National Engineering Laboratory for Tree Breeding, People's Republic of China.
Biotechnol Lett. 2011 Jun;33(6):1239-47. doi: 10.1007/s10529-011-0545-4. Epub 2011 Feb 4.
A MADS-box gene, designated PtAP3, was isolated from a floral bud cDNA library derived from Populus tomentosa. Analysis by multiple alignments of both nucleotide and amino acid sequences, together with phylogenetic analysis, revealed that PtAP3 is an ortholog of Arabidopsis AP3. Analysis of RNA extracts from vegetative and reproductive tissues of P. tomentosa by RT-PCR indicated that PtAP3 is expressed in roots, stems, leaves and vegetative and floral buds. Notably, the expression of PtAP3 fluctuated during floral bud development between September and February with differences between male and female buds. In the former, a gradual down-regulation during this period, interrupted by a slight up-regulation in December, was followed by a sharper up-regulation on February. In developing female floral buds, expression was stable from September to November, sharply up-regulated in December, and then gradually down-regulated until February. The functional role of PtAP3 was investigated in transgenic tobacco plants. Of 25 transformants, nine displayed an earlier flowering phenotype compared with the wild type plants. Furthermore, transgenic tobacco had faster growth and more leaves than untransformed controls. The traits proved to be heritable between the T0 and T1 generations. Our results demonstrate a regulatory role of the PtAP3 gene during plant flowering and growth and suggest that the gene may be an interesting target for genetic modification to induce early flowering in plants.
从毛白杨的花芽 cDNA 文库中分离出一个 MADS 框基因，命名为 PtAP3。通过核苷酸和氨基酸序列的多重比对分析以及系统发育分析，表明 PtAP3 是拟南芥 AP3 的同源基因。通过 RT-PCR 对毛白杨营养组织和生殖组织的 RNA 提取物进行分析表明，PtAP3 在根、茎、叶和营养芽及花芽中表达。值得注意的是，PtAP3 的表达在 9 月至 2 月的花芽发育过程中波动，雌雄芽之间存在差异。在前者中，在此期间逐渐下调，12 月略有上调，然后在 2 月急剧上调。在发育中的雌性花芽中，从 9 月到 11 月表达稳定，12 月急剧上调，然后逐渐下调直到 2 月。在转基因烟草植物中研究了 PtAP3 的功能作用。在 25 个转化体中，有 9 个与野生型植物相比表现出更早的开花表型。此外，转基因烟草的生长速度比未转化的对照更快，叶片也更多。这些特性在 T0 和 T1 代之间是可遗传的。我们的结果表明 PtAP3 基因在植物开花和生长过程中起调节作用，并表明该基因可能是遗传修饰诱导植物早期开花的一个有趣靶标。
