title: Infection biology and defence responses in sorghum against Colletotrichum sublineolum.
abstract: OBJECTIVE
  To investigate the infection biology of Colletotrichum sublineolum (isolate CP2126) and defence responses in leaves of resistant (SC146), intermediately resistant (SC326) and susceptible (BTx623) sorghum genotypes.
  
  
  RESULTS
  Infection biology and defence responses were studied quantitatively by light microscopy, H(2)O(2) accumulation by DAB staining and HRGP accumulation by immunological methods. Inhibition of conidial germination and appressorium formation may represent prepenetration defence responses on the leaf surface. Inducible defence responses in the resistant genotypes included decreases in formation of appressoria as well as accumulation of H(2)O(2), HRGPs and phytoalexins. Concomitant with these inducible responses, fungal growth was stopped during or just after penetration in genotypes SC146 and SC326. High levels of H(2)O(2) accumulating at late infection stages (5 days after inoculation) in the susceptible genotype BTx623 correlated with necrosis and tissue degeneration.
  
  
  CONCLUSIONS
  The early accumulation of H(2)O(2) and HRGPs indicates roles in defence whereas the late accumulation in genotype BTx623 correlated with successful pathogenesis.
  
  
  CONCLUSIONS
  The fact that there is a significant correlation between induced accumulation of H(2)O(2), papilla formation and cell wall cross-linking, as evidenced by HRGP accumulation, and cessation of pathogen growth in resistant genotypes may help exploit host resistance in sorghum.
authors.affiliation: Department of Plant Biology and Biotechnology, Faculty of Life Sciences, University of Copenhagen, Frederiksberg C, Denmark.
authors.forename: P
authors.initials: P
authors.lastname: Basavaraju
authors.forename: N P
authors.initials: NP
authors.lastname: Shetty
authors.forename: H S
authors.initials: HS
authors.lastname: Shetty
authors.forename: E
authors.initials: E
authors.lastname: de Neergaard
authors.forename: H J L
authors.initials: HJ
authors.lastname: Jørgensen
mesh_terms: D020231:Colletotrichum / Q000472:pathogenicity*; D006023:Glycoproteins / Q000378:metabolism*; D054884:Host-Pathogen Interactions; D006861:Hydrogen Peroxide / Q000378:metabolism*; D010935:Plant Diseases / Q000382:microbiology; D018515:Plant Leaves / Q000166:cytology / Q000378:metabolism / Q000382:microbiology; D010940:Plant Proteins / Q000378:metabolism*; D045868:Sorghum / Q000378:metabolism* / Q000382:microbiology; D013172:Spores, Fungal / Q000472:pathogenicity
chemical_list: D006023:Glycoproteins; D010940:Plant Proteins; C005488:extensin protein, plant; D006861:Hydrogen Peroxide