genetic diversity of rhizobia isolated from astragalus adsurgens growing in different geographical regions of china.the genetic diversity among 95 isolates from astragalus adsurgens was investigated using molecular biological methods. all of the isolates and 24 reference strains could be differentiated by aflp, rep-, eric- and box-pcr fingerprinting analysis. by cluster analysis of the data, 31 aflp and 38 rep-pcr genomic groups were delineated, indicating considerable genetic diversity among the isolates. fifty-four representative strains were further analyzed by rflp of pcr-amplified 16s and 23s rdna, revea ...200111566387
[intergeneric somatic hybridization between astragalus adsurgens pall and medicago sativa l].the protoplast fusion was induced between astragalus adsurgens pall and agrobacterium rhizogenes-transformed cell line of medicago sativa l. by use of peg method. putative somatic hybrid cells were selected based on the observation that only intergeneric hybrid cells continued to divide on the dpd medium without any phytohormone while the cells and clusters derived from parental cells did not survive further. after being cultured, the somatic hybrid calli were obtained. although both of the pare ...200415323417
mesorhizobium septentrionale sp. nov. and mesorhizobium temperatum sp. nov., isolated from astragalus adsurgens growing in the northern regions of china.ninety-five rhizobial strains isolated from astragalus adsurgens growing in the northern regions of china were classified into three main groups, candidate species i, ii and iii, based on a polyphasic approach. comparative analysis of full-length 16s rrna gene sequences of representative strains showed that candidate species i and ii were mesorhizobium, while candidate species iii, which consisted of non-nodulating strains, was closely related to agrobacterium tumefaciens. the phylogenetic relat ...200415545425
symptomology and etiology of a new disease, yellow stunt, and root rot of standing milkvetch caused by embellisia sp. in northern embellisia sp. has been established as the cause of a new disease of the herbaceous perennial forage legume, 'standing milkvetch' (astragalus adsurgens pall.) in northern china, which severely reduces plant density and degrades a. adsurgens stands. the disease was common at an experimental location in gansu province where it was recognized by the occurrence of stunted plants with reddish-brown stems and yellow and necrotic leaf blades. an embellisia sp. was isolated from symptomatic stem, lea ...200717492492
different mesorhizobium species associated with caragana carry similar symbiotic genes and have common host ranges.fourteen strains representing 11 caragana-nodulating mesorhizobium genomic species were identified as representing mesorhizobium amorphae, mesorhizobium huakuii, mesorhizobium septentrionale and groups related to mesorhizobium plurifarium, mesorhizobium temperatum, mesorhizobium tianshanense and mesorhizobium mediterraneum by sequencing of the 16s rrna gene, 16s-23s internal transcribed spacer, partial housekeeping reca gene, and previously performed sodium dodecyl sulfate polyacrylamide gel ele ...200818422620
mesorhizobium caraganae sp. nov., a novel rhizobial species nodulated with caragana spp. in china.five rhizobial strains representing the largest group in the genus mesorhizobium associated with caragana spp. in china were characterized taxonomically. phylogenetic analysis based on 16s rrna gene sequences indicated that these microsymbionts belonged to the genus mesorhizobium, with mesorhizobium tianshanense usda 3592(t), mesorhizobium temperatum sdw018(t) and mesorhizobium mediterraneum upm-ca36(t) as the closest neighbours (>/=99.5 % 16s rrna gene sequence similarity). genotypic fingerprin ...200818984708
a comparative analysis of molecular diversity of erect milkvetch (astragalus adsurgens) germplasm from north china using rapd and issr markers. 200919160038
[spatial distribution of arbuscular mycorrhizal fungi in astragalus adsurgens root-zone soil in mu us sand land].this paper studied the spatial distribution of arbuscular mycorrhizal (am) fungi in astragalus adsurgens root-zone soil in mu us sand land under five different ecological conditions. the results showed that the colonization and spore density of am fungi differed significantly with sampling sites and soil depths. the highest colonization rate and spore density of am fungi were found in 10-30 cm soil layer, and the highest spore density was at dingbian site. ningtiaoliang and tawan sites had the h ...200819288728
mesorhizobium shangrilense sp. nov., isolated from root nodules of caragana species.five strains of bacteria isolated from nodules of caragana bicolor and caragana erinacea in yunnan province of china were classified within the genus mesorhizobium in the class alphaproteobacteria. the highest degree of 16s rrna gene sequence similarity was determined to be to mesorhizobium loti lmg 6125(t) (99.7 %) and mesorhizobium ciceri upm-ca7(t) (99.7 %). polyphasic taxonomic methods including sds-page of whole-cell soluble proteins, comparative housekeeping sequence analysis of atpd, glni ...200919643905
Mesorhizobium silamurunense sp. nov., a novel species nodulated with Astragalus species in China.Four rhizobial strains representing a previously defined novel group in the genus Mesorhizobium associated with Astragalus species in China were further characterized using a polyphasic approach. Phylogenetic analysis of 16S rRNA gene sequences showed that these Gram-negative bacteria belonged to the genus Mesorhizobium with Mesorhizobium plurifarium LMG 11892T as the closest neighbour sharing a sequence similarity of 99.8%. Polyphasic taxonomic methods including comparative sequence analysis of ...201122058324
