Characterization of gene conferring resistance to U.S. Russian wheat aphid

Russian wheat aphid (Diuraphis noxia Kurdjumov) is a highly invasive and destructive wheat pest evolving rapidly to overcome host resistance. Most Russian wheat aphid (RWA) resistance genes have lost effectiveness to new RWA biotypes. Novel genes conferring resistance to multiple RWA biotypes are needed to sustain wheat production. The gene Dn7 confers resistance to all U.S. RWA biotypes. However, Dn7 was identified in rye and is closely linked to the undesirable Sec1 gene encoding monomeric secalins, which reduce dough strength and cause sticky dough; thus, negatively affect wheat end-use quality.

Scientists from Stillwater, OK and Manhattan, KS identified a new gene designated as Dn625139 in the Iranian landrace PI 625139, which confers resistance to all five U.S. RWA biotypes, namely RWA1, RWA2, RWA3/7, RWA6, and RWA8. They mapped Dn625139 to the short arm of chromosome 7D and developed markers that can be used to tag Dn625139 in breeding populations.

Dn625139 can be widely used to enhance RWA resistance in wheat breeding and is an ideal alternative to Dn7. The molecular markers developed in this study, published in Crop Science, can facilitate the rapid introgression of Dn625139 into locally adapted cultivars to enhance wheat RWA resistance.