A soybean pattern recognition receptor conferring broad-spectrum pathogen and pest resistance regulates expression of several NLR receptor proteins

Overexpressors of Glycine max disease resistant 1 (GmDR1) exhibits broad-spectrum resistance against Fusarium virguliforme, soybean cyst nematode (SCN), spider mites, and soybean aphids in soybean. To understand the mechanisms of broad-spectrum immunity mediated by GmDR1, we investigated the transcriptomes of a strong and a weak GmDR1-overexpressors following treatment with chitin, a pathogen- and pest-associated molecular pattern (PAMP) found in these organisms. The strong and weak GmDR1-overexpressors exhibited altered expression of 6,098 and 992 genes, respectively, as compared to the nontransgenic control following chitin treatment. However, only 192 of these genes exhibited over two-fold changes in expression levels in both strong and weak GmDR1-overexpressors as compared to the control. MapMan analysis of the 192 genes revealed 64 biotic stress-related genes, of which 53 were induced and 11 repressed as compared to the control. The 53 chitin-induced genes include nine that encode receptor kinases, 13 encode nucleotide-binding leucine-rich repeat (NLR) receptor proteins, seven encoding WRKY transcription factors, four ethylene response factors, and three MYB-like transcription factors. Investigation of a subset of these genes revealed three receptor protein kinases, seven NLR proteins, and one WRKY transcription factor genes that are induced following F. virguliforme and SCN infection. The integral plasma membrane GmDR1 protein most likely recognizes PAMPs including chitin and activates transcription of genes encoding receptor kinases and NLR proteins. GmDR1 could be a pattern recognition receptor that regulates the expression of several NLRs for expression of PAMP-triggered immunity and/or priming the effector triggered immunity.