Genome-wide analysis of the XTH gene family and functional analysis of DlXTH23.5/25 during early longan somatic embryogenesis

Abstract

IntroductionXyloglucan endotransglucosylase (XET)/hydrolase (XTH) is a cell wall-modifying protein that affects cell expansion and loosening of the cell wall.ResultsThis study focused on the regulatory mechanism of DlXTH genes during early somatic embryogenesis (SE) and the heat stress response in longan. Mining of the available D. longan genome sequence yielded 25 putative XTH genes. Transcript profiles based on RNA sequencing (RNA-seq) data showed that most of the 17 detected DlXTH genes were highly expressed in the embryogenic callus (EC) (8) and globular embryo (GE) (8), and 13 of them responded significantly to heat stress. The assay for transposase-accessible chromatin sequencing (ATAC-seq) data analysis showed that in terms of chromatin accessibility, 22 of the 25 DlXTH genes were open during early SE, and most of the peak DlXTH genes with transcription differences during early SE were associated with high levels of H3K4me1. The most differentially expressed genes, DlXTH23.5 and DlXTH25, were selected for analysis. According to subcellular localization and quantitative real-time PCR (qRT-PCR) analysis, DlXTH23.5/25, which encode cell membrane-localized proteins, were expressed at the highest level in the GE and significantly responded to heat stress. Dual-luciferase assays and transient transformation showed that the transcription factors (TFs) DlWRKY31, DlERF1, and DlERF5 might bind to the DlXTH23.5/25 promoters to activate gene transcription. Transient overexpression of TFs and DlXTH23.5/25 induced XET activity in Nicotiana benthamiana leaves. Under heat stress in the longan EC, the XET activities and expression levels of TFs and DlXTH23.5/25 were significantly increased, and a high concentration of XET might inhibit longan SE.DiscussionsThus, the regulatory network composed of DlXTH23.5/25 and its related TFs may regulate early longan SE and participate in the regulatory pathway of longan under heat stress via cell wall repair through the action of XET.

Dissection of quantitative trait nucleotides and candidate genes associated with agronomic and yield-related traits under drought stress in rapeseed varieties: integration of genome-wide association study and transcriptomic analysis

“…Upregulation of the XTH13, NAC072 and FadA genes was observed in the two contrasting varieties ( Supplementary Figures S7C–F ). The XTH gene family is involved in various physiological processes in plants, especially in abiotic stress responses and cell elongation ( Ma et al., 2022 ). The XTH genes have been regulated by TF NAC by directly binding to the promoter region of the XTH genes improving stress tolerance ( Tao et al., 2022 ).…”

Genome-Wide Analysis of the Xyloglucan Endotransglucosylase/Hydrolase (XTH) Gene Family: Expression Pattern during Magnesium Stress Treatment in the Mulberry Plant (Morus alba L.) Leaves

“…XTH s represent a category of plant enzymes responsible for regulating xyloglucan crosslinking within cell walls, playing a pivotal role in the control of plant growth and development [ 49 , 50 ]. The role of XTH genes is not only limited to cell wall elongation but also plays a part in plant responses to various environmental stresses.…”

Genome-Wide Analysis of the Xyloglucan Endotransglucosylase/ Hydrolase (XTH) Gene Family: Expression Pattern During Magnesium Stress Treatment in the Mulberry Plant (<em>Morus alba L</em>)

“…XTHs represent a category of plant enzymes responsible for regulating xyloglucan crosslinking within cell walls, playing a pivotal role in the control of plant growth and development [49,50]. The role of XTH genes is not only limited to cell wall elongation but also plays a part in plant responses to various environmental stresses.…”