Abstract
Phosphatidylcholine (PC) turnover is known as an adaptive response of eukaryotic cell to abiotic stress. In plants, PC is the major phospholipid constitutes of cell membrane and synthesized via CDP-choline pathway. The first step is catalyzed by choline kinase (CK). We obtained Arabidopsis T-DNA insertion lines of CK isogenes, and found that ck2 (At1g74320) mutant showed late-flowering. Under control condition, PC content in leaves of ck2 mutant was decreased about 18% compared to WT. Germination rate of ck2 and ck3 (At4g09760) mutants in medium supplemented with NaCl were decreased compared to WT. When seedlings were grown with NaCl after germination, ck2 and ck3 mutant showed significantly decreased biomass production. In Arabidopsis, CK2 is thought to be involved in PC production of leaves and plant growth, and the function of CK3 is important for maintaining NaCl tolerance of plants. Now, we investigate the CK activity in ck k/o and antisense-knockdown plants under salt stress.
