Plant innate immunity is a potential surveillance system of plants and
is the first line of defense against invading pathogens. The immune
system is a sleeping system in unstressed healthy plants and is
activated on perception of the pathogen-associated molecular patterns
(PAMP; the pathogen's signature) of invading pathogens. The PAMP
alarm/danger signals are perceived by plant pattern-recognition
receptors (PRRs). The plant immune system uses several second messengers
to encode information generated by the PAMPs and deliver the information
downstream of PRRs to proteins which decode/interpret signals and
initiate defense gene expression. This book describes the most
fascinating PAMP-PRR signaling complex and signal transduction systems.
It also discusses the highly complex networks of signaling pathways
involved in transmission of the signals to induce distinctly different
defense-related genes to mount offence against pathogens.