Résumé
Strawberry (
F
ragaria
×
ananassa
) fruits contain high concentrations of flavonoids. In unripe strawberries, the flavonoids are mainly represented by proanthocyanidins (
PA
s), while in ripe fruits the red‐coloured anthocyanins also accumulate. Most of the structural genes leading to
PA
biosynthesis in strawberry have been characterized, but no information is available on their transcriptional regulation. In
A
rabidopsis thaliana
the expression of the
PA
biosynthetic genes is specifically induced by a ternary protein complex, composed of
A
t
TT
2 (
A
t
MYB
123),
A
t
TT
8 (
A
tb
HLH
042) and
A
t
TTG
1 (
WD
40‐repeat protein).
A strategy combining yeast‐two‐hybrid screening and agglomerative hierarchical clustering of transcriptomic and metabolomic data was undertaken to identify strawberry
PA
regulators.
Among the candidate genes isolated, four were similar to
AtTT2
,
AtTT8
and
AtTTG1
(
FaMYB9
/
FaMYB11
,
FabHLH3
and
FaTTG1
, respectively) and two encode putative negative regulators (
FaMYB5
and
FabHLH3∆
). Interestingly,
FaMYB9
/
FaMYB11
,
FabHLH3
and
FaTTG1
were found to complement the
tt2‐1
,
tt8‐3
and
ttg1‐1 transparent testa
mutants, respectively. In addition, they interacted in yeast and activated the
A
rabidopsis
BANYULS
(anthocyanidin reductase) gene promoter when coexpressed in
P
hyscomitrella patens
protoplasts.
Taken together, these results demonstrated that
FaMYB9
/
FaMYB11
,
FabHLH3
and
FaTTG1
are the respective functional homologues of
AtTT2
,
AtTT8
and
AtTTG1
, providing new tools for modifying
PA
content and strawberry fruit quality.