title: Identification and characterization of SHORTENED UPPERMOST INTERNODE 1, a gene negatively regulating uppermost internode elongation in rice.
abstract: In rice, the elongated internodes are derived from the vegetative shoot apical meristem (SAM), and the transition of the SAM from the vegetative to the reproductive stage induces internode elongation. In this study, we characterize two shortened uppermost internode mutants (sui1-1 and sui1-2). During the seedling and tillering stages, sui1 plants are morphologically similar to wild-type plants. However, at the heading stage, the sui1-1 mutant exhibits a shortened uppermost internode and a partly sheathed panicle, and the sui1-2 mutant shows an extremely shortened uppermost internode and a fully sheathed panicle. Gibberellin treatment results in elongation of every internode, but the shortened uppermost internode phenotype remains unaltered. Microscopic analysis indicates that cell length of sui1-1 uppermost internode exhibits decreased. Map-based cloning revealed that SUI1 is located on Chromosome 1, and encodes a putative phosphatidyl serine synthase (PSS) family protein. Searches for matches in protein databases showed that OsSUI1 contains the InterPro domain IPR004277, which is conserved in both animal and plant kingdoms. Introduction of a wild-type SUI1 gene fully rescued the mutant phenotype of sui1-1 and sui1-2, confirming the identity of the cloned gene. Consistent with these results, the SUI1-RNAi transgenic plants displayed decreased elongation of the uppermost internode. Our results suggest that SUI1 plays an important role in regulating uppermost internode length by decreasing longitudinal cell length in rice.
authors.affiliation: State Key Laboratory of Rice Biology, China National Rice Research Institute, Chinese Academy of Agricultural Sciences, 359 Tiyuchang Road, Hangzhou, China.
authors.forename: Li
authors.initials: L
authors.lastname: Zhu
authors.forename: Jiang
authors.initials: J
authors.lastname: Hu
authors.forename: Keming
authors.initials: K
authors.lastname: Zhu
authors.forename: Yunxia
authors.initials: Y
authors.lastname: Fang
authors.forename: Zhenyu
authors.initials: Z
authors.lastname: Gao
authors.forename: Yinghong
authors.initials: Y
authors.lastname: He
authors.forename: Guangheng
authors.initials: G
authors.lastname: Zhang
authors.forename: Longbiao
authors.initials: L
authors.lastname: Guo
authors.forename: Dali
authors.initials: D
authors.lastname: Zeng
authors.forename: Guojun
authors.initials: G
authors.lastname: Dong
authors.forename: Meixian
authors.initials: M
authors.lastname: Yan
authors.forename: Jian
authors.initials: J
authors.lastname: Liu
authors.forename: Qian
authors.initials: Q
authors.lastname: Qian
mesh_terms: D002874:Chromosome Mapping; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000737:chemistry; D018744:DNA, Plant / Q000737:chemistry; D018519:Meristem / Q000235:genetics / Q000378:metabolism; D009154:Mutation; D012275:Oryza / Q000235:genetics* / Q000378:metabolism; D010802:Phylogeny; D010940:Plant Proteins / Q000235:genetics* / Q000378:metabolism / Q000502:physiology; D034622:RNA Interference; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA
chemical_list: D018076:DNA, Complementary; D018744:DNA, Plant; D010940:Plant Proteins