Secretome prediction of Phakopsora pachyrhizi expressed in planta (Glycine max)

Soybean rust caused by the obligate biotrophic fungus Phakopsora pachyrhizi is the most important biotic stress on soybean fields leading to over 80% losses. The disease has caused serious damage to soybean culture since 2001 in Brazil. the laser capture microdissection (LCM) was used to isolate the foliar mesophyll cells of rust infection sites and access site-specific pathogen molecules involved in the parasitism. RNA was extracted from the isolated cells, amplified, and sequenced with Solexa plataform. The generated paired-end sequences (54 bp) were mapped to the soybean genome and gene models (http://www.phytozome.net) and remaining reads were used to perform an ab initio assembly of P. pachyrhizi transcripts expressed at 10 dpi in planta. The assembly generated 36,350 unique P. pachyrhizi sequences (unisequences) expressed at 10 dpi in planta. A bioinformatic pipeline allowed us predict 895 potential secreted proteins of P. pachyrhizi containing: signal peptide, small ORF, high cystein content and characteristic domains of biotrophic fungi.