Effectors: key actors in phytopathology

Effectors are small molecules, mostly proteins, produced by microorganisms that use them to interact with their hosts. Regarding plant hosts, effectors suppress plant immunity by interfering with microorganism perception, signaling, and biosynthesis of phytoregulators, among other processes. In recent years, interest in effectors in phytopathology has grown due to their contribution to phytopathogen virulence and, by extension, their impact on agricultural production. However, effector molecules are complex. On one hand, these molecules are secreted for the benefit of the phytopathogen and often trigger disease susceptibility. However, plants have evolved receptors that recognize some effectors, and this recognition can trigger disease resistance. Essentially, some effectors safeguard plant health, while others promote disease development. This review focuses on the effectors of phytopathogens and their functions, as well as the mechanisms that many of them use to overcome plant innate immunity, making them key players in phytopathology. Finally, the potential uses of effectors in the agricultural sector and the challenges associated with their application are described.