玉米内生细菌

<正>拮抗内生细菌对寄主植物具有促生、防病、杀虫及固氮等多方面的生物学作用,是植物病害防治的天然资源菌,并且能够作为外源基因载体,为杀虫、防病、固氮等外源植物基因导入植物体内提供了一种很好的     

香蕉植株内生细菌群落多态性研究

采用平板法对香蕉(Musa nana)植株的内生细菌进行分离纯化,并采用细菌脂肪酸法进行鉴定。结果表明,从香蕉的健康植株和感病植株中共分离得到内生细菌21属24种。从健株分离得到9种内生细菌,其中根、茎和叶分别分离到6种、2种和8种内生细菌。从病株分离得到15属17种内生细菌,其中根、茎和叶分别分离到3种、11种和6种。香蕉健株根部的内生细菌含量最高,达5.195×106cfu g-1,下部叶片内生细菌的含量最低,仅为30 cfu g-1;香蕉病株茎部内生细菌的数量显著高于其他部位,达1.05×107cfu g-1。这说明香蕉在不同生长状态下,其内生细菌的种类和数量存在多样性。     

玉米内生细菌资源研究进展

植物内生菌存在于植物的各个器官,种类繁多,对植物的生长发育具有重要作用。玉米是最重要粮食作物之一,通过研究玉米与其内生细菌的关系,对增产玉米以及生物防治有积极意义。本文归纳了玉米内生细菌资源的分离与收集,包括内生细菌的多样性及新种的鉴定;介绍了玉米内生细菌与宿主的相关性;总结了玉米内生细菌的生物学作用,包括抑菌性、耐受性、固氮作用和促生作用,以及内生细菌对玉米作用机制;并对玉米内生细菌研究趋势进行了前景展望,旨在为玉米内生细菌的研究提供参考。     

香菇品种遗传多样性RAPD分子标记的研究

对32个中国栽培香菇品种和2个野生子实体的遗传多样性进行了RAPD标记研究,9个引物共扩增出113条DNA带,83.19%具有多态性。结果显示,34个香菇菌株间均有遗传上的差异,但遗传相关性极高,表明中国栽培菌株间的遗传背景单一。     

癌组织中的遗传不稳定性的RAPD分析(简报)

肿瘤仍然是导致人类死亡的重要原因,由于缺乏深刻了解癌症的发生机制,尽管在过去25年中肿瘤的诊断和治疗都取得很大的进展,但肿瘤病人的存活率并没有显著的提高。目前有很多癌基因和抑癌基因如P16、P53、P73、ras、DCC和RB等     

烟草内生细菌种群动态研究

经过对 7个田间种植的烟草品种不同栽培时期、不同组织内生细菌种群动态研究表明 ,不同品种内生细菌种群有一定程度差异。同一品种中有的内生细菌为常住菌群 ,有的为暂居菌群 ,带菌量根中最高 ,茎次之 ,叶中最低。在整个生育期中 ,7个品种内生细菌数量表现出从种子到出苗期大幅增加 ,从出苗期到十字期又大幅度下降 ,随后从缓苗期到伸根期再一次急剧增加并维持在一个较高水平。通过对烟草这一重要经济作物内生细菌种群动态变化研究 ,可为烟草病虫害生物防治和促生增产研究提供理论基础。     

亚欧美栗疫病菌群体的遗传多样性

从 12 0个随机引物中筛选出条带清晰、主带明显、重复性好的 9个引物 ,对来自不同地域和寄主的 7个群体的 14 2个栗疫病菌菌株进行 RAPD分析。 9个引物共扩增出条带 12 4条 ,其中多态性条带 111条 ,多态性比率为 89.5 2 %。利用 Popgen3.2软件对供试群体进行遗传多样性分析和 UPGMA聚类。结果表明 ,中国地区 4个群体间的遗传相似性较大 ,与美国、意大利和日本群体间的相似性较小 ;美国和意大利群体间的遗传相似性较大 ,且它们与日本群体间的相似性大于与中国群体间的相似性。病原菌群体的遗传变异率为 0 .2 35 1,其中在地区水平上 ,82 .34%由群体内的变异引起 ,17.6 6 %由群体间的差异引起 ,群体间的基因流动值为 2 .3311;而在寄主水平上 ,则 79.4 2 %由群体内的变异引起 ,2 0 .5 8%由群体间的差异引起 ,群体间的基因流动值为 1.92 97     

