The Soybean Stem Growth Habit Gene Dt1 Is an Ortholog of Arabidopsis TERMINAL FLOWER1
The Soybean Stem Growth Habit Gene Dt1 Is an Ortholog of Arabidopsis TERMINAL FLOWER1
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大豆茎生长习性基因 Dt1 是拟南芥 TERMINAL FLOWER1 的直系同源基因
DOI：
10.1104/pp.109.150607
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发表时间：
2010-05-01
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：
Liu, Baohui;Watanabe, Satoshi;Abe, Jun
经典遗传分析表明，大豆的有限生长习性受有限生长茎（Dt1）基因座上的一个隐性等位基因控制。为了解析决定性习性的分子基础，我们从大豆基因组中分离了豌豆（Pisum sativum）TERMINAL FLOWER1a的两个直向同源物GmTFL1a和GmTFL1b。定位分析表明，GmTFL1b是Dt1的候选者。尽管它们的氨基酸高度一致，但这两个基因具有不同的转录谱。GmTFL1b在根和茎的顶端分生组织中表达，而GmTFL1a主要在未成熟种子中表达。GmTFL1b转录物在确定系和不确定系的早期营养生长期间在SAM中积累，但此后在确定系中突然丢失。来自不确定系的GmTFL1b基因组区域的引入补充了确定系中的茎生长习性：产生更多的节，并且推迟了末端总状花序的开花。Dt1和GmTFL1b之间的同一性也被证实与病毒诱导的基因沉默实验。综上所述，我们的数据表明Dt1编码GmTFL1b蛋白，并且茎生长习性由该基因的变异决定。dt1等位基因可能通过伴随着成花诱导的GmTFL1b表达的早期损失来调节确定的习性，尽管它在成花的非诱导期正常地起作用。16个品种的DNA多态性与茎生长习性的关联检验表明，第4外显子的一个氨基酸替换决定了成花诱导后SAM的命运。
Classical genetic analysis has revealed that the determinate habit of soybean (Glycine max) is controlled by a recessive allele at the determinate stem (Dt1) locus. To dissect the molecular basis of the determinate habit, we isolated two orthologs of pea (Pisum sativum) TERMINAL FLOWER1a, GmTFL1a and GmTFL1b, from the soybean genome. Mapping analysis indicated that GmTFL1b is a candidate for Dt1. Despite their high amino acid identity, the two genes had different transcriptional profiles. GmTFL1b was expressed in the root and shoot apical meristems (SAMs), whereas GmTFL1a was mainly expressed in immature seed. The GmTFL1b transcript accumulated in the SAMs during early vegetative growth in both the determinate and indeterminate lines but thereafter was abruptly lost in the determinate line. Introduction of the genomic region of GmTFL1b from the indeterminate line complemented the stem growth habit in the determinate line: more nodes were produced, and flowering in the terminal raceme was delayed. The identity between Dt1 and GmTFL1b was also confirmed with a virus-induced gene silencing experiment. Taken together, our data suggest that Dt1 encodes the GmTFL1b protein and that the stem growth habit is determined by the variation of this gene. The dt1 allele may condition the determinate habit via the earlier loss in GmTFL1b expression concomitant with floral induction, although it functions normally under the noninductive phase of flowering. An association test of DNA polymorphisms with the stem growth habit among 16 cultivars suggested that a single amino acid substitution in exon 4 determines the fate of the SAM after floral induction.