The APSES transcription factor LmStuA is required for sporulation, pathogenic development and effector gene expression in Leptosphaeria maculans.
Leptosphaeria maculans causes stem canker of oilseed rape (Brassica napus). The APSES transcription factor StuA is a key developmental regulator of fungi, involved in morphogenesis, conidia production and also more recently described as required for secondary metabolite production and for effector gene expression in phytopathogenic fungi. We investigated the involvement of the orthologue of StuA in L. maculans, LmStuA, in morphogenesis, pathogenicity and effector gene expression. LmStuA is induced during mycelial growth and at 14 days after infection, corresponding to the development of pycnidia on oilseed rape leaves, consistent with the function of StuA described so far. We set up the functional characterization of LmStuA using an RNA interference approach. Silenced LmStuA transformants showed typical phenotypic defects of StuA mutants with altered growth in axenic culture and impaired conidia production and perithecia formation. Silencing of LmStuA abolished the pathogenicity of L. maculans on oilseed rape leaves and also resulted in a drastic decrease in expression of at least three effector genes during in planta infection, suggesting either that LmStuA regulates, directly or indirectly, the expression of several effector genes in L. maculans or that the infection stage in which effectors are expressed is not reached when LmStuA expression is silenced.
INRA, UMR 1290 INRA-AgroParisTech BIOGER, Avenue Lucien Brétignières, F-78850, Thiverval-Grignon, France.
Jessica L
JL
Soyer
INRA, UMR 1290 INRA-AgroParisTech BIOGER, Avenue Lucien Brétignières, F-78850, Thiverval-Grignon, France.
Audrey
A
Hamiot
INRA, UMR 1290 INRA-AgroParisTech BIOGER, Avenue Lucien Brétignières, F-78850, Thiverval-Grignon, France.
Bénédicte
B
Ollivier
INRA, UMR 1290 INRA-AgroParisTech BIOGER, Avenue Lucien Brétignières, F-78850, Thiverval-Grignon, France.
Marie-Hélène
MH
Balesdent
INRA, UMR 1290 INRA-AgroParisTech BIOGER, Avenue Lucien Brétignières, F-78850, Thiverval-Grignon, France.
Thierry
T
Rouxel
INRA, UMR 1290 INRA-AgroParisTech BIOGER, Avenue Lucien Brétignières, F-78850, Thiverval-Grignon, France.
Isabelle
I
Fudal
D001203:Ascomycota / Q000235:genetics / Q000472:pathogenicity / Q000502:physiology*; D029688:Brassica napus / Q000382:microbiology; D015966:Gene Expression Regulation, Fungal; D013172:Spores, Fungal / Q000235:genetics; D014157:Transcription Factors / Q000502:physiology*; D037521:Virulence Factors / Q000235:genetics
D014157:Transcription Factors; D037521:Virulence Factors
Leptosphaeria maculans; conidiation; effectors; morphogenesis; oilseed rape; regulation