Abstract
Linolenic acid composition of lipids (LAC) suppresses flowering in Arabidopsis thaliana. Compared to 22°C, a low temperature (15°C) increases LAC and retards flowering in wild-type plants (Col). Since the floral retardation by low temperatures was reduced by triple mutations in FAD3, FAD7 and FAD8 encoding enzyme synthesizing LA, it is considered to be attributed to LAC. Here we investigated the relationship between LAC-dependent flowering and AP1 function. A decrease in contents followed AP1 expression when Col was grown at 22°C. The triple mutant plants showed earlier expression of AP1, while 35S-FAD3 plants showed delayed expression of AP1 with late flowering. The early-flowering phenotype in 35S-AP1 plants was suppressed by low temperatures or a cross with 35S-FAD3 plants. Taken together, LAC regulates AP1 at the levels of transcription and protein.
