赤桉抗风和生长性状的SSR关联分析

【目的】为了解赤桉抗风性和寻找与赤桉抗风相关联的分子标记,对影响桉树抗风性状的有利等位变异及携带优异等位变异的载体材料进行了分析,为桉树抗风分子育种奠定基础。【方法】以109份赤桉栽培种组成的半同胞群体为材料,利用关联分析方法对多态性高的107对SSR引物进行基因型检测,利用Structure2.3.4软件对供试材料进行群体结构和连锁不平衡分析的基础上,采用TASSEL 3.0软件的混合模型MLM程序,对与赤桉抗风有关的树高、胸径、材积、风害指数4个性状进行关联分析,根据计算的表型效应值,鉴别和统计优异的等位位点。【结果】通过群体遗传结构分析将109份赤桉材料分为2个亚群。通过关联分析,获得与抗风性状相关联的等位变异位点25个(P<0.05),生长及抗风性状表型变异的解释率为9.26%～71.14%,平均解释率为36.27%。其中与树高性状相关标记最多,为13个,贡献率最高的是EUCeSSR235(71.14%),增加树高表型效应最大的等位变异是EUCeSSR352-320,载体品种有9个; 与胸径显著相关的标记有7个,贡献率最高的是EUCeSSR332(63.29%),EUCeSSR489-128是增加表型效应最大等位变异,载体品种有11个; 与材积显著相关的标记有5个,贡献率最高的标记是EUCeSSR332(61.38%),增加表型效应最大的等位变异是EUCeSSR489-128,载体品种有11个; 与风害指数显著相关的标记有10个,贡献率最高的是EUCeSSR235(71.14%),减少表型效应最大的等位变异是EUCeSSR875-90,载体品种有34个。同时检测到7个标记与2个以上性状相关联,标记EUCeSSR332与树高、胸径、材积、风害指数等4个性状均同时关联,该标记对4个性状表型变异解释率超过60%。标记EUCeSSR484、EUCeSSR352、EUCeSSR570和EUCeSSR422与树高和风害指数2个性状均关联,EUCeSSR489和 EUCeSSR114标记与树高和材积2个性状关联。【结论】109份赤桉供试材料的群体遗传结构简单,连锁不平衡水平低。基于 SSR 的关联分析,发掘了与赤桉抗风性状相关的优异等位变异基因,可用于桉树抗风性状分子标记辅助育种。

SSR association analysis of Eucalyptus camaldulensis wind resistance and growth traits

Abstract: 【Objective】To elucidate Eucalyptus camaldulensis wind resistance, identify molecular markers and favorable alleles, and select genetic materials with favorable alleles for breeding wind resistant eucalyptus. 【Method】One-hundred and nine E. camaldulensis half-sibs were selected as materials and 107 pairs of SSR primers with high polymorphism were used for genotype detection with a correlation analysis method. Structure 2.3.4 software was used to analyze population structure and calculate linkage disequilibrium statistics. Association analysis with four E. camaldulensis wind resistant traits, including tree height, diameter-at-breast-height(DBH), volume, and wind damage index, was carried out using TASSEL 3.0 software together with the mixed linear model(MLM)methods. Based on the phenotypic effects, excellent allele loci were identified and counted. 【Result】 The 109 E. camaldulensis materials were divided into two subgroups based on population genetic structure analysis. Twenty-five SSR markers(P<0.05)related to wind resistance were obtained by association analysis, which explained the 9.26%-71.14% phenotypic variation of growth traits and wind resistance, with an average interpretation rate of 36.27%. Thirteen markers were related to tree height; the highest contribution rate was observed for EUCeSSR235(71.14%), the maximum allelic variation in phenotypic effect was exhibited by EUCeSSR352-320, and nine typical materials were detected. Seven markers correlated significantly with DBH. The highest contribution rate was demonstrated by EUCeSSR332(63.29%), while EUCeSSR489-128 had the greatest variation in phenotypic effect, and 11 typical materials were detected. Five markers were related to volume; the highest contribution rate was exhibited by EUCeSSR332(61.38%), EUCeSSR489-128 had the greatest variation in phenotypic effect, and 11 typical materials were detected. Ten markers were related to wind resistance index; EUCeSSR235 had the highest contribution rate(71.14%), EUCeSSR875-90 had the greatest variation in phenotypic effect, and 34 typical materials were detected. Seven markers were associated with >2 traits; EUCeSSR332 was related to tree height, DBH, volume, and wind damage index, which could explain the phenotypic variation rate of >60%. EUCeSSR484, EUCeSSR352, EUCeSSR570, and EUCeSSR422 were associated with two tree height and wind damage index traits and EUCeSSR489 and EUCeSSR114 were associated with tree height and volume. 【Conclusion】The genetic structure of the 109 E. camaldulensis materials was simple and the linkage disequilibrium was low. Based on the SSR association analysis, a number of excellent E. camaldulensis wind resistance allelic variation genes were identified and the selected molecular markers were provided for Eucalyptus breeding.