大麦籽粒蛋白质及其相关功能成分含量的QTL分析

【目的】研究大麦籽粒蛋白质与功能成分含量的相关关系及其QTL,为功能大麦遗传改良、基因克隆及分子辅助育种奠定理论基础。【方法】以紫光芒裸二棱为母本,Schooner为父本构建包含193个株系的RIL群体,结合SSR技术和QTL Ici Mapping V3.3软件构建遗传连锁图谱,借助完全区间作图法(ICIM)对两年大麦籽粒蛋白质、总黄酮和γ-氨基丁酸(GABA)含量进行QTL检测;同时分析蛋白质、总黄酮和GABA含量之间的相关性。【结果】亲本及RIL群体籽粒蛋白质、总黄酮及GABA含量表现出较大差异,且呈连续变异正态分布,适宜进行QTL定位。构建了一张全长为2 224.29 c M,两标记间平均距离为16.48 c M的遗传连锁图谱,包括7个连锁群,135个标记位点。共检测到20个QTL,其中,控制蛋白质含量的9个QTL分别定位于1H、2H、4H、6H和7H连锁群染色体。表型变异率范围为4.11%—18.86%,解释表型变异率大于10%的3个主效QTL(13.30%、15.45%和18.86%)分别位于6H和7H染色体。经两年试验检测发现2个相同的QTL位点,分别位于4H BMAG0740—BMAG0808和6H Ebmac0806—GBM1270;控制总黄酮含量的7个QTL分别定位于2H、5H、6H和7H染色体。表型变异率范围为6.06%—29.01%,解释表型变异率大于10%的5个主效QTL(10.38%、15.27%、17.55%、24.17%和29.01%)分别位于2H、6H和7H染色体。经两年试验检测发现1个相同的QTL位点,位于7H EBmatc0016—Bmag0206;控制GABA含量的4个QTL分别定位于4H、5H、6H和7H染色体,表型变异率范围为5.44%—14.87%,最大变异率为14.87%的主效QTL位于7H染色体。控制蛋白质含量与总黄酮含量的基因同位于2H、6H和7H染色体,控制蛋白质含量与GABA含量的基因重合在4H、6H和7H染色体,控制总黄酮含量与GABA含量的基因同位于5H、6H和7H染色体。控制这三种成分的QTL主要位于6H和7H,尤其是6H Ebmac0806—GBM1270影响蛋白质、总黄酮和GABA含量,且加性作用方向一致,有极显著相关性。相关性分析结果表明,蛋白质、总黄酮与GABA含量之间呈极显著正相关。【结论】大麦籽粒蛋白质、总黄酮和GABA含量的相关性分析与其部分QTL定位结果一致,揭示了蛋白质和功能成分含量之间紧密的遗传关系。

QTL Mapping of Protein and Related Functional Components Content in Barley Grains

【Objective】The objective of this study is to identify the QTLs controlling protein content, total flavonoids content, gamma-aminobutyric acid (GABA) content in barley grains and analyze their correlation, which could be a theoretical basis for genetic modification, gene cloning and molecular assisted breeding of the functional barley. 【Method】Based on two-year experiment data, a barley SSR genetic linkage map constructed by a total of 193 RIL population derived from the cross between Ziguangmangluoerleng (female parent) and Schooner (male parent) and the Inclusive Composite Interval Mapping(ICIM) method was used to identify the QTLs of protein, total flavonoids and GABA content. The correlations among the contents of three components were also analyzed. 【Result】 The two parents and RIL population have significant differences in protein, total flavonoids, and GABA content, showed continuous variation and normal distribution, which are suitable for QTL mapping. The map covered 2224.29cM with a mean density of 16.48cM per locus, including 7 linkage groups and 135 marker loci. A total of 20 QTLs for protein content, total flavonoids content, GABA content were detected. Nine QTL for protein content were localized on chromosomes 1H, 2H, 4H, 6H and 7H. It explained phenotypic variation range from 4.11% to 18.86%, 3 major QTL were localized on 6H and 7H, which explained 13.30%, 15.45% and 18.86% phenotypic variance. Two of the same QTL loci were found that localized on 4H BMAG0740-BMAG0808 and 6H Ebmac0806-GBM1270 based on two-year experiment. Seven QTL for total flavonoids content were localized on chromosomes 2H, 5H, 6H and 7H. It explained phenotypic variation range from 6.06% to 29.01%, 5 major QTL were localized on 2H, 6H and 7H, which explained 10.38%, 15.27%, 17.55%, 24.17% and 29.01% phenotypic variance. One of the same QTL loci was found that localized on 7H EBmatc0016-Bmag0206 based on two-year experiment. Four QTL for GABA content were localized on chromosome 4H, 5H, 6H and 7H. It explained phenotypic variation range from 5.44% to 14.87%, the highest phenotypic variance was 14.87%, which localized on 7H. QTLs controlling protein content and total flavonoids content were mapped and mainly localized on 2H, 6H and 7H, QTLs controlling protein content and GABA content were mainly localized on 4H, 6H and 7H, QTLs controlling total flavonoids content and GABA content were mainly localized on 5H, 6H and 7H. So QTLs for three components were mainly localized on 6H and 7H, especially on the 6H Ebmac0806-GBM1270 interval, and they all affected protein, total flavonoids and GABA content, the contribution rates of additive effects were the same, and there was a significantly correlation. The correlation analysis showed that the significantly positive correlations were existed among protein, total flavonoids and GABA content. 【Conclusion】the correlations of protein content, total flavonoids content, GABA content are consistent with the correlations of QTLs controlling those components. It revealed the close genetic relationship between protein and functional components.