Identification of GA20ox2 as a target of ATHB2 and TCP13 during shade response

Ora Son; Chaoyue Zhang; Xiaoyu Yang; Le Thi Duc; Yoon-Sun Hur; Kyoung Hee Nam; Soon-Young Choi; Choong-Ill Cheon; Sunghan Kim

doi:10.3389/fpls.2023.1158288

Identification of GA20ox2 as a target of ATHB2 and TCP13 during shade response

Front Plant Sci. 2023 Apr 21:14:1158288. doi: 10.3389/fpls.2023.1158288. eCollection 2023.

Authors

Ora Son¹, Chaoyue Zhang¹, Xiaoyu Yang¹, Le Thi Duc¹, Yoon-Sun Hur², Kyoung Hee Nam¹, Soon-Young Choi¹, Choong-Ill Cheon¹, Sunghan Kim¹

Affiliations

¹ Department of Biological Science and Institute of Women's Health, Sookmyung Women's University, Seoul, Republic of Korea.
² Department of Systems Biology, Yonsei University, Seoul, Republic of Korea.

Abstract

The shade avoidance syndrome (SAS) is a collective adaptive response of plants under shade highlighted by characteristic phenotypes such as hypocotyl elongation, which is largely mediated by concerted actions of auxin and GA. We identified ATHB2, a homeodomain-leucine zipper (HD-Zip) domain transcription factor known to be rapidly induced under shade condition, as a positive regulator of GA biosynthesis necessary for the SAS by transactivating the expression of GA20ox2, a key gene in the GA biosynthesis pathway. Based on promoter deletion analysis, EMSA and ChIP assay, ATHB2 appears to regulate the GA20ox2 expression as a direct binding target. We also found that the GA20ox2 expression is under negative control by TCP13, the effect of which can be suppressed by presence of ATHB2. Considering a rapid induction kinetics of ATHB2, this relationship between ATHB2 and TCP13 may allow ATHB2 to play a shade-specific activator for GA20ox by derepressing a pre-existing activity of TCP13.

Keywords: ATHB2; GA20ox2; GAF1; TCP13; shade avoidance syndrome.

Grants and funding

This research was supported by Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education (NRF-2021R1I1A1A01056744, 2020R1I1A1A01074533) and by Sookmyung Women’s University Research Cluster Program Grants (3-2203-0004).