National Geographic photographer Anand Varma, left, and Black Hills State University graduate student Riston Haugen at a field site.
A Black Hills State University graduate student’s research on a rust fungus’s ability to manipulate the genes of a wild mustard plant and create a fake flower recently caught the attention of National Geographic.

National Geographic photographer Anand Varma contacted BHSU graduate student Riston Haugen last month looking for details about an ongoing research project that Haugen is conducting with Dr. David Siemens, BHSU associate professor of biology.  

Varma and Haugen connected through Dr. Barbara Roy, who served as Siemens' postdoctoral advisor. Roy, a professor at the University of Oregon, studied the plant interaction in Colorado in the early 90s.

Example of a wild mustard plant with its true flowers.
Example of the pseudoflower resulting from the infection of the rust fungus.
“We are actively researching it so (Varma) decided to come up here,” Haugen said. “Varma contacted me about the assignment he was working on, and I arranged to show him around the Black Hills region where the interaction naturally occurs. A few weeks later, we were out in the field searching for specimens to photograph.”

Haugen, a graduate student in the BHSU Integrative Genomics program, has been researching the effects the fungus has on the plants for the past few years. He extracted genetic material from affected and non-affected plants to see the difference in the gene expression profiles and identify the genes the fungus was likely manipulating. Haugen has also had international experience centered on his research. He worked with Dr. Liliana Cano and Dr. Sophien Kamoun at the Sainsbury Laboratory, a plant science research center in Norwich, England, on a parallel study involving pseudoflowers.

 “The infection alters host plant development, morphology, and physiology to produce a flower mimic that fools pollinators of neighboring plant species into dispersing fungal gametes,” Haugen said.  “It is an interesting phenomenon. We are trying to get a better understanding of the extent to which a parasite can manipulate gene expression in its host.”

The pseudoflowers are made by a parasitic rust fungus that invades particular species of wild mustard plants taking over the growth of the plants. The parasite suppresses the plant’s ability to produce its own bell-shaped flowers. Instead, an infected mustard plant creates a sweet-smelling yellow artificial bloom composed of modified leaves.

The wild mustard plants produce flowers naturally, however, they bloom later and produce tiny white flowers, not large, yellow ones, Haugen said. These yellow pseudoflowers attract insect pollinators that facilitate sexual reproduction for the fungus, he said.

The National Geographic article may not appear for more than a year, Haugen said noting that he is excited to see if the Black Hills research makes it into the final cut.

He added that he enjoyed working with Varma and was able to observe the development of pseudoflowers more closely and gain a new and different perspective on the interaction.