LABORATORY MEMBERS

Dr. Myeong-Je Cho, Associate Specialist
I have been working in this laboratory for seven years, involved in a project to over-express elements of a natural redox system based on thioredoxin. Adding the thioredoxin system to poor quality flour in vitro leads to a leavened loaf; its addition to the milk allergen, b -lactoglobulin reduces its allergenicity in a dog model. To investigate whether over-expressing elements of the system in vivo could result in improved quality cereal grains, I first developed relatively genotype-independent transformation systems for barley, wheat, rice, corn, oats, sorghum and a number of grass species (Cho et al., 1998, 1999, 2000). We then introduced constructs into barley, wheat, rice and sorghum that would lead to overexpression of components of the thioredoxin system in the endosperm. To date we have verified positive effects in barley, with a faster germinating seed that has higher levels of starch-degrading enzymes earlier in the germination process (Cho et al., 2001). Studies in wheat are underway on lowering allergenicity. I have also studied the genomic instability caused by the transformation process, developing strategies to mitigate its negative effects (Choi et al., 2002).

Dr. Rajvinder Kaur, Associate Specialist
I came to the laboratory in 2003, after obtaining Ph.D. degrees in Plant and Microbial Biology at the Australian National University and in Biological Chemistry at Punjab Agricultural University. I had no experience with transforming crop species but took on a project focused on improving the nutritional quality of sorghum. Although used mostly as an animal feed in the United States, sorghum is an important food crop for 300 million of the world’s poorest people in Africa.  My project involves introducing genes that we hope will increase the digestibility of sorghum since a high percentage of the calories (starch and protein) in sorghum is not digestible, in sharp contrast to other cereal crops. In addition cereals are not a complete source of protein since they lack certain key amino acids.  For this reason we are also introducing naturally occurring proteins that are high in these amino acids into the sorghum grain. I am also working on developing technologies that would allow us to develop genetically engineered crops that do not also contain selectable marker genes like those for antibiotic resistance.

Ling Meng, Graduate Student
I am involved in experiments focused on understanding transgene expression stability. I have conducted studies on two, sibling barley lines, which differ only in transgene expression stability. It appears that the difference between the line that stably expresses the transgene and the one that does not relates to methylation of certain regions of the promoter. I am also looking at the consequences on transgene expression f crossing a silenced plant with a nonsilenced plant and the effects of environmental stresses on transgene expression stability. I am conducting investigations on the mechanisms of transgene silencing in single-copy plants whose transgenes were delivered using the Ds-gene delivery system.

Dr. Jaswinder Singh, Associate Research Specialist
I recently came to the laboratory from Australia, where I worked on a project aimed at characterizing the seed storage proteins of wheat, utilizing a genetics and proteomics approach. My current project is focused on the use of the maize Ds transposable element as a tool to perform functional genomics in barley. We are attempting to develop hundreds of plants with mapped, independently transposed Ds elements, scattered throughout the genome. Researchers can then use lines with Ds elements near their gene of interest to cross with plants expressing Ac transposase in order to identify nearby genes by functional inactivation. The research will involve advanced technical skills, such as cereal transformation capabilities, nonradioactive DNA and RNA analysis, vector construction, cross-hybridization of parental plants, inverse PCR and mapping, and chromosomal architecture studies using DNase I. The project involves a collaboration with laboratories at Oregon State, the USDA-ARS in Aberdeen ID and the Max Planck Institute in Cologne Germany.

Dr. Shibo Zhang, Associate Specialist
My main research interest is to develop an understanding of the genetic and molecular mechanisms responsible for plant cell totipotency. Using identified plant developmental genes (e.g., kn1, ZmLEC1, ZmCDC2) as molecular makers, expression analysis was conducted using in situ RNA hybridization and immunolocalizations (Zhang et al., 1998; Zhang et al., 2002). Using these methods we showed that in vitro plant morphogenesis is likely to follow pathways similar to those involved in in vivo plant development, once somatic cells have acquired the competence to develop. We hope to use a genomic approach utilizing microarrays to identify early triggering factors during in vitro plant morphogenesis that permit somatic cells to undergo the entire process of plant development from a single cell, a phenomenon known as totipotency. I have also developed transformation technologies, based on the use of cultured meristematic tissues (Zhang et al., 1999). I am also involved in developing a database for the current barley genomics project that is on-going in the laboratory as well as using protein and gene databases to do comparative genomics among cereals and between cereals and Arabidopsis.

COLLABORATORS

Phil Bregitzer
Research Geneticist
National Small Grains Germplasm Research Facility
USDA-ARS, Aberdeen, ID USA
Phone: 208-397-4162 / Fax: 208-397-4165 / E-mail: pbregit@uidaho.edu

Bob B. Buchanan
Professor, Department of Plant and Microbial Biology
111 Koshland Hall
University of California
Berkeley, CA 94720-3102
Phone: 510-642-3590 / Fax: 510-642-7356 / E-mail: view@nature.berkeley.edu

Ian Godwin
Assoc. Prof. in Plant Molecular Genetics
School of Land and Food Sciences
The University of Queensland, Brisbane QLD 4072
Australia
Phone: +61-7-3365-2141 / Fax: +61-7-3365-1177
E-mail: i.godwin@mailbox.uq.edu.au
http://pig.ag.uq.edu.au/molecular

Patrick Hayes
Dept. of Crop and Soil Science
Oregon State University
Corvallis, OR 97331
Phone: 541-737-5878 / Fax: 541-737-1589 / E-mail: patrick.m.hayes@orst.edu

Meira Ziv
Professor, The Hebrew University of Jerusalem
Faculty of Agriculture, Department of Agriculture Botany and
The Warburg Center for Biotechnology in Agriculture
P.O. Box 12, Rehovot 76100
Israel
Phone: 972-8-9481915 / Fax: 972-8-9467763 / E-mail: meira@agri.huji.ac.il

FORMER LAB MEMBERS

Postdoctoral Associates
Hae-Woon Choi (Chungnam National University, Korea)
Sheila Colby (Hitachi)
Petra Frey (ETH, Zurich)
Hyun-Kyung Kim
Thomas Koprek (Max Planck Institute, Cologne)
David McElroy (DeKalb Plant Genetics, Maxygen)
Yuechun Wan (Monsanto)
Hyun-Suk Yu (University of California, Davis)
Xiao-Hong Yu (Brookhaven National Laboratory, Upton, NY)
Rui Yun (Technician, Stanford University)

Graduate Students
Christiana Acquaye (Graduate Student in Ghana)
Wen Jiang (Lab Assistant, Genentech, SSF)
Rosalind Williams-Carrier (Lab technician, University of Oregon)