title: The Arabidopsis Transcription Factor NAC016 Promotes Drought Stress Responses by Repressing AREB1 Transcription through a Trifurcate Feed-Forward Regulatory Loop Involving NAP.
abstract: Drought and other abiotic stresses negatively affect plant growth and development and thus reduce productivity. The plant-specific NAM/ATAF1/2/CUC2 (NAC) transcription factors have important roles in abiotic stress-responsive signaling. Here, we show that Arabidopsis thaliana NAC016 is involved in drought stress responses; nac016 mutants have high drought tolerance, and NAC016-overexpressing (NAC016-OX) plants have low drought tolerance. Using genome-wide gene expression microarray analysis and MEME motif searches, we identified the NAC016-specific binding motif (NAC16BM), GATTGGAT[AT]CA, in the promoters of genes downregulated in nac016-1 mutants. The NAC16BM sequence does not contain the core NAC binding motif CACG (or its reverse complement CGTG). NAC016 directly binds to the NAC16BM in the promoter of ABSCISIC ACID-RESPONSIVE ELEMENT BINDING PROTEIN1 (AREB1), which encodes a central transcription factor in the stress-responsive abscisic acid signaling pathway and represses AREB1 transcription. We found that knockout mutants of the NAC016 target gene NAC-LIKE, ACTIVATED BY AP3/PI (NAP) also exhibited strong drought tolerance; moreover, NAP binds to the AREB1 promoter and suppresses AREB1 transcription. Taking these results together, we propose that a trifurcate feed-forward pathway involving NAC016, NAP, and AREB1 functions in the drought stress response, in addition to affecting leaf senescence in Arabidopsis.
authors.affiliation: Department of Plant Science, Plant Genomics and Breeding Institute, Research Institute of Agriculture and Life Sciences, Seoul National University, Seoul 151-921, Korea.
authors.forename: Yasuhito
authors.identifier: http://orcid.org/0000-0002-0432-6767
authors.initials: Y
authors.lastname: Sakuraba
authors.affiliation: Department of Plant Science, Plant Genomics and Breeding Institute, Research Institute of Agriculture and Life Sciences, Seoul National University, Seoul 151-921, Korea.
authors.forename: Ye-Sol
authors.identifier: http://orcid.org/0000-0002-8351-5311
authors.initials: YS
authors.lastname: Kim
authors.affiliation: Department of Plant Science, Plant Genomics and Breeding Institute, Research Institute of Agriculture and Life Sciences, Seoul National University, Seoul 151-921, Korea.
authors.forename: Su-Hyun
authors.identifier: http://orcid.org/0000-0001-9461-5652
authors.initials: SH
authors.lastname: Han
authors.affiliation: Department of Plant Science, Plant Genomics and Breeding Institute, Research Institute of Agriculture and Life Sciences, Seoul National University, Seoul 151-921, Korea.
authors.forename: Byoung-Doo
authors.identifier: http://orcid.org/0000-0001-7215-2781
authors.initials: BD
authors.lastname: Lee
authors.affiliation: Department of Plant Science, Plant Genomics and Breeding Institute, Research Institute of Agriculture and Life Sciences, Seoul National University, Seoul 151-921, Korea Crop Biotechnology Institute, GreenBio Science and Technology, Seoul National University, Pyeongchang 232-916, Korea ncpaek@snu.ac.kr.
authors.forename: Nam-Chon
authors.identifier: http://orcid.org/0000-0002-9827-2287
authors.initials: NC
authors.lastname: Paek
mesh_terms: D000375:Aging / Q000502:physiology; D017360:Arabidopsis / Q000502:physiology*; D029681:Arabidopsis Proteins / Q000096:biosynthesis / Q000502:physiology*; D050976:Basic-Leucine Zipper Transcription Factors / Q000096:biosynthesis / Q000502:physiology*; D003681:Dehydration / Q000503:physiopathology; D015536:Down-Regulation; D018506:Gene Expression Regulation, Plant / Q000502:physiology*; D055786:Gene Knockout Techniques; D018515:Plant Leaves / Q000502:physiology; D015398:Signal Transduction / Q000502:physiology; D014157:Transcription Factors / Q000502:physiology*
chemical_list: D029681:Arabidopsis Proteins; D050976:Basic-Leucine Zipper Transcription Factors; D014157:Transcription Factors; C508877:At1g45249 protein, Arabidopsis; C588366:NAC016 protein, Arabidopsis; C110811:NAP protein, Arabidopsis