Role of polyamines in the infection of sugarcane buds by Ustilago scitaminea spores

Experimental infection of sugarcane buds from sensitive (Barbados 42231) an d resistant (Mayari 5514) cultivars of sugarcane hybrids to smut with telio spores of Ustilago scitaminea leads to a remarkable increase of both free a nd conjugated polyamines. Whereas resistant buds mainly produce free putres cine, the sensitive cultivars produce acid soluble-conjugated well as acid insoluble-conjugated spermidine and spermine after infection. A net maximum of both polyamines is reached 13 or 17 d after infection and levels decrea se later. This maximum after infection is always higher than that found for non-infected buds. Variation of cadaverine, also produced by sugarcane bud s, does not show any clear correlation with smut development. (C) Elsevier, Paris.