Sangwon Lee, a researcher at Purdue University, prepared an anthracnose sample. Lee is part of a research team working to make sorghum more resilient to improve the food security of millions of people. Credit: Purdue University/Tom Campbell photo
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Scientists are working to refine the speed, strength, and semi-immunity attributes in important food crops, such as superheroes, that will help protect the weak.
Scientists have reached a milestone in Superman’s pursuit of the sorghum crop, identifying a single gene that provides broad protection against anthracnose, rust and target fungal diseases.
Taking a closer look at the plant genome, they also discovered what could be the kryptonite of this supernatural power and the unusual piece of motile DNA involved in it. disease resistance.
The newly discovered gene, called Anthracnose Resistance Gene1, or ARG1, is unusual in several ways, said Tesfaye Mengisti, professor and interim chair of the Department of Botany and Plant Pathology at Purdue University.
“Although there is some natural resistance to fungal disease in sorghum, the genes that confer this broad resistance have not been identified,” he said. “It’s amazing that one gene This leads to resistance across a broad spectrum of fungi and various types of anthracnose.”
A team of Purdue University researchers, including 2009 World Food Award winner Gibessa Ejeta, made the discovery through a project supported by the United States Agency for International Development (USAID) to feed the Future Innovation Lab for collaborative research on sorghum and millet.
Climate change is expected to increase the number and severity of plant diseases, said Mengisti, who led the research.
“We need stronger disease control to maintain global food supplies, and this amazing crop is one step ahead of us,” said Mengisti. “Different types of sorghum have evolved with different strengths and resistance to disease. Through genetics and plant science, we try to help them in the process of adapting to a changing environment.”
By finding the gene responsible for the desired trait, scientists can create biomarkers that allow breeders to quickly test for its presence and incorporate it into sorghum varieties that contain other beneficial properties. The team’s work is detailed in a research paper in the journal plant cell.
“The importance of this work cannot be overemphasized,” said Egita, Distinguished Professor of Agricultural Science at Purdue University and Executive Director of the Purdue Center for Global Food Safety. “This is a significant scientific achievement and the culmination of decades of collaborative research to improve Purdue’s sorghum together with partners in developing countries.”
Sorghum is a key grain crop for food security worldwide, said Mengisti, who is part of the next step in plant science at Purdue and the Purdue Center for Plant Biology.
“It’s a very tough plant in many ways, but fungal disease can wipe it out,” he said. “Anthracnose is one of the most important pathogens and attacks all parts of the plant: leaves, stems and heads. Anthracnose leaves nothing for food, its main use is in Africa; or biofuels and animal feed, and their uses in the United States.” ”
A successful step to feed the future
In 2014, the United States Agency for International Development (USAID) through its Feed the Future Innovation Lab for collaborative research on sorghum and millet operated by Kansas State University made an initial investment in research on host plant resistance to anthracnose in Ethiopia.
“Our goal is to improve the food security and security of sorghum farmers and consumers in Ethiopia and West Africa,” said Timothy Dalton, laboratory director and professor of agricultural economics at Kansas State. “
Mengiste and a previous team of scientists affiliated with the Feed the Future Innovation Lab and from Ethiopia have successfully developed a cultivar called Merera, a type of sorghum that has increased disease, bird resistance and better yields.
“With climate change events or the necessity to produce dry land crops such as the movement of sorghum to areas with high rainfall or irrigated areas, leaf diseases become more important,” said Egita. “Exactly in a situation where strong genes become so important.”
“Chemical control is often ineffective, uneconomical and creates environmental problems,” he said. “A more effective, economically sustainable and environmentally friendly disease control strategy involves the use of disease-resistant plant genotypes. This is what farmers want, because they are adopting a new strain of sorghum.”
Unusual gene affected by parasite DNA
ARG1 upregulation is unusual; It is embedded in the second gene, and both genes appear to be altered by small pieces of motile DNA called transposable elements.
Transposable elements such as molecular viruses or parasites live in the genome and are passed from generation to generation, said Damon Leech, professor of botany and plant pathology involved in the research.
The gene that includes ARG1 is sense antisense RNA. His expression contradicts that of ARG1, he said, leading to a situation where the two could interfere with each other.
All sorghum plants have copies of these two genes, he said, but susceptible sorghum species express too much antiallergic RNA and too little ARG1, which also appear to encode nonfunctional proteins. Disease-resistant ARG1 transcripts are expressed at much higher levels, encode functional proteins, and bind to rejected antisense RNA genes, resulting in less interference.
This is where transportable items seem to come into play, Lich said.
“The introduction of interchangeable goods is often dangerous,” he said. “However, in this case, the transposable element appears to be beneficial by ‘reprogramming’ both genes to increase resistance to fungal pathogens. And on the one hand, it fixes systems that don’t work in plants.”
Lisch discovered the transposable element associated with ARG1 when he examined the genome of a disease-resistant and susceptible sorghum strain. study convertible items And other portable DNA, which he likes to search “for fun” in the genome that is shared among his colleagues.
“Transformable elements are known to be involved in several human and plant diseases, but their involvement in disease resistance is rare — currently,” he said. “Thanks to advances in technology, we were able to identify the DNA strands of this parasite in the gene sequence, and find them everywhere.
Combine applied and basic research
The results may inform other genetic research in sorgum and other plant species, as well as ways to adjust gene expression, Mengist said. The combination of basic and applied research provides rich information. Some will be used now, and others could lead to future innovations.
“We could have stopped after identifying the ARG1 gene, but we dig deeper,” he said. “Otherwise, we might think we could easily fix the proteins involved in resistance. We now have a much greater understanding of gene regulation and additional insight into a new field that could be revolutionary in botany.”
Sorghum, a relative of corn, has been tested for disease resistance on a Pennsylvania farm
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Sangon Lee et al., Broad-spectrum innate resistance in sorghum is conferred by complex regulation of immune receptor genes embedded in natural anti-allergic transcripts, plant cell (2021). DOI: 10.1093/plcell/koab305–
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quote: One Gene Closer to Sorghum (2022, 12 Jan) Retrieved 12 Jan 2022 from https://phys.org/news/2022-01-gene-closer-super-sorghum.html
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