Abstract
Arabidopsis inflorescence stems elongate rapidly and straightly. We have isolated fiz1 and fiz2 mutants that show frizzy or curling inflorescence stems and pedicels in Arabidopsis. Cell elongation of shoot, etiolated hypocotyl and root was inhibited in these mutants. Moreover the root hair also developed abnormally. The fis1 phenotypes were semi-dominant. The fiz2 phenotypes were also semi-dominant in hypocotyl and root. We found the missense mutation of ACT8 and ACT2 in fiz1 and fiz2, respectively. Each mutation point was mapped on another subdomain of an actin molecule. The act2 mutant by T-DNA insertion, when transformed by ACT2 genome containing fiz1 mutation, became an extremely smaller plant than the fiz1 and the fiz2 mutants. It was thought that the fiz1 mutation had stronger dominant-negative effects than the fiz2 mutation.
