Starch, a vital dietary component and crucial for bio-ethanol generation, is synthesized by plants during photosynthesis. Augmenting starch output holds promise for human and animal nutrition, as well as bioenergy. Our previous work involved cloning the homolog gene DRM2 from Purslane and subsequently overexpressing PoDRM2 in Arabidopsis. Comparative analysis between wild-type Columbia and homozygous PoDRM2 transgenic lines revealed a substantial increase in plant size and nearly a 90% rise in fresh biomass per plant in PoDRM2 lines, indicating a potentially heightened efficiency in photosynthesis. We conducted further investigations into starch synthesis and accumulation in leaves. Iodine staining revealed that PoDRM2 transgenic Arabidopsis lines accumulated significantly more starch than the control under both dark and light conditions. Additionally, total carbohydrates in the leaves of transgenic lines more than doubled that of the wild type. Furthermore, PoDRM2 lines exhibited higher chlorophyll content compared to the control. These findings strongly indicate that PoDRM2 serves as a crucial regulator of starch accumulation. PoDRM2, encoding a methyltransferase, was implicated in altering the methylation status of over 2,500 genes through genome-wide bisulfite sequencing. Notably, 55 out of 61 genes involved in the photosynthesis pathway were affected, underscoring the significant role of DNA methylation in regulating starch accumulation and photosynthesis in plants.
