Features

The rice artist

For biologist Herbert Kronzucker, creating a new 'miracle' rice may be the key to solving world hunger

by Andrew Westoll

Rice plants are being grown from tissue culture at the International Rice Research Institute, head-quartered in Los Banos, Philippines. Professor Herbert Kronzucker collaborates closely with researchers at IRRI.

Twelve thousand years ago, somewhere in the verdant valleys along the Yangtze River in southern China, an anonymous hunter-gatherer made a discovery that would reverberate around the planet. Instead of scouring the surrounding tropical vegetation for wild rice as he and his brethren had done for generations, he decided to plant old rice grains in a rudimentary garden. After the monsoon rains had come and gone and those seeds had flourished into tall productive plants, that farmer and his family feasted like never before.

This story is apocryphal, but it illustrates how local discoveries have the power to change the course of human history. Once Chinese farmers domesticated rice, the practice radiated outward, blown by the winds of poverty and hunger to embed itself into the culture of an entire hemisphere. Today, 3 billion people—nearly half the planet—depend on rice as their staple food.

“The story of human nutrition is the story of grains,” says Herbert Kronzucker, professor of biological sciences at the University of Toronto Scarborough and a Canada Research Chair in systems biology. “And the biggest contributor to this story is rice.”

Over 21 percent of all human food energy comes from rice; no other organism comes close to providing us with more. But as much as he respects the Oryza genus of plants, Kronzucker is tracking a looming storm that rice will not be able to weather in its current form.

“There’s a crisis,” says the scientist. “It’s been a crisis for some time. And it’s one of the fundamental crises on the planet.”

With more than 7 billion mouths to feed, world hunger is our most persistent societal challenge. Today, nearly 1 billion people are considered “undernourished” by the United Nations Food and Agriculture Organization (FAO). Food prices have reached record levels and show no signs of dropping, and while paying more at the supermarket may be a mere inconvenience to most Canadians, upticks like these can be catastrophic to societies already perched on the knife edge of poverty. The survival of hundreds of millions of people is at stake. This explains the food riots of 2008 and 2011 in Bangladesh, Indonesia and Tunisia.

In November last year, the FAO issued a new report that rang the alarm bells especially clearly. It warned that 25 percent of the earth’s land is now highly degraded, due mainly to erosion, drought and salt infiltration. In other words, workable farmland is becoming saltier and drier, and disappearing at a rapid rate as the planet’s population continues to grow. According to the FAO, unless this trend is reversed, we will have no hope of feeding the population of nearly 9 billion people expected by 2050.

Kronzucker sees loss of farmland as one of the central challenges of our times. This is because our most important grain, rice, is the least able to survive such ravages. “Of all the major crops,” he says, “rice is the most water-intensive, and it is also incredibly sensitive to salt.” Kronzucker’s research team at UTSC hopes to help stem the tide of world hunger by helping guide the creation of a new kind of rice plant, one that can thrive in increasingly salty, dry conditions. Their quest is to create nothing less than a super strain of rice.

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In stark contrast with the beautiful, sweeping rice paddies of Asia, Kronzucker’s research takes place in sophisticated austerity. In his laboratory in the basement of the Science Research Building at UTSC, hydroponic nurseries are housed in monolithic, hermetically sealed greenhouses, which Kronzucker refers to as his team’s “Mercedes” nurseries. Inside, bathed in artificial daylight, rice plants are grown from seed in diverse, radio-labelled biochemical environments. The experiments provide him with clues as to which genes are the rice plant’s Achilles’ heels.

“We want to find the targets in the physiology and biochemistry of the plant that present bottlenecks for growth and for yield,” explains Kronzucker. “We look for traits that determine the ability of a rice plant to withstand major stresses like salt stress, and that improve water-use efficiency.”

In terms of water use, his recent research reveals a critical relationship between two basic agricultural nutrients: potassium and nitrogen. When the potassium–nitrogen ratio in the growth media is shifted in favour of potassium—an experimental process called “physiological poising”—total plant biomass is significantly boosted. The increased potassium also constricts the transportation system for water in the rice plant’s roots (protein channels called aquaporins) without reducing the number of panicles on the plant, the number of grains per panicle or the total biomass of the plant.

“We want rice to be less thirsty but to give us the same, or better, yield,” explains Kronzucker. “Any small dent we can make in the plant’s consumption of water would be considered a major breakthrough.” The potassium–nitrogen ratio and its effect on aquaporins could be key.