the response of dark septate endophytes (dse) to heavy metals in pure culture.dark septate endophytes (dse) occur widely in association with plants exposed to heavy metal stress. however, little is known about the response of dse exposed to heavy metals. in this study, five dse were isolated from the roots of astragalus adsurgens pall. seedlings growing on lead-zinc mine tailings in china. based on morphological characteristics and dna sequence analyses, the isolates were identified as gaeumannomyces cylindrosporus, paraphoma chrysanthemicola, phialophora mustea, exophial ...201223118914
diverse nodule bacteria were associated with astragalus species in arid region of northwestern china.the legume species of astragalus as traditional chinese medicine source and environmental protection plants showed an extensive distribution in the arid region of northwestern china. however, few rhizobia associating with astragalus have been investigated in this region so far. in this study, 78 endophytic bacteria were isolated from root nodules of 12 astragalus species and characterized by the pcr-rflp of 16s rrna gene and symbiotic genes together with the phylogenetic analysis. results showed ...201524115208
[genetic diversity of rhizobia isolated from shrubby and herbaceous legumes in shenmu arid area, shaanxi, china].legume, with a strong resistance to the adverse environmental conditions, is one of pioneer plants in the desert region and plays an important role in the protection of the ecological environment. in this study, the symbiosis of rhizobia associating with shrubby and herbaceous legumes in shenmu area, shaanxi, china was characterized by the 16s rrna pcr-rflp and sequence analysis of involved genes. a total of 55 strains were isolated and purified, including 30 strains from the shrubby legume amor ...201425223023
[allelopathic effects of the humus soils from betula platyphylla and quercus liaotungensis pure plantations on 9 kinds of common shrubs and herbs].the humus soils were collected from betula platyphylla and quercus liaotungensis pure plantations and woodless land separately where the site conditions were basically the same, and taken as medium for potting culture test of 9 kinds of shrubs or herbs in plastic greenhouse to assess the allelopathic effects of humus soils of pure plantations on shrubs or herbs. humus soils from b. platyphylla plantation significantly inhibited the seed germinations of medicago sativa and melilotus officinalis, ...201425223017
a re-examination of the taxonomic status of embellisia astragali.the plant pathogen embellisia astragali causes a disease termed yellow stunt and root rot in standing milk-vetch (astragalus adsurgens). the genus embellisia and 12 allied genera were redefined as being synonymous with alternaria in 2013. however, that taxonomic revision did not include e. astragali. the objective of this study was to determine the taxonomic status of this fungal species by comparing its morphological and molecular characteristics with those of other species. a phylogenetic tree ...201626693723
contrasting water use pattern of introduced and native plants in an alpine desert ecosystem, northeast qinghai-tibet plateau, china.plant water use patterns reflect the complex interactions between different functional types and environmental conditions in water-limited ecosystems. however, the mechanisms underlying the water use patterns of plants in the alpine desert of the qinghai-tibet plateau remain poorly understood. this study investigated seasonal variations in the water sources of herbs (carex moorcroftii, astragalus adsurgens) and shrubs (artemisia oxycephala, hippophae rhamnoides) using stable oxygen-18 isotope me ...201626519579
[study on microscopic identification of astragalus complanatus and a. adsurgens seeds].astragalus adsurgens seed is one of the most common adulterants of astragali complanati semen in the market, whose morphological characteristics are very similar with a. complanatus seeds (astragali complanati semen). many identification methods have been reported, such as morphological identification, fluorescence method, ultraviolet spectrophotometry, tlc, hplc, protein electrophoresis and so on, but there's no much about microscopic identification. in the present study, the morphological char ...201526281544
design of species-specific pcr method for the detection of pathogen embellisia astragali in standing milk vetch seeds.embellisia astragali is an important seedborne pathogenic fungus responsible for yellow stunt and root rot of standing milk vetch (astragalus adsurgens). the current detection methods that are based on culture and morphological identification are time-consuming, laborious and not always reliable. a pcr-based diagnostic method was developed with the species-specific primer pairs aatpf and aatpr designed from the sequence of the plasma membrane atpase gene of e. astragali. the specificity of the p ...201525511534
[mechanisms of grass in slope erosion control in loess sandy soil region of northwest china].by adopting the method of simulated precipitation and from the viewpoint of slope hydrodynamics, in combining with the analysis of soil resistance to erosion, a quantitative study was made on the mechanisms of grass in controlling the slope erosion in the cross area of wind-water erosion in loess plateau of northwest china under different combinations of rainfall intensity and slope gradient, aimed to provide basis to reveal the mechanisms of vegetation in controlling soil erosion and to select ...201323717998
differential effects of legume species on the recovery of soil microbial communities, and carbon and nitrogen contents, in abandoned fields of the loess plateau, china.plant-soil interactions are known to influence a wide range of ecosystem-level functions. moreover, the recovery of these functions is of importance for the successful restoration of soils that have been degraded through intensive and/or inappropriate land use. here, we assessed the effect of planting treatments commonly used to accelerate rates of grassland restoration, namely introduction of different legume species medicago sativa, astragalus adsurgens, melilotus suaveolens, on the recovery o ...201223064665
