DH1, a LOB domain-like protein required for glume formation in rice
DH1, a LOB domain-like protein required for glume formation in rice
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DOI：
10.1007/s11103-007-9283-3
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发表时间：
2008-03-01
影响因子：
5.1
通讯作者：
Pan, X.
中科院分区：
文献类型：
--
作者：
Li, A.;Zhang, Y.;Pan, X.
T-DNA标签技术是一种高通量的鉴定和克隆植物功能基因的方法。本研究对4416个T-1水稻T-DNA标记株系进行了筛选，发现了一个船体退化、雌雄蕊裸露的突变体dh 1（degenerated hull 1）。dh 1穗上约60%的小花不能形成正常的内稃和外稃。相反，它们形成退化的膜状或丝状器官，并伴有浆片、雄蕊和雌蕊不同程度的缺失。使用TAIL-PCR（热不对称交错PCR）分离的T-DNA侧翼的361 bp基因组序列与突变表型共分离。Blasting和基因预测的结果表明，T-DNA插入到一个功能预测基因的启动子区，位于其转录起始位点（TSS）上游283 bp处。预测的基因编码一个LOB（侧向器官边界）结构域样蛋白。RT-PCR分析表明，目的候选基因DH 1在dh 1突变体中的转录水平显著降低。在野生型植物中，针对DH 1的RNAi可以部分地导致dh 1的突变表型。在补体实验中，DH 1也可以拯救突变表型。利用融合表达载体pDH 1：：GFP进行转化，结果表明，DH 1在腋芽、幼穗和花器官中表达，在根、叶、节和秆中不表达，在幼嫩组织中表达较强，在成熟器官中表达较弱。dh 1在相对较长的光照条件下比在较短的光照条件下表现出更高的突变表型，这意味着较短的光照诱导了功能上与DH 1冗余的基因的表达，并部分补偿了功能的丧失。首次报道了参与水稻花器官发育的LOB结构域基因。
T-DNA tagging is a high throughput strategy for identifying and cloning functional genes in plants. In this study, we screened 4416 lab-created T-1 rice T-DNA tagged lines and identified a mutant, designated dh1 (degenerated hull1), with phenotype of degenerated hull and naked pistils and stamens. Approximately 60% florets on the dh1 panicle defected in forming normal palea and lemma. Instead, they formed degenerative velum-like or filamentous organs accompanying with the lack of lodicules, stamens and pistils at different degree. A 361 bp of genomic sequence flanking the T-DNA isolated using TAIL-PCR (Thermal asymmetric interlaced PCR) co-segregated with the mutation phenotype. Results of blastn and gene prediction revealed the T-DNA inserted into the promoter region of a function-predicted gene at 283 bp upstream of its transcription start site (TSS). The predicted gene encoded a LOB (Lateral Organ Boundaries) domain-like protein. RT-PCR analyses indicated the transcription level of target candidate gene, DH1, decreased significantly in dh1 mutant. RNAi aimed at DH1 in wild type plants could partially result in the mutation phenotype of dh1. DH1 could also rescue the mutation phenotype in the complement experiment. The result of transformation by a fused expression vector, pDH1::GFP, revealed that DH1 had the keen spatial and temporal characteristics of expressing at axillary bud, young panicle and floral organs but not at root, leaf, node and culm, and strongly expressing at young tissues but weakly at mature organs. The dh1 presented severer mutation phenotype under relatively longer daylight than under shorter daylight implied that shorter daylight induced the expression of gene(s) redundant to DH1 in function and partially compensated for the loss-of-function. It is the first time to report the LOB-domain gene participating in the development of floral organs in rice.