Laser microporous film packaging combined with 1-methylcyclopropene treatment delays lignification in water bamboo shoots during storage by regulating calcium and reactive oxygen species signaling

Lignification causes a rapid decline in the edible value of water bamboo shoots ( Zizania latifolia , WBS) after harvest. This study investigated the effect of combining laser microporous film (LMF) packaging with 1-methylcyclopropene (1-MCP) treatment on the lignification of postharvest WBS. WBS was packaged with LMF bag with or without 1-MCP and stored at 4 ± 1 °C for 45 days; no treatment as a control. Compared with the control group, the LMF+1-MCP was more effective, reducing the lignin content by 14.7 % after 45 days of storage ( p < 0.05). The LMF+1-MCP treatment significantly retarded the decrease in whiteness index, total protein, total soluble solids, soluble sugar, and reducing sugar contents ( p < 0.05). The combined treatment also significantly enhanced the antioxidant capacity, with the superoxide dismutase, ascorbate peroxidase, catalase, and calcium-transporting adenosine triphosphatase activities increasing 2.09-, 1.22-, 1.53-, and 2.03-fold, respectively, while oxidative stress markers (superoxide anion, hydrogen peroxide, and malondialdehyde) decreased to 49.8−79.3 % of control levels ( p < 0.05). Enzymes driving calcium signaling and lignification (calcium-regulated phosphatases, phenylalanine ammonia-lyase, cinnamate-4-hydroxylase, 4-coumarate:CoA ligase, cinnamyl alcohol dehydrogenase, peroxidase, and laccase) were reduced by 12.5−67.7 % compared to untreated controls ( p < 0.05). Additionally, the LMF+1-MCP treatment markedly suppressed the transcript levels of ZlCML27 family genes, particularly ZlCML27-37 , as well as lignification-related genes including ZlPAL-2 , Zl4CL-3 , Zl4CL-4 , ZlF5H-3 , ZlCCoAOMT-1 , ZlCOMT-1 , ZlCAD-1 , ZlLAC-1 , and ZlLAC-3 ( p < 0.05). These results indicate that the LMF+1-MCP treatment inhibited nutrient loss and the accumulation of reactive oxygen species and calcium signaling transduction, thereby limiting the gene expression of lignin biosynthesis-related enzymes and ultimately delaying lignification. Our findings provide new insights into the mechanism of postharvest lignification in WBS and offer an alternative technology for preserving WBS during storage. • LMF+1-MCP delayed lignification and extend shelf life of water bamboo shoots; • LMF+1-MCP inhibited the gene expression of lignin biosynthesis-related enzymes; • LMF+1-MCP limited the H 2 O 2 –Ca 2+ signaling; • ZlCML27-37 genes may be closely related to lignification; • Regulation mechanism of LMF+1-MCP in lignification of WBS was proposed.