Josie Heimsoth

By Josie Heimsoth | Bond LSC

When it comes to making better crops, CRISPR-Cas9 based gene editing have revolutionized plant science with its ability to more precisely and quickly alter plant DNA.

But the technology can also aid researchers in finding weaknesses in the enemies of crops like rice.

Bing Yang, a Bond Life Sciences Center researcher and MU professor of plant sciences, recently used the genome editing tool to modify bacteria responsible for rice blight, and it may be the answer scientists are looking for. He recently published his results in the journal Nature Communications Biology.

Bacterial blight causes a tremendous reduction in rice yields, and researchers, including Yang, made it their goal to understand the genetic basis of the bacteria to provide insight into host-pathogen interactions to plan effective control of blight.

“This disease could be a model system for the study of bacterial pathogens to effectively understand more crop diseases,” Yang said. “If we understand the disease, it can help us reduce other chronic diseases.”

Bacterial blight also causes the wilting and yellowing of leaves. Plants battle the microscopic bacteria, which colonize inside tissues to prevent the plant’s ability to deliver water and nutrients to the rest of the plant. These invasive bacteria do this to achieve their only purpose, which is to survive and reproduce.

The bacteria tend to thrive when the plant is at its weakest, “so that’s why there’s no effective and chemical way to cure or to control the disease,” Yang said. “The only effective way is making it genetically resistant.”

Though CRISPR-Cas9 can modify plants by precisely cutting DNA and then letting natural DNA repairing processes take over, bacteria genes can’t be edited that easily.

When infecting plants, bacteria try to take over the sucrose transporter system, which transports sugar out of resource and engages in plant growth and responses to abiotic stress. Without editing bacteria, there is no way of telling which genes play a role in causing disease, so Yang’s lab modified different genes with CRISPR-Cas9 deaminase until a modified bacteria stopped  hijacking a plant and killing it.

“If that [edited] gene in the bacteria cannot cause disease in the rice, it means that gene plays an essential role to help the bacteria cause disease,” Yang said.

CRISPR-Cas9 deaminase is what Yang’s lab uses for a wide range of genome editing applications in eukaryotes and prokaryotes. To achieve the result they desired, they needed to produce the right amount of CRISPR-Cas9 deaminase, otherwise it cannot have a desired effect on the bacteria cells.

“You want to express CRISPR-Cas9 deaminase in the bacteria cell, but not make it too high or too low,” Yang said. “If the deaminase is too low, you won’t see the effect on the bacteria, but if it’s too high, it kills the bacteria cell. You need to find the good sum.”

For Yang, rice is a crop that has been in his life from childhood in China to his current research. His father farmed the crop, and now, Yang continues to study its most significant disease, which is capable of killing up to 75 percent of a rice crop.

One of the benefits that sets CRISPR-Cas9 technology apart from others is it has given Yang’s lab results faster. Bacterial gene editing takes time and usually other methods have taken several months, while CRISPR-Cas9 deaminase gave them results in a number of weeks, making it a speedy research tool.

“You can look into the bacterial genes in groups and see which group helps the bacteria infect the rice,” Yang said. “It tremendously saves time and unlocks the bacteria much easier.”

These efforts are changing the game for gene modifying in bacteria, and with time could stop bacteria from having devastating impacts. Not only will the research help in rice, but can also serve with understanding bacterial disease in other plants, too.

The next step is to make this gene editing system more efficient.

“This is a very useful tool, which is not only benefited my lab, but also other labs which work on plant diseases,” Yang said.

Yang’s research is published in the paper, “Efficient CRISPR-Cas9 based cytosine base editors for phytopathogenic bacteria” in the publication Nature Communications Biology on January 17, 2023. You can read more about the study here.

By Josie Heimsoth | Bond LSC

Laxman Gangwani had a choice to make in January of last year. His old friend, Chris Lorson had an opportunity at MU that was difficult to pass up.

Gangwani and Lorson, principal investigator at Bond Life Sciences Center and professor of veterinary pathobiology, have known each other for more than 20 years while they were post-docs in different labs in Massachusetts. They would attend conferences for families with children diagnosed with spinal muscular atrophy across the United States, and thanks to a new opportunity to join MU’s faculty, they can collaborate and work on research projects together in the Midwest.

“It’s a small world,” Gangwani said.

Gangwani, a newly named professor of veterinary pathobiology, joined Bond LSC as part of Mizzou Forward, an effort to strengthen innovation in research and elevate Mizzou as one of the best research universities in the country.

Before coming to MU, Gangwani was a professor at Texas Tech for 12 years. He worked in the department of molecular and translational medicine. He ultimately decided that now was the time to try something new.

“I’m very excited to be here,” Gangwani said. “One of my motivations for coming here was to expand my research program. The facilities that I need are here, so I’m looking forward to it.”

Gangwani’s research program focuses on understanding the molecular basis neurodegeneration associated with the pathogenesis of motor neuron disorders — including spinal muscular atrophy (SMA), amyotrophic lateral sclerosis (Lou Gehrig’s Disease) and other neurological disorders such as Alzheimer’s disease (AD) and AD-related dementia (ADRD).

