How exactly bacterial pathogens cause diseases in plants remains a mystery and continues to frustrate scientists working to solve this problem. Now Wenbo Ma, a young plant pathologist at the University of California, Riverside, has performed research on the soybean plant in the lab that makes major inroads into our understanding of plant-pathogen interactions, a rapidly developing area among the plant sciences.
Her breakthrough research can help scientists come up with effective strategies to treat crops that have succumbed to disease or, when used as a preventative measure, to greatly reduce their susceptibility to disease.
In a paper published in the March issue of the journal Cell Host & Microbe, Ma, an assistant professor of plant pathology and microbiology, and her colleagues show that the bacterial pathogens target isoflavones, a group of compounds in plant cells that defend the plant from bacterial infection, resulting in a reduction in isoflavone production.
An arms race
First, the pathogens inject virulence bacterial proteins, called HopZ1, through needle-like conduits into the plant cells. These proteins then largely reduce the production of the isoflavones and promote disease development. However, by sensing the presence of HopZ1, the plants mount a robust resistance against the pathogen, including the production of a very high amount of isoflavones. At this point, the pathogen must come up with new strategies by either changing the kind of proteins it injects into the plant, not injecting any proteins at all, or injecting virulence proteins in a way that helps them escape detection by the plant. In this way, the virulence bacterial proteins and the plant host engage in an endless "arms race."
"One question we are still trying to answer is how at the molecular level the bacterial virulence proteins promote disease," Ma said. "Some scientists have shown that these proteins block signaling transduction pathways in the plant, which eventually weakens plant immunity. We are introducing a fresh perspective on this topic, namely, that the pathogens evolved strategies to directly attack the production of plant antimicrobial compounds, such as isoflavones, thus compromising the plant's defense mechanism."
Closing the circle
According to Ma, her results can be extrapolated to understand how plants defend themselves when attacked by pathogens. She is pleased to be resuming research first studied by UC Riverside's Noel Keen, the late plant scientist and a pioneer in molecular plant pathology, who did fundamental groundbreaking work on understanding how isoflavones and isoflavone-derived compounds play a role in defending plants against microbial infection.
"This was an important topic of study about 30 years ago, but then the topic was dropped by researchers and it lost momentum," Ma said. "My lab is now revisiting the problem. Of course, we still have many questions to answer. We need to fully understand how isoflavones function to protect plants so that we can design specific strategies aimed at better protecting the plant."
Ma's lab is also interested in understanding what makes pathogens what they are. Why is it that among ecologically similar bacteria, some cause disease while others do not? Her lab is also studying how plants evolve mechanisms to protect themselves from infection, how pathogens subvert this defense and become virulent again.
"Pathogens get wise to the disease-fighting strategies we use in agriculture," Ma said. "This is evolution at work. But with fundamental knowledge on how pathogens cause disease we can develop sustainable and applicable strategies to combat disease."
About Wenbo Ma
Ma received her doctoral degree in biology in 2003 at the University of Waterloo, Canada. Thereafter, she did postdoctoral research for three years at the University of Toronto, Canada. She joined UCR in 2006. Her awards and honors include a Regents' Faculty Fellowship at UCR, a postdoctoral fellowship from the Natural Sciences and Engineering Research Council of Canada, and the W.B. Pearson Medal from the University of Waterloo.
She chose the soybean plant to study because the pathogen she was interested in, Pseudomonas syringae, attacks the soybean plant. Soybean is the second largest crop and the largest agricultural export in the United States. In addition to being an important human and animal food crop, it is also a major feedstock for biodiesel.
Ma was joined in the research by UCR's Huanbin Zhou (first author of the research paper and a postdoctoral researcher in the Ma group), Jian Lin, Aimee Johnson, Robyn Morgan and Wenwan Zhong. Zhong is an assistant professor in the Department of Chemistry.
The research study was supported by grants from the National Science Foundation, UCR-Los Alamos National Laboratory collaborative program for plant diseases and the U.S. Department of Agriculture Experimental Station Research Support Allocation Process.
The University of California, Riverside (www.ucr.edu) is a doctoral research university, a living laboratory for groundbreaking exploration of issues critical to Inland Southern California, the state and communities around the world. Reflecting California's diverse culture, UCR's enrollment has exceeded 20,500 students. The campus will open a medical school in 2012 and has reached the heart of the Coachella Valley by way of the UCR Palm Desert Graduate Center. The campus has an annual statewide economic impact of more than $1 billion.
A broadcast studio with fiber cable to the AT&T Hollywood hub is available for live or taped interviews. To learn more, call (951) UCR-NEWS.
Iqbal Pittalwala | EurekAlert!
Researchers invent tiny, light-powered wires to modulate brain's electrical signals
21.02.2018 | University of Chicago
The “Holy Grail” of peptide chemistry: Making peptide active agents available orally
21.02.2018 | Technische Universität München
For the first time, a team of researchers at the Max-Planck Institute (MPI) for Polymer Research in Mainz, Germany, has succeeded in making an integrated circuit (IC) from just a monolayer of a semiconducting polymer via a bottom-up, self-assembly approach.
In the self-assembly process, the semiconducting polymer arranges itself into an ordered monolayer in a transistor. The transistors are binary switches used...
Breakthrough provides a new concept of the design of molecular motors, sensors and electricity generators at nanoscale
Researchers from the Institute of Organic Chemistry and Biochemistry of the CAS (IOCB Prague), Institute of Physics of the CAS (IP CAS) and Palacký University...
For photographers and scientists, lenses are lifesavers. They reflect and refract light, making possible the imaging systems that drive discovery through the microscope and preserve history through cameras.
But today's glass-based lenses are bulky and resist miniaturization. Next-generation technologies, such as ultrathin cameras or tiny microscopes, require...
Scientists from the University of Zurich have succeeded for the first time in tracking individual stem cells and their neuronal progeny over months within the intact adult brain. This study sheds light on how new neurons are produced throughout life.
The generation of new nerve cells was once thought to taper off at the end of embryonic development. However, recent research has shown that the adult brain...
Theoretical physicists propose to use negative interference to control heat flow in quantum devices. Study published in Physical Review Letters
Quantum computer parts are sensitive and need to be cooled to very low temperatures. Their tiny size makes them particularly susceptible to a temperature...
15.02.2018 | Event News
13.02.2018 | Event News
12.02.2018 | Event News
21.02.2018 | Life Sciences
21.02.2018 | Life Sciences
21.02.2018 | Materials Sciences