Histone Deacetylase HDT1 is Involved in Stem Vascular Development in Arabidopsis.

Yongzhuo Zhang,Xiaorui Guo,Jiaxue Zhang,Ziyi Cheng,Bin Yin,Bing Wang,Di Liu,Yadi Liu,Hai Lu,Xiatong Liu,Hui Li

doi:10.3390/ijms20143452

Yongzhuo Zhang, Xiaorui Guo + Show 9 more

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https://doi.org/10.3390/ijms20143452

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Abstract

Histone acetylation and deacetylation play essential roles in eukaryotic gene regulation. HD2 (HD-tuins) proteins were previously identified as plant-specific histone deacetylases. In this study, we investigated the function of the HDT1 gene in the formation of stem vascular tissue in Arabidopsis thaliana. The height and thickness of the inflorescence stems in the hdt1 mutant was lower than that of wild-type plants. Paraffin sections showed that the cell number increased compared to the wild type, while transmission electron microscopy showed that the size of individual tracheary elements and fiber cells significantly decreased in the hdt1 mutant. In addition, the cell wall thickness of tracheary elements and fiber cells increased. We also found that the lignin content in the stem of the hdt1 mutants increased compared to that of the wild type. Transcriptomic data revealed that the expression levels of many biosynthetic genes related to secondary wall components, including cellulose, lignin biosynthesis, and hormone-related genes, were altered, which may lead to the altered phenotype in vascular tissue of the hdt1 mutant. These results suggested that HDT1 is involved in development of the vascular tissue of the stem by affecting cell proliferation and differentiation.

Highlights

The vascular system connects the leaves and other organs with the roots in vascular plants, which is essential for supporting the plant’s body structure and for transporting water, nutrients, and signaling components
Our results revealed that HDT1 is involved in regulating cell division and secondary growth-related genes, and influences the cell number, cell size, and deposition of cell wall components during vascular tissue development
Our data revealed that loss of HDT1 increases lignin content while causing cell wall thickening during xylem development, which suggests that HDT1 regulates secondary cell wall formation and lignin biosynthesis

Summary

Introduction

The vascular system connects the leaves and other organs with the roots in vascular plants, which is essential for supporting the plant’s body structure and for transporting water, nutrients, and signaling components. The vascular cambium is characterized by its multipotent stem cell identity and continued proliferation and differentiation into new xylem and phloem cells during vascular development [1]. Molecular and genetics studies have revealed that hormone and transcription factors regulate vascular tissue proliferation and differentiation. Auxin induces the formation and differentiation of primary cambium cells by directing polar auxin gradients, enabling plants to develop functional vascular bundles [2]. Many transcription factors are involved in the process of cambium cell differentiation, including HD-ZIP III [5,6], NAC [7,8,9], and MYB [10,11,12,13], which are expressed in vascular tissue to regulate cambium activity and vascular development

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