Journal Article

TaCKX6-D1, the ortholog of rice OsCKX2, is associated with grain weight in hexaploid wheat

Bao-Shi Zhang, Ji-Zeng Jia, Yong-Liang Zhao, Lei Zhang, Li-Feng Gao, Guang-Yao Zhao, Rong-Hua Zhou

2012

Overview

The cytokinin oxidase / dehydrogenase (CKX) gene plays a principal role in controlling cyto-kinin 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 a–e, 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.

• Publisher: New Phytologist Trust,Blackwell Publishing Ltd,Wiley Subscription Services, Inc
• Subject: Alleles / association / Association analysis / Biomarkers / Biomarkers - metabolism / Breeding / Chromosome Mapping / Chromosomes, Plant / Chromosomes, Plant - genetics / Chromosomes, Plant - metabolism / classification / Cloning, Molecular / Cultivars / cytokinin oxidase/dehydrogenase / Cytokinins / Divergence / DNA sequences / Domestication / Evolution, Molecular / Evolutionary genetics / Expressed Sequence Tags / Gene expression / Gene Expression Regulation, Plant / Gene mapping / Genes, Plant / Genetic Association Studies / genetics / genomics / Germplasm / Grain / grain weight / Grains / growth & development / haplotype / Haplotypes / hexaploidy / Introns / Linkage analysis / loci / metabolism / Molecular genetics / ortholog / Oxidoreductases / Oxidoreductases - genetics / Oxidoreductases - metabolism / Phylogeny / Plant breeding / Plant domestication / Plant growth substances / Plant Proteins / Plant Proteins - classification / Plant Proteins - genetics / Plant Proteins - metabolism / Pollination / Polyploidy / Quantitative Trait Loci / Rice / seed development / Seeds / Seeds - genetics / Seeds - growth & development / Seeds - metabolism / Selection, Genetic / Transcription, Genetic / Triticum / Triticum - genetics / Triticum - growth & development / Triticum - metabolism / Weight / Wheat