IMMUNOBOOSTER

NATURAL IMMUNITY IN PLANTS

Through evolution, plants have developed multiple strategies to detect a great number of pathogens and microorganisms with the help of specific immune receptors. Those pattern recognition receptors (PRR) are located in the plant membrane, and are used to identify pathogen-associated molecular patterns (PAMPs). Upon detection of a pathogen on the cell surface, PAMP-triggered immunity (PTI) is activated, which normally stops the infection before the foreign invader damages the plant. However, some pathogens have developed a way to avoid that PTI, either by hindering the recognition of the plasma membrane or by secreting effector proteins into the cytoplasm of plant cells, thus altering resistance responses. Similarly, plants have evolved and developed a mechanism called effector-triggered immunity (ETI).

EFFECTOR-TRIGGERED

The ETI allows to identify the effector proteins that microorganisms use to avoid the PTI with the help of plant resistance proteins, which manage to block microbial growth, but not before the pathogen has effectively invaded a small area. In order to explain this additional defense mechanism, a hypothesis called “gene-for-gene” was developed, according to which for each avirulence gene (Avr) of a specific pathogen, a related resistance gene (R) can be found in the host. The interaction between those genes is what triggers defense responses.