SOBIR1 and AGB1 independently contribute to nonhost resistance to Pyricularia oryzae (syn. Magnaporthe oryzae) in Arabidopsis thaliana.

Rice blast caused by Pyricularia oryzae (syn. Magnaporthe oryzae) is a disease devastating to rice. We have studied the Arabidopsis-P. oryzae pathosystem as a model system for nonhost resistance (NHR) and found that SOBIR1, but not BAK1, is a positive regulator of NHR to P. oryzae in Arabidopsis. AGB1 is also involved in NHR. However, the genetic interactions between SOBIR1, BAK1, and AGB1 are uncharacterized. In this study, we delineated the genetic interactions between SOBIR1, BAK1, and AGB1 in NHR to P. oryzae in Arabidopsis and found SOBIR1 and AGB1 independently control NHR to P. oryzae in Arabidopsis pen2-1 mutant plants. Furthermore, XLG2, but not TMM, has a positive role in penetration resistance to P. oryzae in Arabidopsis pen2-1 mutant plants. Our study characterized genetic interactions in Arabidopsis NHR. Abbreviations: PRR: pattern recognition receptor, RLK: receptor-like kinase, RLP: receptor-like protein, BAK1: BRASSINOSTEROID INSENSITIVE 1-ASSOCIATED RECEPTOR KINASE 1, BIR1: BAK1-INTERACTING RECEPTOR-LIKE KINASE 1, SOBIR1: SUPPRESSOR OF BIR1-1-1, AGB1: ARABIDOPSIS G PROTEIN ß-SUBUNIT 1, XLG2: EXTRA-LARGE G PROTEIN 2.