GENETIC AND BIOCHEMICAL MECHANISMS OF RESISTANCE TO BARLEY AND CEREAL YELLOW DWARF VIRUSES AND FUNGI
Location: Crop Production and Pest Control Research
Title: Potential New Genes for Resistance to Mycosphaerella Graminicola Identified in Triticum Aestivum x Lophopyrum Elongatum Disomic Substitution Lines
Submitted to: Euphytica
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: November 12, 2009
Publication Date: November 2, 2009
Citation: Anderson, J.M., Bucholtz, D.L., Sardesai, N., Santini, J.B., Gyulai, G., Williams, C.E., Goodwin, S.B. 2009. Potential New Genes for Resistance to Mycosphaerella Graminicola Identified in Triticum Aestivum x Lophopyrum Elongatum Disomic Substitution Lines. Euphytica. 172:251-262.
Interpretive Summary: Wild relatives of wheat such as wheatgrasses are resistant to many diseases that affect wheat. A collection of lines containing different individual chromosomes from a related wheatgrass was tested for resistance to several different important wheat pathogens and an insect pest. The results from this study showed that the wheatgrass chromosome 7E carried a gene or genes that gave a high level of resistance to Fusarium head blight (scab). A different wheatgrass chromosome, 6E, contained resistance to leaf blotch, an important leaf pathogen of wheat. This study also revealed that the wheatgrass chromosomes did not carry resistance to Hessian fly or powdery mildew and only slight resistance to barley and cereal yellow dwarf viruses. Because the resistance to Fusarium head blight and leaf blotch was excellent this wheatgrass derived resistance has the potential to be a very important new source of resistance to these diseases. This research will be used by plant breeders and other plant scientists to develop wheat lines that contain this Fusarium head blight and leaf blotch resistance which can then be added to current resistant lines to form wheat cultivars with durable high level resistance.
Lophopyrum species carry many desirable agronomic traits, including disease resistance, which can be transferred to wheat by interspecific hybridizations. To identify potentially new genes for disease and insect resistance carried by individual Lophopyrum chromosomes, 19 of 21 possible wheat cultivar Chinese Spring × Lophopyrum elongatum disomic substitution lines were tested for resistance to barley yellow dwarf virus (BYDV), cereal yellow dwarf virus (CYDV), the Hessian fly Mayetiola destructor, and the fungal pathogens Blumeria graminis and Mycosphaerella graminicola (anamorph: Septoria tritici). Low resistance to BYDV-PAV and moderate resistance to CYDV-RPV occurred in the disomic substitution lines containing 1E and 2E-3E, respectively, compared with Chinese Spring, but viral titers were significantly higher than those of two Lophopyrum species tested. This suggested that genes on more than one Lophopyrum chromosome are required for complete resistance to these two viruses. All of the substitution lines were susceptible to Mayetiola destructor and one strain of B. graminis. Disomic substitution lines containing wheatgrass chromosomes 1E and 6E were significantly more resistant to M. graminicola compared to Chinese Spring. Although neither chromosome by itself conferred resistance as high as that in the wheatgrass parent, they do appear to contain potentially new genes for resistance against this pathogen that could be useful for future plant-improvement programs.