seedling biomass partition and water use efficiency of switchgrass and milkvetch in monocultures and mixtures in response to various water availabilities.seedling biomass and allocation, transpiration water use efficiency (twue), and species competition between switchgrass (panicum virgatum l.) and milkvetch (astragalus adsurgens pall.) were investigated in a pot-cultivated experiment under different levels of water availability. the experiment was conducted using a simple replacement design in which switchgrass and milkvetch were grown in growth chamber with ten seedlings per pot, in three combinations of the two species (0:10, 5:5 and 10:0). fi ...201020437177
nutritional study on embellisia astragali, a fungal pathogen of milk vetch (astragalus adsurgens).embellisia astragali is a strong, virulent pathogen that develops within milk vetch (astragalus adsurgens). in order to determine nutrient requirements, the fungus was cultured on 9 carbon sources, 9 nitrogen sources, and 13 growth media in the dark at 25 degrees c. growth rates and sporulation capacity were measured after 4 and 12 weeks. all carbon sources supported growth, but only soluble starch, inulin, and dextrose supported sporulation. in general, better growth was obtained on disaccharid ...200919224390
evaluation of plant-microorganism synergy for the remediation of diesel fuel contaminated soil.the remediation of diesel fuel contaminated soil over a 2-year period by the plant-microorganism synergy was evaluated. results indicated that the growth of astragalus adsurgens was affected significantly, when the diesel fuel concentration was higher than 10 g kg(-1) dry soil. after a 2-year period, the removal of diesel fuel was >67%, and about 58-70% removal of aromatic hydrocarbons was obtained in these treatments. the removal of diesel fuel and its components was 13-30% higher than that of ...200818493697
a new species, embellisia astragali sp. nov., causing standing milk-vetch disease in china.a new species, embellisia astragali sp. nov., is described from necrotic leaves, petioles and stems of astragalus adsurgens in china. the morphology of e. astragali is compared and contrasted to that of four similar species, e. abundans, e. oxytropis, e. phragmospora and e. telluster. the fungus grew intercellularly in stems and leaf blades and intracellularly in leaves. it was isolated from most sources of seeds at frequencies of 0.1-44.6%. growth rates of colonies on potato-carrot agar, potato ...200717883032
[comparison of ecophysiological characteristics of seven plant species in semiarid loess hilly-gully region].the diurnal course of photosynthetic rate, transpiration rate, and leaf water potential (psi l) of five plant species in north shaanxi loess hilly-gully region were measured in dry seasons. based on the daily maximum photosynthetic and transpiration rates, daily total assimilation and transpiration, and diurnal change characteristics of psi l, the test plants were classified into different eco-adaptation types. panicum virgatum l. had high photosynthetic rate, low transpiration rate and high wat ...200717650846
[responses of medicago sativa and astragalus adsurgens seedlings growth and water use to soil moisture regime].in the semi-arid area of loess plateau, seasonal drought often occurs during the vegetative stage of grass plants, leading to the subsequent serious reduction of their yield. aimed to study the responses of the seedlings growth and water use of two perennial leguminous grasses medicago sativa and astragalus adsurgens to different soil moisture regimes, a pot experiment was installed with five treatments, i.e., adequate water supply (hw), moderate water stress (lw), soil drying gradually from hw ...200516515181
[effects of cultured astragalus adsurgens root on other plants growth].by using orthogonal design, this paper investigated the growth of cultured prairie milk vetch (astragalus adsurgens) root on the b5 medium with different contents of sucrose, macro-and microelements and organic supplements, and adopting the method of filter paper-culture in petri-dish, studied the effects of a. adsurgens culture filtrate on the seedling growth of radish (raphanus sativus) and wheat (triticum aestivum). the results showed that the effect of a. adsurgens culture filtrate on r. sat ...200516011183
regeneration of astragalus adsurgens via somatic embryogenesis from cell suspension protoplasts.protoplasts from 4-day-old embryogenic cell suspension cultures of astragalus adsurgens, when cultured in km8p medium which ammonium concentration was reduced to 2.5 mmol/l and supplemented with 0.5 mg/l naa, 1.0 mg/l 2, 4-d, 0.7 mg/l ba and 0.4 mol/l glucose, underwent cell sustained divisions and formed cell colonies at a frequency of 16%-20%. preplasmolysis or low temperature treatment of suspension cells prior to enzyme incubation enhanced colony formation. following proliferation on ms medi ...199912548868
[improved protoplast-derived plants of astragalus adsurgens through somatic embryogenesis].embryogenic callus was obtained only from hypocotyl explants of astragalus adsurgens and light inhibited the formation of embryogenic callus. a high yield (1.2 x 10(6)/g f. wt.) of protoplasts with high viability (over 80%) could be isolated from 10-day-old embryogenic callus. protoplasts were induced to undergo sustained division and to form cell colonies when cultured in agarose-solidified medium (kmp) containing 1/4 strength of mineral salts and supplemented with 1.5 mg/l 2, 4-d, 0.5 mg/l ba ...200010883269
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