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United States Department of Agriculture

Agricultural Research Service

Title: Expressed Sequence Tag Analysis of the Soybean Rust Pathogen Phakopsora Pachyrhizi

Authors
item Posada-Buitrago, Martha - DOE, LAWRENCE BERKELEY NA
item Frederick, Reid

Submitted to: Fungal Genetics and Biology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: June 10, 2005
Publication Date: November 21, 2005
Citation: Posada-Buitrago, M.L., Frederick, R.D. 2005. Expressed sequence tag analysis of the soybean rust pathogen phakopsora pachyrhizi. Fungal Genetics and Biology. 42:949-962.

Interpretive Summary: Soybean rust, caused by the fungal pathogen Phakopsora pachyrhizi, is a devastating disease in most soybean growing regions throughout the world except North America and Europe. No soybean cultivars have been identified that are resistant to all rust strains. In order to develop novel methods for controlling this disease, it is important to develop an understanding of the molecular processes that occur throughout the infection process. In this study, we examined gene expression during an early stage of the infection process by conducting DNA sequencing of Expressed Sequence Tags (ESTs) from germinating P. pachyrhizi spores. Genes identified in this study will facilitate our understanding of the biology and evolution of this obligate fungal pathogen and advance our efforts to develop effective means for soybean rust control.

Technical Abstract: Soybean rust, caused by the obligate fungal pathogen Phakopsora pachyrhizi, is a devastating disease in most soybean growing regions throughout the world except North America and Europe. No soybean cultivars have been identified that are resistant to all rust isolates. In order to develop novel methods for controlling this disease, it is important to develop an understanding of the molecular and biochemical processes that occur throughout the infection process. In this study, we examined gene expression during an early stage of the infection process by sequencing Expressed Sequence Tags (ESTs) from germinating P. pachyrhizi urediniospores. Single pass sequence analysis of 908 clones revealed a total of 488 unique ESTs of which 107 appeared as multiple copies. 431 sequences displayed significant similarities to sequences deposited in the non-redundant protein database, while the remaining 477 sequences showed weak or no similarities to database entries. Of the 908 sequences queried against the EST database at the National Center for Biotechnology Information using the BLASTN algorithm, 33 cDNA clones revealed high or moderate similarities to plant and fungal sequences. Using the Expressed Gene Anatomy Classification (EGAD), approximately 19.0% of these ESTs were involved in primary metabolism, 7.7% in gene/protein expression, 5.1% in cell structure and growth, 4.2% in cell division, 3.2% in cell/organism defense and 2.8% in cell signaling/cell communication. Approximately 57.8% of the identities were to hypothetical proteins and proteins with unknown function.

Last Modified: 7/31/2014
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