by Klaas van Wijk

Maize leaf

The National Science Foundation (genome program) has just awarded $5.6 million towards a new 4 year collaborative project between researchers at Yale and Cornell University. Plant Biology Faculty Klaas van Wijk, Robert Turgeon and adjunct member Thomas Brutnell (at the BTI) will work in close collaboration with Cornell computational biologist Qi Sun at Cornell's Computational Biology Service Unit (CBSU), and with Tim Nelson at Yale and Peng Liu at Iowa State University.

This project concerns a Comparative Analysis of C3 and C4 Leaf Development in Rice, Sorghum and Maize. The C4 grasses include essential cereal crops, such as maize and sorghum, and some of the most promising biofuel crops such as switchgrass (Panicum virgatum). In leaves of such C4 grasses photosynthetic activities are partitioned between two morphologically and biochemically distinct bundle sheath (BS) and mesophyll (M) cells. This C4 specialization makes C4 plants more efficient, leading to more biomass accumulation, in particular when water is limited and/or the ambient temperatures are high. C4 differentiation occurs along a developmental gradient.

by Klaas van Wijk

TEM of maize leaft showing mesophyll and bundle sheath cells with their chloroplasts

During evolution, C4 plants evolved from C3-type ancestral species, with particular frequency among the grasses. The objectives of the new project are to compare the quantitative and qualitative patterns of transcripts, proteins, metabolic activities and anatomy at discrete stages and in specific cell types in rice (a C3 plant), maize and sorghum, and to develop a model of the regulatory networks governing C4 anatomy and function. These experimental datasets will be linked by new informatics tools for comparative transcriptional and proteome analysis. The detailed cellular gradient framework will provide the foundation for a systems biology approach to understanding C4 biology.