AbstractsBiology & Animal Science

Plants are sessile organisms that are surrounded by pathogens. To stay healthy, they need a complex and sensitive immune system. Specific pattern-recognition receptors (PRRs) localized on the plasma membrane can recognize conserved motifs from pathogens and transduce the signal into the cell to initiate defence responses. The receptor-like kinase BAK1-INTERACTING RECEPTOR-LIKE KINASE 1 (BIR1), functions as a negative regulator of plant immunity. bir1-1 exhibits spontaneous cell death and constitutive defence responses that are dependent on SUPPRESSOR OF BIR1,1 (SOBIR1) and PHYTOALEXIN DEFICIENT 4 (PAD4). Here I present the evidence that ER-quality control, a collective mechanism ensuring that only native proteins are produced by the secretary pathway, plays important roles in regulating defence responses in bir1-1. Five components in ER-quality control pathways, including CRT3, UGGT, STT3a, ERdj3b and SDF2, are all required for the immune responses in bir1-1. Western blot analysis showed that mutations in CRT3, ERdj3b and UGGT lead to reduced accumulation of SOBIR1 protein. The data suggest that ER-quality control plays an important role in the accumulation of SOBIR1 and is required for the defence responses in bir1-1.