Bulletin Spring‧Summer 2001

Prof. Hon-ming Lam received his BS and M.Phil. from the Department of Biology of The Chinese University in 1985 and 1987 respectively. He then pursued research at Northwestern University, obtaining his Doctor of Philosophy in molecular biology in 1992. He worked as a research scientist at New York University prior to joining his alma mater as an assistant professor in 1997. He is also a visiting professor to Sichuan University and The Chinese Academy of Agricultural Science. Prof. Lam's current research interest is plant molecular biology, in particular, plant signal transduction, crop improvement, plant functional genomics, and using plants as bioreactors. He is now the deputy director of the Area of Excellence on Plant and Fungal Biotechnology, one of three research programmes selected for funding by the University Grants Committee among all universities in Hong Kong. Prof. Lam's research output has been published in international journals, including Nature, Proceedings of the National Academy of Sciences USA, Annual Review of Plant Physiology and Plant Molecular Biology, Plant Cell, Plant Journal, and Plant Physiology. leaves and f r u i ts in the f o r m o f free asparagine, and stored as protein in seeds for future use. In ASN1 overexpressing lines, the protein content in seeds is some five to ten per cent higher as compared to the controls. This result is consistent with the traditional wisdom in seed selection for propagation. Implications of the Findings This research shows that the nitrogen metabolism of a plant can be altered by the manipulation of a single gene. In particular, it shows that in ASN1 overexpressing lines , the dramatic increase in free asparagine w i l l mean that the additional nitrogen resources are subsequently allocated to seeds. The study o f Arabidopsis thaliana not only elucidates the transportation and storage of nitrogen in plants, but the results also have great implications for cereal crops. Previous p h y s i o l o g i c al studies have show n that nitrogen re-allocation, especially during leaf senescence, is very important for efficient grain-filling of cereals. Prof . Lam indicated that in the future, it w i ll be important to test whether overproduction of asparagine i n ASN1 transgenic cereals w i l l also enhance the n i t r ogen content o f seeds i n these important crop plants, and to determine whether such enhancement is a t the expense of other vita l metabolic components. Prof. Lam is currently concentrating on ASN1 while beginning to develop research into ASN2 and ASN3. He predicts that the prime function o f ASN2 may be to combat stressful conditions, while little is known about ASN3 due to its l o w l e v e l o f expression. Asparagine Synthetase Genes: Their Roles in Plant Growth and Development 33