Soil-borne pathogen Phytophthora sojae is an oomycete that causes devastating damage to soybean yield.  To mine original resistant genes in soybean is an effective and environmentally-friend approach controlling the disease.  In this study, soybean proteins were extracted from the first trifoliolates infected by predominant P. sojae race 1 and analyzed by two-dimensional gel electrophoresis.  Nineteen differently-expressed protein spots were detected, and 10 of them were further applied for Matrix-Assisted Laser Desorption/Ionization Time of Flight Mass Spectrometry Assay.  One protein containing a dirigent (DIR) domain was identified and belonged to the DIR-b/d family.  Therefore, it was named as GmDRR1 (Glycine max Disease Resistance Response 1).  Then, GmDRR1 gene was pathologically confirmed to be involved in the resistant to P. sojae in soybean.  GmDRR1-GFP (green fluorescent protein) fusion proteins localized in the cell membrane.  qRT-PCR results showed GmDRR1 gene expressed differently in P. sojae resistant- and susceptible-soybean cultivars.  By the promoter analysis, we found a haplotype H8 was existing in most resistant soybean varieties, while a haplotype H77 was existing in most susceptible soybean varieties.  The H77 haplotype had seven SNPs (C to A, G to C, C to A, T to A, T to C, T to C, and T to A) and two single nucleotide insertions.  The results supported that the expression difference of GmDRR1 genes between P. sojae resistant- and susceptible-soybean cultivars might depend on the GmDRR1 promoter SNPs.  The results suggested that GmDRR1 was a dirigent protein involved in soybean resistant to P. sojae and paved a novel way for investigation of the molecular regulatory mechanism of the defense response to P. sojae in soybean.

dirigent domain ,  GmDRR1 ,  soybean , Phytophthora sojae ,  oomycete ,  proteomics