【作者】 钟珉菡；

【导师】 杨瑞武；

【作者基本信息】 四川农业大学 ， 植物学， 2008， 硕士

【摘要】 赖草属Leymus Hochst.是禾本科Poaceae小麦族Triticeae Dumortier的一个重要多年生属,全世界大约有30个种和19个亚种,从北海的沿岸地区,越过中亚到东亚直至阿拉斯加和北美西部的广阔地域均有分布,多数种类集中于中亚和北美的高山。我国原记载约10种,加上近年来报道的新分类群,共25个种,4个亚种和3个变种,主要分布于西北、华北、东北及西南地区。该属的多数物种为草原和草甸的主要组成成分,许多种类是优良的牧草,具有较高的饲用价值。由于赖草属植物常生长在盐碱地和干早半干早的山坡、地埂,该属植物的有些物种对寒冷、干早、盐碱土等不良环境具有高度的适应性。同时,有些赖草属物种还具有抗病虫、穗大、粒多、粒大、高光效等优良特性。因此,作为麦类作物育种的重要三级基因源,赖草属植物对改良遗传基础日益狭窄的麦类作物有重要意义。然而,有关该属植物的起源、系统地位、物种界限、种间(内)亲缘关系等问题,仍然存在较大的分歧。针对赖草属物种中Ns基因组的供体物种以及另一个基因组的来源问题,本研究利用同工酶、醇溶蛋白及RAPD标记对14种赖草属植物和10种近缘属二倍体物种的系统关系进行了分析。主要结果如下:1.利用垂直平板聚丙烯酰胺凝胶电泳(PAGE)对赖草属、冰草属、偃麦草属、澳冰草属、拟鹅观草属、新麦草属和大麦属7个属24个物种的酯酶同工酶和超氧化物歧化酶同工酶进行比较分析。结果表明:①7个属24个物种共出现24种不同的同工酶酶谱,电泳分离出迁移率不同的45条酶带;②Leymus chinensis与Leymus其它13个种的亲缘关系较远,与Hordeum bogdanii的亲缘关系较近;Psathyrostachys juncea与Leymus的亲缘关系很近;③相似染色体组的物种聚类在一起;④两种同工酶的分析结果与细胞学及分子标记的研究结果基本一致。2.利用酸性聚丙烯酰胺凝胶电泳(A-PAGE)对赖草属12种和冰草属、偃麦草属、澳冰草属、拟鹅观草属、新麦草属和大麦属7个属10个种共22份材料进行醇溶蛋白遗传分析。结果表明:①7个属22份材料共出现22种不同的醇溶蛋白图谱,22种图谱中分离出的52条带纹,多态性高达100%,说明属间和种间具有丰富的醇溶蛋白多态性;②Psathyrostachys juncea与Psa.huashanica的亲缘关系较远,而Psa.juncea与Leymus的亲缘关系很近;③含有相似染色体组的物种能各自聚类在一起,它们具有较近的亲缘关系;④醇溶蛋白的分析结果与细胞学及分子标记的研究结果基本一致,表明醇溶蛋白能够用于小麦族多年生物种系统亲缘关系分析。3.对14个赖草属物种和10个近缘属物种进行基因组特异RAPD标记。选用小麦族中6个基本基因组(E、H、P、St、W、Ns)的特异RAPD引物进行PCR扩增检测,结果表明:①14个赖草属物种具有Ns基因组特异的RAPD标记,而没有P和E基因组的特异的RAPD标记;②Leymus ramosus具有W基因组特异的RAPD标记;L.triticoides、L.ramosus、L.paboanus、L.chinensis、L.pseudoracemosus具有St基因组特异的RAPD标记;L.angustus、L.arenarius、L.multicaulis、L.karelinii、L.tianshanicus、L.paboanus、L.cinereus、L.chinensis、L.racemosus具有H基因组特异的RAPD标记;③L.paboanus、L.chinensis不仅出现了H基因组的特异性条带,还出现了St基因组的特异性条带;L.ramosus不仅出现了W基因组的特异性条带,还出现了St基因组的特异性条带。结合本实验的研究结果,赖草属植物为多重起源,Ns基因组来自新麦草属,Psathyrostachys juncea与赖草属系统关系较近。赖草属不含E、P基因组,St、W和H基因组参与了部分赖草属物种的起源。更多还原

