NAC transcription factor ATAF1 negatively modulates the PIF‐regulated hypocotyl elongation under a short‐day photoperiod

• Published in: Plant, cell and environment Vol. 47; no. 8; pp. 3253 - 3265
• Main Authors: Li, Taotao, Fang, Ke, Tie, Yu, Lu, Yuxin, Lei, Yuxin, Li, Weijian, Zheng, Ting, Yao, Xiuhong
• Format: Journal Article
• Language: English
• Published: United States Wiley Subscription Services, Inc 01-08-2024
• Subjects: Arabidopsis thaliana‐activating factor 1; Cell growth; Cycle protein; cycling Dof factor; Daylength; Deficient mutant; Elongation; Gene expression; Meristems; Photoperiods; phytochrome‐interacting factor; Plant growth; Seedlings; Transcription factors; cycling Dof factor; Arabidopsis thaliana‐activating factor 1; phytochrome‐interacting factor
• ISSN: 0140-7791; 1365-3040; 1365-3040
• DOI: 10.1111/pce.14944

Day length modulates hypocotyl elongation in seedlings to optimize their overall fitness. Variations in cell growth‐associated genes are regulated by several transcription factors. However, the specific transcription factors through which the plant clock increases plant fitness are still being elucidated. In this study, we identified the no apical meristem, Arabidopsis thaliana‐activating factor (ATAF‐1/2), and cup‐shaped cotyledon (NAC) family transcription factor ATAF1 as a novel repressor of hypocotyl elongation under a short‐day (SD) photoperiod. Variations in day length profoundly affected the transcriptional and protein levels of ATAF1. ATAF1‐deficient mutant exhibited increased hypocotyl length and cell growth‐promoting gene expression under SD conditions. Moreover, ATAF1 directly targeted and repressed the expression of the cycling Dof factor 1/5 (CDF1/5), two key transcription factors involved in hypocotyl elongation under SD conditions. Additionally, ATAF1 interacted with and negatively modulated the effects of phytochrome‐interacting factor (PIF), thus inhibiting PIF‐promoted gene expression and hypocotyl elongation. Taken together, our results revealed ATAF1–PIF as a crucial pair modulating the expression of key transcription factors to facilitate plant growth during day/night cycles under fluctuating light conditions.
Summary statement
This study identified Arabidopsis NAC transcription factor Arabidopsis thaliana‐activating factor (ATAF1) as a novel repressor of hypocotyl elongation under short‐day conditions. ATAF1 controls the transcription levels of key regulator CDF1/5 by repressing the central regulators phytochrome‐interacting factor via protein–protein interaction.