Functional analysis of the LACERATA gene of Arabidopsis provides evidence for different robes of fatty acid omega-hydroxylation in development

We describe lacerata (Icr) mutants of Arabidopsis, which display various de velopmental abnormalities, including postgenital organ fusions, and report cloning of the LCR gene by using the maize transposon Enhancer/Suppressor-m utator (En/Spm). The pleiotropic mutant phenotype could be rescued by genet ic complementation of Icr mutants with the wild-type LCR gene. The LCR gene encodes a cytochrome P450 monooxygenase, CYP86A8, which catalyzes omega -h ydroxylation of fatty acids ranging from C12 to C18:1, as demonstrated by e xpression of the gene in yeast. Although palmitic and oleic acids were effi cient substrates for LCR, 9,10-epoxystearate was not metabolized. Taken tog ether with previous studies, our findings indicate that LCR-dependent omega -hydroxylation of fatty acids could be implicated in the biosynthesis of c utin in the epidermis and in preventing postgenital organ fusions. Striking ly, the same pathway seems to control trichome differentiation, the establi shment of apical dominance, and senescence in plants.