HISTONE DEACETYLASE 9 promotes hypocotyl‐specific auxin response under shade

• DOI: 10.1111/tpj.16410
• Publication Date: 2023-07-31T11:45:42Z
• Authors: Nguyen Hoai Nguyen; Benny Jian Rong Sng; Hui Jun Chin; Ian Kin Yuen Choi; Hock Chuan Yeo; In‐Cheol Jang
• Keywords: Phytochrome; Petiole (insect anatomy); Cotyledon; Shade avoidance

Vegetative shade causes an array of morphological changes in plants called avoidance syndrome, which includes hypocotyl and petiole elongation, leaf hyponasty, reduced growth, early flowering rapid senescence. Here, we show that loss-of-function mutations HISTONE DEACETYLASE 9 (HDA9) attenuated the shade-induced elongation Arabidopsis. However, hda9 cotyledons petioles under were not significantly different from those wild-type, suggesting a specific function HDA9 response to shade. expression levels stable its protein was ubiquitously detected cotyledon, root. Organ-specific transcriptome analysis unraveled induced set auxin-responsive genes, such as SMALL AUXIN UPREGULATED RNAs (SAURs) AUXIN/INDOLE-3-ACETIC ACIDs (AUX/IAAs) their induction impaired hda9-1 hypocotyls. In addition, binding loci SAUR15/65, IAA5/6/19 ACS4 increased The genetic organ-specific gene analyses further revealed may cooperate with PHYTOCHROME-INTERACTING FACTOR 4/7 regulation elongation. Furthermore, PIF7 proteins found interact together thus it is suggested recruit regulate shade/auxin responsive genes Overall, our study unravels can work one component hypocotyl-specific transcriptional regulatory machinery activates auxin at leading this organ