Author(s): Talhinhas, Pedro ; Carvalho, Rita ; Tavares, Sílvia ; Ribeiro, Teresa ; Azinheira, Helena ; Ramos, Ana Paula ; Silva, Maria do Céu ; Monteiro, Marta ; Loureiro, João ; Morais-Cecilio, Leonor
Date: 2023
Persistent ID: http://hdl.handle.net/10400.5/28714
Origin: Repositório da Universidade de Lisboa
Subject(s): Basidiomycota; Pucciniales; rust fungi; nuclear cycle; haploid nuclei; diploid nuclei; FISH; flow cytometry
Within Eukaryotes, fungi are the typical representatives of haplontic life cycles. Basidiomycota fungi are dikaryotic in extensive parts of their life cycle, but diploid nuclei are known to form only in basidia. Among Basidiomycota, the Pucciniales are notorious for presenting the most complex life cycles, with high host specialization, and for their expanded genomes. Using cytogenomic (flow cytometry and cell sorting on propidium iodide-stained nuclei) and cytogenetic (FISH with rDNA probe) approaches, we report the widespread occurrence of replicating haploid and diploid nuclei (i.e., 1C, 2C and a small proportion of 4C nuclei) in diverse life cycle stages (pycnial, aecial, uredinial, and telial) of all 35 Pucciniales species analyzed, but not in sister taxa. These results suggest that the Pucciniales life cycle is distinct from any cycle known, i.e., neither haplontic, diplontic nor haplodiplontic, corroborating patchy and disregarded previous evidence. However, the biological basis and significance of this phenomenon remain undisclosed.
