Regulatory DNA Sequences Controlling Gene Expression in Leaf Phloem Cells.

This chapter discusses the regulatory DNA sequences that enable cell-type-specific gene expression in leaf phloem tissues, focusing on phloem parenchyma, companion cells, and sieve elements. Molecular biology techniques, including reporter gene analysis, single-cell RNA sequencing, and live imaging, especially when combined with bioinformatic analysis, are powerful tools for identifying key promoter regions and/or cis-regulatory elements responsible for targeted expression. However, identifying conserved, cell type-specific promoter sequences across diverse plant species for cell-specific regulation remains challenging in high-throughput contexts. Through this review, we aim to provide insights into the cellular functions of the phloem cell types and facilitate precise genetic modifications to manipulate agronomic traits. We anticipate that identifying phloem cell-type specific regulatory elements will have significant implications for biotechnological applications aimed at improving crop productivity and resilience, highlighting the potential for tailored gene expression strategies in plant vascular tissues.