高粱抗旱性数量性状位点基因定位研究进展

Research Advance on Mapping Quantitative Trait Loci of Drought Resistance in Sorghum

干旱是作物生产的一个主要限制因子。研究作物对干旱胁迫反应的遗传因素,可以为改良作物的抗旱性提供可靠的理论依据。高粱对干旱有广泛的适应性,是禾本科作物中研究抗旱性的优良模式作物。高粱对干旱抗性分为开花前抗旱性和开花后抗旱性。花前干旱影响穗子大小、穗粒数及籽粒产量;花后干旱会造成叶片、植株的死亡,导致炭腐病和倒伏发生并影响籽粒的饱满度,二者均能造成严重的产量损失。持绿是高粱的一种抗旱机制,具持绿性状的基因型,在开花后遇水分胁迫时抗旱抗植株过早衰老,籽粒正常灌浆。采用不同遗传背景的重组近交系(RIL)群体和近等基因系(NIL),并结合分子遗传学手段研究持绿数量性状位点(QTL),发现了多个基因组区段控制对开花前和开花后水分胁迫的抗性,找到了多个在不同环境中持续表达的持绿QTL。持绿QTL的分子遗传分析为进一步理解高粱及其它禾本科作物抗旱性的生理机制奠定了基础。

Drought is a major constraint to crop production worldwide. Understanding genetic factors associated with crop response to drought stress will provide a dependable theoretical foundation for improving drought resistance. Sorghum (Sorghum bicolor L. Moench) widely adapts to drought environment and has become a model crop for studying drought resistance among the grass family. Sorghum responses to drought stress include preflowering and postflowering two stages. Preflowering drought affects the size of head, kernel number per panicle and grain yield. Postflowering drought leads to death of leaves and plants, charcoal rot, stalk lodging and significant yield loss. Stay green is a drought resistance mechanism in sorghum. Genotypes with stay green give resistance to premature senescence and grain filling normally during the postflowering water stress. Recombinant inbred lines (RILs) with different genetic backgrounds and nearisogenic lines (NILs) were developed to study the stay green QTLs by molecular genetic method, which identified several genomic regions controlling postflowering drought resistance. Some major stay green QTLs were consistently identified across various environments. The molecular genetic dissection of the stay green QTLs will provide an approach to better understanding the physiological mechanism of drought resistance in sorghum and other grasses. 