This finding may seem straightforward: increase potassium in the soil and Bob’s your uncle. But on a mechanistic level, this is extraordinary. Just by changing the biochemical environment in which a plant grows, Kronzucker can change the very expression of its genes.

“There has always been an art to bringing out the best in what a genome has to offer,” says Kronzucker, whose experimental results may one day lead to the creation of a super strain of rice. “What we’ve found, over and over again, is that without having to tinker with the setup—such as by introducing a gene from a fish or by knocking a gene out—we can capitalize on the enormous plasticity already present in the plant’s genome. We search for the environmental conditions in which the plant makes more copies of the gene we need. That’s how we get these magical tricks to happen.”

The Kronzucker lab gets its rice seeds from the International Rice Research Institute (IRRI) in the Philippines. Located in the town of Los Baños, southeast of Manila, the IRRI is the world’s preeminent hub for rice science. In the 1960s, research into hybrid rice types at IRRI led to the creation of a “miracle strain” of rice, known as IR8, which was instrumental in the near-tripling of the rice yield in Asia and helped usher in the Green Revolution. Kronzucker did a three-year post-doc at IRRI as a Rockefeller Fellow in the late 1990s, back when it was still led by head plant breeder and 1996 World Food Prize winner Gurdev Singh Khush. Kronzucker continues to collaborate with the institute and with Khush, who is now at the University of California, Davis.

“Because of the interconnectedness of the issues we’re looking at, our partnership with international centres is critical,” notes Kronzucker. “We must have constant flow of information and conversation, rather than silos in which people protect their data from each other at all costs.”

IR8 and its follow-up varieties represent one of the most important breakthroughs in food security in the history of the developing world; they have saved untold millions of lives. But today, the miracle is waning. Amid increasing salt and drought, rice yields are dropping. The search for a replacement for IR8 and its successors—a new miracle strain—is more urgent than ever.

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Central to tackling the issue of world hunger in a meaningful way is the recognition that its root causes are myriad. Together with Malcolm Campbell, vice-principal (research) at UTSC, and Greg Vanlerberghe, chair of the biological sciences department, Kronzucker envisions the establishment of the Canadian Centre for World Hunger Research (CCWHR), housed at UTSC. Through such initiatives, the campus would become a leading hub for scholarship on all aspects of the problem of world hunger.

“The ultimate vision for the [CCWHR] is to find solutions to world hunger in a multidisciplinary way,” says Vanlerberghe. “We need to look at the politics of it, the social science of it, the economics of it, in addition to the biology of it.” The first step, now under way, is to continue hiring top researchers who focus on crop productivity. As capacity in the biological sciences builds, the hope is that colleagues in other departments will be inspired to collaborate.

“Hunger is an issue of international importance,” says Vanlerberghe, “but as far as I know, we don’t have a centre with this kind of research focus anywhere in Canada. It’s a niche that Canada should be filling, and the University of Toronto Scarborough ought to fill it.”

Aside from the scholarly perspective, there is another reason UTSC is well positioned to become a leader in the study of world hunger. The student body—and the surrounding eastern-GTA community itself—is home to many new Canadians from China, India, Bangladesh and Pakistan, places where citizens are much more likely to have an intimate understanding of the stark real-life repercussions of hunger.

“During my annual lecture on how science can help fight world hunger, you can hear a pin drop,” says Kronzucker. “Half the class sticks around afterward to ask questions. I am flooded with emails asking ‘What can I do?’ or ‘How can I help?’ The human potential we have at Scarborough is really impressive. Our students want to be involved with this.”

As our apocryphal Chinese hunter-gatherer demonstrated some 12,000 years ago, and as Gurdev Khush and his colleagues at IRRI confirmed just 50 years ago, experimental thinking has the power to change the world for the better, no matter where it takes root. Herbert Kronzucker and his research team are on the trail of something extraordinary, a new strain of rice that could save hundreds of millions of lives. But in keeping with his role as an educator as well as a researcher—or perhaps in an effort to lessen the tremendous responsibility of such a quest—Kronzucker shows a knack for reducing his work to the barest of scientific bones.

“When genes are combined in a new way, the very same genes can be expressed in an entirely novel way,” says Kronzucker, as he pulls the door shut to one of his Mercedes nurseries, plunging his lab into darkness. “When you do this, you can get some surprising results.”

To learn how you can help support the proposed CCWHR at UTSC, contact gzinaty@utsc.utoronto.ca.