TaCKX6-D1, the ortholog of rice OsCKX2, is associated with grain weight in hexaploid wheat
TaCKX6-D1, the ortholog of rice OsCKX2, is associated with grain weight in hexaploid wheat
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DOI：
10.1111/j.1469-8137.2012.04194.x
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发表时间：
2012-08-01
期刊：
影响因子：
9.4
通讯作者：
Jia, Ji-Zeng
中科院分区：
文献类型：
--
作者：
Zhang, Lei;Zhao, Yong-Liang;Jia, Ji-Zeng
细胞分裂素氧化酶/脱氢酶（CKX）基因在控制细胞分裂素水平中起主要作用，并且已被证明是影响水稻粒数的主要数量性状位点（QTL）。然而，小麦CKX基因的单倍型的功能和评价还有待阐明。本研究克隆了水稻OsCKX 2的小麦直向同源基因TaCKX 6-D1，通过连锁作图、关联分析和基因表达分析，确定其单倍型变异体与千粒重显著相关。鉴定了5种TaCKX 6-D1单倍型，命名为ae。开发了一个indel标记来鉴定与较高粒重相关的单倍型a。单倍型a在授粉后8 d的种子中的表达相对于单倍型B有所降低。中国小麦种质TaCKX 6-D1基因在现代栽培品种、地方品种和野生种间的序列变异表明存在明显的驯化特征。TaCKX 6-D1可作为小麦高产育种的一个有用基因。提出了TaCKX 6-D1等位基因的挖掘和利用策略。我们的研究还揭示了小麦籽粒发育和驯化的机制，以及比较基因组学中直系同源物的功能分歧。
The cytokinin oxidase/dehydrogenase (CKX) gene plays a principal role in controlling cytokinin levels and has been shown to be a major quantitative trait locus (QTL) affecting grain number in rice. However, the function and evaluation of the haplotypes of the wheat CKX gene have yet to be illustrated. In this study, TaCKX6-D1, a wheat ortholog of rice OsCKX2, was cloned and its haplotype variants were determined to be significantly associated with the 1000-grain weight on the basis of linkage mapping, association analysis and gene expression analysis. Five TaCKX6-D1 haplotypes, designated ae, were identified. An indel marker was developed to identify haplotype a, which was associated with higher grain weight. Haplotype a showed decreased expression relative to haplotype b in seeds at 8 d after pollination. Sequence variations among modern cultivars, landraces and wild species suggest a significant domestication signature at the TaCKX6-D1 locus in Chinese wheat germplasm. TaCKX6-D1 may serve as a useful gene for the breeding of high-yielding wheat. A strategy for allele mining and utilization of TaCKX6-D1 was proposed. Our study also sheds light on the mechanisms of grain development and domestication of wheat, as well as the functional divergence of orthologs in comparative genomics.