Sorghum stay-green QTL individually reduce post-flowering drought-induced leaf senescence
Sorghum stay-green QTL individually reduce post-flowering drought-induced leaf senescence
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DOI：
10.1093/jxb/erl225
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发表时间：
2007-01-01
影响因子：
6.9
通讯作者：
Mullet, John
中科院分区：
文献类型：
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作者：
Harris, Karen;Subudhi, P. K.;Mullet, John
高粱是食物、饲料和生物燃料的重要来源，特别是在半干旱的热带地区，因为这种谷物很好地适应了恶劣的、容易干旱的环境。高粱花后的干旱适应与保持绿色表型有关。利用来自BTx642和RTx7000的群体，研究人员将导致这一复杂性状的等位基因定位到4个主要QTL: Stg1-Stg4。构建了包含BTx642 DNA的近等基因RTx7000系，该系跨越了4个stay-green QTL中的一个或多个。利用跨越4个保持绿色QTL的62个DNA标记分析了每个RTx7000 NIL中BTx642 DNA区域的大小和位置。RTx7000 NILs鉴定含有BTx642 DNA完全或部分跨越Stg1、Stg2、Stg3或Stg4。NILs还被鉴定出包含每个QTL的子部分和四个主要保持绿色QTL的各种组合。对仅含Stg1、Stg2、Stg3和Stg4的4个RTx7000 NILs的生理分析表明，这些位点上的BTx642等位基因都与保持绿色表型有关。含有Stg2对应的BTx642 DNA的RTx7000 NILs在末干旱条件下比RTx7000或其他RTx7000 NILs在成熟时保留了更多的绿叶面积。在花后水分亏缺的情况下，Stg2、Stg3和Stg4 NILs也表现出比RTx7000延迟衰老的趋势，但所有Stg NILs的叶片衰老速率都不同程度地低于RTx7000，其中Stg2 NILs表现得尤为明显。与RTx7000相比，Stg1和Stg4 NILs的花期叶片更绿，SPAD值更高。本研究构建的RTx7000 NILs为深入分析保绿生理、保绿QTL之间的相互作用以及该性状相关基因的图谱克隆提供了起点。
Sorghum is an important source of food, feed, and biofuel, especially in the semi-arid tropics because this cereal is well adapted to harsh, drought-prone environments. Post-flowering drought adaptation in sorghum is associated with the stay-green phenotype. Alleles that contribute to this complex trait have been mapped to four major QTL, Stg1-Stg4, using a population derived from BTx642 and RTx7000. Near-isogenic RTx7000 lines containing BTx642 DNA spanning one or more of the four stay-green QTL were constructed. The size and location of BTx642 DNA regions in each RTx7000 NIL were analysed using 62 DNA markers spanning the four stay-green QTL. RTx7000 NILs were identified that contained BTx642 DNA completely or partially spanning Stg1, Stg2, Stg3, or Stg4. NILs were also identified that contained sub-portions of each QTL and various combinations of the four major stay-green QTL. Physiological analysis of four RTx7000 NILs containing only Stg1, Stg2, Stg3, or Stg4 showed that BTx642 alleles in each of these loci could contribute to the stay-green phenotype. RTx7000 NILs containing BTx642 DNA corresponding to Stg2 retained more green leaf area at maturity under terminal drought conditions than RTx7000 or the other RTx7000 NILs. Under post-anthesis water deficit, a trend for delayed onset of leaf senescence compared with RTx7000 was also exhibited by the Stg2, Stg3, and Stg4 NILs, while significantly lower rates of leaf senescence in relation to RTx7000 were displayed by all of the Stg NILs to varying degrees, but particularly by the Stg2 NIL. Greener leaves at anthesis relative to RTx7000, indicated by higher SPAD values, were exhibited by the Stg1 and Stg4 NILs. The RTx7000 NILs created in this study provide the starting point for in-depth analysis of stay-green physiology, interaction among stay-green QTL and map-based cloning of the genes that underlie this trait.