Diagnosis Of Fungal Pathogens Research Articles

A chromosome-level genome assembly of Zasmidium syzygii isolated from banana leaves.

Accurate taxonomic classification of samples from infected host material is essential for disease diagnostics and genome analyses. Despite the importance, diagnosis of fungal pathogens causing banana leaf diseases remains challenging. Foliar diseases of bananas are mainly caused by 3 Pseudocercospora species, of which the most predominant causal agent is Pseudocercospora fijiensis. Here, we sequenced and assembled four fungal isolates obtained from necrotic banana leaves in Bohol (Philippines) and obtained a high-quality genome assembly for one of these isolates. The samples were initially identified as P. fijiensis using PCR diagnostics; however, the assembly size was consistently 30 Mb smaller than expected. Based on the internal transcribed spacer (ITS) sequences, we identified the samples as Zasmidium syzygii (98.7% identity). The high-quality Zasmidium syzygii assembly is 42.5 Mb in size, comprising 16 contigs, of which 11 are most likely complete chromosomes. The genome contains 98.6% of the expected single-copy BUSCO genes and contains 14,789 genes and 10.3% repeats. The 3 short-read assemblies are less continuous but have similar genome sizes (40.4-42.4 Mb) and contain between 96.5 and 98.4% BUSCO genes. All 4 isolates have identical ITS sequences and are distinct from Zasmidium isolates that were previously sampled from banana leaves. We thus report the first continuous genome assembly of a member of the Zasmidium genus, forming an essential resource for further analysis to enhance our understanding of the diversity of pathogenic fungal isolates as well as fungal diversity.

Use of SCAR-PCR in diagnostics of stem base pathogens of the Rhizoctonia and Oculimacula genus

The aim of the paper is to compare the efficacy of SCAR-PCR assay and conventional diagnostic technique (visual assessment, isolation on PDA medium) in the identification of fungi from the genera <i>Rhizoctonia</i> and <i>Oculimacula</i> from winter triticale, rye, and barley during the shooting stage. The usefulness of molecular diagnosis of fungal pathogens in crop plants has been demonstrated. The application of SCAR- -PCR assay allowed early detection of the following pathogens: <i>O. yallundae</i>,<i> O. acuformis</i>, <i>R. cerealis</i> and <i>R. solani</i>, in plant tissues. This method was particularly effective in detection of <i>R. solani</i>. The research showed the usefulness of PCR markers for early detection of fungal pathogens, even if symptoms were not visible. Using the PCR technique, especially in combination with conventional methods, substantially increases the precision and effectiveness of disease diagnostics.