Abstract
In Arabidopsis thaliana, a pair of homeobox genes, ARABIDOPSIS THALIANA MERISTEM LAYER1 (ATML1) and PROTODERMAL FACTOR2 (PDF2), play a role in regulating the expression of L1 layer-specific genes. atml1-1 pdf2-1 double mutants show striking defects in the differentiation of shoot epidermal cells. PDF2 and ATML1 belong to the HD-ZIP IV gene family, which consists of 16 genes in the Arabidopsis genome. Expression data on promoter-GUS gene fusions suggested that most of the HD-ZIP IV members are mainly expressed in epidermal tissues. Their transcript levels were reduced in atml1-1 pdf2-1 double mutants. Analyses of T-DNA insertion mutants of each HD-ZIP IV gene revealed that all mutants except known gl2, anl2, and hdg11, exhibit no abnormal phenotypes.
In this study, we constructed double mutants of pdf2-1, atml1-1, or atml1-2, and all other members of this family and examined their phenotypes. We observed reduced fertility in some mutant combinations.
