Os09g0502100
The rice Os09g0502100 was reported as lagging growth and development 1 (lgd1)[1] is screened from the Taiwan Rice Insertional Mutant (TRIM) database [2] ,showing multiple defects, including reduced number of tillers, plant height and grain yield, and abnormal panicle morphology.
Contents
Annotated Information
Figure 1. Detailed phenotypic analyses of lgd1 plants(from reference) [1].
Figure 2. tiller bud and internodes of lgd1 plants(from reference) [1].
Function
The precise function of LGD1 are still unclear [1] :
- The LGD1 C terminus contains three features: (i) a vWA domain, which is a well-characterized domain present indifferent proteins with multiple functions in animal systems; (ii) a coiled-coil domain; and (iii) a bipartite NLS.
- The RNA binding assay verified that the C-terminus of LGD1 have the RNA binding activity through the dimeric forms.
- Further study on the role of LGD1 as an RNA binding protein, as well as its probable functions intranscription, pre-mRNA splicing and polyadenylation to RNA modification, transport, localization.
Mutation
The phenotype of lgd1 [1]:
- The homozygous mutant conferred slow growth at the seedling stage, reduced plant height,delayed flowering and maturity, produced fewer tillers during the early phases and abnormal panicle morphology(Figure 1a–c). In particular, the difference in plant height is significant during the vegetative stage, but this difference ceases towards maturity.After the ripening stage, mature panicles of wild-type plants showed ‘compact and droopy’ architecture (Figure 1d), but lgd1 panicles were ‘open and erect’, with primary branches growing across the main rachis (Figure 1e).
- The delayed growth and the reduced number of tillers in lgd1 were the result of delayed tiller bud formation at the four-leaf stage (Figure 2a) and the presence of fewer unelongated internodes, from which tiller buds usually arise (Figure 2b).
Expression
LGD1 expression patterns[1]:
Figure 3. Mapping of multiple transcripts(from reference) [1].
- LGD1 encodes multiple transcripts using different transcription start sites (TSSs) in multiple promoter regions with unique spatiotemporal expression profiles.At least six LGD1 transcript variants were found and named LGD1.1–LGD1.6 according to their TSS positions and sizes (Figure 3).
- LGD1.1 was expressed in all tissues examined except for leaf blade, whereas LGD1.2 was highly expressed only in the panicle and spikelet branches, and LGD1.3 showed patterns similar to LGD1.2 but included in the node. Transcript LGD1.4, however, was expressed in all tissues except root and leaf blade, the two small transcripts LGD1.5 and LGD1.6 were the most abundant, and were found in thepanicle (P), node (N) and leaf sheath (LS), where obvious phenotypes were observed in lgd1.
Figure 4. Phylogenetic tree of plant-specific LGD1 proteins(from reference) [1].
Evolution
Evolutionary relationship of LGD1 with its orthologs[1]:
- LGD1is present as a single copy gene in the rice genome.
- The phylogenetic tree of evolutionary relationship of LGD1 with its orthologs in other plants was drawn by BlastP of the protein sequences. The tree analysis shows that Brachypodium, barley and rice are positioned in one clade. Orthologs from maize and sorghum, however, are in the other clade. Other dicots, namely grapes, castor and Populus, showed weak homology to LGD1.
Knowledge Extension
- Semi-dwarf cultivars showing reduced plant height are more resistant to wind and flood damage during the monsoon season, and decreased plant height significantly increases the harvest index. The plant hormones gibberellin [3] and brassinosteroid[4] play essential roles in determining semi-dwarfism in rice.
- Tiller initiation and subsequent outgrowth are regulated by both genetic and environmental signals, The mutant of Monoculm 1 (MOC1), a gene encoding a GRAS family transcription factor, conferred a single culm and suggested that it might function as a critical switch during axillary meristem development[5]. The rice mutant of floral organ number 1 (FON1), encoding a receptor-like kinase, caused altered vegetative growth, reduced tiller number and semi-dwarfism[6]. Another rice mutant of fine culm 1(FC1) , functions as a negative regulator of axillary bud growth[7].
Labs working on this gene
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei, Taiwan
- Molecular and Biological Agricultural Sciences, Taiwan International Graduate Program, National Chung-Hsing University –Academia Sinica, Taipei, Taiwan
- Graduate Institute of Biotechnology, National Chung-Hsing University, Taichung, Taiwan
- Biotechnology Center, National Chung-Hsing University, Taichung, Taiwan
References
- ↑ 1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 Saminathan Thangasamy, Pei-Wei Chen1, Ming-Hsing Lai, Jychian Chenand Guang-Yuh Jauh (2012) Rice LGD1 containing RNA binding activity affects growth and development through alternative promoters. The Plant Journal, 71, 288–302.
- ↑ Hsing, Y.I., Chern, C.G., Fan, M.J. et al. (2007) A rice gene activation/knockout mutant resource for high throughput functional genomics. Plant Mol. Biol. 63, 351–364.
- ↑ Sasaki, A., Ashikari, M., Ueguchi-Tanaka, M. et al. (2002) Green revolution: a mutant gibberellin-synthesis gene in rice. Nature, 416, 701–702.
- ↑ Yamamuro, C., Ihara, Y., Wu, X., Noguchi, T., Fujioka, S., Takatsuto, S.,Ashikari, M., Kitano, H. and Matsuoka, M. (2000) Loss of function of a rice brassinosteroid insensitive1 homolog prevents internode elongation and bending of the lamina joint. Plant Cell, 12, 1591–1606.
- ↑ Li, X., Qian, Q., Fu, Z. et al. (2003) Control of tillering in rice. Nature, 422, 618–621.
- ↑ Moon, S., Jung, K.H., Lee, D.E., Lee, D.Y., Lee, J., An, K., Kang, H.G. and An, G.(2006) The rice FON1 gene controls vegetative and reproductive develop- ment by regulating shoot apical meristem size. Mol. Cells, 21, 147–152.
- ↑ Takeda, T., Suwa, Y., Suzuki,M., Kitano, H., Ueguchi-Tanaka,M., Ashikari,M.,Matsuoka, M. and Ueguchi, C. (2003) The OsTB1 gene negatively regulates lateral branching in rice. Plant J. 33, 513–520.
