A subtilisin-like protein from soybean contains an embedded, cryptic signal that activates defense-related genes.
Among the arsenal of plant-derived compounds activated upon attack by herbivores and pathogens are small peptides that initiate and amplify defense responses. However, only a handful of plant signaling peptides have been reported. Here, we have isolated a 12-aa peptide from soybean (Glycine max) leaves that causes a pH increase of soybean suspension-cultured cell media within 10 min at low nanomolar concentrations, a response that is typical of other endogenous peptide elicitors and pathogen-derived elicitors. The amino acid sequence was determined and was found to be derived from a member of the subtilisin-like protease (subtilase) family. The sequence of the peptide was located within a region of the protein that is unique to subtilases in legume plants and not found within any other plant subtilases thus far identified. We have named this peptide signal Glycine max Subtilase Peptide (GmSubPep). The gene (Glyma18g48580) was expressed in all actively growing tissues of the soybean plant. Although transcription of Glyma18g48580 was not induced by wounding, methyl jasmonate, methyl salicylate, or ethephon, synthetic GmSubPep peptide, when supplied to soybean cultures, induced the expression of known defense-related genes, such as Cyp93A1, Chib-1b, PDR12, and achs. GmSubPep is a unique plant defense peptide signal, cryptically embedded within a plant protein with an independent metabolic role, providing insights into plant defense mechanisms.
Pearce
Gregory
G
Institute of Biological Chemistry, Washington State University, Pullman, WA 99164-6340, USA. pearce@wsu.edu
Yamaguchi
Yube
Y
Barona
Guido
G
Ryan
Clarence A
CA
D018528:ATP-Binding Cassette Transporters / Q000235:genetics; D000595:Amino Acid Sequence; D001483:Base Sequence; D002478:Cells, Cultured; D002688:Chitinases / Q000235:genetics; D003577:Cytochrome P-450 Enzyme System / Q000235:genetics; D004305:Dose-Response Relationship, Drug; D020869:Gene Expression Profiling; D018506:Gene Expression Regulation, Plant / Q000187:drug effects*; D006863:Hydrogen-Ion Concentration / Q000187:drug effects; D007113:Immunity, Innate / Q000235:genetics; D008969:Molecular Sequence Data; D009842:Oligopeptides / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology; D010935:Plant Diseases / Q000235:genetics; D010937:Plant Growth Regulators / Q000494:pharmacology; D018515:Plant Leaves / Q000201:enzymology / Q000235:genetics; D010940:Plant Proteins / Q000737:chemistry / Q000235:genetics* / Q000494:pharmacology; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017386:Sequence Homology, Amino Acid; D030262:Soybean Proteins / Q000235:genetics; D013025:Glycine max / Q000166:cytology / Q000201:enzymology / Q000235:genetics*; D020860:Subtilisin / Q000737:chemistry / Q000235:genetics* / Q000494:pharmacology
D018528:ATP-Binding Cassette Transporters; D009842:Oligopeptides; D010937:Plant Growth Regulators; D010940:Plant Proteins; D030262:Soybean Proteins; D003577:Cytochrome P-450 Enzyme System; C042062:cytochrome P450 CYP93A1 (Glycine max); D002688:Chitinases; D020860:Subtilisin