利用RAPD技术分析实验用比格犬的遗传背景

目的　运用RAPD技术对实验用比格犬 (Beagle)进行遗传背景分析。方法　筛选的 16个RAPD引物对 4 0个样品的分析 ,共得到 93个扩增条带。结果　所有样品的相似系数 80 4 %到 10 0 %间变动 ,平均相似系数为93 2 8% ,聚类分析得到了这些个体的同源树资料。结论　本遗传背景资料可以为以后的比格犬繁育生产和生物医药学的研究应用提供技术指导     

玉米苗期内生细菌的种群初探及有益内生细菌的筛选

从3个供试玉米品种(川单13、川单418、川单416)苗期分离、纯化内生细菌68株,经形态及理化特征鉴定,分属5个不同的属,微球菌属和芽孢杆菌属为优势属.芽孢杆菌属细菌鉴定出5个种.供试品种中内生细菌种群数量各不相同,种群数量由多到少依次是川单13、川单418和川单416.通过抑菌谱和拮抗菌发酵液对种子萌芽率的影响,筛选出两株抑菌谱广,对玉米种子萌发无抑制作用的内生芽孢细菌BH和B98.盆栽实验显示,两株细菌均对玉米植株具有促生作用,对玉米纹枯病具有防治效果.     

玉米根系内生细菌种群及动态分析

2000-2002年,先后对辽宁省14个玉米主栽品种进行了根系内主要细菌种群分析．结果表明．玉米内生细菌的主要种群为芽孢杆菌属(Bucillus spp．),此外还包括肠杆菌属、沙雷氏杆菌属、假单胞菌属、黄单胞菌属和棍状杆菌属．其中Bacillus分布最广,已鉴定出8个种,包括枯草芽孢杆菌、巨大芽孢杆菌、蜡状芽孢杆菌、地衣芽孢杆菌、炭疽芽孢杆菌、蕈状芽孢杆菌、短小芽孢杆菌、环状芽孢杆菌．Bacillusspp．总量占根系内生细菌总量比苗期和成株期分别为75．5％和76．6％．内生细菌在不同玉米品种和不同生育期之间存在程度不同的差异．研究发现,品种的遗传背景与其内生细菌的种类和数量显著相关．     

南方红豆杉不同居群遗传多样性的RAPD研究

用随机扩增多态性方法对广东、湖南、江西等3省的12个南方红豆杉自然居群进行了基因组DNA多态性分析,从100条引物中共筛选出10个引物,获得RAPD谱带86条,多态性谱带占51％。聚类分析结果表明：南方红豆杉居群间的遗传距离与这些居群的地理分布相关,即相同或相邻产地的居群间的遗传距离较小,不同产地个体间的遗传距离较大。粤北南方红豆杉的9个居群的遗传多样性较低,可能与近年来资源遭到严重破坏,及其生长缓慢、种子萌发率低、成活率不高等原因有关。     

长筒石蒜居群遗传多样性RAPD分析

利用RAPD标记对长筒石蒜3个居群的遗传多样性及分化程度进行了研究。12条随机引物扩增出94个可分析位点,多态位点比率(PPB)为65.96%,表明长筒石蒜具有比较高的遗传多样性。经POP-GENE32分析表明:Nei’s基因多样性指数(h)为0.1897,香农多样性指数(Ⅰ)为0.2945,基因分化系数(GST)为0.1191,基因流(Nm)为3.6980。经WINAMOVA分析表明:居群内遗传变异占71.75%,而居群间只占28.25%。遗传多样性分析表明,各居群的遗传多样性水平由高到低为琅琊山居群>宝华山居群>盱眙居群。遗传分化表明:长筒石蒜各居群间遗传分化程度较低;大部分遗传变异存在于居群内部,表明其具有较强的进化潜力,自然情况下不会处于濒危状态,野生种质资源的破坏,主要来自于人为干扰。     

