Caracterização cultural, morfológica, molecular e patogênica de isolados de Colletotrichum spp. associados à antracnose da Pimenta-de-cheiro (Capsicum chinense Jacq.) no Estado do Amazonas

Abstract

In the Amazon the smell of pepper culture (Capsicum chinense Jacq.) Is subject to attack by many pathogens, especially fungal diseases, among these anthracnose caused by Colletotrichum spp., is one of the most important, because it causes damage to fruit and prevents the marketing. Given the commercial importance of this disease, this study aimed to characterize morphocultural, molecular and pathogenic isolates of Colletotrichum spp. from fruits with symptoms of anthracnose in pepper-of-smell, collected in producing municipalities of Amazonas state (Iranduba, Itacoatiara, President Figueiredo and Manaquiri). The mycelial growth index ranged from 19.29 to 12.77 mm. The color of colonies ranged from white to dark gray. The colony reverse color varied from white, brown, cream, orange, dark brown, black and gray. Most of the isolates were moderately abundant aerial growth, followed by abundant and reduced air. The observed conidia were the oblong/cylindrical type, with dimensions ranging from 15.4 to 9.0 mm in length, 5.5 to 2.9 mm in width and 4.0 to 2.6 μm ratio length width. The format of appressoria were rounded, slightly lobed and lobed, with dimensions of length ranging from 14.6 to 7.3 μm width from 8.8 to 5.2 m and length / width ratio from 1.7 to 1.1 μm. Five isolates did not produce appressoria. The pathogenicity test possible to observe that the isolates from President Figueiredo, Itacoatiara, Manaquiri and Iranduba showed high variability in the mean diameter of lesions (mm), aggressiveness index (%) and incidence (%) when inoculated in different species of Capsicum. Genotyping by Ap- PCR showed genetic diversity within and among isolates of the same origin. The results show possibly the existence of more than one species of Colletotrichum associated with anthracnose in pepper-of-smell in the state of Amazonas.