ARS | Publication request: Constructing physical and genomic maps for Puccinia striiformis f. sp. tritici,the wheat stripe rust pathogen, by comparing its EST sequences to the genomic sequence of P. graminis f. sp. tritici,the wheat stem rust pathogen

Submitted to: Comparative and Functional Genomics
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: December 18, 2009
Publication Date: December 20, 2009
Repository URL: http://downloads.hindawi.com/journals/cfg/2009/302620.pdf
Citation: Ma, J., Chen, X., Wang, M., Kang, Z. 2009. Constructing physical and genomic maps for Puccinia striiformis f. sp. tritici,the wheat stripe rust pathogen, by comparing its EST sequences to the genomic sequence of P. graminis f. sp. tritici,the wheat stem rust pathogen. Comparative and Functional Genomics Comparative and Functional Genomics Vol. 2009, Article ID 302620.

Interpretive Summary: The wheat stripe rust fungus does not have a known alternate host for sexual reproduction, which makes it impossible to study gene linkages through classic genetic and molecular mapping approaches. In this study, we compared 4,219 expression sequence tags (ESTs) of the fungus to the genomic sequence of the wheat stem rust fungus. The percentages of homologous genes varied greatly among different EST libraries of the stripe rust fungus with 54.51%, 51.21% and 13.61% for the spore, germinated spore and haustorial libraries, respectively, with an average of 33.92%. The 1,432 stripe rust genes with significant homology with stem rust sequences were grouped into linkages corresponding to 237 stem rust supercontigs. The linkage relationship was demonstrated by 12 pairs (57%), out of 21 selected stripe rust gene pairs, through PCR screening of a stripe rust bacterial artificial chromosome (BAC) library. The results indicate that the stem rust genome sequence is useful in constructing stripe rust physical maps.

Technical Abstract: The wheat stripe rust fungus, Puccinia striiformis f. sp. tritici (Pst), does not have a known alternate host for sexual reproduction, which makes it impossible to study gene linkages through classic genetic and molecular mapping approaches. In this study, we compared 4,219 Pst expression sequence tags (ESTs) to the genomic sequence of P. graminis f. sp. tritici (Pgt), the wheat stem rust fungus, using BLAST searches. The percentages of homologous genes varied greatly among different Pst libraries with 54.51%, 51.21%, and 13.61% for the urediniospore, germinated urediniospore, and haustorial libraries, respectively, with an average of 33.92%. The 1,432 Pst genes with significant homology with Pgt sequences were grouped into physical groups corresponding to 237 Pgt supercontigs. The physical relationship was demonstrated by 12 pairs (57%), out of 21 selected Pst gene pairs, through PCR screening of a Pst BAC library. The results indicate that the Pgt genome sequence is useful in constructing Pst physical maps.