Conservation and diversification of meristem maintenance mechanism in Oryza sativa:: Function of the FLORAL ORGAN NUMBER2 gene
Conservation and diversification of meristem maintenance mechanism in Oryza sativa:: Function of the FLORAL ORGAN NUMBER2 gene
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DOI：
10.1093/pcp/pcl025
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发表时间：
2006-12-01
影响因子：
4.9
通讯作者：
Hirano, Hiro-Yuki
中科院分区：
文献类型：
--
作者：
Suzaki, Takuya;Toriba, Taiyo;Hirano, Hiro-Yuki
为了阐明调控单子叶植物分生组织维持的遗传机制，我们研究了基因FLORAL ORGAN NUMBER 2（FON 2）在水稻中的功能。FON 2突变导致花分生组织扩大，导致花器官数量增加，尽管营养和花序分生组织基本正常。分子克隆显示FON 2编码一个小的分泌蛋白，含有CLE结构域，与拟南芥中的CLAVATA 3密切相关。FON 2转录本定位于水稻植株地上部分所有分生组织的顶端区域，表现出与拟南芥CLV 3相似的表达模式。FON 2的组成型表达导致花器官和花的数量减少，表明花和花序分生组织的大小都减小。FON 2的这种作用需要FON 1的功能，FON 1是CLV 1的直系同源物。FON 2的组成型表达也会导致拟南芥茎顶端分生组织的提前终止，这一表型与CLV 3的组成型表达所导致的表型相似。结合我们之前对FON 1的研究，这些结果清楚地表明，水稻中的FON 1-FON 2系统与拟南芥中的CLV信号系统相对应，并表明这些系统对干细胞身份的负调控可能主要在被子植物中的广泛植物中保守。此外，我们提出了一个模型的分生组织的维持在水稻中，包括一个独立的FON 2-FON 1的替代途径的遗传调控。
To elucidate the genetic mechanism that regulates meristem maintenance in monocots, here we have examined the function of the gene FLORAL ORGAN NUMBER2 (FON2) in Oryza sativa ( rice). Mutations in FON2 cause enlargement of the floral meristem, resulting in an increase in the number of floral organs, although the vegetative and inflorescence meristems are largely normal. Molecular cloning reveals that FON2 encodes a small secreted protein, containing a CLE domain, that is closely related to CLAVATA3 in Arabidopsis thaliana. FON2 transcripts are localized at the apical region in all meristems in the aerial parts of rice plants, showing an expression pattern similar to that of Arabidopsis CLV3. Constitutive expression of FON2 causes a reduction in the number of floral organs and flowers, suggesting that both the flower and inflorescence meristems are reduced in size. This action of FON2 requires the function of FON1, an ortholog of CLV1. Constitutive expression of FON2 also causes premature termination of the shoot apical meristem in Arabidopsis, a phenotype similar to that caused by constitutive expression of CLV3. Together with our previous study of FON1, these results clearly indicate that the FON1-FON2 system in rice corresponds to the CLV signaling system in Arabidopsis and suggest that the negative regulation of stem cell identity by these systems may be principally conserved in a wide range of plants within the Angiosperms. In addition, we propose a model of the genetic regulation of meristem maintenance in rice that includes an alternative pathway independent of FON2-FON1.