Life between the lines: genomics and evolution of wheat stripe rust
John Rathjen
Australian National University
Abstract
Wheat stripe rust caused by the fungal pathogen Puccinia striiformis f. sp. tritici (Pst) currently devastates crops on all continents where wheat is grown. Like all rust fungi, Pst is quickly able to overcome host resistance (R) genes, leading to boom and bust scenarios in grain production. The fungus is dikaryotic (two haploid nuclei) with a high repetitive DNA content which makes deciphering the genome architecture especially difficult. Here I will describe using long-read sequencing and a diploid-aware assembler to assemble the most complete Pst genome assembly to date (83 Mb, 156 contigs, N50 of 1.5 Mb), providing phased haplotype information for over 92% of the genome. Comparisons of the phase blocks revealed high interhaplotype diversity of over 6%. More than 25% of all genes lack a clear allelic counterpart. When we investigated genome features that potentially promote the rapid evolution of virulence, we found that candidate virulence effector genes are spatially associated with conserved genes commonly found in basidiomycetes. I contrast this with a recently sequenced genome of a more recent Pst lineage, and discuss progress on cloning effectors recognised by the host immune system known as avirulence (Avr) genes.
Time: May. 29th, 2018, 16:00-18:00
Venue: New Biology building, Room 143
Host: Prof. Yule Liu
举办单位：生命科学联合中心
