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During 2017-2019, leaves and stems with dark brown lesions containing hypophyllous telia surrounded by chlorotic halos were collected from Sphaeralcea angustifolia plants located in Axapusco, State of Mexico. Based on the morphological characteristics of pycnia, aecia and telia observed by light microscopy and scanning electron microscopy, the fungus Puccinia sherardiana was identified. Uredial stage was not present during the observation period. Identity verification was carried out by phylogenetic analysis with sequences of part of the 28S gene from ribosomal DNA. In addition, pathogenicity tests were done on S. angustifolia leaves by inoculating teliospores. The inoculated plants developed symptoms 15 days after inoculation, the signs beginning with the presence of aecia in the epidermis of the host and later telia were formed, completing the Koch Postulates. Puccinia sherardiana was previously described as a rust with a microcyclic life cycle on species of the genera Alcea, Malvastrum, Sidalcea and Sphaeralcea , belonging to the Malvaceae family, however, this study revealed that this plant pathogenic fungus has a demicyclic life cycle. |
