Abstract
Arabidopsis thaliana PROTODERMAL FACTOR 2 (PDF2) encodes a HD-ZIP type IV transcription factor and is indicated to play a critical role in maintaining the identity of the L1 cells. PDF2 overexpressing plants (35S::PDF2) exhibited normal shoot development. However, it showed late flowering phenotype only under long day conditions. This flowering phenotype indicates that in 35S::PDF2 there is some defects in the photoperiodic pathway not like fwa dominant mutant. Then the circadian expression of photoperiodic pathway genes were analyzed. In 35S::PDF2 the day time peak of CO expression was lost.
Using yeast-two-hybrid screening, 14 candidates which interact with PDF2 and are not related with L1 layer development were obtained. Two of these candidates, SHOOT GRAVITROPISM 5 (SGR5) and PLASTID TRANSCRIPTION FACTOR 1 (PTF1) are assumed to be related with flowering. SGR5 has a high similarity to maize ID1, a defect in ID1 causes late flowering. ptf1 mutant causes late flowering only under short day conditions.
