Submitted to: Meeting Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 5/1/2005
Publication Date: 9/1/2005
Citation: Chen, X., Ling, P., Wang, M.N. 2005. Identification of genes in the stripe rust pathogen (puccinia striiformis) and use of gene-specific primers to determine evolutionary relationships among formae speciales of p. striiformis with other fungi. Meeting Proceedings. Global Landscapes in Cereal Rust Control. Sept. 20-21, 2005, University of Sydney, Australia. pg 51.
Interpretive Summary: To identify genes of Puccinia striiformis, a fungal pathogen causing stripe rust on cereal crops and grasses, we have constructed a bacterial artificial chromosomal (BAC) library and a full-length cDNA library from urediniospores of race PST-78 of P. striiformis f. sp. tritici, the wheat stripe rust pathogen. This race represents a group of new races that were first identified in the year 2000 and have caused the widespread epidemics in the U.S. since 2000. The full-length cDNA library consisted of 42,240 clones with an average cDNA insert of 1.5kb.
Technical Abstract: A total of 18 specific primers were designed based on the DNA sequences of 16 selected genes with clear functions. Primers based on genes encoding for the differentiation-related protein (Pstc30M9), the conidium formation protein (Pstc10I12), MAPK (Pstc55B10) and deacetylase (Pstc10C3) were used to identify polymorphisms among seven cereal rust species or formae speciales: the wheat stripe rust (P. striiformis f. sp. tritici), barley stripe rust (P. striiformis f. sp. hordei), bluegrass stripe rust (Puccinia f. sp. poae), orchard grass stripe rust (P. striiformis f. sp. dactylidis), wheat stem rust (P. graminis f. sp. tritici), wheat leaf rust (P. triticina), and barley leaf rust (P. hordei) pathogens. The primers for the MAPK gene (Pstc55B10F/R) and deacetylase gene (Pstc10C3) amplified the same size of DNA fragments from the genomic DNAs of the wheat stripe rust and barley stripe rust isolates, but did not amplify from other stripe rust formae speciales and other rust species, indicating that these primers are useful in separating the wheat and barley stripe rusts from other rusts, and that both wheat and barley stripe rust formae speciales are more closely related to each other than to other stripe rust formae speciales and other rust pathogens. We are currently conducting tests to determine the usefulness of these gene-specific primers in detecting polymorphisms among isolates of P. striiformis f. sp. tritici.