The hypersensitive induced reaction and leucine-rich repeat proteins regulate plant cell death associated with disease and plant immunity.

Abstract

Pathogen-induced programmed cell death (PCD) is intimately linked with disease resistance and susceptibility. However, the molecular components regulating PCD, including hypersensitive and susceptible cell death, are largely unknown in plants. In this study, we show that pathogen-induced Capsicum annuum hypersensitive induced reaction 1 (CaHIR1) and leucine-rich repeat 1 (CaLRR1) function as distinct plant PCD regulators in pepper plants during Xanthomonas campestris pv. vesicatoria infection. Confocal microscopy and protein gel blot analyses revealed that CaLRR1 and CaHIR1 localize to the extracellular matrix and plasma membrane (PM), respectively. Bimolecular fluorescent complementation and coimmunoprecipitation assays showed that the extracellular CaLRR1 specifically binds to the PM-located CaHIR1 in pepper leaves. Overexpression of CaHIR1 triggered pathogen-independent cell death in pepper and Nicotiana benthamiana plants but not in yeast cells. Virus-induced gene silencing (VIGS) of CaLRR1 and CaHIR1 distinctly strengthened and compromised hypersensitive and susceptible cell death in pepper plants, respectively. Endogenous salicylic acid levels and pathogenesis-related gene transcripts were elevated in CaHIR1-silenced plants. VIGS of NbLRR1 and NbHIR1, the N. benthamiana orthologs of CaLRR1 and CaHIR1, regulated Bax- and avrPto-/Pto-induced PCD. Taken together, these results suggest that leucine-rich repeat and hypersensitive induced reaction proteins may act as cell-death regulators associated with plant immunity and disease.

• Authors: Hyong Woo Choi, Young Jin Kim, Byung Kook Hwang
• Journal: Molecular plant-microbe interactions : MPMI (Mol Plant Microbe Interact) Vol. 24 Issue 1 Pg. 68-78 (Jan 2011) ISSN: 0894-0282 [Print] United States
• PMID: 20635864 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Apoptosis Regulatory Proteins
• Leucine-Rich Repeat Proteins
• Plant Proteins
• Proteins

Topics

• Apoptosis Regulatory Proteins (metabolism)
• Arabidopsis (genetics, metabolism)
• Capsicum (genetics, immunology, metabolism, microbiology)
• Cell Death
• Gene Silencing
• Leucine-Rich Repeat Proteins
• Molecular Sequence Data
• Plant Cells
• Plant Diseases (classification)
• Plant Leaves (microbiology)
• Plant Proteins (genetics)
• Plants (immunology)
• Proteins (metabolism)
• Tobacco (genetics, immunology, microbiology)
• Transcription, Genetic
• Xanthomonas campestris (pathogenicity)