Wheat is a staple crop that suffers from severe economic yield losses worldwide by insect herbivore feeding. Cereal aphids are one of the major wheat pests, solitary feed from the plant phloem sap. They consume water and nutrients from the plant, thus depending on the host metabolism. To increase yield, it is imperative to identify new genes and alleles that confer resistance to herbivore attacks. The goal of our research was to identify markers associated with aphid fitness by exploiting the tetraploid wild emmer wheat (WEW; Triticum turgidum ssp. dicoccoides) germplasm, one of the progenitors of domesticated wheat, possesses untapped resources from its numerous desirable traits, including aphid resistance. Thus, we measured the chlorophyll level of 203 WEW accessions and conducted genome-wide association studies (GWAS). We identified a SNP that is associated with the alternative allele that possessed high chlorophyll and high aphid progeny relative to the wildtype allele. A metabolic profile indicated that several nitrogen-containing compounds were higher in the alternative allele accessions, while non-nitrogen compounds were lower in these accessions relative to the wildtype allele. This SNP is located 1,102 bp upstream to the terminator of a RING-type Zinc finger. To study the function of this gene, we ectopically expressed in tobacco leaves the RING gene from the sequenced WEW accession 'Zavitan,' which is associated with the wildtype allele. The RING overexpressed leaves had shown a reduction in aphid progeny and nitrogen-containing metabolites relative to the empty vector. We suggest that this RING is involved in determining the carbon-nitrogen balance of the wheat, which affects the aphid performance.
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