During the life cycle of plants and animals, a single cell produces a multicellular organism with many different specialized cell types. But how does it happen? How and why does asymmetrical cell division -- in which a single cell divides into two daughter cells with different characteristics -- happen? These are fundamental questions, and they are the primary research focus of NYU plant molecular biologist Philip N. Benfey.
Benfey works with plants because there is a relatively small number of different tissue types in plants as compared to animals. In particular, Benfey is interested in the root systems of plants. This is again for reasons of simplicity. The root has a simple radial structure, its growth is continuous, it is transparent and there are a small number of cell types.
In the May 26 issue of Cell, Benfey reports that he has identified a gene that governs how plant cells proliferate and organize to form root systems.
According to Benfey, the research has important implications for both biology and bioengineering. Benfey's article is entitled "The SHORT-ROOT Gene Controls Radial Patterning of the Arabidopsis Root through Radial Signaling." In the Cell article, Benfey reports that the Arabidopsis plant's SHORT-ROOT (SHR) gene governs asymmetric cell division in the root's cortex and endodermis (the layer of cells that regulates what chemicals are absorbed into the plant.)
In addition, Benfey found that the SHR gene governs the specific characteristics of the endodermis. By manipulating where in the plant the SHR gene was expressed, the researchers were able to manipulate the number of endodermal cell layers made in the root.
Benfey said, "Our findings have potential biotechnology applications and also implications for evolutionary biology."
"Our research findings might be used to improve such agronomic traits as tolerance for salinity and reliance on fertilizer. Because roots normally grow underground, it is very difficult to breed for roots that are best suited for a particular environment. The use of genetic engineering may provide a better means of addressing this problem.
From an evolutionary standpoint, it has been unclear how organs formed from very different cell division processes could end up with essentially the same tissues in the same places. Extending molecular research from Arabidopsis to roots of other species provides a unique system to understand the evolution of meristem organization both during embryogenesis and vegetative growth."
Philip Benfey received his Ph.D. in 1986 from Harvard Medical School. He then held a post-doctoral fellowship at the Rockefeller University, working on the regulation of gene expression in higher plants. He was appointed an assistant professor at the Rockefeller University in 1990 and then moved his laboratory to NYU in 1991 to set up an independent Plant Molecular Biology program.
This research was funded by grants from the National Institute of Health.
Journal
Cell