Tandemly duplicated Arabidopsis genes that encode polygalacturonase-inhibiting proteins are regulated coordinately by different signal transduction pathways in response to fungal infection.
Polygalacturonase-inhibiting proteins (PGIPs) are plant proteins that counteract fungal polygalacturonases, which are important virulence factors. Like many other plant defense proteins, PGIPs are encoded by gene families, but the roles of individual genes in these families are poorly understood. Here, we show that in Arabidopsis, two tandemly duplicated PGIP genes are upregulated coordinately in response to Botrytis cinerea infection, but through separate signal transduction pathways. AtPGIP2 expression is mediated by jasmonate and requires COI1 and JAR1, whereas AtPGIP1 expression is upregulated strongly by oligogalacturonides but is unaffected by salicylic acid, jasmonate, or ethylene. Both AtPGIP1 and AtPGIP2 encode functional inhibitors of polygalacturonase from Botrytis, and their overexpression in Arabidopsis significantly reduces Botrytis disease symptoms. Therefore, gene duplication followed by the divergence of promoter regions may result in different modes of regulation of similar defensive proteins, thereby enhancing the likelihood of defense gene activation during pathogen infection.
Ferrari
Simone
S
Department of Genetics, Harvard Medical School, Massachusetts General Hospital, Boston, Massachusetts 02114, USA.
Vairo
Donatella
D
Ausubel
Frederick M
FM
Cervone
Felice
F
De Lorenzo
Giulia
G
D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000235:genetics* / Q000382:microbiology; D029681:Arabidopsis Proteins / Q000235:genetics* / Q000378:metabolism; D020171:Botrytis / Q000254:growth & development*; D003517:Cyclopentanes / Q000494:pharmacology; D005030:Ethylenes / Q000494:pharmacology; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D007113:Immunity, Innate / Q000235:genetics; D008969:Molecular Sequence Data; D005810:Multigene Family / Q000235:genetics; D054883:Oxylipins; D010940:Plant Proteins / Q000235:genetics*; D011096:Polygalacturonase / Q000037:antagonists & inhibitors; D020156:Salicylic Acid / Q000494:pharmacology; D017386:Sequence Homology, Amino Acid; D015398:Signal Transduction / Q000235:genetics* / Q000502:physiology; D020080:Tandem Repeat Sequences / Q000235:genetics*; D015533:Transcriptional Activation
D029681:Arabidopsis Proteins; D003517:Cyclopentanes; D005030:Ethylenes; D054883:Oxylipins; C081479:PGIP protein, plant; C473614:PGIP1 protein, Arabidopsis; C473615:PGIP2 protein, Arabidopsis; D010940:Plant Proteins; C011006:jasmonic acid; C036216:ethylene; D011096:Polygalacturonase; D020156:Salicylic Acid