Sorghum growers may soon have new cultivars that protect against “anthracnose,” a fungal disease that can inflict devastating yield losses of up to 50%. Researchers from the USDA’s Agricultural Research Service (ARS) and Purdue University have discovered a gene that can help fortify the cereal crop against anthracnose, opening the door to disease-resistant cultivars.
Sorghum is the fifth-most widely grown cereal crop in the world, and for good reasons. It is a valuable source of human food, providing 12 essential nutrients while also being gluten free. Sorghum is also an important forage for livestock and feedstock for biofuels. Most varieties are incredibly drought- and heat-tolerant, as well as nitrogen-efficient, qualities that have made it especially important in arid and semi-arid regions, where the grain is one of the staples for poor and rural people.
“It is a very resilient plant in many ways, but fungal diseases can wipe it out,” Tesfaye Mengiste, a professor and interim head of Purdue’s Department of Botany and Plant Pathology said. “Anthracnose is one of the most significant of these pathogens and attacks all parts of the plant: leaves, stalk and head. It leaves nothing that can be used for food, its primary use in Africa; or biofuels and animal feed, its uses in the United States.”
Genetic-based disease resistance is the most effective and sustainable approach to combating anthracnose. However, natural resistance has been poorly understood and can be impacted by high temperatures, potentially leaving crops unprotected above a certain threshold.
Now, Purdue University scientists, led by Demeke Mewa, have discovered a new gene, known as “Anthracnose Resistance Gene 2” (ARG2), that could provide disease-resistance. It works by orchestrating a series of defense responses to early infection by the anthracnose fungus, preventing its spread to the rest of the plant and grain heads. Resistance also remained stable when plants carrying the gene were exposed to temperatures of 100 degrees Fahrenheit.
The researchers note that ARG2 did not effectively protect sorghum from all races (types) of anthracnose. However, they believe combining ARG2 with other similar genes – either through breeding or genetic tweaking – will help broaden the protections. (Sources: USDA, Phys.org)
