Os05g0595300
The rice NRR(nutrition response and root growth) gene responds to the deficiency of macronutrients and affects rice root growth.
Contents
Annotated Information
Function
NRR gene is a single-copy gene located on chromosome 5, which contains four exons and three introns embedded in the protein-coding region[1].NRR encodes two kinds of transcripts that have the same 5'end but differ in the location of their 3'ends: the longer transcripts terminate at the 3'UTR within the fourth exon, whereas the 3'ends of the shorter transcripts are situated in the second intron at a region of 165–204 bp from the donor splicing site. We have designated the longer and shorter transcripts as NRRa and NRRb, respectively. NRRa is composed of all the four exons and encodes a protein (NRRa) with 308-aa residues. NRRb contains only the first two exons and produces a 223-aa protein (NRRb), with the last residue valine derived from the first three nucleotides of intron 2.
NRR plays an important role in the responses of rice root architecture to nutrients.Compared to the previously reported genes, such as LPI[2] and OsPHR2[3], with response only to P deprivation, the transcripts of NRRa and NRRb act as new components to regulate the rice root architecture in response to N or P nutrient starvation.
NRR responded to multi-nutrient deprivation stress. Further investigation of the down stream genes regulated by NRR will facilitate the understanding of the molecular mechanism of root development controlled by NRRin response to macronutrient.
GO assignment(s): GO:0048364
Expression
NRR expresses constitutively in rice tissues of root, stem, leaf,and panicle, and its expression level in seedling roots was enhanced under N, P, or NPK combined nutrient starvation.
Overexpressing or RNAi silencing of NRR in rice showed that silencing the expression of NRRa and/or NRRb led to the insensitivity of the -P starvation response in rice seedling root growth, and displayed extra elongation of primary and adventitious roots compared to controls. Conversely, overexpression of NRRa in rice caused the inhibited root growth under regular growth conditions.These suggested that the expression of both NRRa and NRRb are important components of the response to the deprivation of N and P, acting as repressors of root growth.
Additionally, the transcript level of NRRa was significantly higher than that of NRRb in all detected organs. It is possible that the splicing of NRRb is an evolutionary vestige, while maintaining a function of root growth regulation. This function is evidenced by the present study in which NRRb knock-down plants displayed longer root growth compared to the wild-type plants.
Evolution
No homologous protein was identified in rice following a BLAST search of the NCBI database with the deduced amino acid sequence of NRRa. However, NRRa-like proteins were found in Zea mays, Sorghum bicolor, Ricinus communis, Glycine max, Vitis vinifera, Medicago truncatula, Populus trichocarpa, Arabidopsis thaliana, and Physcomitrella. Those from monocotyledonous plants Zea mays and Sorghum bicolor shared sequence identities of 57.0–68.9% to NRRa, but those from dicotyledonous plants exhibited identities below 50%.
Amino acid sequence alignments of NRRa and NRRb with these homologous proteins showed that the conserved sequences were mainly located on five regions corresponding to the 55–80, 114–143, 178–189, 214–224, and 253–300-aa residues of NRRa, respectively.
Labs working on this gene
- State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China
- National Plant Gene Research Center, Beijing 100101, China
- Graduate School of the Chinese Academy of Sciences, Beijing 100039, China
- Department of Ornamental Horticulture and Landscape Architecture, China Agricultural University, Beijing 100193, China
- Current address: School of Life Science and Technology, University of Electronic Science and Technology of China, Chengdu 610054, China
- State Key Laboratory of Rice Biology, National Rice Research Institute, Hangzhou 310006 China
References
- ↑ 1.0 1.1 1.2 Zhang, Yu-Man, et al.A novel rice gene, NRR responds to macronutrient deficiency and regulates root growth. Molecular plant 5.1 (2012): 63-72.
- ↑ Sa´nchez-Caldero´n, L., Lo´pez-Bucio, J., Chaco´n-Lo´pez, A., Gutie´rrezOrtega, A., Herna´ndez-Abreu, E., and Herrera-Estrella, L.(2006). Characterization of low phosphorus insensitive mutants reveals a crosstalk between low phosphorus-induced determinate root development and the activation of genes involved in the adaptation of Arabidopsis to phosphorus deficiency. Plant Physiol.140,879–889.
- ↑ Zhou, J., Jiao, F.C., Wu, Z., Li, Y., Wang, X., He, X., Zhong, W., and Wu, P.(2008).OsPHR2is involved in phosphate-starvation signaling and excessive phosphate accumulation in shoots of plants.Plant Physiol.146,1673–1686.
