Tubulin genes and promotors

The main scope of plant biotechnology is to introduce desirable traits into agronomically important crops. Several transgenic crops have already become available that carry charcateristics modified by transformation. Current approaches rely on the transformation with genes that are under the control of promotor seqeunces cloned from different heterologous sources. This approach may suffer from the low efficiency in both expression and stability of the introduced sequence. In addition, the promotor sequences that are commmonly used may not be those that are best suited for the plant of interest. This chapter will focus on an approach based on tubulin genes that may overcome some of these problems. The idea of this approach is to find a more "natural" method for plant transformation by exploiting features that are specific for coding and promotor sequences of tubulin genes. All plants contain tubulin and tubulins can therefore be exploited to design systems for homologous plant transformation that make use of specific characteristics of these genes. For instance, one could isolate new promotor sequences that confer tissue-specific or ubiquitous expression and use them for the production of transgenic plants that are more resistant to stress or drugs. The characteristics of plant tubulin genes and gene products will therefore be reviewed with focus on research that could possibly lead to appllications in biotechnology. In the final part of the chapter, a potential application of tubulin features forplant transformation will be discussed and a versatile molecular tubulin kit (VMTK) system for plant transformation will be proposed.