茶树炭疽病抗性的 QTL 分析

摘要

In order to provide a basis for breeding tea plants with anthracnose resistance, 170 F1 plants, derived from LJ43♀×BHZ♂, were used to constructed a linkage map by SSR markers. Field observation and indoor test were carried out in 2014. The data of phenotypic characters were used for QTL mapping and analysis by the method of MQM mapping. A pathogen was isolated from a diseased leaf of the F1 plants, and its gene sequence of ITS had 99%similarity with Colletotrichum sp. based on NCBI BLAST. The plants grown in open field were more easy to be infected by the pathogen than those grown in rooms. Eight QTLs were detected in six different linkage groups by QTL analysis. The LOD and PVE of individual QTLs ranged from 2.53 to 6.80 and 5.6% to 13.8%, respectively. A main QTL with LOD 6.80 and PVE 13.8% was detected in LG10.%以茶树 SSR 遗传连锁图谱为基础，选取龙井43为母本，白毫早为父本的170株 F1遗传群体为试验材料，于2014年对该群体分别进行了茶树炭疽病抗性性状的田间观测和室内侵染试验，并采用复合区间作图法对该性状进行 QTL 定位与分析。结果显示：从 F1群体病叶上分离纯化出一种茶树炭疽病病菌 HZ-1，经NCBI BLAST 比对，其 ITS 基因序列与炭疽菌（Colletotrichum sp.）的亲缘关系最近，序列相似度为99%。对F1群体的炭疽病抗性表型分析发现，田间环境下的感病单株的占比（41%）高于室内环境（24%）。QTL 分析显示，在6个不同的遗传连锁群（Linkage group，LG）上共检测到8个 QTLs，单个 QTL 的 LOD 阈值变幅为2.53~6.80，单个 QTL 的表型变异贡献率的变幅为5.6%~13.8%。LG10存在1个控制茶树炭疽病抗性性状的主效 QTL，LOD 值6.80，表型变异贡献率13.8%。