Caracterização da agressividade de isolados de Colletotrichum de maracujá amarelo com marcadores bioquímico, fisiológico e molecular

Abstract

Anthracnose is the most important post harvest disease of yellow passion fruit, whose etiologic agent has been identified in Brazil as Colletotrichum gloeosporioides. For pathogen characterization, 33 isolates were obtained from three producing regions of Pernambuco State. Morphological characters, such as color of the colony, conidial form and dimension, perithecium production and specific primers for C. gloeosporioides, C. acutatum and "Colletotrichum of Passiflora" allowed the identification of Glomerella cingulata pathotype 1, G. cingulata pathotype 2, Colletotrichum sp. from Passiflora and Colletotrichum sp. from yellow passion fruit. Yellow passion fruit inoculations showed two isolate groups, one with high aggressiveness (GA-1) and another with low aggressiveness (GA-2). Biochemical markers, such as amilolytic, cellulolytic, lipolytic and proteolytic enzymatic activities and physiological markers, such as mycelial growth, did not separate isolates into groups by aggressiveness. Standard markers produced by DNA amplification of isolates, using RAPD primers, showed that GA-1 isolates were more genetically related to each other than GA-2 isolates, evidencing GA-1 isolates with more recent evolution. The DNA amplifications of isolates with OPA-9 primer generated a marker that allowed grouping of 85.7% of GA-1 isolates, but included some GA-2 isolates with aggressiveness close to that of GA-1 isolates; therefore, OPA-9 primer can be used to characterize Colletotrichum spp. isolates with high aggressiveness in genetic resistance programs.