Submitted to: American Phytopathological Society Annual Meeting
Publication Type: Abstract Only
Publication Acceptance Date: 4/1/2011
Publication Date: 6/1/2011
Citation: Cuomo, C., Szabo, L.J., Grabherr, M., Mauceli, E., Young, S., Zeng, Q., Sakthikumar, S., Bakkeren, G., Fellers, J.P., Katagiri, F., Glazebrook, J., Tsuda, Y., Stoddard, T.J., Tsuda, K., Chen, X., Yin, C., Hulbert, S. 2011. New insights into the obligate biotrophic lifestyle of rust fungi through comparative genomics. American Phytopathological Society Annual Meeting. 101:S208. Interpretive Summary:
Technical Abstract: Wheat production continues to be plagued by rust pathogens and with the recent race shifts there is an increased concern regarding world food security. Three distinct rust fungi caused disease in wheat: Puccinia graminis f. sp. tritici (Pgt), stem rust or black stem rust; P. striiformis f. sp. tritici (Pst), stripe rust or yellow rust; P. triticina (Pt), leaf rust or brown rust. These three rust fungi have complex life cycles and the asexual dikaryotic uredinial stage is the only practical form for genomic sequence analysis and assembly. Genomes of these rust fungi are large (89 – 127 Mb) and complex with a high level of repetitive sequences (approximately 45%) primarily due to massive proliferation of transposable elements. These genomes are highly polymorphic within and between isolates; Pgt contains ~ 1 SNP/kb between haploid genomes within an uredinial spore. Of the 18,240 predicted proteins in the Pgt genome, approximately 1,000 are small-secreted proteins (SSPs) and may be involved in athogenicity. Gene expression analysis using microarray and RNA-sequencing identified a subset of the SSPs that are highly up regulated in planta and/or isolated haustoria. In addition, many of these SSPs are differentially expressed between races of Pgt. Transient expression analysis is being used to determine the function of a selected set of SSPs. Comparative analysis of these three wheat rust genomes (Pgt, Pst and Pt) will be discussed.