The SCARFACE gene is required for cotyledon and leaf vein patterning

Mechanisms controlling vein patterning are poorly understood. We describe a recessive Arabidopsis mutant, scarface (sfc), which maps to chromosome 5. sfc mutants have vein pattern defects in cotyledons, leaves, sepals and petals. In contrast to the wild type, in which these organs all have linear veins that are continuous with at least one other vein, in sfc mutants these organs9 secondary and tertiary veins are largely replaced by small segments of discontinuous veins, which we call vascular islands. Patterning defects are manifest in cotyledon provascular tissue, suggesting that the patterning defect occurs early in organogenesis. sfc mutants have exaggerated responses to exogenous auxin. Analysis of monopteros (mp(T370)) sfc-1 double mutants suggested that SFC has partially overlapping functions with MP in patterning of both primary and secondary veins.