Two Coordinately Regulated Homologs of FLOWERING LOCUS T Are Involved in the Control of Photoperiodic Flowering in Soybean
Two Coordinately Regulated Homologs of FLOWERING LOCUS T Are Involved in the Control of Photoperiodic Flowering in Soybean
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DOI：
10.1104/pp.110.160796
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发表时间：
2010-11-01
期刊：
影响因子：
7.4
通讯作者：
Abe, Jun
中科院分区：
文献类型：
--
作者：
Kong, Fanjiang;Liu, Baohui;Abe, Jun
开花位点T（开花位点T）是拟南芥（Arabidopsis thaliana）中一个关键的开花整合子，在许多植物物种中具有同源基因，无论光周期响应类型如何，都可以编码花原。在大豆（Glycine max）这一古多倍体物种中，我们鉴定出了10个FT同源基因，它们被排列成5对连锁基因，位于不同的同源染色体区域。FT的两个同源基因GmFT2a和GmFT5a在短日（SD）条件下（诱导大豆开花）表达量高，且呈日表达模式，黎明后4小时表达量最高。在长日（LD）条件下，GmFT2a和GmFT5a的表达下调，且不遵循日模式。LD处理下开花启动时间远长于SD处理，且LD处理下只有GmFT5a转录本发育较晚。拟南芥异位表达分析证实，GmFT2a和GmFT5a与拟南芥FT具有相同的功能，但GmFT5a的作用更为突出。一个含有两个光敏色素A （PHYTOCHROME A， PHYA）基因的双突变大豆品系在LD下表达了高水平的GmFT2a和GmFT5a，并且在LD下的开花时间略早于SD下的野生型。GmFT2a和GmFT5a的表达水平受phya介导的光周期调控系统的调控，GmFT5a的表达也受LD中不依赖光周期的系统的调控。综上所述，我们的研究结果表明，GmFT2a和GmFT5a协调控制开花，使大豆能够适应广泛的光周期环境。
FLOWERING LOCUS T (FT) is a key flowering integrator in Arabidopsis (Arabidopsis thaliana), with homologs that encode florigens in many plant species regardless of the type of photoperiodic response. We identified 10 FT homologs, which were arranged as five pairs of linked genes in different homoeologous chromosomal regions, in soybean (Glycine max), a paleopolyploid species. Two of the FT homologs, GmFT2a and GmFT5a, were highly up-regulated under short-day (SD) conditions (inductive for flowering in soybean) and had diurnal expression patterns with the highest expression 4 h after dawn. Under long-day (LD) conditions, expression of GmFT2a and GmFT5a was down-regulated and did not follow a diurnal pattern. Flowering took much longer to initiate under LD than under SD, and only the GmFT5a transcript accumulated late in development under LD. Ectopic expression analysis in Arabidopsis confirmed that both GmFT2a and GmFT5a had the same function as Arabidopsis FT, but the effect of GmFT5a was more prominent. A double-mutant soybean line for two PHYTOCHROME A (PHYA) genes expressed high levels of GmFT2a and GmFT5a under LD, and it flowered slightly earlier under LD than the wild type grown under SD. The expression levels of GmFT2a and GmFT5a were regulated by the PHYA-mediated photoperiodic regulation system, and the GmFT5a expression was also regulated by a photoperiod-independent system in LD. Taken together, our results suggest that GmFT2a and GmFT5a coordinately control flowering and enable the adaptation of soybean to a wide range of photoperiodic environments.