Auxin response factors ARF6 and ARF8 promote jasmonic acid production and flower maturation.
Pollination in flowering plants requires that anthers release pollen when the gynoecium is competent to support fertilization. We show that in Arabidopsis thaliana, two paralogous auxin response transcription factors, ARF6 and ARF8, regulate both stamen and gynoecium maturation. arf6 arf8 double-null mutant flowers arrested as infertile closed buds with short petals, short stamen filaments, undehisced anthers that did not release pollen and immature gynoecia. Numerous developmentally regulated genes failed to be induced. ARF6 and ARF8 thus coordinate the transition from immature to mature fertile flowers. Jasmonic acid (JA) measurements and JA feeding experiments showed that decreased jasmonate production caused the block in pollen release, but not the gynoecium arrest. The double mutant had altered auxin responsive gene expression. However, whole flower auxin levels did not change during flower maturation, suggesting that auxin might regulate flower maturation only under specific environmental conditions, or in localized organs or tissues of flowers. arf6 and arf8 single mutants and sesquimutants (homozygous for one mutation and heterozygous for the other) had delayed stamen development and decreased fecundity, indicating that ARF6 and ARF8 gene dosage affects timing of flower maturation quantitatively.
Nagpal
Punita
P
Department of Biology, University of North Carolina at Chapel Hill, CB #3280, Coker Hall, Chapel Hill, NC 27599-3280, USA.
Ellis
Christine M
CM
Weber
Hans
H
Ploense
Sara E
SE
Barkawi
Lana S
LS
Guilfoyle
Thomas J
TJ
Hagen
Gretchen
G
Alonso
José M
JM
Cohen
Jerry D
JD
Farmer
Edward E
EE
Ecker
Joseph R
JR
Reed
Jason W
JW
D017360:Arabidopsis / Q000235:genetics* / Q000502:physiology; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D003517:Cyclopentanes / Q000378:metabolism*; D017931:DNA Primers; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D035264:Flowers / Q000254:growth & development* / Q000378:metabolism / Q000648:ultrastructure; D018628:Gene Dosage / Q000502:physiology; D018507:Gene Expression Regulation, Developmental; D018506:Gene Expression Regulation, Plant; D007210:Indoleacetic Acids / Q000378:metabolism; D008855:Microscopy, Electron, Scanning; D009154:Mutation / Q000235:genetics; D020411:Oligonucleotide Array Sequence Analysis; D054883:Oxylipins; D010641:Phenotype; D010937:Plant Growth Regulators / Q000378:metabolism*; D030821:Plants, Genetically Modified; D011058:Pollen / Q000502:physiology
D029681:Arabidopsis Proteins; D003517:Cyclopentanes; D017931:DNA Primers; D004268:DNA-Binding Proteins; D007210:Indoleacetic Acids; D054883:Oxylipins; D010937:Plant Growth Regulators; C495666:auxin response factor 8, Arabidopsis; C011006:jasmonic acid