Mechanisms of Thiamine‐Induced Plant Resistance: Biochemical Insights and Applications

ABSTRACT Thiamine (vitamin B1) is widely recognised as a cofactor in primary metabolic pathways. Recent studies have shown its potential to enhance plant resistance against various pathogens, including bacteria, fungi, viruses and aphids. Thiamine application activates defence responses through multiple biochemical mechanisms, including reactive oxygen species (ROS) signalling, salicylic acid (SA)‐mediated pathways and antioxidant activity modulation. This review explores the biochemical processes underlying thiamine's action as a resistance inducer, such as ROS modulation, enhancement of systemic acquired resistance (SAR) and augmentation of plant structural defences. We discuss how thiamine triggers key signalling cascades, leading to the induction of defence‐related proteins and phenolic metabolism. Furthermore, we highlight the molecular and physiological impacts on plant–pathogen interactions of exogenous thiamine application, demonstrating its role in pathogen inhibition and growth restriction. Future research on thiamine's stability, delivery methods, and application in agricultural practices could enhance its use as an ecofriendly alternative to chemical pesticides. Thiamine's potential as a resistance inducer represents a promising avenue for sustainable crop protection strategies, minimising environmental impact and addressing the challenges of plant–pathogen resistance evolution.