New reports of Rhizopus and Mucor (Mucorales, Mucoromycota) causing post-harvest rot in tropical fruits in Brazil

Mucorales includes saprobic and facultative phytopathogenic fungi that cause soft rot in various fruits and vegetables. Among Mucorales, Rhizopus and Mucor are frequently reported associated with post-harvest losses and devaluation of agricultural products. The aim of this study was to identify and describe Mucorales species from fruits and vegetables with soft rot symptoms and to confirm the pathogenicity of the isolates in their hosts. Fruits and vegetables with symptoms of soft rot were collected in markets located in the city of Recife, Pernambuco, Brazil. In total, 66 Mucorales isolates were obtained from 18 different hosts. Using morphological and phylogenetic (LSU and ITS rDNA sequences) approaches, we have identified 41 isolates of R. stolonifer and 25 distributed among M. inaequisporus, M. merdicola and M. variisporus. The pathogenicity of these fungi was confirmed, and lesions with fungal structures appeared between 2 and 7 days. This study brings the first report of M. inaequisporus causing soft rot in cashew pseudofruit, guava and red jambo fruits, as well as the first evidence of association of this species with breadfruit. This is the first time that M. merdicola is reported as a plant pathogen, specifically causing soft rot in watermelon fruit. In addition, this is the first report of M. variisporus causing soft rot in banana fruit; the first report of R. stolonifer infecting avocado, eggplant and pear fruits in Brazil. We are also providing the first register of the latter species as plant pathogen of achachairu fruit.