Unser 10. Leibniz Plant Biochemistry Symposium am 7. und 8. Mai war ein großer Erfolg. Thematisch ging es in diesem Jahr um neue Methoden und Forschungsansätze der Naturstoffchemie. Die exzellenten Vorträge über Wirkstoffe…
Omanische Heilpflanze im Fokus der Phytochemie IPB-Wissenschaftler und Partner aus Dhofar haben jüngst die omanische Heilpflanze Terminalia dhofarica unter die phytochemische Lupe genommen. Die Pflanze ist reich an…
Geschmack ist vorhersagbar: Mit FlavorMiner. FlavorMiner heißt das Tool, das IPB-Chemiker und Partner aus Kolumbien jüngst entwickelt haben. Das Programm kann, basierend auf maschinellem Lernen (KI), anhand der…
Trujillo, M.; TROEGER, M.; NIKS, R. E.; Kogel, K.-H.; Hückelhoven, R.;Mechanistic and genetic overlap of barley host and non-host resistance to Blumeria graminisMol. Plant Pathol.5389-396(2004)DOI: 10.1111/j.1364-3703.2004.00238.x
Non‐host resistance of barley to Blumeria graminis f.sp. tritici (Bgt ), an inappropriate forma specialis of the grass powdery mildew fungus, is associated with formation of cell wall appositions (papillae) at sites of attempted fungal penetration and a hypersensitive cell death reaction (HR) of single attacked cells. Penetration resistance and HR are also typical features of race‐non‐specific and race‐specific resistance of barley to the appropriate Blumeria graminis f.sp. hordei (Bgh ), raising the question of whether genotypic differences in the cellular response of barley to Bgt are detectable. First, we analysed fungal penetration frequencies and HR in different barley accessions known to show altered non‐host resistance. In genotypes with limited resistance to inappropriate cereal rust fungi, we concomitantly detected low penetration resistance to Bgt and significant differences of HR rates during attack from Bgt . Second, we tested barley mutants known to show altered host responses to Bgh . The rar1‐mutation that suppresses many types of race‐cultivar‐specific resistances did not influence the non‐host response of the Bgt‐isolate used in this study. However, mutants of Ror1 and Ror2 , two genes required for full race non‐specific penetration resistance of mlo‐barley to barley powdery mildew fungus, exhibited altered defence response to Bgt , including higher frequencies of fungal penetration. On these mutants, growth of the inappropriate fungus was arrested subsequent to penetration by HR. Together, the data show that barley defence response to the wheat powdery mildew fungus is determined by similar factors as race‐specific and race‐non‐specific resistance to appropriate Bgh.
Publikation
Hückelhoven, R.; Trujillo, M.; Kogel, K.-H.;Mutations in Ror1 and Ror2 genes cause modification of hydrogen peroxide accumulation in mlo-barley under attack from the powdery mildew fungusMol. Plant Pathol.1287-292(2000)DOI: 10.1046/j.1364-3703.2000.00032.x
Race nonspecific resistance of barley against the barley powdery mildew fungus (Blumeria Graminis f.sp. Hordei, Speer, Bgh ) is mediated by recessive mlo alleles and is controlled by at least two additional genes ‘required for ml o‐specified disease resistance’ (Ror1 and Ror2 ). The pathogenesis‐related accumulation of hydrogen peroxide (H2O2) was comparatively analysed in a susceptible barley line (Hordeum vulgare L. Cv Ingrid, genotype Mlo Ror1, Ror2 ), a resistant Ingrid backcross line carrying the mutant allele mlo5 (BCIngrid‐mlo5, genotype mlo5 Ror1 Ror2 ), and in the moderately susceptible mutants A44 and A89 (genotypes mlo5 Ror1 ror2 and mlo5 ror1‐2 Ror2, respectively). In situ localization of H2O2 was performed by microscopic detection of 3,3‐diaminobenzidine (DAB) polymerization. In BCIngrid‐mlo5 , penetration resistance against Bgh attack was closely correlated to H2O2 accumulation in cytoplasmic aggregates and cell wall appositions beneath the appressorium. In contrast, H2O2 accumulation was almost completely absent in susceptible Ingrid. Lines with mutations in Ror genes showed less H2O2 accumulation beneath appressoria, but more interaction sites with whole cell H2O2 accumulation and hypersensitive cell death response than resistant BCIngrid‐mlo5 . Thus, mutations in Ror1 or Ror2 genes influence the cellular pattern of H2O2 accumulation in mlo plants attacked by Bgh . The data support the hypothesis that H2O2 accumulation is involved in resistance to fungal penetration.