Jasmonate controls late development stages of petal growth in Arabidopsis thaliana.
In Arabidopsis, four homeotic gene classes, A, B, C and E, are required for the patterning of floral organs. However, very little is known about how the activity of these master genes is translated into regulatory processes leading to specific growth patterns and the formation of organs with specific shapes and sizes. Previously we showed that the transcript variant BPEp encodes a bHLH transcription factor that is involved in limiting petal size by controlling post-mitotic cell expansion. Here we show that the phytohormone jasmonate is required for control of BPEp expression. Expression of BPEp was negatively regulated in opr3 mutant flowers that are deficient in jasmonate synthesis. Moreover, the expression of BPEp was restored in opr3 flowers following exogenous jasmonate treatments. Expression of the second transcript variant BPEub, which originates from the same gene as BPEp via an alternative splicing event, was not affected, indicating that BPEp accumulation triggered by jasmonate occurs at the post-transcriptional level. Consistent with these data, opr3 exhibited an increase in petal size as a result of increased cell size, as well as a modified vein pattern, phenotypes that are similar to those of the bpe-1 mutant. Furthermore, exogenous treatments with jasmonate rescued petal phenotypes associated with loss of function of OPR3. Our data demonstrate that jasmonate signaling downstream of OPR3 is involved in the control of cell expansion and in limiting petal size, and that BPEp is a downstream target that functions as a component mediating jasmonate signaling during petal growth.
Brioudes
Florian
F
Reproduction et Développement des Plantes, Centre National de la Recherche Scientifique, Institut National de la Recherche Agronomique-Université Lyon 1-ENSL, IFR128 BioSciences, Ecole Normale Supérieure, 46 allée d'Italie, 69364 Lyon Cedex 07, France.
Joly
Caroline
C
Szécsi
Judit
J
Varaud
Emilie
E
Leroux
Julie
J
Bellvert
Floriant
F
Bertrand
Cédric
C
Bendahmane
Mohammed
M
D017360:Arabidopsis / Q000235:genetics* / Q000254:growth & development; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D051792:Basic Helix-Loop-Helix Proteins / Q000235:genetics / Q000378:metabolism*; D049108:Cell Enlargement; D003517:Cyclopentanes / Q000378:metabolism*; D018744:DNA, Plant / Q000235:genetics; D035264:Flowers / Q000254:growth & development*; D018507:Gene Expression Regulation, Developmental; D018506:Gene Expression Regulation, Plant; D009154:Mutation; D010088:Oxidoreductases / Q000378:metabolism; D054883:Oxylipins / Q000378:metabolism*; D010937:Plant Growth Regulators / Q000378:metabolism*; D012323:RNA Processing, Post-Transcriptional
D029681:Arabidopsis Proteins; D051792:Basic Helix-Loop-Helix Proteins; D003517:Cyclopentanes; D018744:DNA, Plant; D010088:Oxidoreductases; D054883:Oxylipins; D010937:Plant Growth Regulators; C514196:BIGPETAL protein, Arabidopsis; C011006:jasmonic acid; C416525:OPR3 protein, Arabidopsis