Son Ora, Zhang Chaoyue, Yang Xiaoyu, Duc Le Thi, Hur Yoon-Sun, Nam Kyoung Hee, Choi Soon-Young, Cheon Choong-Ill, Kim Sunghan
Department of Biological Science and Institute of Women's Health, Sookmyung Women's University, Seoul, Republic of Korea.
Department of Systems Biology, Yonsei University, Seoul, Republic of Korea.
Front Plant Sci. 2023 Apr 21;14:1158288. doi: 10.3389/fpls.2023.1158288. eCollection 2023.
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 , a key gene in the GA biosynthesis pathway. Based on promoter deletion analysis, EMSA and ChIP assay, ATHB2 appears to regulate the expression as a direct binding target. We also found that the expression is under negative control by TCP13, the effect of which can be suppressed by presence of ATHB2. Considering a rapid induction kinetics of , this relationship between ATHB2 and TCP13 may allow ATHB2 to play a shade-specific activator for by derepressing a pre-existing activity of TCP13.
避荫综合征（SAS）是植物在遮荫条件下的一种适应性反应，其特征表型包括下胚轴伸长，这主要由生长素和赤霉素（GA）的协同作用介导。我们鉴定出ATHB2，一种已知在遮荫条件下会迅速被诱导的同源异型域-亮氨酸拉链（HD-Zip）结构域转录因子，它通过反式激活GA生物合成途径中的关键基因的表达，成为SAS所需的GA生物合成的正调控因子。基于启动子缺失分析、电泳迁移率变动分析（EMSA）和染色质免疫沉淀分析（ChIP），ATHB2似乎作为直接结合靶点调控的表达。我们还发现的表达受TCP13的负调控，而ATHB2的存在可抑制TCP13的这种作用。考虑到的快速诱导动力学，ATHB2与TCP13之间的这种关系可能使ATHB2通过解除TCP13的已有活性，从而作为的遮荫特异性激活因子发挥作用。
