Os01g0197700
Gn1a, is a gene for cytokinin oxidase/dehydrogenase (OsCKX2). Reduced expression of OsCKX2 causes cytokinin accumulation in inflorescence meristems and increases the number of reproductive organs, resulting in enhanced grain yield.
Contents
Annotated Information
Function
Expression level of OsCKX2 can influence the amount of phytohormone cytokinin,Reduced expression of OsCKX2 causes cytokinin accumulation in inflorescence meristems and increases the number of reproductive organs, resulting in enhanced grain yield.Transgenic plants carrying two copies of the sense strand of OsCKX2 that was highly expressed showed reduced grain numbers compared to TC65. However, transgenic plants with antisense strands of OsCKX2 that had reduced levels of expression developed higher grain numbers. OsCKX2 reduce CKX activity in Habataki, NIL-Gn1a, and 5150, and the increased production of CK conjugates to reduce the overall CK activity .
Protein Structure
The OsCKX2 of Koshihikari and Habataki consist of four exons and three introns and encode proteins of 565 or 563 amino acids, respectively. the region between 74 – 255 is FAD-binding PCMH-type domian. it has UDP-N-acetylmuramate dehydrogenase activity, cytokinin dehydrogenase activity and flavin adenine dinucleotide binding.[2]
Expression
transgenic rice harboring an OsCKX2 promoter::β-glucuronidase (GUS) construct. GUS expression was observed mainly in the vascular tissue in developing culms, inflorescence meristems, and young flowers in the T2 generation of transgenic plants . The expression of OsCKX2 in inflorescence meristems might regulate the CK level to control flower number. CK is known to be translocated acropetally via the xylem and systemically via the phloem . The high levels of expression in these tissues suggest that OsCKX2 plays a role in regulating CK levels in the vascular system of developing culms, where CK is transported to the inflorescence meristems[1]. The expression of OsCKX2 will directly influence the amount of cytokinin oxidase/dehydrogenase which degrades the phytohormone cytokinin, so the expression level of OsCKX2 will directly affect the Rice Grain Production by causeing cytokinin accumulation in inflorescence meristems and increases the number of reproductive organs.The expression of OsCKX2 in inflorescence meristems might regulate the CK level to control flower number. CK is known to be translocated acropetally via the xylem and systemically via the phloem (35). The high levels of expression in these tissues suggest that OsCKX2 plays a role in regulating CK levels in the vascular system of developing culms, where CK is transported to the inflorescence meristems.
Evolution
Phylogenetic relationship of CKX proteins in rice and Arabidopsis.[1]
Labs working on this gene
Please input related labs here.
- Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya 464-8601, Japan
- Plant Science Center, RIKEN, Yokohama 230-0045, Japan
References
- ↑ 1.0 1.1 1.2 Ashikari, M., Sakakibara, H., Lin, S., Yamamoto, T., Takashi, T., Nishimura, A., ... & Matsuoka, M. (2005). Cytokinin oxidase regulates rice grain production. Science, 309(5735), 741-745.
- ↑ http://www.uniprot.org/uniprot/Q4ADV8
- ↑ Cite error: Invalid
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- ↑ Functional Identification of OsHk6 as a Homotypic Cytokinin Receptor in Rice with Preferential Affinity for iP.
