Integrated Transcriptome-metabolome Exploration of Lignin Synthesis Pathway during Mango Flower Bud Differentiation

Xiao Mingjuan; Yang Chunmei; Yang Haonan; Zhao Liuchun; Wu Xingen; Hong Mingwei; Yang Rong; Li Xiaoli; Xie Bin; Tian Linkun; Zhou Ling; Peng Lei

doi:10.15933/j.cnki.1004-3268.2026.08.012

Abstract：Using Guifei mangoes as experimental materials,transcriptome and metabolome analyses were conducted on flower buds at three stages after flower-removal treatment and non-flower-removal treatment.The aim was to explore the changes in the expression levels of key enzyme genes and metabolites in the lignin synthesis pathway during the flower bud differentiation process after the flower-removal treatment of mangoes,and provide a reference for revealing the molecular regulatory mechanism of lignin biosynthesis in mango flower bud differentiation.The transcriptome sequencing results showed that a total of 47 614 differentially expressed genes were obtained across the three stages.KEGG enrichment analysis indicated that in the top ten pathways of the three stages,the pathways of plant hormone signal transduction,plant-pathogen interaction,phenylpropanoid biosynthesis,starch and sucrose metabolism,protein processing in the endoplasmic reticulum,plant MAPK signal pathway,and glutathione metabolism pathway were all enriched.The metabolome analysis results showed that 243 differential metabolites were identified across the three stages.Among them,127 differential metabolites were up-regulated,and 116 were down-regulated.In the phenylpropanoid biosynthesis pathway,there were 142 differential genes and 8 differential metabolites.After further screening,63 differential genes and 5 differential metabolites related to the lignin synthesis pathway were found,involving 10 types of enzymes and 5 types of metabolites.There were a total of four enzymes and metabolites related to flower bud differentiation,namely phenylalanine ammonia-lyase(PAL),peroxidase(POD),L-phenylalanine,and chlorogenic acid.Among them,the expression levels of PAL gene,L-phenylalanine,and chlorogenic acid were up-regulated,while the gene expression level of POD was both up-regulated and down-regulated.In conclusion,the expression levels of differential genes and metabolites in the lignin synthesis pathway were mainly up-regulated.