A common plant cell-wall protein HyPRP1 has dual roles as a positive regulator of cell death and a negative regulator of basal defense against pathogens.
Although hybrid proline-rich proteins (HyPRPs) are ubiquitous in plants, little is known about their roles other than as cell-wall structural proteins. We identified the gene HyPRP1 in Capsicum annuum and Nicotiana benthamiana, which encodes a protein containing proline-rich domain and eight-cysteine motif (8CM) that is constitutively expressed in various organs, mostly in the root, but is down-regulated upon inoculation with either incompatible or compatible pathogens. Ectopic expression of HyPRP1 in plants accelerated cell death, showing developmental abnormality with down-regulation of ROS-scavenging genes, and enhanced pathogen susceptibility suppressing expression of defense-related genes. Conversely, silencing of HyPRP1 suppressed pathogen-induced cell death, but enhanced disease resistance, with up-regulation of defense-related genes and inhibition of in planta growth of bacterial pathogens independently of signal molecule-mediated pathways. Furthermore, the secreted 8CM was sufficient for these HyPRP1 functions. Together, our results suggest that a common plant cell-wall structural protein, HyPRP1, performs distinct dual roles in positive regulation of cell death and negative regulation of basal defense against pathogen.
Department of Plant Science, Plant Genomics and Breeding Institute, Seoul National University, Seoul, South Korea.
Seon-In
SI
Yeom
Eunyoung
E
Seo
Sang-Keun
SK
Oh
Ki Woo
KW
Kim
Doil
D
Choi
D000595:Amino Acid Sequence; D002212:Capsicum / Q000235:genetics / Q000276:immunology* / Q000378:metabolism; D016923:Cell Death; D002473:Cell Wall / Q000378:metabolism; D060467:Disease Resistance; D018506:Gene Expression Regulation, Plant; D020868:Gene Silencing; D008969:Molecular Sequence Data; D010935:Plant Diseases / Q000235:genetics*; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D030821:Plants, Genetically Modified / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D055232:Proline-Rich Protein Domains; D014026:Nicotiana / Q000235:genetics / Q000276:immunology* / Q000378:metabolism
D010940:Plant Proteins