A Mendelian Trait for Olfactory Sensitivity Affects Odor Experience and Food Selection

SummaryHumans vary in acuity to many odors [1–4], with variation within olfactory receptor (OR) genes contributing to these differences [5–9]. How such variation also affects odor experience and food selection remains uncertain [10], given that such effects occur for taste [11–15]. Here we investigate β-ionone, which shows extreme sensitivity differences [4, 16, 17]. β-ionone is a key aroma in foods and beverages [18–21] and is added to products in order to give a pleasant floral note [22, 23]. Genome-wide and in vitro assays demonstrate rs6591536 as the causal variant for β-ionone odor sensitivity. rs6591536 encodes a N183D substitution in the second extracellular loop of OR5A1 and explains >96% of the observed phenotypic variation, resembling a monogenic Mendelian trait. Individuals carrying genotypes for β-ionone sensitivity can more easily differentiate between food and beverage stimuli with and without added β-ionone. Sensitive individuals typically describe β-ionone in foods and beverages as “fragrant” and “floral,” whereas less-sensitive individuals describe these stimuli differently. rs6591536 genotype also influences emotional associations and explains differences in food and product choices. These studies demonstrate that an OR variant that influences olfactory sensitivity can affect how people experience and respond to foods, beverages, and other products

Sex Pheromone Evolution Is Associated with Differential Regulation of the Same Desaturase Gene in Two Genera of Leafroller Moths

Chemical signals are prevalent in sexual communication systems. Mate recognition has been extensively studied within the Lepidoptera, where the production and recognition of species-specific sex pheromone signals are typically the defining character. While the specific blend of compounds that makes up the sex pheromones of many species has been characterized, the molecular mechanisms underpinning the evolution of pheromone-based mate recognition systems remain largely unknown. We have focused on two sets of sibling species within the leafroller moth genera Ctenopseustis and Planotortrix that have rapidly evolved the use of distinct sex pheromone blends. The compounds within these blends differ almost exclusively in the relative position of double bonds that are introduced by desaturase enzymes. Of the six desaturase orthologs isolated from all four species, functional analyses in yeast and gene expression in pheromone glands implicate three in pheromone biosynthesis, two Δ9-desaturases, and a Δ10-desaturase, while the remaining three desaturases include a Δ6-desaturase, a terminal desaturase, and a non-functional desaturase. Comparative quantitative real-time PCR reveals that the Δ10-desaturase is differentially expressed in the pheromone glands of the two sets of sibling species, consistent with differences in the pheromone blend in both species pairs. In the pheromone glands of species that utilize (Z)-8-tetradecenyl acetate as sex pheromone component (Ctenopseustis obliquana and Planotortrix octo), the expression levels of the Δ10-desaturase are significantly higher than in the pheromone glands of their respective sibling species (C. herana and P. excessana). Our results demonstrate that interspecific sex pheromone differences are associated with differential regulation of the same desaturase gene in two genera of moths. We suggest that differential gene regulation among members of a multigene family may be an important mechanism of molecular innovation in sex pheromone evolution and speciation

A novel fatty acyl desaturase from the pheromone glands of Ctenopseustis obliquana and C. herana with specific Z5-desaturase activity on myristic acid

