SAZ, a new SUPERMAN-like protein, negatively regulates a subset of ABA-responsive genes in Arabidopsis.
Arabidopsis SUPERMAN (SUP) and members of its family are plant-unique C(2)H(2)-type zinc finger genes that have been implicated in plant growth and development. In this paper, we report that a new SUP-family gene, designated as S A- and A BA-downregulated z inc finger gene (SAZ), is involved in the negative regulation of ABA-mediated signaling. SAZ-GUS fusion proteins were predominantly localized in the nuclei when they were transiently expressed in onion epidermal cells. SAZ transcripts were expressed in the leaves and pistils of very young flower buds. In young seedlings, SAZ expression was downregulated in response to environmental stresses such as drought, salt, ozone and ultraviolet-B irradiation. This downregulation was also observed in response to the phytohormones salicylic acid (SA) and abscisic acid (ABA). SA-responsive downregulation of SAZ was not observed in the npr1-1 mutant, indicating that this regulation is NPR1 dependent. RNAi-mediated knockdown of SAZ (SAZ-kd) resulted in elevated expression of the drought- and ABA-responsive genes rd29B and rab18 under unstressed conditions, and it enhanced the response of these genes to drought and ABA treatment. The expression of several other drought- and/or ABA-responsive genes was not affected by SAZ-kd. Based on these results, we propose that SAZ plays a role in repressing a subset of the ABA-mediated stress-responsive genes in unstressed conditions.
Jiang
Chang-Jie
CJ
Plant Disease Resistance Research Unit, Division of Plant Science, National Institute of Agrobiological Sciences, 2-1-2 Kannondai, Tsukuba, Ibaraki, Japan.
Aono
Mitsuko
M
Tamaoki
Masanori
M
Maeda
Satoru
S
Sugano
Shoji
S
Mori
Masaki
M
Takatsuji
Hiroshi
H
D000040:Abscisic Acid / Q000494:pharmacology*; D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000187:drug effects* / Q000235:genetics / Q000254:growth & development; D029681:Arabidopsis Proteins / Q000235:genetics*; D018507:Gene Expression Regulation, Developmental / Q000187:drug effects; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D005838:Genotype; D005966:Glucuronidase / Q000235:genetics / Q000378:metabolism; D008957:Models, Genetic; D008969:Molecular Sequence Data; D010641:Phenotype; D010937:Plant Growth Regulators / Q000494:pharmacology; D030821:Plants, Genetically Modified; D034622:RNA Interference; D018749:RNA, Plant / Q000235:genetics / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017386:Sequence Homology, Amino Acid; D014157:Transcription Factors / Q000235:genetics*; D016335:Zinc Fingers / Q000235:genetics*
D029681:Arabidopsis Proteins; D010937:Plant Growth Regulators; D018749:RNA, Plant; D011993:Recombinant Fusion Proteins; D014157:Transcription Factors; C096661:superman protein, Arabidopsis; D000040:Abscisic Acid; D005966:Glucuronidase