Arabidopsis HISTONE DEACETYLASE 9 Stimulates Hypocotyl Cell Elongation by Repressing GIGANTEA Expression Under Short Day Photoperiod

Hong Gil Lee; Yeong Yeop Jeong; Hongwoo Lee; Pil Joon Seo

doi:10.3389/fpls.2022.950378

Arabidopsis HISTONE DEACETYLASE 9 Stimulates Hypocotyl Cell Elongation by Repressing GIGANTEA Expression Under Short Day Photoperiod

Front Plant Sci. 2022 Jul 18:13:950378. doi: 10.3389/fpls.2022.950378. eCollection 2022.

Authors

Hong Gil Lee^{1

2}, Yeong Yeop Jeong^{3

4}, Hongwoo Lee¹, Pil Joon Seo^{1

2

3

4}

Affiliations

¹ Department of Chemistry, Seoul National University, Seoul, South Korea.
² Plant Genomics and Breeding Institute, Seoul National University, Seoul, South Korea.
³ Research Institute of Basic Sciences, Seoul National University, Seoul, South Korea.
⁴ Department of Biological Sciences, Sungkyunkwan University, Suwon, South Korea.

Abstract

Developmental plasticity contributes to plant adaptation and fitness in a given condition. Hypocotyl elongation is under the tight control of complex genetic networks encompassing light, circadian, and photoperiod signaling. In this study, we demonstrate that HISTONE DEACETYLASE 9 (HDA9) mediates day length-dependent hypocotyl cell elongation. HDA9 binds to the GIGANTEA (GI) locus involved in photoperiodic hypocotyl elongation. The short day (SD)-accumulated HDA9 protein promotes histone H3 deacetylation at the GI locus during the dark period, promoting hypocotyl elongation. Consistently, HDA9-deficient mutants display reduced hypocotyl length, along with an increase in GI gene expression, only under SD conditions. Taken together, our study reveals the genetic basis of day length-dependent cell elongation in plants.

Keywords: Arabidopsis; GI; HDA9; hypocotyl elongation; photoperiod.