Plant Immune Responses to Pathogens

Pathogen effectors and proteins targeting plant defence proteins produce in the attcked plants mechanisms of defence and protection, in the form of enzymes, decoys, and inhibitors. Plant-fungi interactions have been elucidated in recent years, showing an evolutionary adaptation of hosts and invaders to produce proteases and evolve protease inhibitors. Interactions between protease inhibitors and the target proteases provide information on the ways organisms interact and defend themselves from pathogens. Polygalacturonases and xylanases are fungal enzymes involved in cell wall degradation, and as such are recognised as PAMPs by specific receptors. Plants fight fungal attack by expressing xylanase inhibtors (XIP), polygalacturonase inhibitors (PGIP)s, and glucanases as beta-1-glucanase that degrade fungal walls. Effectors interferes with plant immune response, as well as with plant energy system, NAD, NADP, and metabolism. Plant immunity receptors, resistance genes and TIR domain proteins, activate localised cell death to reduce pathogen spread, and induce systemic aquired resistance. At the same time, specialised plant decoys and bodyguards protect key signaling transducers such as WRKY transcription factors. There is an arm race between plants and their pathogens, biotrophic or necrotrophic fungi, and bacteria. Genetic editing of susceptibility genes and introgression of resistance gene from wild species offer valid systems to produce healthier crops.