【Abstract】 Leymus Hochst.is an important perennial genus of Triticeae Dumortier(Poaceae). It includes about 30 species and 19 subspecies.They are distributed in the coastal areas of North Sea,Central Asia,East Asia,extending to Alaska and the western areas of North America.They are found in particularly large numbers on the mountains of Central Asia and North America.Formerly,it included about 10 species recorded in China.In addition to some new taxon reported in recent years,it includes about 25 species,4 subspecies and 3 varieties,which are mainly distributed in north-western, north,north-eastern and south-western regions in China.Many species of Leymus are not only main components of grasslands and grass marshlands,but also fine varieties of herbage and forge.Growing in saline or alkaline lands,and dry or semi-dry areas,some species are highly adaptable to coldness,dryness and saline or alkaline lands.And some species bear such desirable traits as disease and insect resistance,bigger spikes,more and bigger grains and efficient photosynthesis.Being an important genetic resource, Leymus is of significance to improvement of Triticeae cereal crops.However,the origin and definition of the genus,precise taxonomic ranks and relationships among the species in the genus have been under discussion.The study on genetic diversity of Leymus would provide theoretical foundation for using this genus plants to breed Triticeae crops and herbage.The present study systematically evaluated the systematics relationships of Leymus on isoenzyme,gliadin and RAPD molecular level,and investigated the parental Psathyrostachys ancestries which offered the Ns genome to Leymus and to elucidate the origins of another base genome of Leymus.The main results showed as following:1.The esterase isozyme(EST) and superoxide isozyme(SOD) of 24 species of Leymus,Australopyrum,Agropyron,Lophopyrum,Pseudoroegneria,Psathyrostachys and Hordeum in triticeae were analyzed by using polyacrylamid gel electrophoresis (PAGE) technique.The results show as follows:①All the 24 species have significant isozymes polymorphism,a total of 45 bands are separted;②The relationship between L.chinensis and the other 13 species of Leymus is remote,while it is close to Hordeum bogdanii,Psathyrostachys juncea and the species of Leymus have closer relationship;③The species of those which contain similar genomes are clustered together;④The results of isozymes analysis are basically comparable with those obtained from studies on cytology and morphology.2.The gliadin of 22 materials of Leymus,Australopyrum,Agropyron, Lophopyrum,Pseudoroegneria,Psathyrostachys and Hordeum in Triticeae were analyzed by using acid-polyacrylamide gel electrophoresis(A-PAGE).The results show as follows:①All the 22 materials have significant gliadin polymorphism.A total of 52 bands are separated,and the gliadin ploymorphism amounts to 100%.It shows that there is plentiful polymorphism between these genera and species;②The relationship between Psathyrostachys juncea and Psa.huashanica is remote,while Psa.juncea and the species of Leymus have closer relationship;③The species of those which contain similar genomes are clustered together,which suggests they have closer relationship;④The results of gliadin analysis are basically comparable with those obtained from studies on cytology and morphology,which shows that the gliadin patterns is usefulness in the systematic studies of those perennial species in Triticeae.3.Six genome-specific RAPD markers representing Ns,E,W,P,St,H genome respectively were utilized to determine the genome relationships among Leymus and its related species.The results indicated that:the Ns genome-specific RAPD marker presented in 14 polyploid species of Leymus,while the E and P genome-specific RAPD markers absent in 14 polyploid species of Leymus;②the W genome-specific RAPD marker presented in L.ramosus;the St genome-specific RAPD marker presented in L.triticoides,L.ramosus,L.paboanus,L.chinensis,L. pseudoracemosuss;the H genome-specific RAPD marker presented in L.angustus,L. arenarius,L.multicaulis,L.karelinii,L.tianshanicus,L.paboanus,L.cinereus,L. chinensis,L.racemosus;③L.paboanus and L.chinensis had the specific bands of Ns genome,H genome and St genome;L.ramosus had the specific bands of Ns genomes, St genomes and W genomes.Based on these results from this study,we can draw conclusions that:Leymus species have multiple origins.Ns genome arose from the genus Psathyrostachys, While Psa.juncea and the species of Leymus have closer relationship.E and P genome absent in Leymus,While the partial species of Leymus had close phylogenetic relationship with St,W and H genome.更多还原