The role of EjBCM1-like in mediating chlorophyll accumulation during loquat leaf development

Loquat ( Eriobotrya japonica ) is an economically important evergreen fruit tree. Its leaves serve as the primary site of photosynthesis, provide nutrients for fruit development, and are utilized in studies on stress resistance, disease resistance, and medicine. To better define the stages of leaf development in loquat, this study first established characteristic morphological indicators for each developmental phase and generated a high-precision transcriptome dataset. Transcriptomic analysis revealed that the gene Eja14G002720 is involved in leaf development and is light-responsive. It encodes a CAAX-box protein that is a homolog of Arabidopsis thaliana AtBCM1, hence its designation as EjBCM1-like. Functional characterization demonstrated that EjBCM1-like plays a critical role in chlorophyll (Chl) accumulation during loquat leaf development. An electrophoretic mobility shift assay (EMSA) confirmed that EjBCM1-like is a novel target gene of EjHY5. Further dual-luciferase and yeast one-hybrid (Y1H) assays indicated that EjHY5 and EjGLK1 bind to the promoter of EjBCM1-like and regulate its expression. This study provides valuable and precise transcriptomic resources for investigating leaf development in loquat and enhances our understanding of the regulatory network underlying Chl metabolism. • We measured chlorophyll content and leaf morphology during loquat leaf development, and provided transcriptome data. • EjBCM1-like ( Eja14G002720 ) responds to light and promotes chlorophyll accumulation in loquat leaves. • We identified a regulatory relationship that EjHY5 directly targets and binds to the promoter of EjBCM1-like .