Small GTPase Regulates Immune Systems in Response to Infection.

is a necrotrophic fungus that can cause gray mold in over 1400 plant species. Once it is detected by , several defense responses are activated against this fungus. The proper activation of these defenses determines plant susceptibility or resistance. It has been proposed that the RAC/ROP small GTPases might serve as a molecular link in this process. In this study, we investigate the potential role of the Arabidopsis gene during infection with . For that, we evaluated lines, characterized by the overexpression of the gene. Our results reveal that these lines displayed increased susceptibility to infection, with enhanced fungal colonization and earlier lesion development. Additionally, they exhibited heightened sensitivity to bacterial infections caused by and . By characterizing plant canonical defense mechanisms and performing transcriptomic profiling, we determined that lines impaired the plant transcriptomic response before and during infection. Global pathway analysis of differentially expressed genes suggested that influences pathogen perception, cell wall homeostasis, signal transduction, and biosynthesis and response to hormones and antimicrobial compounds through actin filament modulation. Herein, we pointed out, for first time, the negative role of small GTPase during - interaction.