Septoria tritici blotch (STB) caused by Septoria tritici (syn. Zymoseptoria tritici), is one of the most destructive fungal diseases affecting wheat crops (Triticum spp.) globally. The pathogen severely impacts crop yield by reducing green leaf area, hindering plant growth, and decreasing grain size. Management of S. tritici is challenging due to its ability to rapidly evolve and develop resistance to fungicides. Understanding the genetic diversity and distribution of S. tritici population is essential to developing sustainable disease and management strategies.
This study explores the genomic diversity of S. tritici within Australia in comparison to the global population using long-read sequencing. Through this detailed genomic insight, this study aims to identify and characterise various point mutations including insertions, deletions and structural variations specific to the Australian S. tritici population. Isolates from infected wheat leaves collected from various locations in Victoria in 2023 and 2024, Australia, are sequenced using Oxford Nanopore Technologies. The sequenced isolates will also be analysed to identify and differentiate haplotypes associated with varying levels of pathogenicity.
To further understand the virulence of these strains, a seedling assay will be conducted later this year to evaluate their aggressiveness across various differential wheat cultivars. Additionally, RNA-seq transcriptomic analysis will be performed to examine the expression profiles of the identified haplotypes.
This study's dual genomic and transcriptomic approach improves our understanding of disease development and resistance mechanisms. Examining the genomic structure of S. tritici in Australia addresses knowledge gaps about emerging threats to wheat crops, as the pathogen adapts to fungicides and resistant crop varieties. Analysing pathogenic haplotypes across cultivars informs for better cultivar selection and STB pathogenicity patterns. These findings can enhance disease surveillance, equipping growers with insights to improve disease management strategies.