P-173 - Understanding the role of Colletotrichum higginsianum specialized metabolites produced specifically in the biotrophic stage of plant infection

Wednesday, July 16, 2025

13:30 - 15:15

Location: Confex Hall 3

Effector Interference Mechanisms

Presenting Author(s)

AD

Axelle E. Deroubaix (she/her/hers)

Universite Paris-Saclay, INRAE, BIOGER
Palaiseau, Ile-de-France, France

Author(s)

LP

Lorette Pfaff

Universite Paris-Saclay, INRAE, BIOGER
Palaiseau, Ile-de-France, France
CP

Celia Perdrizet

Universite Paris-Saclay, INRAE, BIOGER
Palaiseau, Ile-de-France, France
JV

Justine Vergne

Universite Paris-Saclay, INRAE, BIOGER
Palaiseau, Ile-de-France, France
AC

Anthony Colas

Universite Paris-Saclay, INRAE, BIOGER
Palaiseau, Ile-de-France, France
RO

Richard J. O'Connell

Scientific Advisor of IMAFUN
Université Paris-Saclay, INRAE, UR BIOGER
Palaiseau, Ile-de-France, France
MV

Muriel Viaud

Group Leader team ECCP
Universite Paris-Saclay, INRAE, UR BIOGER
Palaiseau, Ile-de-France, France
JD

Jean-Felix Dallery

Group Leader
Universite Paris-Saclay, INRAE, UR BIOGER
Palaiseau

Plant pathogenic fungi secrete a range of molecules during host infection, including proteins and specialized metabolites (SMs). SMs are small molecules which are mainly known for their phytotoxicity. However, they can have a variety of other bioactivities, including manipulation of immune responses and other plant physiological processes. In fungi, genes encoding enzymes necessary for SM biosynthesis are located at the same genetic locus in so-called Biosynthetic Genes Clusters (BGC). C. higginsianum, the causal agent of anthracnose disease of Brassicaceae, is an hemibiotrophic phytopathogen with a biotrophic phase confined to a single epidermal cell and is able to colonize the model plant Arabidopsis thaliana. Transcriptomic studies of A. thaliana infection stages revealed the specific expression of 19 BGCs, among which 14 were expressed in mature appressoria formed in planta and during the biotrophic phase but not in appressoria formed in vitro nor during the necrotrophic phase, and were termed BHBs (BiotropHic BGCs). To decipher the role of SMs produced by these BHBs, knock-out mutants were generated and their pathogenicity was assayed on plants. This led to the identification of two BHBs required for successful infection. Further characterisation of these mutants and identification of the SMs corresponding to these BHBs is ongoing. Once isolated and structurally characterized, the plant molecular targets of these SMs will be explored.