红掌细菌性疫病抗性遗传分析、连锁图谱构建及QTLs定位

Anthurium (Anthurium andraeanum Linden) is a popular ornamental flower, and China has became one of the main producers and markets in the world. But serious devastation caused by bacterial blight (Xanthomonas axonopodis pv. Dieffenbachiae, Xad) was prevalent in the anthurium industry. For the scarcity of effective research on inheritance of resistance and breeding, which is regarded as the most threatening disease for anthurium production. In this study, based on the identified parent varieties with blight resistance and susceptibility, we emploied self amd incomplete diallel crossing design, combine multiple generations segregation analysis method of major gene plus polygenes mixed genetic model, to investigate the genetic mechanism of blight resistance. In addition, we will use throughput methods for mining and screening of RGAs molecular markers, combine with the developed E-STSs (EST-SSRs, SNPs), to construct genetic linkage map to map QTLs for bacterial blight resistance. Results will reveal the genetic mechanism of blight resistance, facilitate the marker-assisted selection in resistance and other target traits breeding in anthurium. Moreover, this study will enable better expanding of basic research of genomics and molecular genetics in anthurium.

我国已发展为全球主要的红掌生产基地和消费市场，但在生产中普遍遭受细菌性叶疫病的严重威胁。目前红掌抗疫病遗传机制尚无研究，常规抗病育种缺乏成效,主栽品种多表现为抗性不足。本项目利用已鉴定出的广谱抗性和感病红掌种质，进行自交和不完全双列杂交，构建多个抗病分离体，采取多世代联合分析，结合数量性状主基因-多基因遗传的统计方法，解析红掌细菌性疫病抗性的遗传规律；高通量开发出红掌RGAs分子标记，结合已开发的E-STS（包括EST-SSR和EST-SNP）、通用型SRAP等分子标记，使用'Acropolis'×'Alabama'F1群体，构建高密度遗传连锁图谱；筛选共分离或紧密连锁标记，准确定位出红掌抗疫病QTLs位点。研究结果将为解析红掌叶疫病抗性的遗传机制提供重要信息，加速抗疫病及其他性状的分子育种进程；并推动红掌基因组学和分子遗传学等基础领域研究的开展。

红掌（Anthurium andraeanum. Lind）是重要的盆切两用花卉，培育高抗疫病的品种是育种的主要目标之一。本研究采用‘Acropolis’（♀）（抗）× ‘Alabama’（♂）（感）随机筛选的199个单株，通过SLAF-seq高通量开发SNP标记，构建了第一张红掌高密度遗传图谱，并通过接种鉴定，定位相关QTL，主要研究结果如下：. （1）SLAF-seq测序获得1,215.07M reads，测序平均Q30 为90.09%，平均GC 含量为42.09%。本研究共开发了537,356 个 SLAF 标签，母本获得 192,013个SLAF 标签，测序深度为 34.33 X；父本194,587个SLAF标签， 35.46X；子代总数为150,756标签，13.43 X。高质量标签有344,383个，其中多态性标签169,020个，多态性比例达49.08%。. （2）利用“双假测交”策略构建遗传图谱。雄性图距1,896.74cM，上图标记为4,287个，平均图距为0.64cM。雌性图谱距2,326.85cM，上图标记为4,440个，平均图距为0.65cM。整合双亲遗传图谱得到总图距为2,246.36 cM，平均0.37cM中性图。上图7,065个 Marker分布于15条连锁群上，与红掌染色体数目一致。偏分离标记为272，占标记总数的比例为3.85%。上图标记完整度为99.87%。. （3）采用离体叶盘接种法鉴定F1群体及亲本的抗性，通过叶盘坏死周期（TLC）来判断抗性，F1群体TLC范围为2-25天，抗性表现为连续性变异，并在作图群体中呈现正态分布的规律。通过MapQTL6.0检测到3个与抗性有关的QTL，LOD值范围在2.02-2.27，贡献率为4.1%-5.3%。利用GACD1.0检测到24个与抗性相关的QTL。LOD值范围在2.0062-3.1369。贡献率为0.3462%-3.9058%间。. 研究结果为红掌抗性遗传解析及抗病育种提供了基础信息，对其他性状的研究和育种也有借鉴意义。