A gene discovered in bread wheat plants by Purdue University researchers in the US has been found to be resistant to the devastating leaf blotch. According to the scientists, the gene can help reduce the amount of grain lost to the pathogen. This fungus causes enormous wheat crop damage worldwide with yield losses of up to 50 per cent in some places.
"The goal of our work is to find additional resistance genes to the fungus Mycosphaerella graminicola so we can use the lines carrying these genes in our wheat to avoid the breakdown of resistance in the plants," said Stephen Goodwin, associate professor of botany and plant pathology and US department of agriculture-agricultural research service (USDA-ARS) scientist. "Having the markers greatly speeds up the breeding process for resistant plants."
The team used bread wheat species to find the gene and bits of DNA that indicate presence of the naturally occurring gene. These markers facilitate finding plants with the pathogen resistance gene. As soon as a seedling sprouts, a small piece of the young leaf can be ground and then a DNA test can be run. This shows whether the markers are present.
"Using the markers, in a few days you can tell which plants have the resistance gene and which don't," said Goodwin.The researchers discovered the gene Stb8, so named because it is the eighth gene known to provide resistance to Septoria tritici leaf blotch (STB). However, this gene has some differences compared with the ones found previously.
Several of the previously found genes conferred resistance on bread wheat plants for only a few years - up to about 15 years. Stb8 has genetic characteristics that may allow it to be effective for a much longer period of time. The genome containing Stb8 originated from a pasta wheat parent, which is resistant to most strains of the fungus. This may extend the usefulness of the resistance gene for bread wheat.
The other researchers involved in this study are Tika Adhikari, USDA-ARS and department of botany and plant pathology postdoctoral fellow, and Joseph Anderson, USDA-ARS scientist and Purdue department of agronomy assistant professor.The USDA-ARS provided funding for this study.
Results of the Purdue study on resistance to the fungus that causes Septoria tritici leaf blotch are published in the September issue of Phytopathology and appear on the journal's website.