Delivery methods for introducing endophytic bacteria into maize

The effectiveness of fivemethods for delivery of ten endophyticbacteria into maize stem and root tissues wasstudied in greenhouse conditions at EmbrapaMilho Sorgo, Sete Lagoas, MG, Brazil. Thedelivery methods included seed inoculation,soil drench, foliar spray, pruned-root dip andseed inoculation + soil drench. The bacterialendophytes were previously isolated from maizeplants, and reinoculated and recovered aftertreatments from maize, cv BR201. Each of thefive methods led to establishment and recoveryof bacterial endophytes in root tissues, butonly four isolates were recovered by the seedtreatment method. All 10 isolates wererecovered by pruned-root dip and seed treatment+ soil drench. No isolates were recovered instem tissues by the seed treatment method, andin the root by foliar spray method. However,all isolates were recovered in stem tissue bypruned-root dip method. The pruned-root dip wasthe most efficient method to deliver bacterialendophytes into maize. The isolate, BR201, wasrecovered by almost all methods in root andstem tissues. The results demonstrate thatendophytic bacteria can be recovered from maizetissues following inoculation by the differentmethods described, but the delivery depends onthe methods used and the endophytic bacterialisolate.     

A preliminary examination of genetic variation in a peripheral population of Blanding's turtle, Emydoidea blandingii

Random amplified polymorphic DNA (RAPD) was used to compare the Nova Scotia population of Blanding's turtle (Emydoidea blandingii) with several populations from the species' main range. The Nova Scotia population is believed to have been isolated from the main range for 4000-8000 years. Cluster analysis using a neighbour-joining algorithm produced a dendrogram showing the Nova Scotia population clustering separately from those populations in the main range. Analysis of molecular variance shows 34.28% of total variance to be accounted for between the Nova Scotia population and populations in the main range. While this study is preliminary, the results suggest that the Nova Scotia population of Blanding's turtle may be important to the maintenance of genetic diversity in the species.     

Spatially dependent genetic diversity within and between colonies of wild raspberry Rubus idaeus detected using RAPD markers

In the Tayside region of Scotland, red raspberry Rubus idaeus exists both as extensive plantations of clonally propagated cultivars, and as wild populations that inhabit both the cultivated areas and uncultivated uplands to the north. In order to explore the genetic diversity of the wild populations and their degree of similarity to the plantation clones, individual plants in wild populations were sampled from four distinct sites along a 25-km transect northwards from the area of cultivation. The genetic material of each of 45 individuals and the commercial cv. Glen Clova were examined using six RAPD primers giving a total of 63 variable bands. Some identical banding patterns were observed, suggesting vegetative growth up to 20 m, but populations consisted mainly of genetically distinct individuals. Similarity matrices based on the marker bands showed, without exception, that plants were more similar within a site than between sites. None of the populations was closely related to the cv. Glen Clova. Although the most northerly site had the largest proportion of rare bands, there was no general trend between within-site diversity, or similarity to the cultivar, and position on the north-south line. All four sites had unique bands and bands not displayed by the cultivar. However, the genetic diversity of a site appeared to increase as the extent of the sampled area increased, implying that the genetic variation was spatially dependent. For example, maximum and minimum similarities were 100 and 80%, respectively, at interplant distances of 2 m; 100 and 60% at distances of 20 m; 85 and 55% at 200 m and 70 and 40% at 20 km.     

