Cytological, genetic, and molecular analysis to characterize compatible and incompatible interactions between Medicago truncatula and Colletotrichum trifolii.
In this study, a new pathosystem was established using the model plant Medicago truncatula and Colletotrichum trifolii, the causal agent of anthracnose on Medicago sativa. Screening of a few M. truncatula lines identified Jemalong and F83005.5 as resistant and susceptible to Colletotrichum trifolii race 1, respectively. Symptom analysis and cytological studies indicated that resistance of Jemalong was associated with a hypersensitive response of the plant. The two selected lines were crossed, and inoculations with C. trifolii were performed on the resulting F1 and F2 progenies. Examination of the disease phenotypes indicated that resistance was dominant and was probably due to a major resistance gene. Molecular components of the resistance were analyzed through macroarray experiments. Expression profiling of 126 expressed sequence tags corresponding to 92 genes, which were selected for their putative functions in plant defense or signal transduction, were compared in Jemalong and F83005.5 lines. A strong correlation was observed between the number of up-regulated genes and the resistance phenotype. Large differences appeared at 48 h postinoculation; more than 40% of the tested genes were up-regulated in the Jemalong line compared with only 10% in the susceptible line. Interestingly, some nodulin genes were also induced in the resistant line upon inoculation with C. trifolii.
UMR 5546 CNRS-UPS, Pô1e de Biotechnologie Végétale, 24 Chemin de Borde Rouge, BP17 Auzeville, 31326 Castanet-Tolosan, France.
Carine
C
Torregrosa
Stéphanie
S
Cluzet
Joëlle
J
Fournier
Thierry
T
Huguet
Pascal
P
Gamas
Jean-Marie
JM
Prospéri
Marie-Thérèse
MT
Esquerré-Tugayé
Bernard
B
Dumas
Christophe
C
Jacquet
D020231:Colletotrichum / Q000235:genetics / Q000378:metabolism / Q000472:pathogenicity*; D003433:Crosses, Genetic; D020224:Expressed Sequence Tags; D020869:Gene Expression Profiling; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant; D006861:Hydrogen Peroxide / Q000378:metabolism; D029902:Medicago / Q000235:genetics / Q000378:metabolism / Q000382:microbiology*; D010636:Phenols / Q000378:metabolism; D010641:Phenotype; D018515:Plant Leaves / Q000737:chemistry / Q000378:metabolism / Q000648:ultrastructure; D015854:Up-Regulation
D010636:Phenols; D006861:Hydrogen Peroxide