Peroxidase activity in Coffea arabica cultivars resistant and susceptible to coffee berry disease

Coffea arabica L. cultivars were inoculated with Colletotrichum coffeanum and thereafter assayed for peroxidase activity. Peroxidase activity of extracts obtained from non-inoculated hypocotyls, detached and attached berries did not reveal any difference among the resistant and susceptible cultivars. Peroxidase activity was found to increase in all C. arabica cultivars studied after inoculation with C. coffeanum. The highest increases in peroxidase activity were in the inoculated susceptible cultivars. In inoculated hypocotyls, there was no clear difference in peroxidase activity between the medium resistant and resistant cultivars. In inoculated detached and attached berries the medium resistant cultivar K7 was comparable to that in the susceptible cultivars, SL 28 and SL 34, at specific sampling periods. Inoculated hypocotyls and detached berries had the highest range of increase in mean peroxidase activity (56-800%) while attached berries had a range of only 12-76%. This study suggests that high peroxidase activity in cultivars of C. arabica is associated with susceptibility rather than with resistance to C. coffeanum.

Des cultivars de Coffea arabica L. ont ete inocules de
Colletotrichum coffeanum  et ensuite leur activite au
peroxidase a ete determinee. Cette activite, determinee dans
des extraits des hypocotyles non-inocules, des cerises de
cafeier attachees et detachees, n' etait pas differente pour
les cultivars resistants et susceptibles. Apres inoculation 
de Colletotrichum coffeanum, l' activite au  peroxidase
augmentait dans tous les cultivars. La plus haute augmentation
etait observee dans les cultivars susceptibles. Dans des
hypocotyles inocules, il n' y avait pas une difference
significative d'activite de peroxidase parmi les cultivars de
resistance moyenne et les cultivars resistants. Dans les
cerises de cafeier detachees et attachees, le cultivar K7 de
moyenne resistance etait comparable aux cultivars susceptibles
SL 28 et SL 34 e des periodes specifiques d' echantillonage.
L' augmentation moyenne d'activite de peroxidase etait la plus
haute (56-800%) dans les hypocotyles inocules et les cerises
de cafeier detachees tandis que dans les cerises attachees, l'
augmentation etait de 12-76%. Cette analyse montre qu' une
activite elevee de peroxidase dans les cultivars de C. arabica
est associee avec la susceptibilite plutot qu'avec la
resistance contre C. coffeanum.