ABF2, an ABRE-binding bZIP factor, is an essential component of glucose signaling and its overexpression affects multiple stress tolerance.
Phytohormone abscisic acid (ABA) regulates stress-responsive gene expression during vegetative growth, which is mediated largely by cis-elements sharing the ACGTGGC consensus. Although many transcription factors are known to bind the elements in vitro, only a few have been demonstrated to have in vivo functions and their specific roles in ABA/stress responses are mostly unknown. Here, we report that ABF2, an ABF subfamily member of bZIP proteins interacting with the ABA-responsive elements, is involved in ABA/stress responses. Its overexpression altered ABA sensitivity, dehydration tolerance, and the expression levels of ABA/stress-regulated genes. Furthermore, ABF2 overexpression promoted glucose-induced inhibition of seedling development, whereas its mutation impaired glucose response. The reduced sugar sensitivity was not observed with mutants of two other ABF family members, ABF3 and ABF4. Instead, these mutants displayed defects in ABA, salt, and dehydration responses, which were not observed with the abf2 mutant. Our data indicate distinct roles of ABF family members: whereas ABF3 and ABF4 play essential roles in ABA/stress responses, ABF2 is required for normal glucose response. We also show that ABF2 overexpression affects multiple stress tolerance.
Kim
Sunmi
S
Kumho Life and Environmental Science Laboratory, 1 Oryong-dong, Buk-gu, Gwangju 500-712, South Korea.
Kang
Jung-Youn
JY
Cho
Dong-Im
DI
Park
Ji Hye
JH
Kim
Soo Young
SY
D017360:Arabidopsis / Q000235:genetics / Q000254:growth & development / Q000502:physiology*; D029681:Arabidopsis Proteins / Q000378:metabolism*; D050976:Basic-Leucine Zipper Transcription Factors; D004268:DNA-Binding Proteins / Q000378:metabolism*; D051790:G-Box Binding Factors; D017353:Gene Deletion; D005947:Glucose / Q000502:physiology*; D018384:Oxidative Stress; D010641:Phenotype; D030821:Plants, Genetically Modified; D018749:RNA, Plant / Q000235:genetics / Q000302:isolation & purification; D015398:Signal Transduction / Q000502:physiology; D014157:Transcription Factors / Q000378:metabolism*
D029681:Arabidopsis Proteins; D050976:Basic-Leucine Zipper Transcription Factors; D004268:DNA-Binding Proteins; D051790:G-Box Binding Factors; D005947:Glucose; D018749:RNA, Plant; D014157:Transcription Factors; C508877:At1g45249 protein, Arabidopsis