The plant cell wall matrix harbors a precursor of defense signaling peptides.
Proteins of plant cell walls serve as structural macromolecules and play important roles in morphogenesis and development but have not been reported to be the origins of peptide signals that activate genes for plant defense. We report here that the mRNA coding the tomato leaf polyprotein precursor of three hydroxyproline-rich glycopeptide defense signals (called LeHypSys I, II, and III) is synthesized in phloem parenchyma cells in response to wounding, systemin, and methyl jasmonate, and the nascent protein is sequestered in the cell wall matrix. These findings indicate that the plant cell wall can play an active role in defense as a source of peptide signals for systemic wound signaling.
Narváez-Vásquez
Javier
J
Institute of Biological Chemistry, Washington State University, Pullman, WA 99164-6340, USA.
Pearce
Gregory
G
Ryan
Clarence A
CA
D000818:Animals; D002473:Cell Wall / Q000235:genetics / Q000378:metabolism*; D018506:Gene Expression Regulation, Plant; D018551:Solanum lycopersicum / Q000166:cytology / Q000235:genetics / Q000378:metabolism* / Q000648:ultrastructure; D008854:Microscopy, Electron; D010935:Plant Diseases; D010937:Plant Growth Regulators / Q000235:genetics / Q000378:metabolism*; D018515:Plant Leaves / Q000166:cytology / Q000235:genetics / Q000378:metabolism / Q000648:ultrastructure; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D030821:Plants, Genetically Modified; D011498:Protein Precursors / Q000235:genetics / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D018749:RNA, Plant / Q000235:genetics / Q000378:metabolism; D011817:Rabbits; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction; D019076:Transgenes / Q000235:genetics
D010937:Plant Growth Regulators; D010940:Plant Proteins; D011498:Protein Precursors; D012333:RNA, Messenger; D018749:RNA, Plant; D011993:Recombinant Fusion Proteins