Abstract
Carbon and nitrogen availavility is one of the most important factor regulating plant development. To utilize limited resource of carbon and nitrogen efficiently, plants enable to sense and respond to balance of carbon (C) and nitrogen (N) metabolites, called C/N response.
To clarify mechanisms involved in C/N response in higher plants, we had isolated and characterized a mutant named ssv1-D (super survival 1-D) which was resistant to severe C/N nutrition stress (high-sugar and low-nitrogen) conditions. The mutant was due to overexpression of the SSV1 gene and the expressions of C and/or N-regulated genes were not regulated precisely in the ssv1-D mutant. SSV1 loss of function mutant was hypersensitive to change of C/N conditions. The SSV1 gene encodes RING type ubiquitin ligase (E3) and the translated protein showed E3 activity in vitro. These results suggest that the SSV1 regulates C/N response via ubiquitin-26S proteasome system in higher plants.
