Plants are frequently exposed to diverse pathogens such as bacteria, fungi, viruses, and nematodes. Understanding the mechanisms by which plants recognize pathogen attacks and mount defensive responses is crucial for enhancing plant resistance. This review summarizes current knowledge on the effects of pathogen infection on plant growth and development, as well as the mechanisms that plants use to minimize their adverse effects. Additionally, this review offers valuable insights into the mechanisms of host-pathogen interaction, which are key to developing effective disease control strategies. Plant defenses can be broadly categorized into constitutive and induced mechanisms. Constitutive defenses include pre-formed physical barriers like cuticles and cell walls, as well as chemical deterrents such as unfavorable pH and nutrient limitation. Induced defense mechanisms are activated in response to pathogen detection and involve processes such as cell wall fortification, rapid programmed cell death at the infection site, and the synthesis of pathogenesis-related proteins that degrade invading pathogens. Advances in understanding these defense mechanisms offer essential guidance for developing effective strategies to protect agricultural crops from pathogens.