First Report of a Leaf Blight Caused by Pyricularia pennisetigena on Cenchrus echinatus in Paraguay

The genus contains several fungal species known to cause diseases on plants in the Poaceae family (Klaubauf et al. 2014; Wang et al. 2019). While sampling for during March-2015 and April-2018, common weed L. was observed with leaf lesions in and around experimental wheat fields in the departments of Canindeyú and Itapúa. samples from both locations displayed similar leaf lesions, varying from small light brown pinpoint to elliptical brown lesions with greyish center. Symptomatic leaves were surface disinfested and cultured on potato dextrose agar (PDA) amended with 1% gentamicin at 25°C. Two monosporic isolates were obtained, one from Itapúa (ITCeh117) and the other from Canindeyú (YCeh55). The isolates were subsequently grown on oatmeal agar (OA) and PDA under a 12-h photoperiod at 25°C and evaluated after ten days for colony diameter, sporulation, macroscopic and microscopic features. Colonies on OA reached up to 4.8 cm diameter and were light grey, whereas colonies on PDA reached up to 5.3 cm diameter and were brown with grey centers, with cottony mycelium and broad white rims. Mycelium consisted of smooth, hyaline, branched, septate hyphae 4-4.5 µm diameter. Conidiophores were erect, straight or curved, unbranched, medium brown and smooth. Conidia were solitary, pyriform, pale brown, smooth, granular, 2-septate, 32-33 × 9-10 μm; truncated with protruding hilum and varied in length from 1.0 to 1.5 μm and diameters from 2.0 to 2.2 μm. Both isolates were similar and identified as , according to morphological and morphometric characteristics (Klaubauf et al. 2014). Subsequently, genomic DNA was extracted from each isolate using the primers described in Klaubauf et al. (2014) to amplify and sequence the internal transcribed spacers (ITS), partial large subunit (LSU), partial RNA polymerase II large subunit gene (RPB1), partial actin gene (ACT), and partial calmodulin gene (CAL). Sequences from each isolate (YCeh55/ITCeh117) were deposited in GenBank with the following submission ID for ITS: MN947521/MN947526, RPB1: MN984710/MN984715, LSU: MN944829/MN944834, ACT: MN917177/MN917182, and CAL: MN984688/MN984693. Phylogenetic analysis was conducted using the software Beast v1.10.4. The results obtained from the concatenated matrix of the five loci placed these isolates in the clade. To confirm pathogenicity, each isolate was adjusted to 5×104 conidia/ml of sterile water and plants were sprayed with the conidial suspension for isolate YCeh55, ITCeh117 or sterile