Incidence and viability of Acremonium endophytes in tall fescue accessions from North Spain     

J.A. Oliveira  V. Castro 《Genetic Resources and Crop Evolution》1997,44(6):519-522

The tall fescue (Festuca arundinacea Schreb.) seed collection of the Centro de Investigaciones Agrarias de Mabegondo was surveyed to determine Acremonium infection rates. One hundred seeds from each of 19 accessions were microscopically examined for endophyte. Seventeen accessions (90%) contained endophyte with a range of 7 to 100%. Leaf sheaths of seedlings from the infected accessions were examined to determine the percentage of infection with viable endophyte. Only seven (41%) of the seventeen infected accessions collected and stored in 1995 at 4°C and 45–50% relative humidity contained viable endophyte with a range of 70 to 100%. While existing germplasm collections of Festuca arundinacea can provide only a small basis of Acremonium germplasm for study, newly collected Festuca arundinacea accessions will offer a greater diversity of Acremonium genotypes.  相似文献   

Rapid uptake of N-ammonium and glycine-C, N by arbuscular and ericoid mycorrhizal plants native to a Northern California coastal pygmy forest     

Kai Coshow Rains  Caroline S. Bledsoe 《Soil biology & biochemistry》2007,39(5):1078-1086

While it is well established that plants are able to acquire nitrogen in inorganic form, there is less information on their ability to ‘short circuit’ the N cycle, compete with microbes, and acquire nitrogen in organic form. Mycorrhizal fungi, known to enhance nutrient uptake by plants, may play a role in organic N uptake, particularly ericoid mycorrhizas. We asked the question—Can mycorrhizal fungi increase the ability of plants to take up organic N, compared to inorganic N? Here, we report on the abilities of three plant species, ericoid mycorrhizal Rhododendron macrophyllum and Vaccinium ovatum and arbuscular mycorrhizal Cupressus goveniana ssp. pigmaea, to acquire C and/or N from an organic and an inorganic N source. All three species are native to a California coastal pygmy forest growing in acidic, low-fertility, highly organic soils. In a pot study, glycine-α¹³C, ¹⁵N and ¹⁵N-ammonium were applied to pygmy forest soil for 17 or 44 h. Ericoid mycorrhizal species did not demonstrate a preference for either inorganic or organic sources of N while Cupressus acquired more NH₄-N than glycine-N. For all species, glycine-N uptake did not increase after 17 h suggesting glycine uptake and glycine immobilization occurred rapidly. Both glycine-N and glycine-C were recovered in shoots and in roots suggesting that all species acquired some N in organic form. Regression analyses of glycine-N and glycine-C recovery in root tissue indicate that much of the glycine was taken up intact and that the minimum proportion of glycine-N recovered in organic form was 85% (Cupressus) and 70% (Rhododendron). Regressions were non-significant for Vaccinium. For all species, glycine-N remained predominantly in roots while glycine-C was transferred to shoots. In contrast, NH₄-N remained in roots of ericoid plants but was transferred to shoots of arbuscular mycorrhizal Cupressus. Since net N mineralization rates in pygmy forest soils are low, our results suggest that organic N may be an important N source for plants in this temperate coniferous ecosystem regardless of mycorrhizal type. Acquisition of amino acid C by these species also may partially offset the carbon cost to plants of hosting mycorrhizal fungi.  相似文献   

疯草内生真菌研究进展   总被引：2，自引：0，他引：2  

陈基萍  马尧  路浩  王占新  赵宝玉 《动物医学进展》2011,32(2):77-81

疯草含有疯草毒素,动物采食后能引起以慢性神经机能紊乱为特征的中毒病,是世界范围内危害草原畜牧业最严重的毒草之一.对疯草主要有毒成分苦马豆素来源问题的研究发现,疯草内生真菌与苦马豆素之间具有极为密切的关系.近年来,科研工作者对多种疯草的内生真菌进行分离,并对其与疯草的相互关系进行了深入研究.论文主要介绍了近年来国内外有关...  相似文献   

