Mechanisms of resistance of new wheat gene Dn10 in comparison with other Dn genes resistant to Russian wheat aphid

Authors: Puterka, Gary; Xu, Xiangyang; Li, Genqiao; CARVER, BRETT - Oklahoma State University; GUO, PEIGUO - Guangzhou University

Submitted to: Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/9/2019
Publication Date: 7/1/2020
Citation: Puterka, G.J., Xu, X., Li, G., Carver, B.F., Guo, P. 2020. Mechanisms of resistance of new wheat gene Dn10 in comparison with other Dn genes resistant to Russian wheat aphid. Crop Science. 60:1782-1788. https://doi.org/10.1002/csc2.20051.
DOI: https://doi.org/10.1002/csc2.20051

Interpretive Summary: The Russian wheat aphid (RWA) is a pest of wheat that sucks plant juice and caused damage and death to wheat, barley and oats. Plants can be made resistant to this pest by breeding genes that occur in nature in wild grass and wheat relatives. This has been done in wheat using the Dn4 gene that was transferred from wild wheat to wheat varieties in the United States. These resistant varieties were effective in preventing damage from RWA infestations from 1995 to 2003. In 2003 a new race of RWA appeared which was termed biotype 2 (RWA2). The appearance of this new biotype was able to overcome most of the RWA resistance genes that were available to breeders. A new resistance gene called Dn10 was recently discovered by plant breeders that is resistant to the RWA2. We tested several biotypes of the Russian wheat aphid, RWA1 and RWA2 on plants with the Dn10 gene to determine how they resist damage and how growth was affected in comparison to five other resistance genes. Dn10 was found to resist damage similar to other resistance genes. However, Dn10 was more resistant to plant stunting than most of the other resistance genes. This new resistance gene is a valuable addition to the short list of genes currently available to wheat breeders.

Technical Abstract: The Russian wheat aphid (RWA, Diuraphis noxia Kurdjumov) is a global pest of wheat (Triticum aestivum L.) that became a significant problem to wheat and barley (Hordeum vulgare L.) in the United States soon after it was detected in 1986. Russian wheat aphid-resistant wheat varieties expressing theDn4gene were effective in managing the first biotype, RWA1, from 1995–2003 until a new biotype, RWA2, overcame this resistance in 2003. Currently, only three genes are useful in developing RWA2 resistance in wheat. A new gene, Dn10, was recently discovered that is resistant to RWA2. This study characterized the effects that RWA1 and RWA2 had on the damage (leaf chlorosis and leaf roll) and growth components (plant height and leaf number) of plants expressing RWA resistance genes Dn4, Dn7, Dn10, Dn2401, Dn626580, and Dn2414 and the susceptible ‘Yuma’ 22 d after infestation. All plant genotypes that were RWA resistant expressed strong resistance to leaf chlorosis and leaf roll after RWA1 feeding. Results were similar for RWA2 except for theDn4genotype, which was equally susceptible as Yuma. Plant height was reduced by 50% for susceptible Yuma and Dn626580 by RWA1 and RWA2 feeding. Plant height and leaf reduction from RWA2 feeding on the susceptible Dn4 genotype were also reduced by 50%, whereasDn7,Dn10, andDn2414reductions were <23%.Dn10exhibited strong resistance to RWA1 and RWA2 feeding damage comparable with Dn7 and Dn2414 and showed less reduction in plant height than Dn2401 and Dn626580, which makes it a potentially valuable gene for wheat breeding programs.