Infection biology and defence responses in sorghum against Colletotrichum sublineolum

TY - JOUR

T1 - Infection biology and defence responses in sorghum against Colletotrichum sublineolum

AU - Puttalingaiah, Basavaraju

AU - Shetty, Nandini Prasad

AU - Shetty, H. S.

AU - Neergaard, Eigil de

AU - Jørgensen, Hans Jørgen Lyngs

PY - 2009

Y1 - 2009

N2 - Aims: 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.Methods and Results: Infection biology and defence responses were studied quantitatively by light microscopy, H2O2 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 H2O2, 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 H2O2 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 H2O2 and HRGPs indicates roles in defence whereas the late accumulation in genotype BTx623 correlated with successful pathogenesis.Significance and Impact of the Study: The fact that there is a significant correlation between induced accumulation of H2O2, 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.

AB - Aims: 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.Methods and Results: Infection biology and defence responses were studied quantitatively by light microscopy, H2O2 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 H2O2, 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 H2O2 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 H2O2 and HRGPs indicates roles in defence whereas the late accumulation in genotype BTx623 correlated with successful pathogenesis.Significance and Impact of the Study: The fact that there is a significant correlation between induced accumulation of H2O2, 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.

U2 - 10.1111/j.1365-2672.2009.04234.x

DO - 10.1111/j.1365-2672.2009.04234.x

M3 - Journal article

C2 - 19302494

SN - 1364-5072

VL - 107

SP - 404

EP - 415

JO - Journal of Applied Microbiology

JF - Journal of Applied Microbiology

IS - 2

ER -