Dominant mutations atCer-yy change barley spike wax into leaf blade wax

Abstract

Keywords: [~-diketones, p r i m a r y alcohols, epicuticular, early maturation, elongase, lipid, biosynthesis Seventeen mutations resulting in an apparent loss of the epicuticular wax on barley spikes have been shown by complementation, test cross and F2 analyses to be dominantly inherited alterations of the Cer-yy gene. The chemical composition determined by the four alleles 966, 968, 975 and 984 differs from that determined by the wild type in that none of the [~-ketoacyi derived lipids (~-diketones, hydroxy-I~-diketones and esters containing alkan-2-ols) are synthesized while the composition of the other wax lipids (alkanes, primary alcohols, aldehydes, esters containing alkan-I-ols and free acids) is markedly altered toward that characteristic of leaf blade waxes.We suggest that the Cer-yy gene determines a regulatory component which upon mutation activates the gends) in the spike for the leaf blade acyl elongase system and at the same time represses the spike acyl and I~-ketoacyl elongase systems.

The Inhibitor of wax 1 locus (Iw1) prevents formation of β‐ and OH‐β‐diketones in wheat cuticular waxes and maps to a sub‐cM interval on chromosome arm 2BS

“…The Cer ‐ cqu gene in barley maps to a similar region on chromosome arm 2HS as Iw1 on wheat 2BS; however, only one of 522 mutations is dominant (King and von Wettstein‐Knowles, ). All 18 Cer ‐ yy induced mutations are dominant, analogous to Iw1 , but Cer ‐ yy maps to chromosome 1H (Lundqvist and von Wettstein‐Knowles, ; von Wettstein‐Knowles, ). As a number of barley and wheat varieties carry dominant alleles of these inhibitors, identifying the molecular nature of Iw1 and Cer ‐ yy is of great interest.…”

Development and Genetic Characterization of an Advanced Backcross-Nested Association Mapping (AB-NAM) Population of Wild × Cultivated Barley

“…This association falls in the region of the most significant glossy sheath locus, and is likely due to the interaction between glossy spike and glossy sheath. The highly-significant region on chromosome 1HS is coincident with the location of the Eceriferum-yy (Cer-yy) barley mutants, which exhibit a reduction of wax production on the barley spike (Lundqvist and Wettstein-Knowles 1982;Druka et al 2011).…”

“…This association falls in the region of the most significant glossy sheath locus, and is likely due to the interaction between glossy spike and glossy sheath. The highly-significant region on chromosome 1HS is coincident with the location of the Eceriferum-yy (Cer-yy) barley mutants, which exhibit a reduction of wax production on the barley spike (Lundqvist and Wettstein-Knowles 1982;Druka et al 2011).The black hull phenotype was only identified in four individuals. Thus, there appear to be many spurious associations, including peaks on chromosomes 2H, 3H, 4H, and 6H with significance ranging from 2log(P) = 7.03 to 2log(P) = 30.41 (File S1).…”

Biochemistry and Molecular Biology of Wax Production in Plants

“…All 17 cer-yy alleles are dominant and change the primary alcohol composition of barley spike wax into a composition indistinguishable from that of wildtype barley leaf blade wax (62). To account for this phenotype, the authors hypothesized that the mutant cer-yy allele activates the acyl-reduction pathway in leaf blades and suppresses the acyl-reduction and β-ketoacylreduction pathways in barley spikes.…”