杀真菌剂对旗草内生真菌的除菌研究     

黄东益  黄小龙 《安徽农业科学》2008,36(30)

[目的]研究杀真菌剂去除旗草内生真菌的效果。[方法]采用杀真菌剂Benomyl、Propiconazole、Folicur对感染内生真菌Acremonium implicatum的旗草植株进行杀菌处理,通过内生真菌的特异PCR检测,评价不同处理的除菌效果。[结果]每种处理都有除菌作用,但都不能100%地去除内生真菌。相对而言,杀真菌剂在低浓度(10~25μg/L)长时间(35 d)沙培处理的效果比高浓度(75~150μg/L)短时间(5 h)的浸根处理效果好。[结论]杀真菌剂Benomyl、Propiconazole、Folicur对旗草内生真菌的去除有一定的效果,采用低浓度沙培处理效果较好。  相似文献   

Improvement of simazine degradation by inoculation of corn and soybean plants with rhizobacteria     

Takashi Ozawa  Ryota Yoshida  Yoshiaki Wakashiro  Hitomi Hase 《Soil Science and Plant Nutrition》2013,59(8):1295-1299

We isolated the strains of aerobic bacteria, that were able to use the simazine (2-chloro4,6-bis(ethylamino)-s-triazine) herbicide as a sole source of nitrogen, from the roots of corn plants and the nodules of soybean plants. Partial base sequences of 16S rRNA genes and physiological characteristics of the representative isolates revealed that they belonged to Agrobacterium radiobacter and Bradyrhizobium japonicum, respectively. Inoculation of corn plants with the isolates of A. radiobacter resulted in a faster decrease in the amount of simazine in vermiculite soil. Neither bacteria nor corn plants alone were able to promote the decrease in the amount of simazine. Soybean plants modulated by the isolates of B. japonicum were more sensitive to simazine in a hydroponic medium compared to non-nodulated soybeans, though a significant decrease in the amount of simazine in the media was observed. The results obtained in the present study indicate that the rhizosphere of corn and soybean plants containing root nodules is an appropriate habitat for simazine-degrading bacteria to degrade the herbicide.  相似文献   

Fungal endophytes in grasses from semi-arid permanent grasslands of western Spain     

I. Zabalgogeazcoa  B. R. Vázquez de Aldana  A. García Ciudad  B. García Criado 《Grass and Forage Science》2003,58(1):94-97

Abstract A survey of grass species associated with Epichloë and Neotyphodium fungal endophytes was made in permanent semi‐arid grasslands of western Spain. Endophytes were isolated from 11 of 49 grass species analysed. Infected plants of Festuca arundinacea, Festuca rubra, Dactylis glomerata and Lolium perenne were detected at most locations studied. The grasses, Agrostis castellana, Brachypodium phoenicoides and Festuca ampla, are previously unknown endophyte hosts. The results obtained show that endophyte–grass interactions are present in the grasslands where this study was conducted.  相似文献   

The evaluation of endophyte toxin residues in sheep fat     

SC Finch  LR Fletcher  JV Babu 《New Zealand veterinary journal》2013,61(1):56-60

Abstract

AIM: To monitor changes in concentrations of lolitrem B and epoxy-janthitrems in the fat of sheep grazing perennial ryegrass infected with wild-type- and AR37-endophyte, respectively, during the time of year when ryegrass staggers would be expected to be observed.

METHODS: Ten 5-month-old lambs with no previous exposure to endophytes were grazed on either wild-type (containing lolitrem B, n = 5) or AR37 (containing epoxy-janthitrems, n = 5) endophyte-infected perennial ryegrass (Lolium perenne L.) pastures between October 2008 and June 2009. Animals were regularly assessed for ryegrass staggers using the Keogh scale (0 = no signs, 5 = severe tremors). When a score of > 3.5 was observed animals were removed from the treatment pastures for 1 month. Fat biopsy samples were taken from each animal at approximately monthly intervals and analysed for endophyte metabolites using high performance liquid chromatography (HPLC) methods developed during this study. Regular herbage samples were also taken and concentrations of endophyte metabolites measured.

