Similarities and differences in plant and animal immune systems — what is inhibiting pathogens?

Abstract

Similarities and differences in the immune systems of plants and animals are discussed in relation to non-specific and specific immunity (resistance), systemic acquired resistance (immune memory), transgenerational immune memory and gene silencing. Furthermore, we attempt to answer the question "what is inhibiting or killing pathogens during the immune (resistance) process"? Therefore, the possible roles of reactive oxygen species and antioxidants in pathogen inhibition are evaluated in different types of plant disease resistance.Keywords: plant and animal immunity, immune memory, reactive oxygen species, antioxidants.If we consider immunity (resistance) to pathogen infections in the case of plants and animals, similarities or analogous mechanisms seem surprising but differences could be also important. The two systems seem to be "so far and yet so close", as was expressed by Maekawa et al. (2011) in an excellent paper. The detailed unraveling of the mechanisms of plant immunity followed vertebrate immunity research with a 40-50 years delay, in spite of the fact that Ward (1902) as early as 110 years ago has shown that some lines of bromes (Bromus inermis) react to infection of a rust fungus (Puccinia dispersa) with an "immune response".The essence of both plant and animal immunity is the recognition and protection against the foreign (the non-self). In the course of immune reactions non-specific and specific plant or animal receptors detect non-specific and specific pathogen elicitor molecules also called antigens in animal systems. The first class of plant or animal receptors recognizes the non-specific "pathogen-associated molecular patterns" (PAMP) or "microbe-associated

Reactive Oxygen Species and Plant Disease Resistance

“…tritici) a rapid, early accumulation of O 2 ÁÀ is already detectable 1 day after inoculation, much earlier than during HR-type host resistance of barley to its own powdery mildew (B. graminis f. sp. hordei), as assayed by nitro blue tetrazolium (NBT) tissue staining (Király et al 2013).…”

Crossing the kingdom border: Human diseases caused by plant pathogens

“…Non-specific receptors are generally membraneassociated pattern-recognition receptor (PRR) proteins that recognize pathogen-associated molecular patterns (PAMP) or microbe-associated molecular patterns (MAMP) that are commonly produced by bacteria (Boller and Felix, 2009;Newman et al, 2013). Specific receptors, namely nucleotide-binding oligomerization domain and leucine-rich repeat-containing proteins or, specifically, resistance proteins (R-proteins) in plants detect pathogen effectors inside host cells (Király et al, 2013). One key difference between animal and plant immune systems is that only animal immune systems employ adaptive immunity whereas both animal and plant cells employ innate immunity (Nurnberger et al, 2004).…”

Grindstone: Grinding... and Human Sacrifice? Why?

“…During my time on field in the territory of Vas and Győr-Sopron Counties the only mass grave or 'deviant burial' (like the Early Iron Age ones from Pusztataskony 57 in Eastern Hungary and Stillfried 58 ) I had the chance to unearth was dated to a later period of the Middle Ages.…”