玉米抗粗缩病及灰斑病基因的初步定位

【作者】 史利玉；

【导师】 潘光堂； 李新海；

【作者基本信息】 四川农业大学 ， 作物遗传育种， 2007， 硕士

【摘要】 玉米是世界上重要的粮食、饲料及工业原料作物。玉米粗缩病和灰斑病是影响产量高低的重要因素，培育和种植抗病品种是防治病害的经济有效途径，而抗病育种的成效取决于对抗源和抗病遗传规律的认识。本论文拟开展抗玉米粗缩病及灰斑病基因定位研究，为抗病育种技术创新及种质改良提供理论依据。主要研究结果如下：(一)以黄早4×掖107组合衍生的179个F8代株系为供试群体，在玉米粗缩病的重病区(山西临汾与河北保定)两年种植，获得三个环境下的田间统计数据(05临汾、06年临汾及06年保定)；并应用此群体构建了相应的玉米分子图谱，包括74个SSR分子标记，覆盖10条玉米染色体；运行WinQTLCart2.5软件进行QTL定位。采用三种病情指标，病株率(BZL)、病指(BZ)、校正病指(JZBZ)，综合三个环境共检测出4个抗病QTL位点，分别位于第1、2、5、9染色体上，可解释的表型变异率介于4.9％～43.5％。其中，第1、2、5染色体上的等位基因来自黄早4；第9染色体上的等位基因来自掖107。对三个环境的病情指标进行联合QTL分析，共检测到2个抗病QTL，位于第1染色体和第5染色体上。(二)采用生物信息学手段，收集已定位的57个玉米抗灰斑病QTL，构建用于抗病QTL定位和分子标记发掘的整合图谱，确定出7个一致性QTL。分别位于染色体1.06(1个)、2.06(1个)、3.04(1个)、4.06(1个)、4.08(1个)、5.03(1个)与8.06(1个)区域，图距分别为552.53cM、425.72cM、279.2cM、368.97cM、583.21cM、308.68cM和446.14cM。从Gramene网站收集95个水稻和33个玉米抗性相关基因序列，基于水稻和玉米基因组间同源片断的共线性关系，构建了抗性基因整合图谱。通过拟合玉米抗灰斑病QTL和抗性基因整合图谱，在染色体2.06、3.04和8.06三个热点抗病QTL区间内，分别确定2个(Rgene-32、ht1)、4个(Rgene-5、rp3、scmv2及wsm2)和4个(ht2、Rgene-6、Rgene-8和Rgene-7)位置候选基因，为精细定位和克隆抗病基因创造了条件。更多还原

【Abstract】 Maize is one of the most important crops in China, and both maize rough dwarf virus (MRDV) and gray leaf spot (GLS) are two sever disease limiting yeild production annually. Developing and cultivating resistant hybrids is an effective approach to control the maize diseases, while breeding efforts for resistance rely largely on good understanding of the genetic mechanism. In this study, QTL identification for MRDV and GLS resistance were characterized. The results are follows:(1) The population consisting of 179 F8 families derived from a cross between Ye107 (susceptible parent) and Huangzao4 (resistance) was evolutated for MRDV resistance in replicated field trials in two ’hot spots’, Linfen Shanxi province and Baoding Hebei province in China over two years. Genotypic and and G×E variances for disease incidence were highly significant in the population. Composite interval mapping on a linkage map constructed with 74 SSR markers, identified four QTL using three disease index (disease percentage, disease index and modified index), one earch on chromosome 1, 2, 5 and 9,which signification influenced resistance to MRDV. Individual QTL accounted for 4.9% to 43.5% of the phenotypic variance. The resistance alleles of QTL on chromosome 1, 2 and 5 originated from Huangzao4, while the resistance allele of QTL on chromosome 9 derived from Ye107.These QTL have protential use in molecular marker-assisted selection for MRDV resistance in maize.(2) Wide differences were investigated for GLS resistance among maize germplasm sources, and most of the sources of resistance to GLS identified inherited in a quantitative manner, and a number of QTL for GLS resistance have been found using molecular markers. In this paper, the integration QTL map for GLS resistance in maize was constructed by compiling a total of 57 QTL available with Genetic Map IBM2 2005 neighbors as reference. Twenty-six "real QTL" and seven "consensus QTL" were identified by refining these 57 QTL using overview and meta-analysis approaches. Seven "consensus QTL" were found on chromosome 1.06, 2.06, 4.06, 4.08, 5.03 and 8.06, and the map coordinates were 552.53cM, 425.72cM, 279.20cM, 368.97cM, 583.21cM, 308.68cM and 446.14cM, respectively. Using a synteny conservation approach based on comparative mapping between maize genetic map and rice physical map, a total of 69 rice and maize resistance genes collected from websites Gramine and Maize GDB were projected onto maize genetic map IBM2 2005 Neighbors, and 2 (Rgene32, ht1), 4 (Rgene5, rp3, scmv2, wsm2) and 4 (ht2, Rgene6, Rgene8 and Rgene7) positional candidate genes were found in three "consensus QTL" on chromosomes 2.06, 3.04 and 8.06, respectively. Results suggest that the combination of meta-analysis of gray leaf spot in maize and sequence homologous comparison between maize and rice can be an efficient strategy for identifying major QTL and corresponding candidate genes for gray leaf spot.更多还原