Impact of melatonin application on lignification in water bamboo shoot during storage

Melatonin, a crucial bioactive molecule, involved in several physiological processes in plants. This study investigated the effects of melatonin (MT) treatment on lignification, including firmness, lignin, lignified-enzyme activities, the expression patterns of genes encoding corresponding enzymes and transcription factors in water bamboo shoot during storage for 8 days. MT treatment decreased the firmness and content of lignin. It inhibited the degradation of total phenols and ascorbic acid and delayed the lignin biosynthesis, via reducing the activities of phenylalanine ammonia-lyse cinnamyl alcohol dehydrogenase and peroxidase, as well as lignin biosynthesis-related genes expression levels. Transcription factors of ZlNAC1, ZlNAC2, ZlNAC3 and ZlNAC4 from NAC family and ZlMYB1 and ZlMYB2 from MYB family were increased in water bamboo shoot after harvest and MT-treated markedly reduced their expression. Therefore, our findings supply a fundamental understanding of MT treatment suppression of lignification and establish a foundation for further research on transcriptional regulation.