000			01328nam a2200145Ia 4500
008			220216s9999 xx 000 0 und d
100			_aDAuzac J
245		0	_aToxic oxygen : protection against pathogens
260			_bPlantations, Recherche, Developpement _c1996
300			_a153-170
520			_aOxygen can occur in different chemical configurations, which can be more active and even toxic for both microorganisms and higher life forms. It has been shown in man that these active forms in fact play a dual role. They can cause serious diseases but their toxicity can also protect man, and indeed plants, against attacks from pathogenic microorganisms. This paper recounts the history and leads on to describe the most recent work to demonstrate that the active forms of oxygen(including H2O2 and the superoxide ion) are involved in plant defence machanisms against fungi, bacteria and viruses. H2O2 is directly involved early on in the hypersensitivity reaction that characterizes an incompatible pathogen/host interaction: the pathogen is neutralized very rapidly causing only a few mini-necroses. It also probably involved at a later stage in establishing a wide range of defence mechanisms that necessitate the derepression of host genes.
650			_aPlant defense mechanism
650			_aToxic oxygen
942			_cJS
999			_c53220 _d53220