南繁区稻瘟病菌遗传多样性和群体遗传结构的AFLP分析

【目的】为了明确南繁区稻瘟病菌(Magnaporthe oryzae)的遗传分化情况,【方法】采用AFLP分子标记技术对南繁核心区(三亚、乐东和保亭)和非核心区(琼中、屯昌和定安)共60个稻瘟病菌菌株的遗传多样性和群体遗传结构进行了比较分析。【结果】聚类分析表明,几乎所有菌株都聚在同一个谱系里,并且该谱系没有明显的亚群;群体遗传结构分析表明,核心区群体的多态性位点百分率、Shannon信息指数和基因流分别为87.89%、0.2738和4.2897,高于非核心区群体的81.37%、0.2703和3.5892;然而,核心区群体的Nei基因多样性指数和基因分化系数分别为0.1657和0.1044,低于非核心区群体的0.1662和0.1223。【结论】这些结果表明核心区和非核心区菌株都存在丰富的遗传多样性,不同群体间均存在较多的基因交流,但遗传变异均主要来自群体内;相比之下,核心区菌株的遗传多样性和遗传分化程度较高。     

运用AFLP技术估计毛白杨及其杂种毛新杨的遗传杂合水平

首次报道以毛新杨 (Populustomentosa×P .bolleana)无性系TB0 1×毛白杨 (P .tomentosa)无性系LM5 0的回交子代 12 0株随机个体为材料 ,利用扩增性片断长度多态性 (AFLPs)标记技术研究毛白杨及其杂种毛新杨的遗传平均杂合水平。研究结果表明 :30对不同的AFLP引物组合能够检测到毛白杨的遗传平均杂合水平范围为 9 10 %～ 30 19% ,平均为 18 71% ;而毛新杨的遗传平均杂合范围为 1 39%～ 2 0 31% ,平均杂和水平约为 8 4 7%。因此 ,对于分离群体亲本杂合度来说 ,毛白杨平均杂合度为毛新杨的 2 2 1倍。     

Diversity of the calabash tree (<Emphasis Type="Italic">Crescentia cujete</Emphasis> L.) in Colombia

Germplasm of the calabash tree (Crescentia cujete L.) was collected in five major regions of Colombia, i.e. the Andes, Caribbean, Amazon, Orinoco, and Pacific regions. Collecting this multipurpose tree was guided by the indigenous knowledge of farmers and artisans in each region. Large variation in fruit shapes and sizes was found, of which some forms were typical for certain regions. Overall 56 accessions were collected and roughly classified into 22 types by eight fruit shapes and eight sizes. Molecular markers (Amplified fragment length polymorphisms) were applied to leaf tip tissue originating from vegetatively propagated plants in order to assess the diversity available in the germplasm collected as well as to detect patterns of geographical or morphological similarity. One accession each of C. alata H.B.&K. and C. amazonica Ducke were used as outgroups. Overall, genetic diversity was high (mean Nei and Li’s coefficient of 0.43). No relations could be established between either geographical provenance or fruit morphology and patterns of genetic diversity. Concerning the outgroups, the C. amazonica accession appeared to be a distinct species. The C. alata accession, however, did not seem to be sufficiently distinct from C. cujete to merit species status. The latter material may in fact be a hybrid or serve to challenge the validity of interspecific organization of the genus Crescentia.

Genetic Relationships among Prunus mume var. pendula Using AFLP Markers

Genetic relationships among Prunus mume var. pendula were studied by using AFLP markers. 18 accessions representing 14 cultivars ofPrunus murne var. pendula were selected from the germplasm collection at the Research Center of China Mci Flower. Seven Mse I-EcoR I AFLP primer combinations revealed 450 legible bands, and 269 of which were polymorphic markers. A similarity matrix was prepared using the simple matching coefficient of similarity and Nei‘s (72) distance coefficient. A UPGMA dendrogram demonstrated the genetic relationships of the cultivars. The information given by AFLP markers was basically consistent with the morphological classification and the evolutionary history of the morphotypes, and roughly supported the new revised classification system for Chinese Mci Cultivars. But there were still several exceptions: 1) the ‘Guhong Chuizhi‘ inserted between the ‘Tiaoxue Chuizhi‘ and the ‘Danfen Chuizhi‘; 2) the ‘Wufu Chuizhi‘ kept off the Pink Pendant Form, and the ‘Moshan Chuizhi‘ was removed from Viridiflora Pendant Form; 3) the ‘Danbi Chuizhi‘ and the ‘Shuangbi Chuizhi‘ of Viridiflora Pendant Form got together well but fell within the Pink Pendant Form.     

