Histone modification H3K27me3 is essential during chilling-induced flowering in Litchi chinensis

Xifen Pan; Xingyu Lu; Lijie Huang; Zhiqun Hu; Maogen Zhuo; Yanchun Ji; Bingqi Lin; Jianqin Luo; Peitao Lü; Biyan Zhou

doi:10.1093/plphys/kiae619

Histone modification H3K27me3 is essential during chilling-induced flowering in Litchi chinensis

Plant Physiol. 2024 Nov 20:kiae619. doi: 10.1093/plphys/kiae619. Online ahead of print.

Authors

Xifen Pan¹, Xingyu Lu^{1

2}, Lijie Huang^{1

3}, Zhiqun Hu¹, Maogen Zhuo¹, Yanchun Ji¹, Bingqi Lin¹, Jianqin Luo¹, Peitao Lü⁴, Biyan Zhou¹

Affiliations

¹ Guangdong Litchi Engineering Research Center, College of Horticulture, South China Agricultural University, Guangzhou 510642, China.
² College of Life and Health Science, Kaili University, Kaili 556011, China.
³ Tropical Crops Genetic Resources Institute, Chinese Academy of Tropical Agricultural Sciences, Haikou 571101, China.
⁴ National Key Laboratory for Tropical Crop Breeding, Institute of Tropical Bioscience and Biotechnology, Chinese Academy of Tropical Agricultural Sciences, Sanya 572024, China.

PMID: 39565892
DOI: 10.1093/plphys/kiae619

Abstract

Litchi (Litchi chinensis), a prominent fruit tree in the Sapindaceae, initiates flowering in response to low autumn and winter temperatures. This study investigates the epigenetic regulation of this process, focusing on the marks histone H3 lysine 27 trimethylation (H3K27me3) and its deposition genes during the chilling-induced floral induction and initiation stages. Our genomic analysis delineated the H3K27me3 deposition landscape across the pre-floral induction (PFId), floral induction (FId), and floral initiation (FIn) stages. We identified 5,635 differentially H3K27me3-modified genes (DHGs) in buds and 4,801 DHGs in leaves. Integration of the RNA-seq and ChIP-seq datasets identified 1,001 differentially regulated genes (DRGs) in buds and 675 DRGs in leaves, offering insights into the genes potentially targeted by H3K27me3. To probe the functional role of H3K27me3, we employed GSK343, a histone H3 lysine methyltransferase inhibitor. Treatment with GSK343 during the chilling-induced flowering process led to reduced H3K27me3 deposition at the TREHALOSE-6-PHOSPHATE SYNTHASE 1 (LcTPS1) and FRIGIDA (LcFRI) loci, resulting in increased gene expression. This manipulation delayed flowering and reduced flowering rates, confirming the pivotal role of H3K27me3 in chilling-induced flowering in litchi. Gene co-expression network analysis identified SHORT VEGETATIVE PHASE 10 (LcSVP10) as a crucial regulator in litchi flowering. Overexpression of LcSVP10 in Arabidopsis thaliana delayed flowering, indicating a conserved function in flowering time control. Our results elucidate the molecular and epigenetic mechanisms that govern floral induction in litchi and highlight the potential of epigenetic modifications to regulate flowering time in horticultural plants.

Keywords: H3K27me3; chilling accumulation; flowering; litchi; transcriptome.

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