Kuo-Chen Yeh

I. Discovery of useful plant genes for phytoremediation of heavy metals pollution

In our lab, we initiate to study the mechanisms of heavy metal resistance in higher plants under the mission of Institute of BioAgricultural Sciences . We intend to identify agronomically useful genes/regulatory elements or metal-binding proteins/peptides for phytoremediation. We choose Cd, Cu and Pb as the metal treatments in this study because they are not only key contaminants in Taiwan but also serious problems for the industrial countries. In the early phase of this study, we will employ Arabidopsis as a model system, since Arabidopsis has already been recognized and used as a powerful tool for various studies of plant biology, including plant-environment interactions. Use of the genetic/genomic resources of Arabidopsis for crop improvement has also been established as a feasible and effective approach.

We are carrying out the screening of activation-tagged and other mutagen-induced Arabidopsis mutants for altered resistance to the designated heavy metals and to pursue Arabidopsis transcriptional profiling studies of metal-responsive genes by DNA microarray technology. In addition, searching for metal-binding proteins/peptide sequences is expected to provide beneficial information for sorting out genes associated with potential metal-binding products. The potential role(s) of selected novel Arabidopsis metal-responsive genes in metal resistance and the potential application of such genes for phytoremediation will be analyzed by using transgenic gene silencing and overexpression approaches. Moreover, we are interested in identification and isolation of putative metal-responsive regulatory cis -element(s) and metal-transporters. By cross-referencing the data to be obtained from the studies of other plant stresses in our Institute, possible cross-links among certain specified signal transduction pathway networks and the genes involved in different aspects of plant- environment interactions will also be evaluated. Therefore, this study via networking with other projects in the Institute, including the studies on abiotic/biotic stresses and bio-informatics, is aimed to identify a group of agronomically important and useful genes/regulatory elements. These genes or genetic elements may benefit the establishment of technology systems for future research into molecular breeding of resistance to both biotic and abiotic stresses in tomato and relevant crop plants.

II. Molecular engineering on Chinese medicinal herbs to improve the production of useful phytomedicines

Herbal medicine has been used in remedying disease for thousands of years. The experience of thousands of years has suggested the existence of "medicinal" compounds in particular plants. Knowledge about these compounds and their functions, however, is still in its infancy. The identification of these compounds in medicinal plants is drawing increasing attention from modern pharmaceutical companies. Obtaining these compounds from either direct extraction or through chemical synthesis would be very expensive and would yield quantities too small for wide use.

Medicinal plants produce unique secondary metabolites, which apparently confer their “medicinal” nature. The primary function of these secondary metabolites is believed to influence ecological interactions between the plant and its environment. The engineering of herbal plants or other organisms to act as bioreactors to produce medicinally beneficial compounds is an important goal towards developing new medicines. Comprehensive knowledge regarding the identification of the biosynthetic pathways of targeted compounds will enhance and improve the production of these compounds by allowing for genetic modification of medicinal plants or reconstitution of the compounds in other organisms. We will be using molecular genetics to approach the better understanding of medicinal secondary metabolites. Moreover, it is our goal to improve the quality of medicinal plants through an in depth understanding of medicinal secondary metabolites and by constructing transgenic herbal plants with higher medicinal efficacy.