title: High temperature effects on Pi54 conferred resistance to Magnaporthe oryzae in two genetic backgrounds of Oryza sativa.
abstract: The global temperatures are predicted to rise due to climate change. However, knowledge on the mechanisms underlying the effect of high temperature (HT) on plant pathogen interaction is limited. We investigated the effect of elevated temperature on host phenotypic, biochemical and gene expression patterns in the rice-Magnaporthe oryzae (Mo) pathosystem using two genetic backgrounds, Co39 (Oryzae sativa-indica) and LTH (O. sativa-japonica) with (CO and LT) and without (Co39 and LTH) R gene (Pi54). After exposure to 28°C and 35°C the two genetic backgrounds showed contrasting responses to Mo. At 28°C, CO, Co39 and LTH displayed a more severe disease phenotype than LT. Surprisingly, CO became resistant to Mo after exposure to 35°C. CO and LT were used for further analysis to determine the defence related biochemical and transcriptome changes associated with HT induced resistance. Pre-exposure to 35°C triggered intense callose deposits and cell wall fluorescence of the attacked epidermal cells, as well as, increased hydrogen peroxide (H2O2) and salicylic acid (SA) levels. Transcriptional changes due to combined stress (35°C+Mo) were largely overridden by pathogen infection in both backgrounds, suggesting that the plants tended to shift their response to the pathogen. However, significant differences in global gene expression patterns occurred between CO and LT in response to both single (35°C and Mo) and double stress (35°C+Mo). Collectively, our results suggest that rice lines carrying Pi54 respond to Mo by rapid induction of callose and H2O2, and that these resistance mechanisms are amplified at HT. The relative difference in disease severity between CO and LT at 28°C suggests that the genetic background of japonica rice facilitates the function of Pi54 more than the background of indica rice. The phenotypic plasticity and gene expression differences between CO and LT reveal the presence of intricate background specific molecular signatures that may potentially influence adaptation to plant stresses.
authors.affiliation: Division of Plant Pathology and Crop Protection, Department of Crop Sciences, Georg-August-University Göttingen, Germany; International Rice Research Institute (IRRI), DAPO Box 7777, Metro Manila, Philippines. Electronic address: gonaga@gwdg.de.
authors.forename: Geoffrey
authors.initials: G
authors.lastname: Onaga
authors.affiliation: Erfurt University of Applied Sciences, Horticulture - Plant Production and Climate Change, Leipziger Str. 77, 90085 Erfurt, Germany.
authors.forename: Kerstin
authors.initials: K
authors.lastname: Wydra
authors.affiliation: Division of Plant Pathology and Crop Protection, Department of Crop Sciences, Georg-August-University Göttingen, Germany.
authors.forename: Birger
authors.initials: B
authors.lastname: Koopmann
authors.affiliation: International Rice Research Institute (IRRI), DAPO Box 7777, Metro Manila, Philippines.
authors.forename: Dmytro
authors.initials: D
authors.lastname: Chebotarov
authors.affiliation: Africa Rice Center, P.O. Box 33581, Dar es Salaam, Tanzania.
authors.forename: Yakouba
authors.initials: Y
authors.lastname: Séré
authors.affiliation: Division of Plant Pathology and Crop Protection, Department of Crop Sciences, Georg-August-University Göttingen, Germany.
authors.forename: Andreas
authors.initials: A
authors.lastname: Von Tiedemann
mesh_terms: D002473:Cell Wall / Q000378:metabolism; D057231:Climate Change; D060467:Disease Resistance / Q000235:genetics* / Q000502:physiology*; D020869:Gene Expression Profiling; D018506:Gene Expression Regulation, Plant; D063990:Gene Ontology; D000068617:Genetic Background; D005936:Glucans / Q000378:metabolism; D054884:Host-Pathogen Interactions; D006358:Hot Temperature; D006861:Hydrogen Peroxide / Q000378:metabolism; D020082:Magnaporthe / Q000472:pathogenicity*; D012275:Oryza / Q000235:genetics* / Q000382:microbiology*; D010641:Phenotype; D010935:Plant Diseases / Q000382:microbiology; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D020156:Salicylic Acid / Q000378:metabolism; D013312:Stress, Physiological; D059467:Transcriptome
chemical_list: D005936:Glucans; D010940:Plant Proteins; C048306:callose; D006861:Hydrogen Peroxide; D020156:Salicylic Acid
keywords: Climate change; Genetic background; Magnaporthe oryzae; R genes; Rice