Auxin regulates Arabidopsis anther dehiscence, pollen maturation, and filament elongation.
We provide evidence on the localization, synthesis, transport, and effects of auxin on the processes occurring late in Arabidopsis thaliana stamen development: anther dehiscence, pollen maturation, and preanthesis filament elongation. Expression of auxin-sensitive reporter constructs suggests that auxin effects begin in anthers between the end of meiosis and the bilocular stage in the somatic tissues involved in the first step of dehiscence as well as in the microspores and in the junction region between anther and filament. In situ hybridizations of the auxin biosynthetic genes YUC2 and YUC6 suggest that auxin is synthesized in anthers. In agreement with the timing of auxin effects, the TIR1, AFB1, AFB2, and AFB3 auxin receptor-encoding genes are transcribed in anthers only during late stages of development starting at the end of meiosis. We found that in tir1 afb triple and quadruple mutants, anther dehiscence and pollen maturation occur earlier than in the wild type, causing the release of mature pollen grains before the completion of filament elongation. We also assessed the contribution of auxin transport to late stamen developmental processes. Our results suggest that auxin synthesized in anthers plays a major role in coordinating anther dehiscence and pollen maturation, while auxin transport contributes to the independent regulation of preanthesis filament elongation.
Cecchetti
Valentina
V
Dipartimento di Genetica e Biologia Molecolare, Istituto Pasteur Fondazione Cenci Bolognetti, Università La Sapienza, 00185 Rome, Italy.
Altamura
Maria Maddalena
MM
Falasca
Giuseppina
G
Costantino
Paolo
P
Cardarelli
Maura
M
D017360:Arabidopsis / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism; D029681:Arabidopsis Proteins / Q000235:genetics / Q000502:physiology; D044783:F-Box Proteins / Q000235:genetics / Q000502:physiology; D035264:Flowers / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism*; D018507:Gene Expression Regulation, Developmental; D018506:Gene Expression Regulation, Plant; D049452:Green Fluorescent Proteins; D017403:In Situ Hybridization; D007210:Indoleacetic Acids / Q000378:metabolism*; D008969:Molecular Sequence Data; D011058:Pollen / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D011956:Receptors, Cell Surface / Q000235:genetics / Q000502:physiology
D029681:Arabidopsis Proteins; D044783:F-Box Proteins; D007210:Indoleacetic Acids; D011956:Receptors, Cell Surface; C501405:TIR1 protein, Arabidopsis; D049452:Green Fluorescent Proteins