title: Nonhost resistance of rice to rust pathogens.
abstract: Rice is atypical in that it is an agricultural cereal that is immune to fungal rust diseases. This report demonstrates that several cereal rust species (Puccinia graminis f. sp tritici, P. triticina, P. striiformis, and P. hordei) can infect rice and produce all the infection structures necessary for plant colonization, including specialized feeding cells (haustoria). Some rust infection sites are remarkably large and many plant cells are colonized, suggesting that nutrient uptake occurs to support this growth. Rice responds with an active, nonhost resistance (NHR) response that prevents fungal sporulation and that involves callose deposition, production of reactive oxygen species, and, occasionally, cell death. Genetic variation for the efficacy of NHR to wheat stem rust and wheat leaf rust was observed. Unlike cereal rusts, the rust pathogen (Melampsora lini) of the dicotyledenous plant flax (Linum usitatissimum) rarely successfully infects rice due to an apparent inability to recognize host-derived signals. Morphologically abnormal infection structures are produced and appressorial-like structures often don't coincide with stomata. These data suggest that basic compatibility is an important determinate of nonhost infection outcomes of rust diseases on cereals, with cereal rusts being more capable of infecting a cereal nonhost species compared with rust species that are adapted for dicot hosts.
authors: CSIRO Plant Indudtry, Box 1600, Canberra, ACT, 2601, Australia. michael.ayliffe@csiro.au
authors: Michael
authors: M
authors: Ayliffe
authors: Rosangela
authors: R
authors: Devilla
authors: Rohit
authors: R
authors: Mago
authors: Rosemary
authors: R
authors: White
authors: Mark
authors: M
authors: Talbot
authors: Anthony
authors: A
authors: Pryor
authors: Hei
authors: H
authors: Leung
mesh_terms: D001483:Base Sequence; D001487:Basidiomycota / Q000145:classification / Q000472:pathogenicity*; D003433:Crosses, Genetic; D018744:DNA, Plant / Q000235:genetics; D017343:Genes, Plant; D014644:Genetic Variation; D054884:Host-Pathogen Interactions / Q000235:genetics / Q000502:physiology; D006861:Hydrogen Peroxide / Q000378:metabolism; D020082:Magnaporthe / Q000472:pathogenicity; D009154:Mutation; D012275:Oryza / Q000235:genetics / Q000382:microbiology* / Q000502:physiology; D010935:Plant Diseases / Q000235:genetics / Q000382:microbiology; D015398:Signal Transduction; D013045:Species Specificity
chemical_list: D018744:DNA, Plant; D006861:Hydrogen Peroxide