Polyamine-mediated crosstalk in plant-microbe systems: implications for stress tolerance and crop protection.

The interaction between plants and microbes is a complex network of signaling pathways that plays a pivotal role in plant health and resilience to environmental stressors. Recently, polyamines (PAs), including putrescine, spermidine, and spermine, have emerged as crucial mediators in the crosstalk between plants and microbes. These small molecules are not only involved in cellular growth and differentiation but also significantly influence the plant's response to biotic and abiotic stresses. Research indicates that PAs can enhance the expression of defense-related genes, thereby increasing resistance to pathogens such as Pseudomonas syringae and Hyaloperonospora arabidopsidis. Furthermore, PAs interact with reactive oxygen species (ROS) to form positive feedback loops that amplify defensive responses during pathogen attacks. Additionally, the modulation of polyamine metabolism has been shown to improve crop resilience under stress conditions, suggesting their potential as biostimulants in agricultural practices. This review explores the multifaceted roles of PAs in plant-microbe interactions, highlighting their implications for stress tolerance and crop protection. Understanding the molecular mechanisms underpinning polyamine-mediated crosstalk could lead to the development of innovative strategies for enhancing crop productivity and sustainability in the face of increasing environmental challenges.