Dong Wang, biochemistry and molecular biology, has been honored with one of Harvard University’s two 2018 Sargent Award for Visiting Scholars at the Arnold Arboretum. The award will support his further research on bacteria known as rhizobia. They live in nodules on the roots of legumes to fix nitrogen from the soil, which nurtures the host plant.
“It’s a small award, but a very nice honor,” says Wang of the $5,000 support he will receive for research materials and travel. He believes he may be the first faculty researcher from campus to receive one. “I hope to be on sabbatical and the award will help me to use the arboretum’s plant collection. They have a very nice collection of woody plants from all over the world, in particular from East Asia. I can go there and study roots from these plants without having to travel far.”
Jennifer Normanly, head of the department, says, “Professor Wang is particularly known for providing insight into the molecular mechanisms of plant-microbe interactions during symbiosis – the fascinating and intricate biological process in which certain bacterium are encapsulated in the roots of a host plant, metabolically transformed and controlled by the host plant for its benefit instead of being perceived as a pathogen and barraged with plant defense compounds. His research has the potential to provide solutions to the global need for sustainable agricultural productivity.”
Wang’s work will be valuable “not only to his research program, but to the teaching mission of the department of biochemistry and molecular biology,” she adds.
The Arnold Arboretum offers exceptional resources for woody plant research. It is home to 15,000 living plants and is distinguished as one of the most thoroughly documented collections of temperate woody plants in the world. Taxonomic diversity and breadth within the collection are noteworthy, and the floras of China, Japan and Korea are particularly well represented.
Common legumes familiar to most people are annual crops such as peas and beans, Wang says, but legumes can also be trees such as acacia, and he wants to investigate whether their longer life spans and different ecology lead them to adopt different strategies for hosting rhizobia on their roots. Very little is known about how trees’ deep-penetrating roots recruit rhizobia and retain compatible strains over many growing seasons to satisfy their nutritional needs, he notes.
“Herbaceous plants live for just a year. I want to find out, if you are a perennial, will you have a different strategy for keeping your microbial friends around,” Wang says.
He will collect nodules from trees maintained at the arboretum. Certain groups of legumes have evolved ways to make the survival of their rhizobia dependent on their hosts. This represents a case of plants “domesticating” beneficial microbes for maximal advantage in this relationship, Wang says. Using specimens at the arboretum, he will investigate this and other molecular-level strategies of rhizobial interaction among woody nitrogen-fixing plants.