Novel photosynthesis technology – The solution to the global food security crisis?

Ensuring global food security

The human population is increasing, which means that we need to improve crop productivity to maintain food security. Over the last century, plant breeding and modern agriculture have made large gains in productivity. However, this growth is not keeping pace with demand. If plant photosynthesis could be improved, this would provide breeders with a new tool to increase crop yields. This has been a major research focus over the last 20 years and significant progress has been made in understanding this process. However, crops with improved photosynthesis have yet to be successfully commercialised.

The development of photosynthesis technology

The recent development of a novel photosynthesis technology may change this. The discovery was serendipitous and occurred when scientists, led by Dr. Nick Roberts at AgResearch Ltd, were working on a project to increase the metabolisable energy of forages for grazing ruminants. Their approach was to increase the level of lipids in forage leaves to improve the energy balance in the plant.

The team initially used the model plant species Arabidopsis and developed a technology expressing two novel proteins in the plant. The first was an enzyme called diacylglycerol acetyltransferase 1 (DGAT1) that synthesizes triacylglyceride (TAG) lipids. To protect the TAG from catabolism within the plant, an encapsulating protein called Cysteine Oleosin was co-expressed to enable the formation of stable oil bodies in the plant. This led to a doubling of the leaf lipid levels and in addition the plants grew 50% faster. It was found that the plants had a corresponding 24% increase in photosynthesis.

The technology was then tested in the forage, perennial ryegrass, and very similar increases in leaf lipid levels, photosynthesis and growth rates were achieved. This provides future opportunities for pastoral farmers to maintain or improve their productivity while mitigating some environmental impacts of pastoral grazing systems (methane emissions and nitrogen excretion by grazing ruminants). The result also confirmed that this technology had efficacy in multiple species and it worked in both dicotyledonous and monocotyledonous plants.

The realisation that the team had invented a novel photosynthesis technology, led to the filing of patents around the new structural protein, its ability to increase lipids in the green tissue of plants and the resulting increase in photosynthesis. The novelty of the proteins and the approach led to very broad patent coverage.

Throughout the early research phase, the AgResearch science team had partnered with Kapyon Ventures, a San Diego based incubation firm to develop a Public-Private Partnership model for commercialising biotech traits. This partnership led to the genesis of Zeakal Inc., a plant science company focused on increasing the yield and energy density of major row crops with next generation biotech traits. The original researchers and founders now make up the ZeaKal executive team. The novel photosynthesis technology was trademarked as PhotoSeed and has attracted over US$50M in grant and venture financing.

The development of PhotoSeed

PhotoSeed has applications across a range of crops and can be grouped into three major product areas:

• Row Crops, a yield trait for the major row crops (e.g. soy bean and canola);
• Biofuels, to convert high yield biomass crops to oil crops (e.g. sugar cane);
• Forages, to increase biomass, energy density and feed conversion efficiency.

While commercialisation in forages remains the focus of AgResearch, ZeaKal is leading the effort to commercialise the development of PhotoSeed in the major row crops, specifically soybeans as its first commercial target. The majority (98%) of soybeans are produced in the US, Brazil, and Argentina (219M acres) with China being the largest importer. With the rising global demand for plant oils and protein, it is expected that soybeans will overtake corn as the world’s largest biotech row crop in the next few years.

In addition to commercialising a novel technology, ZeaKal was also the first to pioneer a capital light business model, where it invested and partnered with public research institutions with existing capabilities in soybean and general plant biotechnology. While the virtual operations across two countries came with unique challenges, this approach has allowed the company to minimize capital risk, while targeting development dollars into data and IP generation. The success of this model ultimately came down to careful relationship building, understanding the cultures of the different organisations and effective project management.

In its 2017 field trials, ZeaKal successfully increased photosynthesis in soybeans across multiple PhotoSeed lines. Early in the season, the increased photosynthesis resulted in accelerated growth and more biomass. For farmers, this translates into a crop that has better stand establishment and earlier canopy closure, as well as a larger surface area for light capture. At the end of the season, ZeaKal not only measured increased yield and pod load across events, but also increases in oil content in the seed without decreasing protein.

The future for ZeaKal is very exciting as it continues to trial next generation improvements of its PhotoSeed soybean while branching out into new crop opportunities.