English Seminars
Emerging perspectives on innate immune signaling and inter-organellar communication
| Title | Emerging perspectives on innate immune signaling and inter-organellar communication |
| Lecturer | Dr. Savithramma Dinesh-Kumar (Department of Plant Biology, College of Biological Sciences, University of California Davis) |
| Language | English |
| Date&Time | 12/13/2016 (Tue) 13：30～14：30 |
| Venue | Large Seminar Room |
| Detail | Plants employ cell surface pattern recognition receptors (PRRs) to recognize highly conserved pathogen associated molecular patterns (PAMPs) such as fungal chitin or bacterial flagellin to activate PAMP-triggered immunity (PTI) to limit pathogen growth. Arabidopsis FLS2 and EFR PRRs belong to receptor-like kinases (RLKs) class with variable leucine-rich repeat (LRR) ectodomain and an intracellular kinase signaling domain. The FLS2 recognizes N-terminal 22 amino acid peptide of bacterial flagellin (flg22) and EFR recognizes 18 amino acid N-terminal peptide of bacterial elongation factor Tu (elf18) through their extracellular LRR domain to activate PTI responses. Both EFR and FLS2 functions through receptor-like cytoplasmic kinases (RLCKs). However, the precise mechanistic basis of signal transduction from PRR to RLCKs is unknown. I will discuss our attempts to understand the biochemical basis of signaling from cell-surface immune receptors to intracellular kinases. Emerging evidence suggests that chloroplasts play an important function during innate immunity and they also have a central role in the production of immune signals. Our recent findings demonstrated that chloroplasts dynamically change their morphology by sending out stroma-filled tubular projections known as stromules during immune responses. Interestingly, stromules form complex associations with the nuclei and subsequent clustering of chloroplasts around nuclei during immune response. Our findings show that hydrogen peroxide (H2O2) and SA can induce stromules and H2O2 can move through these chloroplast-to-nuclear connections. Furthermore, a chloroplast-localized defense protein NRIP1 accumulates in the nucleus during an immune response possibly via chloroplast-to-nuclear associations. Consistent with these findings, constitutive induction of stromules leads to enhanced programmed cell death (PCD) response. I will discuss these findings and our recent results on stromule function and chloroplast association with nuclei during plant innate immunity. |
| Contact | 植物免疫学 西條 雄介 (saijo@bs.naist.jp) |