Biotechnology of floral development
- Methods for gene discovery and manipulation.
- Modern agro-biotechnology techniques.
- Reverse genetic system.
- Gene silencing.
- A more favored manipulation method.
- Ectopically express a particular gene or unlink the expression of a gene from its normal regulatory control pathway.
- A constitutive high level of expression of transgenes.
- Gene targets for biotechnology in flowering.
- Floral development and biotechnology in woody perennial species.
The understanding of floral development at a molecular level has proceeded at an unprecedented rate. Molecular genetic studies on two model plants, Antirrhinum and Arabidopsis in particular, have provided the foundation for this progress through the initial identification of genes involved in flowering. Recent efforts at elucidating the regulatory networks controlling the transition to flowering in the model plant Arabidopsis have identified over 80 independent loci, which have important roles in the control of flowering in this species. An even larger number of genes have been discovered controlling events downstream of floral initiation. This extensive compliment of genes also forms very complicated regulatory networks that integrate environmental and developmental mechanisms to coordinate the reproductive process. There have been many excellent review articles published recently, including those found in this volume, that provide an in-depth study of those genes involved in floral timing and floral organogenesis. The reader is encouraged to seek these out in order to appreciate the complexity inherent in the control of this vitally important developmental process.
[...] The relatedness between vine architecture and floral development combined with the apparent conservation of floral regulator sequence identity and expression pattern suggests fertile ground for agro-biotechnology approaches to assist in vine and grape improvement. The recent report of a mutation in the grape homologue of the Arabidopsis GAI gene indicates the important involvement of phytohormones, in particular GA, in the control of floral induction in this species. This is consistent with previous physiological studies. Another woody perennial, like grape, is the kiwifruit. [...]
[...] However, as described earlier, the overexpression of LFY in Arabidopsis and poplar results not only in the acceleration of flowering but also the malformation of floral organs suggesting that LFY expression alone in non-competent meristems is insufficient to trigger complete floral development and that additional unidentified factors are required. Vegetative to reproductive phase change The recently characterized BEL-1 like homeobox class gene regulators, PENNYWISE (PNY) and POUNDFOOLISH when combined as double mutants result in Arabidopsis plants whose meristems remain capable of receiving floral stimuli but are unable to complete the floral transition. [...]
[...] However, very recent work has indicated that the role of this system extends to the transcriptional regulation of certain genes in plants with a strong bias towards transcriptional regulators, some of which appear to be involved in floral development. The mechanism is triggered by the presence of double-stranded RNA species that are then cut into small 19?25 nucleotide RNAs called small interfering RNAs (siRNAs). These siRNAs then prime the system and target homologous sequences for degradation and in some cases interfere with translation. [...]