%0 Book Section
%9 OS CH : Chapitres d'ouvrages scientifiques
%A Martinez, Claude
%A Geiger, Jean-Paul
%A Bresson, Estelle
%A Daniel, Jean-François
%A Dai, G.H.
%A Andray, A.
%A Nicole, Michel
%T Isoperoxidases are associated with resistance of cotton to Xanthomonas campestris pv. malvacearum
%B Plant peroxidases : biochemistry and physiology
%C Genève
%D 1996
%E Obinger, C.
%E Burner, U.
%E Ebermann, R.
%E Penel, C.
%E Greppin, H.
%L fdi:010015353
%G ENG
%I Université de Genève
%K PATHOLOGIE VEGETALE ; COTON ; BACTERIOSE ; VARIETE SENSIBLE ; VARIETE RESISTANTE ; RESISTANCE DE L'HOTE ; ACTIVITE ENZYMATIQUE
%P 322-327
%U https://www.documentation.ird.fr/hor/fdi:010015353
%> https://horizon.documentation.ird.fr/exl-doc/pleins_textes/pleins_textes_7/b_fdi_51-52/010015353.pdf
%W Horizon (IRD)
%X Resistant (Reba B50) and susceptible (Acala 44) cotton plants were investigated for intratissular growth of bacterial populations and peroxidase (POx) activity, after infection of cotyledons with races 18 or 20 from #Xanthomonas ($Axonopodis$) campestris$ pv. #malvacearum$. Considerable multiplication of the bacterial population was noticed in the compatible interaction (Acala 44 / Xcm race 18) ; it was much lower during the incompatible interaction when race 18 was infiltrated into cotyledons of Reba B50. An intermediate level of bacterial growth was obtained when Reba B50 was infiltrated with race known to overcome resistance of this line. High increase in POx activity occurred into the infected cotyledons during incompatible interaction, while the increase was much lower when the interactions were compatible. On leaves, a similar and significant difference in enzyme activity was also observed indicating that the "peroxidase response" was systemically induced in entire resistant plants. Five isoperoxidases were evidenced by IEF in both lines, whether they were infected or not. But only two of them accounted for the increase in activity in infected resistant cotyledons. Microscopy revealed that POx activity, detected at the infection sites two hours after infiltration of the resistant line was mainly located in cell walls and the middle lamella bordering intercellular spaces. Our data indicate that bacterial infection of cotton plants enhanced the activity of two of the preexistent isoperoxidases in resistant plants and suggest that stimulation of POx activity is associated with resistance mechanisms. (Résumé d'auteur)
%$ 076MALPLA07