小麦籽粒蛋白质含量的动态QTL定位

Dynamic QTL Mapping of Wheat Protein Content in Developing Grains

【目的】检测灌浆过程中控制小麦籽粒蛋白质含量(GPC)的条件及非条件QTL,阐明不同时期及不同时段内QTL的表达方式,揭示籽粒蛋白质积累的分子遗传机理。【方法】以花培3号×豫麦57的168个双单倍体(doubled haploid,DH)群体为材料,于6个不同的环境下种植,在籽粒灌浆的5个时期取样,对小麦GPC进行动态QTL分析。【结果】共检测到影响GPC的9个非条件QTL和10个条件QTL。QGpc3A为整个灌浆过程都能表达的非条件QTL,其余条件和非条件QTL只在几个或单独一个时期表达。花后12 d,控制GPC的基因表达活跃,非条件QTL和条件QTL总共能解释表型变异贡献率的42.62%;花后22 d,条件QTL和非条件QTL总共可解释表型变异的贡献率较低,仅为17.43%,GPC降到"低谷"。QGpc4A-1对GPC前期积累有重要意义,QGpc1D和QGpc4A-2对GPC灌浆中后期积累有重要意义。【结论】GPC呈现出"高-低-高"的变化规律,控制GPC的基因在灌浆过程中以一定的时空方式表达。

[Objective] Grain protein content （GPC） is an important quality factor in bread wheat, which is determined by quantitative trait loci （QTLs）. In this study, to attain more genetic information of GPC accumulation, the number and genetic effects of QTLs/genes related to GPC were detected at different seed filling stages. [Method] QTLs/genes related to GPC were studied at five seed filling stages in six different environments, using a doubled haploid （DH） population derived from a cross between two elite Chinese wheat cultivars Huapei 3×Yumai 57. QTL mapping for developmental behavior of GPC was studied by unconditional and conditional quantitative trait locus （QTL） analyses in a mixed linear model. [Result] A total of nine unconditional QTLs and ten conditional QTLs were detected at five seed filling periods. The unconditional QTL named QGpc3A persistently expressed at all seed filling stages may play a most important role for the accumulation of GPC, the rest unconditional QTLs and conditional QTLs were only detected at a few or a special periods. At the period of 12 days after anthesis the gene expression was active, and the QTLs detected could account for 42.62% of phenotypic variation totally. However, the QTLs detected could totally account for only 17.43% of phenotypic variation at 22 d after anthesis with lowest phenotypic value. [ Conclusion ]The dynamic change of GPC show a high - low - high trend and QTLs controlling GPC were developmental stage specific.