Widgets Magazine

Dinneny Lab examines plant growth

Led by plant biology associate professor José Dinneny, the Dinneny Lab explores plant growth in relation to environmental stressors, particularly investigating how plants’ roots sense water availability and characterizing how plants adapt to low-water conditions.

Dinneny first established his independent lab at the Temasek Lifesciences Laboratory at the National University of Singapore, but moved to his practice at Stanford in 2011 when he was recruited by the Carnegie Institute of Sciences Institution for Science in the Department of Plant Biology. Dinneny and his team of researchers have since made advances by employing new approaches and techniques to their field of study.

The research at the Dinneny Lab is centered on how plants interact with their environments. This includes the ways that plants sense changes in the salinity and availability of water in the soil as well as how plants ultimately respond to such changes in their environments in ways that allow them successfully survive.

Lab member and biology Ph.D. student Ying Sun explained why he thought people should care about the research on plants at the Dinneny Lab.

“Plants have a lot to teach us about the world,” Sun said. “We rely on them as not only a food source but also a fuel source … There is so much that we don’t know about plants, and there are a lot of really important discoveries to be made.”

The chief technique used by the team of researchers is light microscopy, in which light is used to observe root growth at various magnifications. The method is used to visualize the localization of proteins, the growth of the plant cells and the expression pattern of genes within the roots of the plant.

The team has also developed a new imaging system called GLO-Roots, which uses a luminescent enzyme called luciferase to aid in the study of gene expression and root architecture. Plants engineered to express this enzyme emit light from their roots. The GLO-Roots system allows the team to study environmental responses at the organ system level.

To explore plant-environment interactions at different scales of organization, the researchers employ a variety of modelling systems. Single-celled organisms such as chlamydomonas are used to study processes at the cellular scale and instances of rapid plant growth. To study these interactions at the tissue and system level, lab members conduct experimentation in the field.

Multicellular systems such as arabidopsis and sorghum are cultivated and observed to study how different soil conditions and water levels influence the growth and architecture of the root system and general plant physiology.

Carnegie Institution for Science postdoc Lina Duan, who has been a member of the lab since its inception in Singapore, uses arabidopsis in her projects as a model organism. Though arabidopsis is a weed, research findings gathered from its study are relevant to the field of agriculture, Duan said.

“It’s not very intuitive for people to see the application side of the project, but in the long term our discoveries about this plant can be applied to crop plants,” she said. “Some of my work and other work being done at the lab involves plants like maize so we are already trying to connect our research to crops.”

An important finding that Dinneny made during his previous research as a postdoc was that plant responses to different environmental conditions vary across different tissue and cell types. This signalled that research had to be done at a finer scale than that which had been conducted previously in order to fully understand how plants respond to environmental stresses.

By conducting research on a finer scale, Dinneny and his team have identified hormone-signalling pathways that act in cell types responsible for changes in growth of the plant. These findings have allowed researchers to manipulate the pathways in order to prevent negative effects on plant growth caused by environmental stresses.

The lab has also uncovered new plant responses to environmental variations. The team was able to identify a process which they termed “hydropatterning.” In this process, plant roots sense the direction of higher concentrations of water in their environments and stimulate the growth of root branches towards those regions.

We think that [hydropatterning] is important for creating a root system that is very efficient at directing growth and branches to regions in the soil that have higher amounts of water and reducing the input or investment that the plant makes in regions that have very limited amounts of water,” Dinneny said.

Maize is used as a model organism for studying the process of hydropatterning. Dinneny explained that the team has encountered different varieties of maize that vary in the amount of hydropatterning they exhibit. While some varieties only make root branches towards water, others direct their root branches towards both water and air. Identifying the gene that controls this difference is a current goal of the researchers at the lab.

According to Dinneny, studying these responses in plants have important real world applications.

“If we identify the difference between these two genomes, we may then be able select for that in particular crop plants,.” he said. “Agriculture is a very destructive human activity in terms of its impact on the environment. If we can grow plants more efficiently, then that means our impact on the environment through agriculture will be more limited.”

Dinneny believes that the work being done at the lab will be particularly beneficial for countries in which low-input agriculture is widely practiced. Through strategic breeding, improvements can be made so that agriculture is more productive.

Studying how plants respond to stressful environments also has useful applications for areas where there are limited water resources available, such as California. Dinneny points out that the use of groundwater resources for growing crops leads to unsustainable withdrawal of water from aquifers.

“Even in a developed country where the agriculture practiced is some of the most sophisticated in the world, there can still be improvements,” he said.

According to Dinneny, the diversity of the team of researchers at the lab is a key reason that the lab has been successful. He hopes that both graduate and undergraduate students from different backgrounds and majors will take advantage of the research opportunities available at the Dinneny Lab.

“It takes people who view the world differently to see things in ways that past generations haven’t,” Dinneny said. “Biological systems are just so immensely complicated. What changes in research are the people who are asking the questions, their backgrounds and their experiences. It’s a very personal process; it’s very amenable to bringing your unique perspectives.”

 

Contact Ruth-Ann Armstrong at ruthanna ‘at’ stanford.edu.