A rice dihydrosphingosine C4 hydroxylase (DSH1) gene, which is abundantly expressed in the stigmas, vascular cells and apical meristem, may be involved in fertility
A rice dihydrosphingosine C4 hydroxylase (DSH1) gene, which is abundantly expressed in the stigmas, vascular cells and apical meristem, may be involved in fertility
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DOI：
10.1093/pcp/pcm084
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发表时间：
2007-08-01
影响因子：
4.9
通讯作者：
Shimada, Hiroaki
中科院分区：
文献类型：
--
作者：
Imamura, Tomohiro;Kusano, Hiroaki;Shimada, Hiroaki
二氢鞘氨醇C4羟基酶是植物和酵母中鞘糖脂的主要成分之一，是植鞘糖苷生物合成过程中的关键酶。水稻基因组包含五个二氢鞘氨醇C4羟基酶DSHI-DSH5的同源基因，其基因产物与酵母对应的SUR2具有高度的同源性。其中检测到DSH1、DSH2和DSH4的表达，DSH1和DSH4与酵母SUR2突变互补。DSH1基因在维管束和顶端分生组织中特异而丰富地表达。特别是在花的柱头中检测到了很强的表达。通过反义基因或RNA干扰(RNAi)抑制DSH1的表达，导致育性严重下降。在DSH1表达被抑制的转化子中，DSH2在叶片中的表达显著增加，而在雌蕊中的表达没有明显增加，这表明DSH1和DSH2的表达具有组织特异性。我们的结果表明，DSH1的产物可能参与植物的生存或生殖过程，而不育的表型显然是由于DSH1在柱头中失去功能所致。研究还表明，DSH1基因的组织特异性表达存在复杂的机制。
Dihydrosphingosine C4 hydroxylase is a key enzyme in the biosynthesis of phytosphingosine, a major constituent of sphingolipids in plants and yeasts. The rice genome contains five homologue genes for dihydrosphingosine C4 hydroxylase, DSHI-DSH5, whose gene products show high degrees of homology to the yeast counterpart, SUR2. Among them, expression of DSH1, DSH2 and DSH4 was detected, and DSH1 and DSH4 complement the yeast sur2 mutation. The DSH1 gene was specifically and abundantly expressed in vascular bundles and apical meristems. In particular, very strong expression was detected in the stigmas of flowers. Repression of DSH1 expression by the antisense gene or RNA interference (RNAi) resulted in a severe reduction of fertility. In the transformants in which DSH1 expression was suppressed, significantly increased expression of DSH2 was found in leaves but not in pistils, suggesting that there was tissue-specific correlation between DSH1 and DSH2 expression. Our results indicate that the product of DSH1 may be involved in plant viability or reproductive processes, and that the phenotype of sterility is apparently caused by loss of function of DSH1 in the stigma. It is also suggested that there is a complex mechanism controlling the tissue-specific expression of the DSH1 gene.