Physiological characteristics and gene regulation mechanism of juvenile leaves of Acer rubrum L. during leaf color transformation in spring

Abstract Acer rubrum L., a widely used ornamental colored-leaf tree species, has great utility in both residential and urban landscaping. However, unsuitable environmental conditions tend to reduce the intensity of color change, greatly reducing value this species. Here, we investigated discoloration A. leaves from red green during maturation. We first quantified leaf-color change L * , b space, found most noticeable difference value, which changed positive (more red) negative green). In leaves, photosynthetic pigment content was four-fold greater than that anthocyanin significantly lowed (a 78.33% decrease). Consistent with this, levels superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), as well non-photochemical quenching, were higher leaves. The activity phenylalanine ammonia lyase (PAL), an initial enzyme synthesis pathway, positively correlated accumulation. contrast, polyphenol oxidase (PPO) not any other indicators. Transcriptome sequencing identified 2,161 differentially expressed genes (DEGs) between (1,253 upregulated). Some these DEGs (e.g., 4-coumarate: coenzyme A ligase ( 4CL ), anthocyanidin synthase ANS PAL flavonol FLS chalcone CHS dihydroflavonol 4-reductase DFR flavanone 3-hydroxylase F3H )) encoded important enzymes metabolic while others MYB111 (EZV62_000212), MYB12 (EZV62_010323), bHLH3 (EZV62_023045)) regulated Our results have led clearer understanding physiological genetic mechanisms underlying provide basis improve properties