Savithramma Dinesh-Kumar, a professor of plant biology and interim chair of the Department of Plant Biology at the University of California, Davis, has received the College of Biological Sciences 2015-2016 Faculty Research Award. Based on colleague nominations, this award is presented annually to acknowledge a single research publication that reflects the exciting, innovative and significant advances in research within the College of Biological Sciences.

Dinesh-Kumar was recognized for his groundbreaking research in plant immunity and the role of chloroplast stromules in programmed cell death. His work was featured in the July 2015 edition of Developmental Cell, a leading academic journal on cell biology.

Through Dinesh-Kumar’s collaboration with Jeffrey Caplan’s team at the University of Delaware, this group of scientists amassed evidence that demonstrates stromules aid in the transportation of messages to the cell’s nucleus during plant immune responses. Stromules are microscopic pockets filled with thick fluid. Although this fluid (stroma) is usually located within the chloroplasts, during immune responses it is packed into a fibrous pocket known as a stromule and sent into the cytosol and nucleus of the cell.

“Our research work published in Developmental Cell was the first that provided a role for these structures,” says Dinesh-Kumar. “This is very exciting and this has opened up an exciting new area of research in plant biology.”

Dinesh-Kumar’s discovery is based on a previous finding that his lab made in which a certain protein, NRIP1, moved from the chloroplasts of plant cells into the cytosol when a pathogenic or viral infection occurred.

The research stromules function through the course of programmed cell death during the cell’s immune response. Stromules are thought to communicate messages initiated by hydrogen peroxide or salicylic acid and surround the nucleus of the cell where they make connections for the transport of signaling molecules and defense proteins.

Plants evolved with receptors that recognize invading pathogens and activate programmed cell death to limit pathogen growth to infected regions. The surface receptors also activate effector-triggered immunity which tells the cell which pathogen is attacking. During pathogen recognition chloroplasts change their structure and start sending out stromules.

“The role of stromules in plant immunity was not known before this publication,” says Steven Theg, professor of plant biology, who is familiar with Dinesh-Kumar’s work. “This appears to be central to the plant’s response to pathogenic attack. Certainly plant immunity was not part of the discussion concerning the role of stromules in chloroplast biology, but it will be now.”

“It is a great honor,” Dinesh-Kumar shared after he received this award. “Considering the research breadth and excellence of faculty members in CBS, it is great that our laboratory research work is recognized through this award.” Dinesh-Kumar’s lab will continue research into the role of stromules, while also investigating cell receptors and pathogen recognition processes.

Dinesh-Kumar’s paper on stromules was nominated as one of 2015’s most groundbreaking papers by the Global Plant Council and was featured as an Editor’s Choice for the American Association for the Advancement of Science’s Science Signaling publication.