Auxin-induced ARF transcription factor degradation defines tissue boundaries
How organs partition themselves into discrete domains with distinct functions is a fundamental question in biology. The gynoecium of flowering plants provides an excellent system to address this question. Here, we show that the boundary between the stigma and style at the gynoecium apex is established by the complementary distribution of the phytohormone auxin and the Auxin Response Factor (ARF), ETTIN (ETT). Mechanistically, auxin induces ETT protein destabilization via the ubiquitin-proteasome pathway. A short sequence motif within an intrinsically disordered region is required for this auxin-triggered degradation. Disruption of this motif leads to ectopic ETT accumulation at the gynoecium apex and consequently abolishes stigma-style boundary development. We further demonstrate that this previously unrecognized mode of auxin-induced ARF instability is evolutionarily conserved among ETT orthologs across angiosperms. In summary, this study reveals how graded auxin distribution affects ARF transcription factor activity, contributing to the establishment of the stigma-style boundary, ensuring correct gynoecium formation and reproductive success in flowering plants.
Authors
- Xiao‐Xue Qi (ORCID: https://orcid.org/0000-0001-8129-5039)
- Hongzhi Kong (ORCID: https://orcid.org/0000-0002-0034-0510)
- Yang Dong (ORCID: https://orcid.org/0000-0003-2117-538X)
- Jie Cheng (ORCID: https://orcid.org/0000-0002-7065-2747)
- Chaobin Li (ORCID: https://orcid.org/0000-0001-7951-0350)
- Chaoying He (ORCID: https://orcid.org/0000-0002-2550-0170)
- Limin Lu (ORCID: https://orcid.org/0000-0001-6973-7877)
- Lars Østergaard (ORCID: https://orcid.org/0000-0002-8497-7657)
- Xiaofeng Fang (ORCID: https://orcid.org/0000-0003-1161-9186)
- C Xu
- Baoqing Ding (ORCID: https://orcid.org/0000-0001-7183-9653)
- Min Chen (ORCID: https://orcid.org/0000-0003-3294-9248)
- Quan Wang (ORCID: https://orcid.org/0000-0003-2912-1263)
- Feng Gao (ORCID: https://orcid.org/0009-0007-4440-8306)
- Bo Xu (ORCID: https://orcid.org/0000-0001-7264-7127)
- Quan Yuan (ORCID: https://orcid.org/0000-0001-7062-3519)
- Yao Zhang (ORCID: https://orcid.org/0000-0002-3225-8255)
- Yining Ding
- Dandan Yang (ORCID: https://orcid.org/0000-0002-2306-0626)
- Zhi-Cheng Hu
- H. M. Hu (ORCID: https://orcid.org/0000-0002-9994-0742)
- Hongqiang Yu
- J Ahn (ORCID: https://orcid.org/0009-0002-3393-2675)
- Yun-Ying Wang
- Qian Xu (ORCID: https://orcid.org/0009-0003-6318-6113)
Institutions
- Nanjing Agricultural University (CN)
- Henan University (CN)
- Chinese Academy of Sciences (CN)
- Beijing Botanical Garden (CN)
- University of Oxford (GB)
- Agricultural Genomics Institute at Shenzhen (CN)
- Institute of Botany of the Slovak Academy of Sciences (SK)
- Institute of Genetics and Developmental Biology (CN)
- Ministry of Agriculture and Rural Affairs (CN)
- Institute of Botany (CN)
- University of Chinese Academy of Sciences (CN)
- China National Botanical Garden
- Tsinghua University (CN)
Publication Details
- Journal
- Proceedings of the National Academy of Sciences
- Published
- 2026-08-25
- DOI
- https://doi.org/10.1073/pnas.2612105123
- Primary Topic
- Plant Molecular Biology Research
- Type
- article
- Field-Weighted Citation Impact
- 0.00
Funders
- National Natural Science Foundation of China
- Biotechnology and Biological Sciences Research Council