Lila O. Vodkin

Research

Overview

The broad areas of research in our laboratory involve gene isolation, regulation, and transfer in higher plants. A major emphasis is to understand how specific plant traits are controlled by gene action at the molecular level.

These investigations exploit unusual mutations and unique genetic resources and they combine a multidisciplinary approach including functional genomics, genetics, biochemistry, and molecular biology.

Develop public genomics resources for soybean

Current projects focus on developing public genomic resources for soybean including a soybean EST (expressed sequence tag) database. We produce cDNA libraries from mRNAs that are expressed in various tissue and organ systems of the plant.

One of the major goals of the "Functional Genomics Program for Soybean" (soybeangenomics.cropsci.uiuc.edu) sponsored by the National Science Foundation, is to develop methods to measure the "global" expression profiles of thousands of soybean genes using microarray technology. We are printing and hybridizing microarrays containing 9,000 genes using mRNAs from various tissues and conditions as probes. The genomics projects will aid in gene discovery and in determining the function of soybean genes in plant growth and development.

Describe molecular bases of naturally occurring mutations

In other research, we are dissecting the genetic and molecular basis of mutations that affect the flavonoid pathway or cell wall protein synthesis (Plant Cell 8: 687-699, 1996; J. Hered. 89:508-515, 1998; Plant Molec. Biol. 40: 603-613, 1999;). We have determined that the biochemical and molecular basis for the soybean I (inhibitor) locus that prevents pigmentation of soybean seed coats is a cluster of genes that all encode the enzyme chalcone synthase (CHS). We have analyzed spontaneous mutations to the recessive i allele which restores pigmentation. Paradoxically, deletions of one member of the gene cluster lead to increased expression of the other members. The behavior of the duplicated CHS genes appears to be a naturally-occurring example of co-suppression or homology-dependent gene silencing phenomena that have been found in transgenic plants. Understanding the mechanism of how the duplicated genes CHS genes are silenced could lead to a better understanding of how to prevent gene silencing problems that are frequently encountered when foreign genes are added to plant genomes by genetic engineering.

Bacterial artificial chromosomes (BAC clones) that contain the CHS gene cluster have been isolated and are being sequenced. The I locus/CHS cluster is physically close to a gene encoding resistance to the cyst nematode, an organism that causes estimated yield losses equivalent to $0.5 billion in U.S. soybean production annually. In collaboration with other laboratories, we are using this knowledge to investigate this chromosome region for isolation and identification of a nematode resistance gene. Isolation of a resistance gene could lead to new strategies for biocontrol of this pest and enhance basic understanding of plant defense mechanisms.

Discover novel promoters with specific expression patterns

We have characterized a promoter preferentially expressed in soybean pods that can be used in strategies for crop improvement such as resistance to pathogens (Plant Molec. Biol. 41:217-231, 1999). We have used model systems as Arabidopsis for testing soybean promoter function in transgenic plants (Plant Science 137: 191-204, 1998).

Genetic engineering of soybean for altered seed composition or metabolic engineering

Recently, we have produced transgenic soybean plants that express foreign genes including the bovine b-casein gene under control of a seed specific promoter in order to examine localization and expression of foreign proteins within the seed (In Vitro Cell Dev. Biol-Plant 35:344-349, 1999). The promoter can be used to modify seed protein quality or quantity or metabolic pathways during seed development.

Current Research Funding

National Science Foundation, Illinois-Missouri Biotechnology Alliance, Illinois Soybean Program Operating Board, United Soybean Board

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