Single-Cell Transcriptome Reveals Aquaporin-Mediated Carbon Nanosol-Induced Growth Promotion of Plants

Carbon nanosol (CNS) is a novel carbon nanomaterial with the potential for enhancing plant growth, yet the underlying mechanism remains unclear. Application of 10 mg L^-1 CNS significantly promotes plant growth, increasing fresh mass by 59.51%. Track of fluorescent labeling CNS reveals that it is rapidly absorbed by roots and entered the vascular bundle and cortex within 2 h. A single-cell transcriptomic atlas of tobacco roots response to CNS treatment is generated, which comprises 7,897 cells representing 13 distinct cell types. CNS is found to affect gene expression in a cell type-specific manner, suggesting the heterogeneity of plant response to CNS. Further pseudo-time trajectory analysis reveals that most cell types undergo cell fate transitions toward a more mature state under CNS treatment. In addition, aquaporin proteins NIPs and TIPs are found to be activated and significantly upregulated in epidermal, cortical, and endodermal cells. Further genetic and physiological findings reveal that growth enhance effect of CNS for tip1;1 and tip2;1 mutants is significantly weakened compared to the wild type, indicating that aquaporins play an important role in CNS-mediated plant growth promotion. Overall, these results provide new insights into the mechanism by which CNS promotes plant growth at the single-cell level.