College of Agriculture, JiangXi Agricultural University, Nanchang 330045, People's Republic of China.
Mol Biol Rep. 2012 Jul;39(7):7525-31. doi: 10.1007/s11033-012-1586-z. Epub 2012 Feb 14.
The molecular basis of flower bud differentiation in flowering Chinese cabbage (Brassica rapa L. ssp. Chinensis var. utilis Tsen et Lee) was studied in this work. Samples were taken from two varieties, the early-blooming "Youqin 49" and the late-blooming "Youqingtiancaixin 80", at five different developmental stages and studied via cDNA-AFLP. Nineteen expression sequence tags (ESTs) associated with bolting or flowering were isolated and cloned. Blast results indicated that 15 ESTs were involved in the synthesis of anthocayanins, photosynthesis, signal transduction, and phytochrome production. Two ESTs had high similarity to hypothetical proteins with unknown function. Two other ESTs shared no similarity to any sequence in the NCBI database and potentially may be newly identified genes. The deduced amino acid sequences of EST amplified by primer A6T4 or A8T4 had high similarity to both dihydroflavonol reductase (DFR) and UDP-D: -apiose/UDP-D: -xylose synthase (AXS), thus was named BrcuDFR-like/BrcuAXS. Using the cDNA sequence, a putative BrcuDFR-like/BrcuAXS gene was cloned and characterized from flowering Chinese cabbage via rapid amplification of cDNA ends (RACE). The full-length cDNA has 1332 bp with an open frame of 919 bp which codes for a polypeptide of 313 amino acids. The corresponding genome sequence is 2,046 bp. Comparison of cDNA and its corresponding genomic sequence indicates that BrcuDFR-like/BrcuAXS contains 9 exons and 8 introns. The temporal expression patterns indicated the gene is more likely to encode the DFR protein, which catalyzes the synthesis of anthocayanins, than UDP-D: -apiose/UDP-D: -xylose synthase (AXS), which catalyzes the conversion of UDP-D: -glucuronate to a mixture of UDP-D: -apiose and UDP-D: -xylose. Further work is needed to determine what role BrcuDFR-like/BrcuAXS plays during floral organ development.
本研究旨在探讨芸薹属白菜型亚种开花种中春花心和晚春心两个品种的花芽分化的分子基础。本研究采用 cDNA-AFLP 技术，从两个品种（早花品种“油青 49”和晚花品种“油青天菜心 80”）的五个不同发育阶段的样本中进行研究。共分离并克隆了 19 个与抽薹或开花相关的表达序列标签（EST）。Blast 结果表明，其中 15 个 EST 参与了花色苷的合成、光合作用、信号转导和光敏色素的产生。两个 EST 与具有未知功能的假定蛋白高度相似。另外两个 EST 与 NCBI 数据库中的任何序列均无相似性，可能是新鉴定的基因。用引物 A6T4 或 A8T4 扩增的 EST 推导的氨基酸序列与二氢黄酮醇还原酶（DFR）和 UDP-D：-阿魏酸/UDP-D：-木糖合酶（AXS）高度相似，因此被命名为 BrcuDFR-like/BrcuAXS。利用 cDNA 序列，通过快速扩增 cDNA 末端（RACE）从开花白菜中克隆并鉴定了一个假定的 BrcuDFR-like/BrcuAXS 基因。全长 cDNA 有 1332 bp，开放阅读框为 919 bp，编码 313 个氨基酸的多肽。相应的基因组序列为 2046 bp。cDNA 与其相应基因组序列的比较表明，BrcuDFR-like/BrcuAXS 含有 9 个外显子和 8 个内含子。该基因的时空表达模式表明，它更有可能编码 DFR 蛋白，该蛋白催化花色苷的合成，而不是 UDP-D：-阿魏酸/UDP-D：-木糖合酶（AXS），该酶催化 UDP-D：-葡萄糖醛酸转化为 UDP-D：-阿魏酸和 UDP-D：-木糖的混合物。需要进一步的工作来确定 BrcuDFR-like/BrcuAXS 在花器官发育过程中扮演的角色。
