Replenishing the global food bowl

Scientists are facing up to the challenge of food security and sustainability on myriad fronts.

By Gary Tippet

Somewhere in the Pearl River valley region of China, perhaps as long ago as 13,500 years according to recent genetic evidence, a prehistoric farmer took a type of wild grass and began the long process of domesticating it into what we now know and love as rice.

Today, a variety of rice is grown on every inhabited continent and it is the staple food of more than half the world’s population, with at least 3.5 billion people dependent on the grain for 20 per cent of their daily energy. In poorer parts of Asia, that figure rises to more than 50 per cent.

But apart from carbs and calories, it gives them little else. Common white, long-grain rice is low in many essential micronutrients such as iron and zinc, with no vitamin A, vitamin C or beta-carotene, and with very little fibre. These deficiencies can lead to serious health consequences, from anaemia and stunted growth to irreversible blindness. However, thanks in part to pioneering biotech research by University of Melbourne plant biologist Associate Professor Alex Johnson, that is changing.

Dr Johnson, of the University’s School of BioSciences, is an expert in the problem of “hidden hunger”, a chronic lack of vitamins and minerals in the human diet, and he and his team have developed a new strain of “biofortified” rice enriched with iron and zinc – promising significant improvements in nutrition, health and quality of life for malnourished millions.

“It’s estimated that one in three children around the world suffer from a lack of micronutrients,” he says. “We need to tackle hidden hunger, and one way to do that is to enrich our staple food crops with minerals and vitamins, referred to as biofortification.”

After completing his PhD at Virginia Tech in the US, Dr Johnson first used genetic modification (GM) technology to make new types of potatoes that were resistant to a major pest, the Colorado Potato Beetle. He then turned his attention to rice, “digging through the genome to see how we could change the genes to make a better rice plant”.

White rice grains contain a mere two-to-five parts per million (ppm) of iron, well short of the 13ppm needed to address rampant iron deficiencies in rice-dependent populations, and the tiny bit that’s in the grain is not very “bio-available”, or easily absorbed into the body. Dr Johnson’s team has studied a variety of genes that help rice to absorb iron from soil, and found that most of these genes only switch on when the plant detects that it is iron-deficient.

“We’ve just changed the way one of these genes is expressed so that it’s on at higher levels all the time,” he says. “You could say, we’ve fooled the rice into thinking it’s iron-hungry.”

It has proved a win-win situation by a factor of three or four – the biofortified grains have reached 15ppm iron in the field; they have had the added benefit of increased zinc concentration; the minerals are bio-available; and, the GM rice is just as high-yielding as existing varieties.

The technology is now being taken into Bangladesh, one of the most rice-dependent countries in the world and one of the worst-affected by iron and zinc deficiency. Meanwhile, Dr Johnson’s team is using the same technology – and the same rice gene – to biofortify the world’s other great staple, wheat. His team is aiming to bring iron biofortified wheat to Pakistan in the near future.

Biofortification is just one area in which University of Melbourne researchers are working to address the pressing issue of world food and nutritional security – defined by Dookie campus-based sustainable agriculture scientist Dr Dorin Gupta as the need to ensure “that all the people, all the time, have the right quantities and, particularly, quality of food, all year round.”

But that ambition is a daunting one.

Professor Timothy Reeves, professor in residence at Dookie, which is part of the Faculty of Veterinary and Agricultural Sciences, was recently awarded the Farrer Medal, the highest honour in Australian agriculture. In his oration, he outlined what he described as the five Grand Challenges to food and nutritional security, which were posing “a perfect storm” for agriculture.

“Globally, for me, these are absolutely humankind’s greatest challenge,” he tells 3010.

With the global population growing by 160 people every minute, the world will need to increase food production by 70 per cent by 2060. And that will need to happen in the face of:

• The loss and degradation of natural resources of air, land and water – with, for instance, one hectare of productive land lost every 7.67 seconds
• Adaptation to climate change – “now a crystal-clear reality right before our eyes”
• Nitrogen fertiliser-use inefficiency
• Food loss and waste
• The neglect and erosion of rural communities, with seven in every 10 people likely to be living in cities by 2050.

“But in addition, it is vitally important to view these challenges in the stark context of nutritional security,” he adds.

“Right now, about 55 per cent of people globally live in cities, but by 2050 we expect almost 70 per cent of people to do so. How we feed people in cities is a vital part of ensuring food security.”

