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bioRxiv · 10.64898/2026.06.12.731836

High Quality Complete Genomes of Two Virulent Field Isolates of Pyricularia oryzae from Portugal

Rosa, P.·Bilro, J.·Ramiro, R. S.·Azevedo, C.
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Abstract

The fungal pathogen Pyricularia oryzae is notorious for causing blast disease in various important cereal crops, including wheat, rice, millet, and oat. Whole-genome-informed data on this pathogen are necessary to better understand the host adaptability of the fungus, including identifying key determinants of infection to enable more precise disease control. Here, we report highly contiguous genome sequences (using long-read PacBio technology) of two isolates from rice paddies in Portugal, M22.7 and T22.2, which exhibit distinctly aggressive symptoms in rice. Both mitochondrial and nuclear sequences were characterised in this study. The resulting nuclear genomes have assembly lengths of 46.4 Mb for M22.7 (198x coverage) and 46.3 Mb for T22.2 (163x coverage), with near-complete BUSCO completeness (98.8%) and a 0% contamination score (EukCC). Phenotypic analysis showed M22.7 to be more virulent than T22.2, which may be explained by the lower number of predicted effector genes and higher transposable element content in M22.7 relative to T22.2. This announcement represents the first genome resource for natural isolates of P. oryzae from Portugal in over 20 years, filling an important data gap from a major European rice-producing country that produces locally adapted rice varieties under specific agro-environmental conditions (near the Atlantic coast).

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Rosa, P., Bilro, J., Ramiro, R. S., Azevedo, C.. 2026-06-16. High Quality Complete Genomes of Two Virulent Field Isolates of Pyricularia oryzae from Portugal. https://doi.org/10.64898/2026.06.12.731836

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