Scientists have identified genes in traditional Asian wheat varieties that can fight yellow rust, a major fungal disease threatening global wheat production. This discovery offers a promising strategy to protect food security by enhancing the disease resistance of commercial wheat crops.
Yellow rust, caused by the fungus Puccinia striiformis f. sp. tritici, affects about 88% of the world's bread wheat production. It poses a significant threat to wheat yields. Researchers at the University of Zurich (UZH) have found that traditional wheat varieties from Asia possess genes that provide resistance to this devastating disease.
The research team, led by Kentaro Shimizu, discovered two genomic regions in traditional Asian wheat varieties that confer resistance to yellow rust. These genes could be transferred to commercial wheat varieties to combat the disease. The study highlights the importance of genetic diversity in traditional wheat varieties for food security.
For decades, wheat breeding has focused on high-yielding varieties, which has reduced the crop's genetic diversity. Traditional wheat varieties, cultivated by farmers in diverse regions, retain a wider genetic base. These varieties, especially those from Asia, offer untapped potential for improving disease resistance in modern wheat.
Katharina Jung, during her PhD, investigated yellow rust resistance in wheat, collaborating with the International Maize and Wheat Improvement Center (CIMMYT) in Mexico and Kyoto University in Japan. She screened traditional and modern wheat varieties from Japan, China, Nepal, and Pakistan. Field trials were conducted in Switzerland and Mexico to identify resistant plants.
Jung identified two previously uncharacterized genomic regions, known as quantitative trait loci (QTLs), that contribute to yellow rust resistance. One region was found in a traditional variety from Nepal, while the other appeared more widely across traditional lines from Nepal, Pakistan, and China in the southern Himalayan region.
The southern Himalayan area is believed to be the origin of the yellow rust pathogen. The researchers hypothesize that traditional varieties from this area might harbor unique and stable resistances to yellow rust. This discovery emphasizes the value of preserving traditional wheat varieties as a source of genetic traits to combat emerging threats.
Conserving genetic diversity and traditional wheat varieties is crucial for combating diseases. Farmers have cultivated these varieties for generations, which is of great value for future food security. The use and benefit-sharing of these varieties should involve close collaboration with local communities, recognizing their knowledge and practices.
The collaboration with Kyoto University was essential for this project. This research underscores the value of international partnerships in scientific progress. The UZH Global Funding Scheme supported the project. The alliance between UZH and Kyoto University was converted into a Strategic Partnership in 2020.