Os06g0610350
The rice Os06g0610350 was reported as OsMOC1 [1] in 2003 by researchers from Chinese Academy of Sciences.
Contents
Annotated Information
Function
- OsMOC1 is a gene that is important in the control of rice tillering. The results from scientists strongly suggest that OsMOC1 has a critical role in the initiation of axillary meristems and formation of tiller buds. As a key regulator of tillering, OsMOC1 (and its homologues in other cereals) could make a significant contribution to future improvement of these crops.
Gene characterization
- The Os06g0610350 (OsMOC1) locus was mapped primarily to the long arm of chromosome 6 of O. sativa between markers R1559 and S1437, and was subsequently fine-mapped to a 20-kilobase (kb) region using newly developed molecular markers. Annotation of the 20-kb sequence identified an open reading frame (ORF) that encodes a protein highly homologous (44% identity) to the tomato LATERAL SUPPRESSOR (LS).
- In tomato, loss-of-function mutation in LS causes abranchless phenotype owing to a failure in axillary meristeminitiation. This result suggests that the rice ORF with homologyto the tomato LS is very probably the MOC1 gene.
Figure 1. MOC1 was mapped within the BAC clone4cA11. BAC, bacteria artificial chromosome; cM, centimorgans; YAC, yeast artificial chromosome. [1].
Mutation
- In the seedling stage, no obvious morphological difference could be observed between OsMOC1 Mutation plants and wild-type plants. However, during the tillering stage, beginning from the fourth complete leaf formation, tillers emerged from sheaths of the subtending leaves in wild-type plants, but no tillers arose from leaf axils of moc1 plants
- Up to the heading stage, wild-type rice plants produced not only primary tillers on the main culm, but also secondary ones on the primary tiller culms. In moc1 Mutation plants mutants, however, no primary tillers other than a main culm could be observed, and therefore no secondary tillers were seen either.
- Similarly, OsMOC1 Mutation plants panicles also produced much fewer rachis-branches and spikelets than did wild-type plants (Fig. 1g, h). In contrast to phenotypic alterations observed in aerial organs, roots appear to be unaffected in moc1 Mutation plants plants.
Figure 1. Phenotype and complementation of the Osmoc1 mutant.(from reference) [1].
Expression Pattern
- RNA in situ hybridization showed that OsMOC1 expression could be detected in a small number of epidermal or subepidermal cells at the leaf axils, before any visible morphological changes.
- Subsequently, OsMOC1 expression was observed in the small protuberance and axillarymeristem, and extended to the entire tiller buds including the axillary leaf primordia and young leaves.
- In contrast to high-level expression in the axillary meristems, OsMOC1 expression was undetectable in the shoot apical meristem (SAM).
Homologues
- Homology analysis demonstrated that MOC1 is a member of the plant-specific GRAS family proteins 6 , which contain several subfamilies including MOC1 and LS for axillary branching 5 , SCR and SHR for root radial patterning 7,8 , PAT1 for light signalling 9 , and GAI, RGA, SLR1, RHT1 and D8 for gibberellin-acids signalling and plant height 10–13 . The GRAS family proteins are characterized by a conserved VHIID motif flanked by two leucine heptad repeats, a conserved C-terminal region, and an N-terminal region varying in length and sequence (Fig. 2c) that may confer specificity.
- In addition, the MOC1 C terminus also contains an SH2-like domain 14 followed by a conserved tyrosine, a potential site for phosphorylation.
Subcellular Localization
Figure 1. Subcellular Localization analysis of MOC1. Osmoc1.(from reference) [1].
- The MOC1–GFP fusion protein is nuclear-localized. The figure shows MOC1–GFP green fluorescence in the nucleus
Knowledge Extension
Tillering in rice (Oryza sativa L.) is an important agronomic trait for grain production, and also a model system for the study of branching in monocotyledonous plants. Rice tiller is a specialized grain-bearing branch that is formed on the unelongated basal internode and grows independently of the mother stem (culm) by means of its own adventitious roots [1] . Rice tillering occurs in a two-stage process: the formation of an axillary bud at each leaf axil and its subsequent outgrowth.[2]
Labs working on this gene
- Institute of Genetics and Developmental Biology, Chinese Academy of Sciences,Beijing 100101, China
- China National Rice Research Institute, Chinese Academy of AgriculturalSciences, Hangzhou 310006, Zhejiang, China
- China Agricultural University, Beijing 100094, China
- Institute of Plant Physiology and Ecology, Chinese Academy of Sciences,Shanghai 200032, China
- National Center for Gene Research, Chinese Academy of Sciences, Shanghai200233, China
References
- ↑ 1.0 1.1 1.2 1.3 1.4 Li, X., Qian, Q., Fu, Z., Wang, Y., Xiong, G., Zeng, D., Wang, X., Liu, X., Teng, S., Hiroshi, F. and Yuan, M., 2003. Control of tillering in rice. Nature, 422(6932), pp.618-621.
- ↑ Hanada, K. in Science of the Rice Plant Vol. 1 Morphology (eds Matsuo, T. & Hoshikawa, K.) 222–258 (Food and Agriculture Policy Research Center, Tokyo, 1993).
