Molecular Mechanism of Xylogenesis in Moso Bamboo (Phyllostachys edulis) Shoots during Cold Storage

Abstract

A bamboo shoot is the immature stem of the woody grass and a nutritious and popular vegetable in East Asia. However, it undergoes a rapid xylogenesis process right after harvest, even being stored in a cold chamber. To investigate the molecular regulation mechanisms of xylogenesis in Moso bamboo (Phyllostachys edulis) shoots (MBSes) during cold storage, the measurement of cell wall polymers (cellulose, hemicellulose, and lignin) and related enzyme activities (phenylalanine ammonia lyase (PAL), cinnamyl alcohol dehydrogenase (CAD), peroxidase (POD), and xylan xylosyltransferase (XylT)) and transcriptomic analysis were performed during cold storage. It was noticed that cellulose and lignin contents increased, while hemicellulose content exhibited a downward trend. PAL, CAD, and POD activity presented an upward trend generally in MBS when stored at 4 °C for 16 days. XylT activity showed a descending trend during the stages of storage, but slightly increased during the 8th to 12th days after harvest at 4 °C. Transcriptomic analysis identified 72, 28, 44, and 31 functional unigenes encoding lignin, cellulose, xylan biosynthesis enzymes, and transcription factors (TFs), respectively. Many of these secondary cell wall (SCW)-related genes showed higher expression levels in the later period of cold storage. Quantitative RT-PCR analysis of the selected genes conformed to the expression pattern. Our study provides a comprehensive analysis of MBS secondary wall biosynthesis at the molecular level during the cold storage process. The results give insight into the xylogenesis process of this economically important vegetable and shed light on solving this problem of the post-harvest industry.

Identification of Homeobox Genes Associated with Lignification and Their Expression Patterns in Bamboo Shoots

“…These results indicated that the winter bamboo shoots had undergone lignification during storage, in which the PeHBs might be involved in the regulating process. Moreover, the content of cellulose was increased and that of hemicellulose gradually decreased along with the storage days ( Figure S7), which was similar to the reported results [56].…”

Physiological Changes of Bamboo (Fargesia yunnanensis) Shoots During Storage and the Related Cold Storage Mechanisms

“…Bamboo shoots are usually harvested with a spade or hoe, which can leave a severe wound at the cut end (Kleinhenz et al, 2000). Therefore, bamboo shoots deteriorate rapidly from mechanical injury during harvest, resulting in significant loss of quality (Li et al, 2019a). The degradation of nutrients and interstitial and woody fibers leads to physical and chemical changes in fresh bamboo shoots, which, in turn, negatively limit the shelf life during storage and affect consumer preferences (Pongprasert et al, 2007).…”

Characterization of Lignin Structures in Phyllostachys edulis (Moso Bamboo) at Different Ages

“…Large-scale plantings of bamboo usually takes no more than six years to reach harvestable size in China. The study of the lignification of bamboo has mostly focused on the growth pattern and anatomical structure of bamboo [17]. However, the chemical quantification of lignin has not been explored at different bamboo ages.…”

“…The purpose of this paper is to investigate the changes in chemical structure and content of lignin of bamboo with ages (1-6 years old). Based on the previous research [17,18], the analysis of bamboo lignin in different years was carried out by Nuclear Magnetic Resonance (NMR), Fourier Transform infrared spectroscopy (FT-IR), Gel Permeation Chromatography (GPC), and changes in lignin chemical structures during the whole lignification process was observed visually.…”