Transcriptomic Analyses Reveal Carbon Dots-Based Seed Priming in the Regulation of Root Growth in Rice

A long-term treatment of nanoparticles significantly affects various biological processes in plants, including growth and development and stress responses. However, effects of carbon dot (CD) priming on the plant growth and development and the underlying molecular mechanisms have not been completely elucidated. To address this, we herein monitored germination rates of rice seeds with/without CD priming followed by transcriptomic assays using rice roots with/without CD priming. We found that CD priming can promote growth of roots and sprouts in a concentration dependent manner but did not have much impact on germination rates ( t -test, * p < 0.05, ** p < 0.01). CD priming exhibited a time dependent effect on transcriptional reprogramming of a subset of genes ( padj < 0.05, |log 2 (fold change)|> 1), including phytohormone-/development-related transcriptional changes during the seed germination process, which may directly link to CD priming related phenotypic changes of roots. In particular, we provided evidence showing that CD priming can change auxin activities and its spatial distribution in roots, which indicates that CD priming can results in transcriptional changes of some genes ( padj < 0.05, |log 2 (fold change)|> 1) related to biogenesis and transport of auxin, thereby affecting root growth and development. Thus, this study for the first time provides some insights into how CD priming affects root development through transcriptional reprogramming in rice; especially it provides evidence showing that CD priming can be used as an active regulator of plant growth and development.