Uncovering the core genetic programs governing plant guard cell biology

Guard cells are specialized cells critical for gas exchange, including carbon dioxide and water. Understanding the genetic programs governing guard cell biology and the set of transcription factors controlling these programs will support the engineering of plants with enhanced water-use efficiency. To date, single-nucleus RNAseq (sNucRNAseq) allows for characterizing the guard cell transcriptome in a few plant species, including the model species Arabidopsis thaliana. To gain a fundamental understanding of the biology and identity of stomata cells, we conducted a comprehensive comparative genomics approach by leveraging sNucRNAseq datasets of stomata cells from four different soybean organs and five different plant species. By identifying the sets of paralogs and orthologs specifically expressed in guard cells, our study reveals the genes, expression modules, and gene networks that drive guard cell identity and function. We also reveal organ- and species-specific programs by identifying genes uniquely expressed in a specific organ and species. The outcome of this research will help prioritize the genes and pathways to optimize guard cell engineering.