Malnutrition in its widest definition is rampant, with 88 per cent of countries having two or more major concerns around nutrition. Two billion people are malnourished and lack key micronutrients, with 800 million of those going to bed hungry every night; 155 million children are stunted and 52 million are wasted; while, on the other hand, 2 billion adults and 41 million children are overweight or obese.

To battle this, Professor Reeves believes the world needs a new revolution of diversified and integrated farming, aiming for – in what might sound like a contradiction – the “sustainable intensification” of agriculture.

“Basically, we have to produce more food from existing land with fewer resources, and do so more efficiently,” he explains. “It can mean very specific things but the way I define it is, you’re looking at agriculture that is regenerating the natural resource – you’re improving soil health, you’re improving biodiversity and you’re improving the resilience and sustainability of our farming lands.

“Sustainable intensification is one of the key pathways to ‘regenerative agriculture’ because it concentrates on those five elements: conservation agriculture, soil health, efficient water management, better genetic material and integrated pest management.”

Researchers in Melbourne and Dookie, near Shepparton, have been tackling many of these challenges – often with ground-breaking results and implications for food security.

In 2017, Dr Gupta and a multi-disciplinary team used a hyper-spectral sensor on board a drone to detect the onset of crop diseases well before they became visible to the naked eye. The sensor, able to capture light in and outside the visible spectrum in 100 times more colour channels than normal digital cameras, was flown over tomato crops, detecting minute changes of pigment indicating early signs of disease. It enabled Dr Gupta and the team to build a spectral library of tomato diseases.

“Matching the surveillance data to the library data with further advancement in interpretation of this data can assist growers to selectively spray well in time before a pathogen can establish to a level of significant damage,” she says. “This is part of precision agriculture; we don’t have to spray all the paddocks. And, in the long term, it’s going to be beneficial for environmental health.”

From Silent Spring to the “insect apocalypse”, populations of many insect species seem to be rapidly shrinking in size with insecticides being blamed. A collapse in European populations of the major pollinator, honeybees – and the subsequent threat to food production – has led to the EU banning some neonicotinoid insecticides.

Whatever the reality of impending Armageddon, the University of Melbourne has a long, impressive history of work towards better and alternative pest control.

Professor Philip Batterham describes himself as “the latest baton carrier in a research relay team” that has studied insecticide resistance at the University since 1977. His team have used genetic approaches to identify the proteins in the insect brain that are targeted by neonicotinoids.

“But more recently, we’ve become interested in the downstream effects of low concentrations of neonicotinoids and other insecticides on non-pest insects,” says Professor Batterham. “We don’t have enough data at the moment. It’s like a jigsaw puzzle with some holes … [but] we need answers – and we need them quickly.”

Professor Ary Hoffmann, Melbourne Laureate Professor in the School of BioSciences, says that in the past, particularly in broad-acre agriculture, farmers would “insurance-spray” relatively cheap broad-spectrum pesticides, “whacking it on just in case. The opposite of that is something we call integrated management, but that’s a more complicated game.”

Professor Hoffmann has worked with the wine industry to increase shelter belts and understory that protect the beneficial insects and mites that prey on pests; developed genetic markers to discover invasion patterns of earth mites; and fought dengue fever using the bacterial parasite Wolbachia, which stops mosquitoes passing on the virus.

His group is now investigating how the same parasite might block the spread of plant viruses.

But the threats to food security are not just out in the broad hectares of wheat, rice and canola. Currently, the fertile food bowl in Melbourne’s hinterland produces enough food to meet 80 per cent of the city’s demand for vegetables and 41 per cent of its total food needs. But as the city’s population heads toward 7 million, that could fall to just 18 per cent.

“Right now, about 55 per cent of people globally live in cities, but by 2050 we expect almost 70 per cent of people to do so,” notes Dr Rachel Carey, an expert in food systems. “How we feed people in cities is a vital part of ensuring food security.

In March, Dr Carey and an inter-faculty team produced a comprehensive and far-reaching plan, Roadmap for a Resilient and Sustainable Melbourne Foodbowl. It outlines a vision for retaining a resilient, healthy and fair food supply for the city, underpinned by key pillars of farmland protection, farm viability, water access and re-use, nutrient recycling through composting city organic waste, and sustainable farming.

All these advances are important in the fight for food and nutritional security, but Professor Reeves warns: “One of the things we have to be careful about is saying something like, ‘If we can get this right, we’ll solve the world’s food problems’. All these are just tools in the whole system. There is no silver bullet.”

Read more: The food fighters