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Asian wheat lines like this one may provide new resistance to Fusarium head blight disease for U.S. wheat. Click the image for more information about it.

Scientists identify specific barley tissues infected by scab   ARS researchers develop method to speed up breeding of scab-resistant barley cultivars   Scientists pit bacteria against fungi to protect wheat

Diverse Wheat Tapped for Antifungal Genes

By Jan Suszkiw
April 1, 2010

Asian wheat may offer novel genes for shoring up the defenses of U.S. varieties against Fusarium graminearum fungi that cause Fusarium head blight (FHB) disease.

According to Agricultural Research Service (ARS) plant molecular biologist Guihua Bai, the FHB resistance found in today's U.S. wheat varieties is primarily based on the Chinese wheat variety Sumai 3 and a few other sources. But there's concern that FHB-causing species of F. graminearum will overcome these resistant sources.

In susceptible varieties, the fungus infects the wheat heads, causing kernels to shrivel up and turn chalky white. The fungus can also produce mycotoxins that reduce the kernels' value and quality, according to Bai, who works at the ARS Hard Winter Wheat Genetics Research Unit in Manhattan, Kan.

In collaboration with Kansas State University scientists, Bai has sought new sources of FHB resistance from exotic wheat lines collected from China, Korea and Japan. These lines include "landrace" populations--domesticated plants that have changed very little since the advent of modern plant breeding.

Of 87 total Asian landrace accessions tested in greenhouse trials, 26 showed high levels of FHB resistance, Bai reports. Grain evaluations also revealed that 15 of them had exceptionally low levels of the mycotoxin deoxynivalenol, which is produced during disease development and can diminish the value of affected kernels as food or feed.

Six of the accessions possessed genes for different forms of FHB resistance known as types I, II and III. Significantly, some of the genes appear unrelated to Sumai 3, suggesting the Asian landraces could broaden the genetic pool of resistance now available for use in breeding U.S. wheat varieties. This, in turn, could help avoid repeat disasters such as the FHB epidemic that swept through the Great Plains from 1998 to 2000, costing America's wheat industry $2.7 billion in losses.

Read more about this research in the April 2010 issue of Agricultural Research magazine.

ARS is the principal intramural scientific research agency of the U.S. Department of Agriculture (USDA). This research supports the USDA priorities of ensuring food safety and promoting international food security.