A novel simple extracellular leucine-rich repeat (eLRR) domain protein from rice (OsLRR1) enters the endosomal pathway and interacts with the hypersensitive-induced reaction protein 1 (OsHIR1).
Receptor-like protein kinases (RLKs) containing an extracellular leucine-rich repeat (eLRR) domain, a transmembrane domain and a cytoplasmic kinase domain play important roles in plant disease resistance. Simple eLRR domain proteins structurally resembling the extracellular portion of the RLKs may also participate in signalling transduction and plant defence response. Yet the molecular mechanisms and subcellular localization in regulating plant disease resistance of these simple eLRR domain proteins are still largely unclear. We provided the first experimental evidence to demonstrate the subcellular localization and trafficking of a novel simple eLRR domain protein (OsLRR1) in the endosomal pathway, using both confocal and electron microscopy. Yeast two-hybrid and in vitro pull-down assays show that OsLRR1 interacts with the rice hypersensitive-induced response protein 1 (OsHIR1) which is localized on plasma membrane. The interaction between LRR1 and HIR1 homologs was shown to be highly conserved among different plant species, suggesting a close functional relationship between the two proteins. The function of OsLRR1 in plant defence response was examined by gain-of-function tests using transgenic Arabidopsis thaliana. The protective effects of OsLRR1 against bacterial pathogen infection were shown by the alleviating of disease symptoms, lowering of pathogen titres and higher expression of defence marker genes.
Zhou
Liang
L
Department of Biology and State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Shatin, Hong Kong.
Cheung
Ming-Yan
MY
Zhang
Qi
Q
Lei
Cai-Lin
CL
Zhang
Shi-Hong
SH
Sun
Samuel Sai-Ming
SS
Lam
Hon-Ming
HM
D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism; D003001:Cloning, Molecular; D011992:Endosomes / Q000378:metabolism*; D018506:Gene Expression Regulation, Plant; D007113:Immunity, Innate; D000090263:Leucine-Rich Repeat Proteins; D018613:Microscopy, Confocal; D008854:Microscopy, Electron; D008969:Molecular Sequence Data; D012275:Oryza / Q000235:genetics* / Q000378:metabolism; D010935:Plant Diseases / Q000235:genetics; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D030821:Plants, Genetically Modified / Q000235:genetics / Q000378:metabolism; D025941:Protein Interaction Mapping; D011506:Proteins / Q000235:genetics / Q000378:metabolism*; D044224:Pseudomonas syringae; D018749:RNA, Plant / Q000235:genetics; D016415:Sequence Alignment; D015398:Signal Transduction; D020798:Two-Hybrid System Techniques
D000090263:Leucine-Rich Repeat Proteins; D010940:Plant Proteins; D011506:Proteins; D018749:RNA, Plant