适于AFLP分析的澳洲坚果DNA提取方法

利用SDS法和改良CTAB法对澳洲坚果两个品种的基因组DNA进行提取试验,结果表明:SDS法与改良CTAB法提取的基因组DNA完整性都比较好,但SDS法获得的DNA含有较多杂质,不能被限制性内切酶消化,改良CTAB法提取的基因组DNA可以完全酶切,DNA质量符合AFLP分析的要求。     

土壤微生物多样性的分子生态学研究方法

传统的平板培养法分离培养和鉴定土壤微生物只能反映极少数微生物的信息,种类只占土壤微生物种类总数的0.1%～1%,分子生态学方法应用于土壤微生物的鉴定显示出极大的优越性.着重阐述了土壤微生物多样性的研究内容、意义及目前的采用分子生态学的方法研究土壤微生物多样性,尤其以DGGE（denaturing gradient gel electrophoresis）分子生物学技术以及RAPD（Random amplified polymorphic DNA ）随机扩增的多态性分析方法更为精确和快速,为土壤微生物多样性研究提供了一个更加广阔的前景.     

紫茉莉品系观赏性状与遗传多样性的AFLP分析

[目的]紫茉莉(Mirabilis jalapa Linn)是中国传统乡土花卉,研究不同种质的观赏性状,对利用这些资源进行杂交育种筛选后代、提高育种的针对性和加快育种进程具有重要的意义.[方法]本研究对具代表性的9个紫茉莉品系进行了株高、花型、花色、童期等观赏性状的比较,并利用扩增片段长度多态性(amplified fragment length polymorphism,AFLP)分子标记技术进行分析.[结果]紫茉莉的观赏性状主要包括株高、花型、花色、童期等,传统分类法可分为高株系统和矮株系统,花型为重瓣和单瓣,其花色有白色、粉色共9种颜色,多样性丰富.通过AFLP技术,采用8对引物组合共扩增出2 569条谱带,其中多态性条带2 488条,多态性条带比率为96.85％,平均每对引物扩增出321个位点,311个多态性位点.9个品系的相似性系数在0.2357～0.6493之问,平均值为0.4425,每个位点的有效等位基因数为1.2044,平均多样性指数为0.2127,遗传相似性系数最高的是5号和8号,达到0.6493,最低的是3和7,为0.2357.[结论]根据遗传相似性系数进行聚类分析,可将紫茉莉品系分为矮株型Ⅰ类和高株型Ⅱ类,分子聚类结果与表型性状特征分类结果较为一致,而在每一类中具体的观赏性状聚类存在一定差异.通过形态性状与分子标记为紫茉莉品系的研究,为进一步育种利用提供参考.     

甘肃省主栽马铃薯品种遗传多样性的AFLP与SSR分子标记分析

利用AFLP和SSR分子标记技术,对甘肃省的16个马铃薯主栽品种进行了遗传多样性分析,结果表明:在AFLP标记分析中,16个马铃薯品种间的遗传距离介于0.244 9~0.649 6,平均值为0.401 2;SSR标记分析中,16个马铃薯品种间的遗传距离介于0.135 9~0.801 4,平均值为0.477 0。AFLP标记具有丰富的多态性和较高的检测效率,SSR标记具有共显性、重复性好、扩增结果稳定等特点,两种技术均被应用于马铃薯品种遗传多样性分析、遗传图谱构建和基因定位等方面。     

橡胶树优异种质的AFLP初步分析

通过AFLP方法,对15份特异种质及在云南植胶区选择的45份优良单株进行了基于遗传相似性系数的UPGMA聚类分析,得到60份优异种质的聚类图,并初步分析了60份种质间的遗传变异情况及AFLP方法对于分析橡胶树遗传变异的实用性,为橡胶树选育工作及该60份种质的进一步鉴定利用奠定基础。     

Evidence of low levels of genetic diversity for the Phytophthora austrocedrae population in Patagonia,Argentina

Phytophthora austrocedrae is a recently discovered pathogen that causes severe mortality of Austrocedrus chilensis in Patagonia. The high level of susceptibility of the host tree, together with the distribution pattern of the pathogen, have led to the hypothesis that P. austrocedrae was introduced into Argentina. The aim of this study was to assess the population structure of P. austrocedrae isolates from Argentina in order to gain an understanding of the origin and spread of the pathogen. Genetic diversity was determined based on amplified fragment length polymorphisms (AFLPs). In total, 48 isolates of P. austrocedrae were obtained from infected A. chilensis trees, representing the geographical range of the host. Four primer combinations were used for the AFLP analysis. Of the 332 scored bands, 12% were polymorphic. Gene diversity (h) ranged from 0·01 to 0·03; the Shannon index (I) ranged from 0·01 to 0·04. A high degree of genetic similarity was observed among the isolates (pairwise S values = 0·958–1; 0·993 ± 0·009, mean ± SD). A frequency histogram showed that most of the isolate pairs were identical. Principal coordinate analysis using three‐dimensional plots did not group any of the isolates based on their geographical origin. The low genetic diversity (within and between sites) and absence of population structure linked to geographic origin, together with the aggressiveness of the pathogen and the disease progression pattern, suggest that P. austrocedrae might have been introduced into Argentina.