However, he wasn’t always involved in researching these neurodegenerative disorders. During his training as post-doc at UMass Medical School, he researched the zinc finger protein, ZPR1, a type of protein that communicates cell division signals from the cytoplasm to the nucleus and helps regulate the proliferation or division of cells. At the time, this protein was being investigated for its role in cancer because it engaged in binding and signaling messages from epidermal growth factor receptor (EGFR), which is mutated in cancer.

Back then, he looked for antibodies to detect and regulate ZPR1 activity to prevent it from helping create more cancer cells. To do so, they created mouse monoclonal antibodies to detect this protein in different species, including yeast, mice and humans. While looking through the different slides with each antibody clone, Gangwani discovered something intriguing.

“I found one slide, one clone, showing me very bright spots in the cell, just like Christmas lights,” Gangwani said. “I took some microscope photos and showed it to my postdoctoral supervisor, Dr. Roger Davis, and he said, ‘Well that’s fantastic! What is it?’ I had never seen anything like it.”

Gangwani noticed a similar phenomenon from another research paper involving the survival motor neuron (SMN) protein, which is mutated in SMA. This discovery was a turning point for him.

“We got a hold of spinal muscular atrophy (SMA) patient cells,” Gangwani said. “And I tested the ZPR1 and SMN interaction, which was disrupted in SMA. It was the most exciting find, so we published these findings in Nature Cell Biology, which was highlighted by News and Views. This was a turning point leading me to research in the field of neurosciences.”

Currently, his lab is looking into the function of ZPR1 and how it can cause nerves to break down. Gangwani discovered that ZPR1 interacts with survival motor neuron (SMN) proteins and found a mutation, SMN1, that disrupts the interaction of these proteins in patients with SMA. ZPR1 also interacts with a translation elongation factor (eEF1A), a contributor to protein synthesis on the ribosome. If it is disrupted, the latter protein complex will result in defects of cell growth.

Protein complexes play an important role in biological processes, and mutations of these complexes can cause different types of human genetic diseases ranging from cancer to neurodegenerative disorders.

Gangwani is also looking into how R-Loops, a three-stranded nucleic acid structure, contribute to neuron degeneration in SMA, ALS and other neurodegenerative diseases. Nucleic acids are chemical compounds serving as the primary information-carrying molecules in cells, also having an important role in protein synthesis. These disorders show dysregulation of R-loops and result in high or low levels of R-loops accumulation suggests that something is wrong.

“If the R-loops persist, that causes a stress on the DNA resulting in double-strand DNA breaks,” Gangwani said. “Cells normally have machinery that can repair DNA breaks, but if these loops keep accumulating and the cell is not able to either resolve R-loops or repair the DNA damage,  the cell is eventually going to die.”

That is also the case for neuron cells. The defect in DNA repair results in neurons unable to repair damage, leading to genomic instability and the demise of the neuron in the patient. The cause is believed to be the interaction between ZPR1 and Senataxin, which helps at the interface of transcription and the DNA response damage. Gangwani found that removing ZPR1 and Senataxin accumulates the R-loop.

For Gangwani, his motivation and research are about helping children with SMA. He wants to be one of the scientists and clinicians that dedicate their efforts to help people with genetic diseases.

“If I could do something for these kids to help them live a better life, then I want to do it,” Gangwani said. “Since then, I have been involved with neurodegenerative disease research.”

Gangwani is now interested in figuring out the downstream targets and signaling mechanisms activated by the disruption of these protein complexes. If his lab is able to identify these molecular targets, it would help develop therapeutic strategies to prevent neurodegeneration and one day prevent some of these debilitating diseases.

MizzouForward is a transformative, $1.5 billion long-term investment strategy in the continued research excellence of the University of Missouri. Over 10 years, MizzouForward will use existing and new resources to recruit up to 150 new tenure and tenure-track faculty to address some of society’s greatest challenges. Investments also will enhance staff to support the research mission, build and upgrade research facilities and instruments, augment support for student academic success, and retain faculty and staff through additional salary support.

By Josie Heimsoth and Cara Penquite | Bond LSC

David Mendoza unflinchingly faces the “black box” of plant science everyday, asking the question, ‘how do plants know if they don’t have enough nutrients?’

Mendoza’s study of micronutrients — elements vital to plant health and energy but only present in small quantities — led him to iron and a collaboration with Ron Mittler on a $1.2 million grant. The grant was awarded by the National Science Foundation in October 2022 to advance the understanding of autonomous leaf-specific iron deficiency responses.

“For iron, the window between being a nutrient and being a very toxic element is really narrow,” said Mendoza, a Bond LSC researcher and associate professor of plant sciences. “So, of course, to me that’s fascinating, right? How something can be so important for life, yet so dangerous that can kill the plant.”

