Cuticular Defects in Oryza sativa ATP-binding Cassette Transporter G31 Mutant Plants Cause Dwarfism, Elevated Defense Responses and Pathogen Resistance.
The cuticle covers the surface of the polysaccharide cell wall of leaf epidermal cells and forms an essential diffusion barrier between plant and environment. Homologs of the ATP-binding cassette (ABC) transporter AtABCG32/HvABCG31 clade are necessary for the formation of a functional cuticle in both monocots and dicots. Here we characterize the osabcg31 knockout mutant and hairpin RNA interference (RNAi)-down-regulated OsABCG31 plant lines having reduced plant growth and a permeable cuticle. The reduced content of cutin in leaves and structural alterations in the cuticle and at the cuticle-cell wall interface in plants compromised in OsABCG31 expression explain the cuticle permeability. Effects of modifications of the cuticle on plant-microbe interactions were evaluated. The cuticular alterations in OsABCG31-compromised plants did not cause deficiencies in germination of the spores or the formation of appressoria of Magnaporthe oryzae on the leaf surface, but a strong reduction of infection structures inside the plant. Genes involved in pathogen resistance were constitutively up-regulated in OsABCG31-compromised plants, thus being a possible cause of the resistance to M. oryzae and the dwarf growth phenotype. The findings show that in rice an abnormal cuticle formation may affect the signaling of plant growth and defense.
University of Lausanne, Department of Plant Molecular Biology, Biophore Building, CH-1015 Lausanne, Switzerland.
Imène
I
Garroum
INRA, UMR-BGPI TA A-54/K, Campus International de Baillarguet, 34398 Montpellier Cedex 5, France Present address: INRA, SupAgro, UMR-BPMP, Bat. 7, 2 place Pierre Viala, 34060 Montpellier, Cedex 2, France.
Przemyslaw
P
Bidzinski
University of Lausanne, Electron Microscopy Facility, Biophore Building, CH-1015 Lausanne, Switzerland.
Jean
J
Daraspe
University of Lausanne, Electron Microscopy Facility, Biophore Building, CH-1015 Lausanne, Switzerland.
Antonio
A
Mucciolo
University of Lausanne, Electron Microscopy Facility, Biophore Building, CH-1015 Lausanne, Switzerland.
Bruno M
BM
Humbel
INRA, UMR-BGPI TA A-54/K, Campus International de Baillarguet, 34398 Montpellier Cedex 5, France.
Jean-Benoit
JB
Morel
University of Lausanne, Department of Plant Molecular Biology, Biophore Building, CH-1015 Lausanne, Switzerland christiane.nawrath@unil.ch.
Christiane
C
Nawrath
D018528:ATP-Binding Cassette Transporters / Q000235:genetics* / Q000378:metabolism; D060467:Disease Resistance / Q000235:genetics; D018506:Gene Expression Regulation, Plant; D020082:Magnaporthe / Q000502:physiology*; D008563:Membrane Lipids / Q000378:metabolism; D009154:Mutation / Q000235:genetics*; D012275:Oryza / Q000033:anatomy & histology* / Q000235:genetics / Q000254:growth & development / Q000276:immunology*; D010641:Phenotype; D010935:Plant Diseases / Q000382:microbiology; D019441:Plant Epidermis / Q000235:genetics* / Q000648:ultrastructure; D010940:Plant Proteins / Q000235:genetics* / Q000378:metabolism
D018528:ATP-Binding Cassette Transporters; D008563:Membrane Lipids; D010940:Plant Proteins; C000521:cutin
ABC transporter; Cuticle; Cutin; Magnaporthe; Pathogen defense; Rice