Beschreibung:
<jats:title>Summary</jats:title><jats:p>The effect of auxin on stamen and pistil development in tobacco flowers was investigated by means of the localized expression of <jats:italic>rolB</jats:italic> (root loci B), an <jats:italic>Agrobacterium</jats:italic> oncogene that increases auxin sensitivity in a cell‐autonomous fashion. When <jats:italic>rolB</jats:italic> is driven by the promoter of the meiosis‐specific <jats:italic>Arabidopsis</jats:italic> gene <jats:italic>DMC1</jats:italic> (disrupted meiotic cDNA 1), expression occurs earlier in male than in female developing organs, resulting in a delay in anther dehiscence with respect to normal timing of pistil development. As a consequence of this developmental uncoupling, self‐pollination is prevented in <jats:italic>pDMC1:rolB</jats:italic> plants. Histological analysis of <jats:italic>pDMC1:GFP</jats:italic> plants indicates that in tobacco, this promoter is active not only in meiocytes but also in somatic tissues of the anther. In contrast, simultaneous expression of <jats:italic>rolB</jats:italic> in anther and pistil somatic tissues, achieved by expressing a construct containing <jats:italic>rolB</jats:italic> under the control of the promoter of the petunia gene <jats:italic>FBP7</jats:italic> (floral binding protein 7), results in a concomitant delay of both anther dehiscence and pistil development without affecting self‐pollination of the plants. Analysis of plants harboring the <jats:italic>pFBP7:GUS</jats:italic> construct shows that in tobacco, this promoter is active not only in the ovules, as described for petunia, but also in pistil and anther somatic tissues involved in the dehiscence program. The delay in anther dehiscence and pistil development could be phenocopied by exogenous application of auxin. Jasmonic acid (JA) could not rescue the delay in anther dehiscence. These results suggest that auxin plays a key role in the timing of anther dehiscence, the dehiscence program is controlled by the somatic tissues of the anther, and auxin also regulates pistil development.</jats:p>