Abstract:

The Waxy gene，a key regulator of amylose synthesis，is central to starch biosynthesis. In this study，bioinformatic analysis identified seven LbWaxy genes in Goji berr（Lycium barbarum L.）. Systematically characterized their expression patterns across multiple tissues at different stages under elevated CO₂ concentrations. Genomic mapping showed that the LbWaxy genes are distributed across four chromosomes，and all encode proteins containing a Glycos_transf conserved domain. The encoded proteins range from 613 to 1 408 aa，with predicted molecular weights of 67.19 to 158.23 kDa and isoelectric points ranging from 5.06 to 8.29. Subcellular localization prediction indicated that all proteins are hydrophilic and primarily cytoplasmic. Phylogenetic analysis demonstrated a conserved evolutionary relationship between LbWaxy and Waxy genes from Solanaceae species and Arabidopsis thaliana，with the proteins clustering into three main groups and six subgroups. Collinearity analysis indicated syntenic relationships between the LbWaxy genes and homologs in tomato（Solanum lycopersicum），pepper（Capsicum annuum），eggplant（Solanum melongena），and Arabidopsis thaliana. Protein-protein interaction network predictions suggested potential interactions between LbWaxy2 and LbWaxy1，LbWaxy4，LbWaxy5，and LbWaxy7. Combined transcriptomic and RT-qPCR analyses revealed differential expression of LbWaxy genes under elevated CO₂ concentrations across tissues and stages. Notably，all seven members showed significant up-regulated in stems at the green fruit stage and in leaves at the different stage. Furthermore，LbWaxy1，LbWaxy2，and LbWaxy7 exhibited significant up-regulated in stems，roots，and fruits at multiple stages，suggesting their role as key regulatory genes in starch synthesis under elevated CO₂ concentrations.

Key words: Lycium barbarum, LbWaxy family genes, amylase, expression analysis, atmospheric CO₂ concentration