Abstract:

Cryptochromes are flavoproteins that share similarity with the sequence of amino acids in DNA photolyase but lack photolyase activity. Among members of cryptochromes gene family in Arabidopsis thaliana, cryptochrome1 (CRY1) and CRY2 primarily mediate blue light inhibition of hypocotyl elongation and photoperiodic promotion of floral initiation, respectively, although their functions do overlap. The cry1cry2 double mutant flowered later than wild-type under long day conditions. Through activation tagging, we identified an early flowering mutant called scc17-D (suppressor of cry1cry2#17-Dominant). TAIL-PCR results showed that a T-DNA insertion located between At1g25440 and At1g25450 in the first chromosome is responsible for the scc17-D  mutant. The scc17-D  mutant displayed dwarfism, reduction in leaf size, reduced length of siliques, and the altered shape of cotyledon pavement cells.

Key words: Arabidopsis thaliana, cryptochrome, photoperiod, activation tagging, flowering

摘要：

隐花色素（cryptochrome，简称CRY）是与DNA光解酶氨基酸序列高度同源的黄素蛋白，但不具有光解酶活性。拟南芥的隐花色素家族中隐花色素1（CRY1）主要抑制下胚轴伸长，隐花色素2（CRY2）主要调节光周期开花，并且这两个光受体具有部分重叠的功能。cry1cry2双突变体在长日条件下比野生型晚开花。采用激活标签的方法，在cry1cry2双突变体背景下筛选到一个早开花突变体scc17-D (suppressor of cry1cry2#17-Dominant)。TAIL-PCR结果表明，scc17-D突变体的T-DNA插入在第一条染色体上的At1g25440和At1g25450两个基因之间。scc17-D突变体表现出植株矮化、叶片变小、果荚变小和子叶表皮细胞形状发生改变等性状。

关键词: 拟南芥；隐花色素；光周期；激活标签；开花