QTL analysis and comparative genomics of herbage quality traits in perennial ryegrass (Lolium perenne L.)
QTL analysis and comparative genomics of herbage quality traits in perennial ryegrass (Lolium perenne L.)
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DOI：
10.1007/s00122-004-1848-9
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发表时间：
2005-01-01
影响因子：
5.4
通讯作者：
Forster, J
中科院分区：
文献类型：
--
作者：
Cogan, N;Smith, K;Forster, J
利用基于分子标记的多年生黑麦草参考遗传图谱，研究了牧草品质变异的遗传控制。限制性片段长度多态性（RFLP），扩增片段长度多态性（AFLP）和基因组DNA衍生的简单重复序列（SSR）为基础的框架标记集的增强，与RFLP位点对应的关键酶的基因参与木质素的生物合成和果聚糖代谢。利用近红外光谱分析技术测定了牧草收获期的粗蛋白质（CP）含量、干物质体内消化率（IVVDMD）、中性洗涤纤维（NDF）含量、代谢能（EstME）和水溶性碳水化合物（WSC）含量等品质性状。采用单标记回归、简单区间作图和复合区间作图方法对6个不同发育阶段（开花期或营养生长期）、地点和年份的水稻品种进行了QTL分析，共检测到42个QTL。在第3、5、7连锁群上检测到一致QTL。LG 3上的区域与各种实验数据集中所有测量的性状的变异相关。LG 7上的区域与除了CP之外的所有性状的变化相关，并且位于木质素生物合成基因位点xlpomt 1（咖啡酸-O-甲基转移酶）、xlpccr 1（肉桂酰CoA还原酶）和xlpssrcad 2.1（肉桂醇脱氢酶）附近。这些基因与小麦（Triticum aestivum L.）为进化过程中基因序列的保守性提供了证据，并为跨种遗传信息传递提供了基础。QTL和功能相关遗传标记之间的共定位的鉴定对于实施标记辅助选择程序和连锁不平衡研究是至关重要的，这将使未来的多年生黑麦草改良策略成为可能。
Genetic control of herbage quality variation was assessed through the use of the molecular marker-based reference genetic map of perennial ryegrass (Lolium perenne L.). The restriction fragment length polymorphism (RFLP), amplified fragment length polymorphism (AFLP) and genomic DNA-derived simple sequence repeat-based (SSR) framework marker set was enhanced, with RFLP loci corresponding to genes for key enzymes involved in lignin biosynthesis and fructan metabolism. Quality traits such as crude protein (CP) content, estimated in vivo dry matter digestibility (IVVDMD), neutral detergent fibre content (NDF), estimated metabolisable energy (EstME) and water soluble carbohydrate (WSC) content were measured by near infrared reflectance spectroscopy (NIRS) analysis of herbage harvests. Quantitative trait locus (QTL) analysis was performed using single-marker regression, simple interval mapping and composite interval mapping approaches, detecting a total of 42 QTLs from six different sampling experiments varying by developmental stage (anthesis or vegetative growth), location or year. Coincident QTLs were detected on linkage groups (LGs) 3, 5 and 7. The region on LG3 was associated with variation for all measured traits across various experimental datasets. The region on LG7 was associated with variation for all traits except CP, and is located in the vicinity of the lignin biosynthesis gene loci xlpomt1 (caffeic acid-O-methyltransferase), xlpccr1 (cinnamoyl CoA-reductase) and xlpssrcad 2.1 (cinnamyl alcohol dehydrogenase). Comparative genomics analysis of these gene classes with wheat (Triticum aestivum L.) provides evidence for conservation of gene order over evolutionary time and the basis for cross-specific genetic information transfer. The identification of co-location between QTLs and functionally associated genetic markers is critical for the implementation of marker-assisted selection programs and for linkage disequilibrium studies, which will enable future improvement strategies for perennial ryegrass.