Jianru Zuo

Our laboratory mainly focuses on the cytokinin signal transduction network and functional genomics by the use of Arabidopsis thaliana as a model system. 

Cytokinin is one of the so-called "classic" plant hormones, and plays an essential role in almost all aspects of plant growth and development. Despite of many years' efforts, very little is known about the genetic control and molecular mechanism of the cytokinin action as well as biosynthesis of the hormone. Using a functional screening strategy, we have been able to identify and characterize several Arabidopsis mutants (designated as plant growth activator or pga mutants) with an altered cytokinin response. We are taking a combined genetic, molecular, cellular, biochemical and genomic approach to functionally characterize pga1 and pga22 mutants, both of which show typical cytokinin response. On the other hand, we are also screening for suppressor mutants of pga1 and pga22. In long term, these studies will be able to provide important and, possibly, critical clues for our understanding on the molecular mechanism of cytokinin signaling, and have substantial impacts on agronomic applications.

The completion of the Arabidopsis genomic sequencing project by an internationally collaborative effort and of the rice genomic sequencing project by Chinese scientists, dominantly by researchers in our Institute, represents a major advance in plant biology. Similar to that in other model species (e.g., yeast, Drosophila and C. elegans), we are now challenged to uncover the function of these seemingly-random assembled nucleotide sequences during the post-genome era. To reveal the precise function of a gene, mutational analysis is a classic approach and, up to date, is still the most powerful tool. A national-wide collaborative project on Plant Functional Genomic was launched on in 2001, mainly sponsored by The Ministry of Science and Technology of China and NSCF. One of the major efforts of the Project is to generate large mutant collections of both Arabidopsis and rice. In contrast to that employing the conventional T-DNA insertional mutagenesis or a constitutive enhancer/promoter-based activation tagging approach, we are using the tightly-controlled and highly-inducible XVE expression system (Zuo et al., Plant J., 24:265, 2000) to generate our mutant collections. The advantage of this inducible expression tagging system will allow us to recover mutations that cause severely developmental defects or even lethality by inducer withdrawal. The Arabidopsis project, coordinated by our laboratory, is expected to complete in 2005 by generating approximately 130,000 mutants. Our laboratory is also a member of the Rice Project team.

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