Iron plays a key role in photosynthesis, giving plants energy. Plants sense if they are running low on it and other micronutrients like manganese and zinc in the leaves, which send signals to the roots and the rest of the plant. In response to those yet unknown signals, the roots start taking in more nutrients from the soil.

Mendoza worked with Mittler, fellow Bond LSC researcher and professor of plant sciences, to uncover how plants sense and respond to iron deficiency. Mittler’s research focuses on the role of reactive oxygen species (ROS) in the regulation of different biological processes, including regulation of iron metabolism.

ROS were once thought to primarily be destructive molecules of destruction because of their tendency to react and break down other molecules but have since been recognized as essential regulators of cellular and systemic signals in plants as well as animals. Additionally, they play an important role in hormonal, physiological, and developmental reactions in plants such as growth and development, defense and acclimation to environmental stress.

The partnership started when Sarah Zandalinas, a former postdoctoral researcher from the Mittler lab, found a protein that causes an iron deficiency response in plants. Communication of these discoveries between the Mendoza and Mittler’s lab led to a more formal collaborative research that included Sam McInturf, a former postdoctoral fellow in the Mendoza lab.

“Very interestingly, Sarah found that mutants of this protein in Arabidopsis — the plant that we work with — plays a [role in] iron deficiency responses,” Mendoza said.

Zandalinas’ protein, called NEET, sparked Mendoza’s interest because a mutation in NEET causes the plant to act like it doesn’t have enough iron even when it actually does. A mutation in NEET triggers a partial iron deficiency response.

“I started to work with NEET proteins in plants way before I came to Mizzou,” Mittler said. “When I started this project, I thought we needed to protect plants and animals from ROS.”

“So, that’s what got us together, Ron’s lab and my lab,” Mendoza said. “We saw that a mutation in this protein induces an iron deficiency response, even though the plant doesn’t lack iron.”

This research intrigued Mittler because he wanted to take any opportunity to learn more about ROS processes.

“This is an opportunity to start dissecting interactions in the cell that are related to ROS,” Mittler said. “People need to know more of what’s happening in plants, so we need to push this research and discover what we can.”

Mittler also looks into the effects of climate change and global warming on plants, and he said it’s important to consider the environmental factors that play into these reactions.

“When under stress conditions, there are several enzymes in the cell that make ROS deliberately as a signaling molecule,” Mittler said. “But ROS is not the same in all parts of the cell. It’s important to look into where ROS is made, how much of it is made and how long it lasts in each part of the cell.”

For Mendoza, a better understanding of what is happening has a long-term role in improving human nutrition.

“If we understand how plants get their nutrients out of the soil, maybe we can work and generate, engineer or develop more nutritious plants for human consumption,” Mendoza said.

Researchers still do not know exactly how the plant senses it is running low on micronutrients, so much more research will go into understanding each step of this signaling mystery.

“Like anything science, everything starts with a cool question,” Mendoza said. “Sometimes we get questions that we didn’t expect, but that opens new opportunities to discover new things.”

By Josie Heimsoth | Bond LSC

Science builds on the work of all those experiments that come before, so it’s no surprise that being frequently cited is an honor that reflects on the quality and importance of a researcher’s work.

Two members of Bond Life Sciences Center once again join a list of the most Highly Cited Researchers for 2022.

Bing Yang and Ron Mittler joined the Clarivate list for “significant and broad influence reflected in their publication of multiple highly cited papers over the last decade,” according to their website. The list recognized 6,938 scientists, only the top one percent from nearly 9 million scientists and scholars.

Mittler, a Bond LSC scientist and MU professor of plant sciences, researches the role of reactive oxygen species (ROS) and the role they play in the regulation of biological processes in plants.

For Yang, a Bond LSC scientist and MU professor of plant sciences, this is his fourth year on the list, and, for Mittler, it is his third. Yang considers a few things once his lab makes a discovery and decides to publish.

“You need to think about the project and what will generate the excitement,” Yang said. “Then when you have this result, you need to decide what journal you want to put it in. Each journal has different readership and visibility, so if you publish in a highly-viewed journal, your paper has the potential to be highly cited.”

Yang works on the development and application of TALEN and CRISPR technologies for targeted genome editing in plant species. His lab works with rice, maize, wheat, sorghum and soybeans.

“I have been doing this research for a long time and it’s fantastic,” Yang said. “Every day there are these new questions and I really want to look for those answers and use tools to understand these topics. It’s exciting.”

Last November, Yang was also elected as an American Association of the Advancement of Science (AAAS) fellow along with two other members of Bond LSC, Chris Lorson and Henry Wan. AAAS fellows are recognized for achievements in teaching, technology, research as well as excellence in communicating and interpreting science to the public.

For Yang, dedication to his research and making it useful for all is the most important thing.

“It is a great pleasure and honor to receive this type of nomination,” Yang said. “But, this isn’t about me. It’s about the research that has been done in the lab from current and previous lab members at MU and my previous university.”

Find out more about Clarivate’s Highly Cited Research list at https://clarivate.com/highly-cited-researchers.