First report of Podosphaera pannosa causing powdery mildew on Rosa chinensis in Brazil

Abstract

Miniature rose (Rosa chinensis Jacq.) is a shrub-plant belonging to Rosaceae family, originated from Asia and cultivated in Brazil for medicinal and ornamental uses. In August 2016, symptoms and signs of powdery mildew were observed on leaves of miniature rose in Guaramiranga municipality, Ceará State. A specimen (OID99) was collected from symptomatic leaves and examined in the Plant Pathology Laboratory of Embrapa Agroindústria Tropical, Fortaleza, Ceará. In the morphological analysis, the fungus presented epiphytic mycelia and erect, septate, hyaline and unbranched conidiophores. The basal cells were cylindrical, straight and slightly curved at the base. Conidia (n = 50) formed chains at the conidiophore apex and were unicellular, hyaline, ellipsoidovoid to doliiform, with fibrosin bodies, measuring 22.7 to 31.9 μm long and 12.4 to 19.5 μm wide. Appressoria in mycelia were simple and nipple-shaped. Chasmothecia were not observed. The morphological characteristics observed were typical of the asexual stage of Podosphaera sensu Braun and Cook (2012). The genomic DNA was extracted with DNeasy Plant Mini Kit (QIAGEN) from pathogen mycelia collected on the host leaves. The polymerase chain reaction (PCR) amplifications of the internal transcribed spacer (ITS) from the rDNA were conducted with ITS1F / P3R primers (Meeboon and Takamatsu 2015). The PCR product Compliance with ethical standards This article does not contain any studies with human participants or animals performed by any of the authors. Conflict of interest The authors declare that have no conflict of interest.