Genetically modified wheat is wheat that has been genetically engineered by the direct manipulation of its genome using biotechnology. As of 2020, no genetically modified wheat is grown commercially, although many field tests have been conducted. One wheat variety, Bioceres HB4 Wheat, is obtaining regulatory approval from the government of Argentina.
Background Wheat is a natural hybrid derived from interspecies breeding. It is theorized that wheat's ancestors (Triticum monococcum, Aegilops speltoides, and Aegilops tauschii, all diploid grasses) hybridized naturally over millennia somewhere in West Asia, to create natural polyploid hybrids, the best known of which are common wheat and durum wheat. Wheat (Triticum spp.) is an important domesticated grass used worldwide for food. Its evolution has been influenced by human intervention since the dawn of agriculture. Interspecies transfer of genes continued to occur in farmers' fields during the shift from the Paleolithic diet to the diet adopted by humans following the Neolithic Revolution, or first green revolution. During the transition from a hunter-gatherer social structure to more agrarian societies, humans began to cultivate wheat and further transform it for their needs. Thus, the social and cultural roots of humans and the development of wheat have intertwined since before recorded history. This process resulted in various wheat species that are grown for specific purposes and climates. In 1873, Wilson cross-pollinated rye and wheat to create triticale. Further transformations using cytogenic hybridization techniques enabled Norman Borlaug, father of the second Green Revolution, to develop wheat species (the semidwarf varieties) that would grow in harsh environments. Recombinant DNA techniques were developed in the 1980s, work began on creating the first transgenic wheat, coincident with the third Green Revolution. Of the three most important cereals in the world (corn, rice, and wheat), wheat was the last to be transformed by transgenic, biolistic methods in 1992, and by Agrobacterium methods in 1997. Unlike corn and rice, its widespread use in the human diet has faced cultural resistance.
Field trials and approvals As of 2013, 34 field trials of GM wheat have taken place in Europe and 419 have taken place in the US. Modifications tested include those to create resistance to herbicides, create resistance to insects and to fungal pathogens (especially fusarium) and viruses, tolerance to drought and resistance to salinity and heat, increased and decreased content of glutenin, improved nutrition (higher protein content, increased heat stability of the enzyme phytase, increased content of water-soluble dietary fiber, increased lysine content), improved qualities for use as biofuel feedstock, production of drugs via pharming, and yield increases. The Argentinian company Bioceres developed a plant with the HaHB4 gene and it was grown under a wide range of growing conditions that showed better adaptation to drought-prone environments, the most important constraint affecting crop yields worldwide.
Bioceres's HB4 The Argentina-based company Bioceres developed a genetically modified wheat variety with higher yield under drought stress. The variety is named for its expression of a transcription factor, HaHB4, from sunflowers and also known as line IND-00412-7. It was approved by the Argentine government in October 2020, with commercial introduction pending approval of the crop for import by Brazil, Argentina's major wheat export partner. On 6 May 2022, HB4 was approved by Food Standards Australia New Zealand.
Monsanto's MON 71800 The transgenic wheat that was furthest developed was Monsanto's MON 71800,r which is glyphosate-resistant via a CP4/maize EPSPS gene. Monsanto received approval from the FDA for its use in food, but withdrew its EPA application in 2004, so the product was never marketed. It also received approval for use as food in Colombia. Studies conducted by Monsanto showed that its nutritional components are equivalent to nontransgenic, commercially available wheat, and animal studies that have used MON 71800 for feed have confirmed this. Environmental Risk assessments have been conducted by Monsanto, and government regulatory agencies have approved its use in food; However, farmers were worried about the potential loss of markets in Europe and Asia due to public refusal of the end product, so Monsanto withdrew its EPA application for Roundup-Ready Wheat. In 2010, Monsanto's partner in India, Mahyco, announced that it planned to seek approval to market GM wheat in India in the next three to five years.
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