Siobhan Brady, an associate professor in the Department of Plant Biology and the Genome Center, was recently named as one of 84 Howard Hughes Medical Institute Faculty Scholars for 2016. As described by HHMI, ‘Faculty Scholars are early career researchers with impressive accomplishments who have strong potential to make groundbreaking contributions.’ The award, jointly announced by HHMI, the Simons Foundation and the Gates Foundation, includes a five-year grant of $1,500,000.
“This is great news and a well-deserved award for one of our star faculty members,” said Savithramma Dinesh-Kumar, chair of the Department of Plant Biology, College of Biological Sciences. “This unique award will empower Siobhan’s group to take the research program to novel new areas in plant biology.”
The award will support Brady’s research on gene networks that regulate growth of plant roots.
“I’m really grateful for the award and what it means for my lab to be able to do some cool and exciting science,” said Brady.
Brady’s lab is especially interested in a cell type called xylem, which forms the network of tubes from roots to shoots that provides both structural support and water transport. They are studying how different genes are switched on or off under different conditions, and how these gene networks create the xylem within the root.
“We want to understand the rules that are responsible for making the xylem cells, and how those rules change in response to a changing environment,” Brady said.
The lab works on Arabidopsis, tomato and sorghum. The new project will focus especially on sorghum, a staple grain for millions of people in Africa that is also being developed as a biofuel crop in the U.S.
Because sorghum grows in a wide variety of environments in Africa, it could give insights into how the crop, and plants in general, can adapt to different conditions, especially drought and water stress, Brady said.
Exploring roots can also tell us about the evolution of plants. Plants originally evolved to grow on top of water, with not much need for structural support or water transport. The evolution of xylem and root systems allowed plants to live on dry land.
“Xylem cells are pretty much responsible for the evolution of plant life that you see around you, from small weeds to sequoia trees,” Brady said. “Hopefully this will give us some evolutionary perspective on the strategies by which plants were able to explore their environment.”
As part of Brady’s efforts to understand how roots develop, her lab has taken promoters of known root genes and fused them to GFP, in order to precisely visualize where each gene is being expressed. In addition to microscopy, the fluorescent tag enables researchers to extract cells and separate the fluorescent ones via flow cytometry. RNA-seq of the sorted cells can then provide a much more targeted picture of cell-type specfic gene expression than was previously possible.
Another focus of Brady’s research is the elucidation of transcriptional networks, the closely regulated series of genetic activations and inactivations responsible for processes of plant development. These networks frequently borrow concepts from electrical engineering, such as feed-back and feed-forward loops, in order to describe genetic phenomena such as the patterning of lateral roots. By transforming individual genes from plants into yeast– along with some other molecular tricks– it is possible to characterize a large number of individual interactions and visualize the sum of their interactions as a type of circuit:
Identifying natural variability in the responsible genes may enable plant breeders to influence root architecture and develop drought-tolerant crops.
Recent publications from the Brady Lab include:
This post was co-authored by Andy Fell of UC Davis News and Media Relations.