The root nodule is a complex symbiotic nitrogen fixation factory,in which cells are highly heterogeneous.However,the differentiation trajectories and interconnection of nodule cells remain largely unknown.In this stud...The root nodule is a complex symbiotic nitrogen fixation factory,in which cells are highly heterogeneous.However,the differentiation trajectories and interconnection of nodule cells remain largely unknown.In this study,we set up a modified protocol for nodule protoplast preparation and performed a single-cell RNA sequencing profiling of the indeterminate Medicago truncatula nodule.We designated 13 cell clusters with specific expression patterns in 14-day post inoculation nodules and constructed a spatial and functional cellular map based on experimental data and bioinformatic analyses.Pseudotime analysis further revealed that two groups of apical meristematic cells develop into symbiotic and un-symbiotic fate cells along their particular trajectories.Biofunction analysis of each cell cluster revealed their particularity and interrelation,especially that the un-infected cells in nitrogen fixation zone are also involved in nitrogen assimilation by undertaking the asparagine synthesis.Collectively,our data offer an important resource for investigating the mechanism of nodule organogenesis and symbiotic nitrogen fixation.展开更多
基金This research was funded by National KeyResearch&Development Program of China(2022YFA0912100)National Natural Science Foundation of China(32070272)Key Projects in Science and Technology of Inner Mongolia(2021ZD0031).
文摘The root nodule is a complex symbiotic nitrogen fixation factory,in which cells are highly heterogeneous.However,the differentiation trajectories and interconnection of nodule cells remain largely unknown.In this study,we set up a modified protocol for nodule protoplast preparation and performed a single-cell RNA sequencing profiling of the indeterminate Medicago truncatula nodule.We designated 13 cell clusters with specific expression patterns in 14-day post inoculation nodules and constructed a spatial and functional cellular map based on experimental data and bioinformatic analyses.Pseudotime analysis further revealed that two groups of apical meristematic cells develop into symbiotic and un-symbiotic fate cells along their particular trajectories.Biofunction analysis of each cell cluster revealed their particularity and interrelation,especially that the un-infected cells in nitrogen fixation zone are also involved in nitrogen assimilation by undertaking the asparagine synthesis.Collectively,our data offer an important resource for investigating the mechanism of nodule organogenesis and symbiotic nitrogen fixation.
