Resumo

MACHADO ASSEFH, C.R et al. La actividad peroxidasa en caña de azúcar (Saccharum spp): evolución temporal de la reacción y su posible rol en la resistencia a la roya marrón (Puccinia melanocephala, H & P Sydow). RIA. Rev. investig. agropecu. [online]. 2013, vol.39, n.2, pp.169-175. ISSN 1669-2314.

Sugarcane brown rust, caused by Puccinia melanocephala, is a foliar disease of concern in almost all countries where sugarcane is grown. The sugarcane breeding programs are in the search for sources of plant oxidaresistance to this pathogen. Since it has been shown that plant peroxidases are involved in defence against phytopathogens, the objective of this study was to compare basal peroxidase activity of two cultivars with contrasting responses to rust, the time course of the peroxidase activity after inoculation with the pathogen and its possible relation to resistance or susceptibility of sugarcane cultivars to rust. Peroxidase activity was measured at 24, 48, 72 and 120 hours after inoculation. Two sugarcane cultivars were used, R570 (highly resistant) and NA86-2280 (highly susceptible). The peroxidase activity increased after inoculation in both cultivars, but increased more rapidly in R570 reaching a maximum at 48 hours after inoculation. A higher activity was detected in R570 throughout the experiment. The differences in the peroxidase activity were found between cultivars and also between inoculated plants and control plants. It is postulated that both basal peroxidase activity and the rate of growth after inoculation, may be complementary mechanisms that promote resistance to rust in sugarcane.

Palavras-chave : Saccharum sp; Puccinia melanocephala; Enzymatic activity.

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