Stomatal maturomics: identifying genes regulating guard cell maturation and function formation from single-cell transcriptomes

Stomata play critical roles in gas exchange and immunity to pathogens. While many genes regulating early stomatal development up to the production of young guard cells (GCs) have been described in Arabidopsis, much less is known about how young GCs develop into mature functional stomata. Here we performed a maturomics study on stomata, with "maturomics" defined as omics analysis of the maturation process of a tissue or organ. We developed an integrative scheme to analyze three public stomata-related single-cell RNA-seq datasets and identified a list of 586 genes that were specifically up-regulated in all three datasets during stomata maturation and function formation. The list, termed sc_586, is enriched with known regulators of stomatal maturation and functions. We selected two candidate G2-like TFs genes, MYS1 and MYS2, from the list to investigate their roles in stomata. Our results showed that these two genes redundantly regulate the size and hoop rigidity of mature GCs, and their double mutations caused mature GCs to have severe defects in regulating their stomatal apertures. Our analysis thus provides a valuable gene list for studying GC maturation and function formation.