Transcription factors SlMYB41, SlMYB92, and SlWRKY71 regulate gene expression in the tomato exodermis

Abstract

Root barrier cell types, such as the endodermis and exodermis, are crucial for plant acclimation to environmental stresses. Deposition of suberin, a hydrophobic polymer, in these cell layers restricts the movement of molecules and plays a vital role in stress responses. This study investigates the role of SlMYB41, SlMYB92, and SlWRKY71 transcription factors (TFs) in regulating suberin biosynthesis in the tomato (Solanum lycopersicum) root exodermis by genetic perturbation. Genetic perturbation of these TFs altered exodermal suberin deposition patterns, indicating the SlMYBs as positive regulators and SlWRKY71 as a negative regulator of suberization. RNA sequencing revealed a significant overlap between differentially expressed genes regulated by these TFs, suggesting a shared regulatory network. Gene set enrichment analyses highlighted their role in lipid and suberin biosynthesis as well as over-representation of exodermis-enriched transcripts. Furthermore, transactivation assays demonstrated that these two MYBs promote the expression of suberin-related genes, while SlWRKY71 represses them. These results indicate a complex antagonistic relationship, advancing our understanding of the regulatory mechanisms controlling exodermis suberization in tomato roots.