RESULTS: Efficient and reproducible methods to analyse both lolitrem B and epoxy-janthitrems in fat were developed. Concentrations of lolitrem B and epoxy-janthitrems in herbage and in sheep fat increased from late November to peak in mid-February. Ryegrass staggers was observed in both groups of sheep at this time. Following 1 month of grazing non-infected pasture mean concentrations in fat of lolitrem B decreased by 43% from 61.8 to 35.3 ppb, and of epoxy-janthitrems by 38% from 1032.0 to 639.5 ppb. Maximum concentrations in herbage of epoxy-janthitrems (35.7 ppm) were higher than of lolitrem B (3.4 ppm), but signs of staggers were less severe in sheep grazing pasture containing the former compared with the latter (median Keogh scores in late February were 2 and 3, respectively), consistent with epoxy-janthitrems being low potency toxins.

CONCLUSION: This study demonstrated that concentrations of epoxy-janthitrems and lolitrem B in sheep fat increased quickly during the initial phase of the study when concentrations in pasture increased, and decreased when animals were removed from pastures containing these compounds. These data will be used in the risk assessment of the endophyte metabolites.  相似文献   

Genetic differentiation between hosts and locations in populations of latent Botrytis cinerea in southern England     

B. A. P. Rajaguru  M. W. Shaw 《Plant pathology》2010,59(6):1081-1090

This study tested the hypothesis that aggressive, localized infections and asymptomatic systemic infections were caused by distinct specialized groups of Botrytis cinerea, using microsatellite genotypes at nine loci of 243 isolates of B. cinerea obtained from four hosts (strawberry (Fragaria×ananassa), blackberry (Rubus fruticosus agg.), dandelion, (Taraxacum officinale agg.) and primrose (Primula vulgaris)) in three regions in southern England (in the vicinities of Brighton, Reading and Bath). The populations were extremely variable, with up to 20 alleles per locus and high genic diversity. Each host in each region had a population of B. cinerea with distinctive genetic features, and there were also consistent host and regional distinctions. The B. cinerea population from strawberry was distinguished from that on other hosts, including blackberry, most notably by a common 154‐bp amplicon at locus 5 (present in 35 of 77 samples) that was rare in isolates from other hosts (9/166), and by the rarity (3/77) of a 112‐bp allele at locus 7 that was common (58/166) in isolates from other hosts. There was significant linkage disequilibrium overall within the B. cinerea populations on blackberry and strawberry, but with quite different patterns of association among isolates from the two hosts. No evidence was found for differentiation between populations of B. cinerea from systemically infected hosts and those from locally infected fruits.  相似文献   

黑核桃内生真菌HJ1油脂提取工艺的研究     

翟梅枝  陈汀汀  李秀红  问小强  刘枫 《西北林学院学报》2010,25(3):151-153

以黑核桃内生真菌HJ1菌体为材料,研究了提取温度、提取时间和料液比对菌体油脂得率的影响。经单因素试验、正交试验及验证试验,结果表明:HJ1油脂得率为22.26%左右,最佳提取工艺条件为:提取温度85℃,提取时间4 h,料液比1∶6。HJ1油脂组成与植物油脂组成相似,可作为制备生物柴油的原料。  相似文献   

银杏内生真菌的分离及其抑菌活性初探   总被引：2，自引：0，他引：2  

田小卫  刘鑫 《北方园艺》2010,(1)

从银杏的茎和根中分离得到32株内生真菌,并对其发酵液和菌丝丙酮提取物的抑菌活性进行了测定。结果表明:筛选出1株对4种供试菌均有强烈抑菌作用的菌株,命名为L25菌株,其抑菌活性成分在90℃以下和对紫外线稳定。  相似文献