Random amplified polymorphic DNA in cattle and sheep: application for detecting genetic variation

The present study investigated the use of the random amplified polymorphic DNA (RAPD) method to detect genetic variation in cattle and sheep. The animals studied consisted of samples from five Finnish cattle breeds: native Eastern (18 animals), Northern (24), Western Finncattle (24), Finnish Ayrshire (24), and Finnish Friesian (18); as well as a white (6 animals) and a grey (9) colour type of Finnsheep. The cattle and sheep populations were analysed with 11 and 13 RAPD primers demonstrating the most repeatable amplification pattern. Two out of ten RAPD fragments tested by cross hybridization showed homology between the two species. The RAPD method did not prove efficient for finding new polymorphisms in either species, because we found only three polymorphic RAPD markers for cattle and seven markers for sheep with different allele frequencies between the breeds. Although there is a greater presence of polymorphic RAPD markers in sheep, according to the similarity indices the sheep populations showed a higher degree of homogeneity than the cattle breeds. However, the interbreed and intrabreed similarity indices for cattle did not suggest any significant differentiation of the Finnish breeds, contrary to earlier results based on blood group and protein polymorphism.     

随机扩增多态DNA技术在遗传育种中的应用

RAPD是一项可以在没有任何分子生物学研究的情况下找出DNA的多态性的技术。本综述了RAPD技术在遗传多样性研究、分类及亲缘关系分析、品种(杂种)鉴定、杂种优势预测、构建遗传图谱、基因定位及基于图谱的克隆,分子标记辅助育种等方面的应用;还总结了RAPD技术的原理、优点、缺点及对策。     

可产生铁载体的春兰根内生细菌多样性

摘要：【目的】了解可产生铁载体的春兰根内生细菌的多样性,以便筛选到高效的植物促生细菌。【方法】采用CAS检测法测定了189株春兰根内生细菌产生铁载体的能力,并结合16S rRNA基因系统发育分析对可产铁载体的春兰根内生细菌多样性进行了研究。【结果】从189株春兰内生细菌中筛选到47株可产生铁载体的细菌,占菌株总数的24.9%。16S rRNA基因系统发育分析结果表明,47株细菌分属于4个系统发育类群（Alphaproteobacteria,Betaproteobacteria,Firmicutes,Actinobacteria）,17个属的31个种。其中放线菌门为最优势类群（42.6%）,芽孢杆菌属（Bacillus）和贪噬菌属（Variovorax）为优势菌属,且贪噬菌属为高产铁载体的主体菌属。另外有2个菌株可能代表两个不同属的新物种。【结论】春兰根中可产生铁载体的内生细菌具有丰富的多样性。     

PCR-RAPD分子生物学技术及其在植物抗病性研究中的应用

PCR—RAPD技术是一种高效的基因组DNA多态性分析技术,能够在对生物细胞或组织中DNA遗传多样性、亲缘关系及系统进化分子标记检测的同时进行基因定位与遗传作图。本综述了PCR—RAPD技术的基本原理和应用范围,以及近年来在植物抗感病品种(品系)间亲缘远近关系分析、植物抗病性遗传基因的DNA分子标记与检测、植物抗病基因的标记和定位、植物抗病基因的分离与克隆、植物抗病育种的分子标记辅助选择与检测等植物抗病性分子机制研究方面的应用,并对该技术所存在的问题及应用前景进行了探讨。     

Applications of DNA genetic markers to the study of plant growth and development

DNA genetic markers, such as restriction fragment length polymorphisms (RFLPs) and random amplified polymorphic DNA markers (RAPDs), are powerful tools for studying the genetics of plant growth and development. DNA markers are defined sequences of DNA that can be used in traditional linkage mapping. Using DNA marker technology, scientists can uncover relationships between cloned cDNA sequences and classically characterized genes. DNA markers make it possible to dissect the contributions of multiple genetic loci underlying complex developmental processes. Moreover, changes in genome organization that occur during development or in response to environmental signals can be monitored using RFLP technology. In the future, it may be possible to clone any gene based solely on its map position. This will involve the use of tightly linked DNA markers as entry points for chromosome walking, in which a series of overlapping genomic clones reaching from the tightly linked DNA marker to the gene of interest are identified.