Comparative Analysis of the Lignification Process of Two Bamboo Shoots Stored at Room Temperature

Abstract

Two types of bamboo shoots, high bamboo (Phyllostachys prominens) shoots (HBSes) and moso bamboo (Phyllostachys edulis) shoots (MBSes), underwent a fast post-harvest lignification process under room temperature storage. To explore the mechanism of lignification in two types of bamboo shoots after post-harvest during room temperature storage, the measurement of cell wall polymers (lignin and cellulose) and enzyme activities of phenylalanine ammonialyase (PAL) and peroxidase (POD), and relative expression of related transcription networks factors (TFs) were performed. The results suggested that the lignification process in HBSes is faster than that in MBSes because of incremental increase in lignin and cellulose contents within 6 days and the shorter shelf-life. Additionally, compared with the expression pattern of lignification-related TFs and correlation analysis of lignin and cellulose contents, MYB20, MYB43, MYB85 could function positively in the lignification process of two types of bamboo shoots. A negative regulator, KNAT7, could negatively regulate the lignin biosynthesis in two types of bamboo shoots. In addition, MYB63 could function positively in HBSes, and NST1 could function negatively in MBSes. Notably, MYB42 may function differently in the two types of bamboo shoots, that is, a positive regulator in HBSes, but a negative regulator in MBSes. Transcription networks provide a comprehensive analysis to explore the mechanism of lignification in two types of bamboo shoots after post-harvest during room temperature storage. These results suggest that the lignification of bamboo shoots was mainly due to the increased activity of POD, higher expression levels of MYB20, MYB43, MYB63, and MYB85 genes, and lower expression levels of KNAT7 and NST1 genes, and the lignification process of HBSes and MBSes had significant differences.