Researcher Yosef Fichman

Yosef Fichman

Bad Boys of Biology Turned Good

November 17, 2020 By Lauren Hines in Research Tags: reactive oxygen species

Yosef Fichman, post doctorate fellow in the Mittler lab, walks through how the lab uses arabidopsis plants for certain experiments. | photo by Lauren Hines, Bond LSC.

By Lauren Hines | Bond LSC

Shaking a bad rap can be hard.

However, the Ron Mittler lab at Bond Life Sciences Center has shifted the scientific community’s thinking from seeing reactive oxygen species (ROS) as destructive to vital.

“It’s always a challenge when you do something for the first time, and people don’t always believe you,” said Mittler, principal investigator. “They want you to prove it.”

ROS are reactive molecules that perform chemical reactions easily. While these molecules cause destruction in cells with these reactions, they can also send widespread messages and regulate many essential processes. However, this benefit of ROS wasn’t always known.

Back in the Day

In the 1980s, the scientific community recognized ROS as important. But according to Mittler, the community also thought ROS only offered destruction to human cells and caused aging.

“All this is not true,” Mittler said. “It’s not that simple to just say that, but there was a big hype about reactive oxygen species being painted as the bad boys of biology, and so forth.”

Then, in 2009 Mittler discovered the ROS wave.

This wave fills in the communication gap in plants left by the lack of something like a central nervous system. Instead, plants use the ROS wave and systemic signaling to respond to stresses. ROS triggers a cell reaction in one area of the plant that triggers the cell next to it and so on creating a wave of activation throughout the plant. This way, the plant can acclimate to its environment and is important since plants don’t have the luxury to get up and move when something threatens them.

Mittler was at the University of Nevada in Reno studying responses to ROS. He was originally looking to develop a reporter system to screen for mutants that are deficient in sensing ROS.

“We noticed that we don’t only record local responses that when we treated one single leaf, we got a systemic response, and, from there, using additional experiments, we developed the ROS wave concept,” Mittler said.

Mittler published his new discovery in Science Signaling, and more papers came, exploring systemic signaling and similar processes, highlighting the importance of the ROS wave to many biological responses.

“Slowly people started to realize that reactive oxygen species are actually important, and they’re doing a good thing,” Mittler said.

What’s Happening Now in the Lab

More than 10 years down the road, Mittler still focuses on ROS. Current Mittler lab post doctorate fellow Yosef Fichman, has taken the baton in the study of ROS waves.

“I was born to a family that was working in agriculture, and my father grew oranges in Israel,” Fichman said. “For a farmer or a person working in agriculture, life revolves around growing plants 365 days a year. In a way, I was always fascinated by plants.”

Fichman and others in the lab have been working towards finding more pieces to the process.

“There is a cliché that says proteins never work alone, so we’d like to know which other ingredients are involved,” Fichman said. “In my latest paper, using mutant plants, we were able to detect more ingredients to this mechanism and expand our knowledge.”

Fichman and others in the Mittler lab worked to image the ROS wave, tested different stresses for the ROS wave to respond to and found more pieces to the puzzle. Fully understanding this process can help researchers eventually create genetically modified crops that withstand more stresses.

What There’s Left to Discover

Currently, researchers don’t know exactly which compartment of the cell is most important in regulating this process or if compartments interact with each other. They also don’t know how it all results in gene expression or how different waves interact with each other and work together.

“There’s a lot to learn because we know that if we just look at this from the narrow window of the ROS wave, we know that it’s important,” Mittler said. “If you don’t have the ROS wave, the plant cannot acclimate properly.”

Though Mittler lab researchers have been hard at work for the past few years dissecting this process, it’s unlikely they’ll stop anytime soon.

“In a way, it’s harder to publish new ideas, but it’s more exciting,” Fichman said. “We are grabbed by our curiosity and we want to find the answer. We want to find the big answers.”

Find more details about Mittler’s current research in the most recent publication found in the Plant Cell journal.

Nature’s cinema: New technique allows plant imaging in real-time

October 23, 2019 By Mariah Cox in Research Tags: Arabidopsis, Ron Mittler

The September issue of Molecular Plant depicts a plant fluorescing in response to reactive oxygen species propogation taken by Yosef Fichman of the Mittler Lab.

By Mariah Cox | Bond LSC

Plant biologists across the country opened their mailboxes last month to the glowing leaves of Arabidopsis on the cover of the latest issue of Molecular Plant.

That cover taken by post-doctoral researcher Yosef Fichman of Bond Life Sciences Center depicts plants fluorescing in response to reactive oxygen species (ROS) propagation, a technique that allows researchers to track plant response to certain stressors.

The novel approach is the first of its kind to image the response of an entire plant, rather than small samples. To make this technique work, Fichman — who works in the lab of Bond LSC’s Ron Mittler — and his collaborators came up with the idea to fumigate the plant with a dye which enters the plant, reacts with ROS inside the plant and fluoresces under an in vivo imaging system (IVIS). From there, the researchers could watch the stress signals of the plant as they evolve in real-time following the application of different stresses.

Soil ‘cookies’ are used to grow Arabidopsis in the lab for use in Fichman’s ROS imaging research. | Photo by Mariah Cox, Bond LSC

ROS are 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 as well as defense and acclimation to environmental stress.

ROS are both beneficial and detrimental to plants. On one hand, they regulate basic biological processes. On the other, if overproduced, they are toxic to cells and can cause cell stress or death. However, recent research by the Mittler lab supports the idea that, at certain levels, ROS can be more beneficial than harmful because they have the power to signal defense mechanisms against stressors in the environment. In essence, it is a way for cells to communicate with each other, creating a domino effect, or wave that sends a message to nearby cells and eventually over long distances within the plant.

Now that they have a technique to detect the fast-moving ROS signal in plants, the researchers can identify the proteins that are involved in the plants’ response to stress. The signal is important because it causes fast adjustments to stress within the environment, which means that other parts of the plant that are not subject to stress can build up protection mechanisms.

“In order to understand plants’ response to stress, we need to know the mechanism of that’s going on in plants,” Fichman said. “Basically, it’s a balance of resources within the plant.”

Currently, the researchers are working with Arabidopsis, but this technique applies to other plant and crop models. Previous methods of tracking biological responses in plants included the arduous process of gene manipulation and expression. The new method allows for a straight-forward approach to tracking and monitoring the biological reactions in plants.

Moving forward the researchers plan to use Arabidopsis mutants and other plants to track the response to different stresses compared to the wild type to see if there are changes in the genes involved. Fichman is particularly interested in the effect of abiotic stresses, such as high-intensity light and leaf destruction by insects.

Arabidopsis under high light — The Mittler lab uses high-intensity light shone directly on the plant’s leaves to imitate light stress in natural environments. | Photo by Mariah Cox, Bond LSC

“Whether you like to call it weather extremes or global climate change, there are changes. Plants are a main food source, so we need to be prepared to create better plants for the future that allows crops to grow in stressful conditions such as high light, less water and heat,” Fichman said. “If plants invest more resources into protecting themselves they will be able to survive these changes and continue to produce food for our future. I’m studying this mechanism in ROS waves and in different pathways to create better plants in the future.”

By understanding the proteins that are involved in plants’ response to stress, researchers can begin to re-engineer plants to survive harsher conditions. Fichman’s technique makes it easier to recognize plants’ responses to stress moving forward.

For Yosef, when it comes to research, imagination is the only limitation.

“In research, we can come up with the craziest ideas and science allows us to check those ideas and discover new things,” Fichman said. “This is why I wake up in the morning.”

This research was published in the September 2019 edition of Molecular Plant.