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January 13, 2019

Wired In: Donald Ort


Each week, staff writer Paul Wood chats with a different high-tech difference-maker. This week, meet Donald Ort, the Robert Emerson Professor of Plant Science and Crop Sciences at the University of Illinois. He is the principal researcher in a project to see if yields can be greatly increased by getting around a chemical glitch in plants.

WI Ort.jpg

Donald Ort, the Robert Emerson Professor of Plant Science and Crop Sciences at the University of Illinois, is shown among test crops. He is the principal researcher in a project to see if yields can be greatly increased by getting around a chemical glitch in plants.

Who is on your team in this research, which has been reported in the journal Science?

Dr. Paul South, who is a postdoctoral associate with the USDA Agricultural Research Service located at the UI. Dr. Amanda Cavanagh, who is a postdoctoral associate in the Carl R. Woese Institute for Genomic Biology here. Helen Liu was an undergraduate student in the Department of Crop Sciences at Illinois. She is now in graduate school at the University of California at Berkeley.

How does your approach to increase crop growth by 40 percent work?

We installed a new pathway into plants that created a biochemical shortcut for the photorespiration (a type of photosynthesis) pathway. The shortcut saved energy that the plant could then reinvest in growth. Because the plants with the shortcut grew faster from the outset, they benefited from the "compound interest" of being larger younger, much in the same way compound interest works in a savings account.

A photosynthetic glitch prevents plants from converting sunlight into energy through photosynthesis. What is the photorespiration process and why does it reduce yield potential?

Photosynthesis relays on the enzyme Rubisco, which is responsible for grabbing carbon dioxide out of the atmosphere. Rubisco is by far the most plentiful enzyme and most plentiful protein on planet. While Rubisco carries out this critical function as the first step in photosynthesis, about 20 percent of the time, it makes a mistake and grabs an oxygen instead. This photosynthetic glitch not only prevents carbon dioxide from being captured, it also produces a toxic compound that the plant expends a great deal of energy to detoxify and recycle in a very complicated biochemical process known as photorespiration. The energy that is expended in photorespiration is not available for plant growth or crop yield.

Photosynthesis uses the enzyme Rubisco and sunlight to turn carbon dioxide and water into sugars that fuel growth and yield. How has it evolved?

The earth is 4.5 billion years old. The earliest direct evidence for photosynthesis shows that it was present on the planet 3.4 billion years ago (this form used hydrogen rather than water as a source of electrons). Oxygen-evolving photosynthesis (i.e., used water as an electron donor) was clearly present on the plant 2.4 billion years ago and perhaps earlier. These photosynthetic oxygen-evolving organisms were responsible for oxygenating the atmosphere (which is now 21 percent oxygen). Rubisco evolved prior to when the atmosphere contained oxygen, no doubt explaining how it evolved in such a way as to be unable to reliably distinguish between oxygen and carbon dioxide, creating the "photosynthetic glitch."

How were university and Department of Agriculture researchers able to create a photorespiratory shortcut to make real-world yield increases?

We co-opted a process from the bacteria E. coli that did what we needed in a much simpler way than plants do, and we also "synthesized" non-natural pathways using naturally occurring enzymes that could efficiently recycle the toxic compound produced when Rubisco grabs oxygen instead of carbon dioxide.

Why did you choose tobacco seedlings to test these ideas?

Tobacco was selected for these proof-of-concept experiments not only for its ease of genetic transformation, but also because it is an ideal model crop that is robust in the field, forms a fully closed canopy and produces large quantities of seed, circumventing the need for numerous seed-amplification generations, further accelerating the timeline to field testing. The photorespiratory mechanism is common to all C3 plants, giving us confidence that tobacco was a good model for crop plants.

With the 21st century's rapidly expanding food demands — for example, population growth and high-calorie diets in developed countries — how important is this research?

Increasing demands for global food production over the next several decades portend a huge burden on the world's shrinking farmlands. Increasing global affluence, population growth, and demands for a bioeconomy will all require increased agricultural productivity, perhaps by as much as 60 to 120 percent over 2005 levels, which is a challenge that current rates of yield improvement will not meet. Improving the efficiency of photosynthesis will be necessary to meet this daunting challenge.

Who are among the supporters?

Realizing Increased Photosynthetic Efficiency (RIPE) is engineering staple food crops to more efficiently turn the sun's energy into yield to sustainably increase worldwide food productivity, with support from the Bill & Melinda Gates Foundation, the Foundation for Food and Agriculture Research and the U.K.'s Department for International Development.

Will these foundations and the world at large see great returns from this investment?

In the RIPE project, we are working on eight different photosynthetic designs, several of which, including our redesign of photorespiration, have passed proof-of-concept experiments. It is important to understand that from proof-of-concept to a crop in a farmer's field takes more than a decade (this is often referred to as the breeding cycle), so it will be 2030 before RIPE photosynthetic improvement traits could be in a farmer's field.

What's your best advice for someone who's starting up in research?

Ask important questions. Biology is exceptionally complicated, so most experimental designs will almost always initially not work, making it important to fail quickly so that the research moves along. Surround yourself with people who know stuff that you don't.

Did you ever make any mistakes that you learned from in your early years?

Not just in my early years; an essential feature of research is making mistakes and learning from them.

TECH TIDBITS ... from DONALD ORT

What are you reading right now? Hans Rolisng's "Factfulness: Ten Reasons We're Wrong about the World and Why Things Are Better Than You Think."

Do you have any wearable electronics? I wear a (rugged, functional) field watch ... but I guess that is just a regular watch.


By: Paul Wood | The News-Gazette

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Photorespiratory Bypass
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