Downregulation of ovule-specific MADS box genes from petunia results in maternally controlled defects in seed development.

A maternally determined seed defect has been obtained by downregulation of the petunia MADS box genes Floral Binding Protein 7 (FBP7) and FBP11. These genes have been previously shown to play central roles in the determination of ovule identity. Aberrant development of the seed coat and consequent degeneration of the endosperm have been observed in transgenic plants in which these two genes are downregulated by cosuppression.

Somatic embryogenesis and shoot regeneration from excised adventitious roots of the rootstock Rosa hybrida L. 'Moneyway'.

Plants were regenerated from excised adventitious roots of the rose rootstock 'Moneyway' via a three step procedure: callus induction, induction of somatic embryos and shoot development. Callus was induced on excised roots after incubation for 4 weeks in the dark on SH-medium (Schenk and Hildebrandt) containing 50 μM 2,4-dichlorophenoxyacetic acid. For embryo induction, calluses were transferred to hormone-free SH-medium and incubated for 8 weeks.

The petunia MADS box gene FBP11 determines ovule identity.

In contrast to the wealth of information relating to genes regulating floral meristem and floral organ identity, only limited data are available concerning genes that are involved in determining and regulating the identity and development of an ovule. We have recently isolated the floral binding protein 11 (FBP11) MADS box gene from petunia and found that it is expressed exclusively in ovule primordia and subsequently in the ovules, suggesting a role for this gene in ovule formation. To test this hypothesis, we constructed a recombinant gene in which the full-size FBP11 cDNA was placed under the control of a strong cauliflower mosaic virus 35S promoter.

A novel class of MADS box genes is involved in ovule development in petunia.

We isolated and characterized two ovule-specific MADS box cDNAs from petunia, designated floral binding protein (fbp) genes 7 and 11. The putative protein products of these genes have approximately 90% of their overall amino acid sequence in common. In situ RNA hybridization experiments revealed that both genes are expressed in the center of the developing gynoecium before ovule primordia are visible.

Functional interaction between the homeotic genes fbp1 and pMADS1 during petunia floral organogenesis.

The petunia MADS box floral binding protein (fbp) gene 1 represents a class B homeotic gene determining the identity of second and third floral whorl organs. Suppression of fbp1, which is highly homologous to the Antirrhinum gene globosa and Arabidopsis gene pistillata, results in the conversion of petals to sepals and stamens to carpels. In contrast to fbp1, the petunia homeotic gene pMADS1, encoding a protein homologous to the Antirrhinum protein DEFICIENS, has been shown to be involved in the formation of petals only.