.  相似文献   

20.
Two bacterial insecticides,Bacillus thuringiensis H-14 andB. sphaericus 1593 were evaluated for larvicidal potency against mosquito larvae ofAedes aegypti. LC50 values showed thatB.thuringiensis H-14 (4×105 spores/ml) had a higher pathogenicity against fourth larval instars ofA. aegypti thanB. sphaericus (3.1×106 spores/ml) by about 7.75 times. Larval selection with LC90 of both pathogens for 8 successive generations caused a decrease in the susceptibility levels of selected strains ofA. aegypti as compared with the original strain. Moreover, the results indicated that the effect of larval selection with the above bioinsecticides led to an obvious reduction in the egg production and hatchability of eggs produced by mosquito adults that developed from surviving larvae.  相似文献   

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