Mutual regulation of Arabidopsis thaliana ethylene-responsive element binding protein and a plant floral homeotic gene, APETALA2.
OBJECTIVE
It has previously been shown that Arabidopsis thaliana ethylene-responsive element binding protein (AtEBP) contributed to resistance to abiotic stresses. Interestingly, it has also been reported that expression of ethylene-responsive factor (ERF) genes including AtEBP were regulated by the activity of APETALA2 (AP2), a floral homeotic factor. AP2 is known to regulate expression of several floral-specific homeotic genes such as AGAMOUS. The aim of this study was to clarify the relationship between AP2 and AtEBP in gene expression.


METHODS
Northern blot analysis was performed on ap2 mutants, ethylene-related Arabidopsis mutants and transgenic Arabidopsis plants over-expressing AtEBP, and a T-DNA insertional mutant of AtEBP. Phenotypic analysis of these plants was performed.


RESULTS
Expression levels of ERF genes such as AtEBP and AtERF1 were increased in ap2 mutants. Over-expression of AtEBP caused upregulation of AP2 expression in leaves. AP2 expression was suppressed by the null-function of ethylene-insensitive2 (EIN2), although AP2 expression was not affected by ethylene treatment. Loss of AtEBP function slightly reduced the average number of stamens.


CONCLUSIONS
AP2 and AtEBP are mutually regulated in terms of gene expression. AP2 expression was affected by EIN2 but was not regulated by ethylene treatment.
Ogawa
Taro
T
Institute of Molecular and Cellular Biosciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-0032, Japan.
Uchimiya
Hirofumi
H
Kawai-Yamada
Maki
M
D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D035264:Flowers / Q000033:anatomy & histology / Q000235:genetics / Q000378:metabolism; D017353:Gene Deletion; D018506:Gene Expression Regulation, Plant; D018398:Homeodomain Proteins / Q000235:genetics / Q000378:metabolism*; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism*; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism; D015854:Up-Regulation
C499534:APETALA2 protein, Arabidopsis; D029681:Arabidopsis Proteins; D004268:DNA-Binding Proteins; D018398:Homeodomain Proteins; D009687:Nuclear Proteins; D010940:Plant Proteins; D012333:RNA, Messenger; C093680:ethylene-responsive element binding protein