Identification of Russian Wheat Aphid (Homoptera: Aphididae) Populations Virulent to the Dn4 Resistance Gene

Abstract

The Russian wheat aphid, Diuraphis noxia (Mordvilko), is a serious worldwide pest of wheat and barley. Russian wheat aphid populations from Hungary, Russia, and Syria have previously been identified as virulent to D. noxia (Dn) 4, the gene in all Russian wheat aphid-resistant cultivars produced in Colorado. However, the virulence of Russian wheat aphid populations from central Europe, North Africa, and South America to existing Dn genes has not been assessed. Experiments with plants containing several different Dn genes demonstrated that populations from Chile, the Czech Republic, and Ethiopia are also virulent to Dn4. The Czech population was also virulent to plants containing the Dnx gene in wheat plant introduction PI220127. The Ethiopian population was also virulent to plants containing the Dny gene in the Russian wheat aphid-resistant 'Stanton' produced in Kansas. The Chilean and Ethiopian populations were unaffected by the antibiosis resistance in Dn4 plants. There were significantly more nymphs of the Chilean population on plants of Dn4 than on Dn6 plants at both 18 and 23 d postinfestation, and the Ethiopian population attained a significantly greater weight on Dn4 plants than on plants containing Dn5 or Dn6. These newly characterized virulent Russian wheat aphid populations pose a distinct threat to existing or proposed wheat cultivars possessing Dn4.

Comparative gut transcriptome analysis reveals differences between virulent and avirulent Russian wheat aphids, Diuraphis noxia

“…In response to D. noxia-related yield losses, numerous D. noxia-resistant varieties of barley and wheat have been developed and deployed, primarily in North America and South Africa (Mornhinweg et al 2006;Tolmay et al 2006). Nevertheless, virulent genotypes of D. noxia referred to as biotypes now exist that are unaffected by otherwise resistant plants (Basky, 2003;Haley et al 2004;Smith et al 2004;Dolatti et al 2005; Burd et al 2006;Malinga et al 2007;Tolmay et al 2006). Therefore, there is an urgent need to understand the relationship between molecular mechanisms of wheat defenses against D. noxia and corresponding D. noxia counter defenses.…”

AFLP genetic diversity analysis in Russian wheat aphid resistant wheat accessions

“…So far, 11 genes conferring resistance to RWA have been identified in wheat accessions from the Mediterranean region, and in related crops, such as rye (Secale cereale L.), and goatgrass (Aegilops tauschii Coss.) (Liu et al 2001;Smith et al 2004;Peng et al 2007). In the U.S., RWA1 resistant cultivars are primarily developed using gene Dn4 from an Iranian source, PI 372129 (Collins et al 2005).…”

Cereal host interactions with Russian wheat aphid: A review

“…Russian wheat aphid populations from Hungary, Russia and Syria have been identified as virulent to the Dn4 resistance gene (Puterka et al 1992, Basky 2002, while populations from Chile, Ethiopia and the Czech Republic also showed virulence to this gene (Smith et al 2004). Virulence to Dn1 , Dn2 , Dn4 , Dn5 , Dn6 was also identified in populations from Colorado, Nebraska and Texas (Haley et al 2004).…”