Loss of a callose synthase results in salicylic acid-dependent disease resistance.
Plants attacked by pathogens rapidly deposit callose, a beta-1,3-glucan, at wound sites. Traditionally, this deposition is thought to reinforce the cell wall and is regarded as a defense response. Surprisingly, here we found that powdery mildew resistant 4 (pmr4), a mutant lacking pathogen-induced callose, became resistant to pathogens, rather than more susceptible. This resistance was due to mutation of a callose synthase, resulting in a loss of the induced callose response. Double-mutant analysis indicated that blocking the salicylic acid (SA) defense signaling pathway was sufficient to restore susceptibility to pmr4 mutants. Thus, callose or callose synthase negatively regulates the SA pathway.
Nishimura
Marc T
MT
Department of Plant Biology, Carnegie Institution, Stanford, CA 94305, USA.
Stein
Monica
M
Hou
Bi-Huei
BH
Vogel
John P
JP
Edwards
Herb
H
Somerville
Shauna C
SC
D000483:Alleles; D017360:Arabidopsis / Q000166:cytology / Q000235:genetics / Q000378:metabolism* / Q000382:microbiology*; D001203:Ascomycota / Q000502:physiology*; D016923:Cell Death; D020869:Gene Expression Profiling; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant; D005936:Glucans / Q000378:metabolism; D005964:Glucosyltransferases / Q000235:genetics* / Q000378:metabolism; D008565:Membrane Proteins; D009154:Mutation; D020411:Oligonucleotide Array Sequence Analysis; D010641:Phenotype; D010935:Plant Diseases; D018515:Plant Leaves / Q000378:metabolism; D020156:Salicylic Acid / Q000378:metabolism*; D029702:Schizosaccharomyces pombe Proteins; D015398:Signal Transduction
D005936:Glucans; D008565:Membrane Proteins; D029702:Schizosaccharomyces pombe Proteins; C048306:callose; D005964:Glucosyltransferases; C020570:1,3-beta-glucan synthase; D020156:Salicylic Acid