Plant-Microbe Interaction: Induced Modifications and Plant Defense System on the Map: A Review

Plant-microbe interactions define a key association of the diverse microbial community with plants through dynamic and complex processes. These microbes associated with plants have been explored for their multifaceted existence since past few decades across the globe. Plants develop mechanisms to survive different stress conditions including biotic and abiotic factors. Plants are known to develop structural and biochemical adaptations for prevention of the attack with phytopathogens and survival. However, these adaptations develop at post-infection stages of the defense mechanism as well. The structural modifications mainly involve the cuticle, cell wall, abscission layer, tylosis, and gum layers. Plants possess strong signaling molecules and pathways that are activated under stress conditions, leading to induced gene expression and metabolic pathways. Molecular and biochemical pathway of plants include several mechanisms such as, plant immunity systems, plant defense pathways pattern triggered immunity (PTI) and effector-triggered immunity including Hypersensitive response (HR), Systematic Acquired Resistance (SAR), and Induced Systemic Resistance (ISR). This review paper aims to study the previous knowledge and current research regarding the defense mechanism of plants against stress conditions. The knowledge of past few years together with the comparative study of different modifications and plant regulatory mechanisms will help understand key components in plant defense and build novel strategies in the future to resist microbial stress conditions to plants.