Sexual communication in the Lepidoptera typically involves a female-produced sex pheromone that attracts males of the same species. The most common type of moth sex pheromone comprises individual or blends of fatty acyl derivatives that are synthesized by a specific enzymatic pathway in the female’s pheromone gland, often including a desaturation step. This reaction is catalyzed by fatty acyl desaturases that introduce double bonds at specific locations in the fatty acid precursor backbone. The two tortricid moths, Ctenopseustis obliquana and C. herana (brown-headed leafrollers), which are endemic in New Zealand, both use (Z)-5-tetradecenyl acetate as part of their sex pheromone. In [i]C. herana[i], (Z)-5-tetradecenyl acetate is the sole component of the pheromone. Labeling experiments have revealed that this compound is produced via an unusual Δ5-desaturation of myristic acid. Previously six desaturases were identified from the pheromone glands of Ctenopseustis and its sibling genus [i]Planotortrix[i], with one differentially regulated to produce the distinct blends used by individual species. However, none were able to conduct the Δ5-desaturation observed in C. herana, and presumably C. obliquana. We have now identified an additional desaturase gene, desat7, expressed in the pheromone glands of both Ctenopseustis species, which is not closely related to any previously described moth pheromone desaturase. The encoded enzyme displays Δ5-desaturase activity on myristic acid when heterologously expressed in yeast, but is not able to desaturate any other fatty acid (C8–C16). We conclude that desat7 represents a new group of desaturases that has evolved a role in the biosynthesis of sex pheromones in moths

The Genomics and Population Genomics of the Light Brown Apple Moth, Epiphyas postvittana, an Invasive Tortricid Pest of Horticulture

The light brown apple moth, Epiphyas postvittana is an invasive, polyphagous pest of horticultural systems around the world. With origins in Australia, the pest has subsequently spread to New Zealand, Hawaii, California and Europe, where it has been found on over 500 plants, including many horticultural crops. We have produced a genomic resource, to understand the biological basis of the polyphagous and invasive nature of this and other lepidopteran pests. The assembled genome sequence encompassed 598 Mb and has an N50 of 301.17 kb, with a BUSCO completion rate of 97.9%. Epiphyas postvittana has 34% of its assembled genome represented as repetitive sequences, with the majority of the known elements made up of longer DNA transposable elements (14.07 Mb) and retrotransposons (LINE 17.83 Mb). Of the 31,389 predicted genes, 28,714 (91.5%) were assigned to 11,438 orthogroups across the Lepidoptera, of which 945 were specific to E. postvittana. Twenty gene families showed significant expansions in E. postvittana, including some likely to have a role in its pest status, such as cytochrome p450s, glutathione-S-transferases and UDP-glucuronosyltransferases. Finally, using a RAD-tag approach, we investigated the population genomics of this pest, looking at its likely patterns of invasion

Multiple and Multi-dimensional Primary-Secondary School Transitions:Using Drama to Facilitate Transitions

Acknowledgements We are grateful to all those in the local authority who helped in the planning and implementation of the project. In particular, we would like to thank all the pupils who took part in the drama workshops and those who participated in the study (young people, parents/carers and professionals) for giving us valuable insights into their transition experiences. Thanks to the local authority for their financial support, the University of Aberdeen for pump prime seed funding, and the University of Dundee for its Innovation and Impact Development Fund.Publisher PDFPublisher PD

Gene expression of <i>desat1</i>, <i>desat5</i>, and <i>desat6</i> in the pheromone gland and abdomen of virgin females in <i>Ctenopseustis obliquana</i>, <i>C. herana</i>, <i>P. excessana</i>, and <i>P. octo</i> relative to housekeeper genes.

<p>In panel (A) the normalised expression levels in the pheromone gland [PG] of <i>C. herana</i> (Che; light brown; n = 20) and <i>C. obliquana</i> (Cob; dark brown; n = 21) was compared with those in the abdomen [Ab] of <i>C. herana</i> (n = 20) and <i>C. obliquana</i> (n = 21), while in panel (B) the normalised expression levels in the pheromone gland of <i>P. excessana</i> (Pex; light green; n = 39) and <i>P. octo</i> (Poc; dark green; n = 24) are compared with those in the abdomen of <i>P. excessana</i> (n = 39) and <i>P. octo</i> (n = 25). Bars are the mean normalized gene expression, with error bars representing SEMs. Different small case letters indicate significant differences between tissues and/or species at the 95% level using the Bonferroni correction for each desaturase gene.</p

Putative positively selected sites and posterior probabilities under M8.

<p>Putative positively selected sites and posterior probabilities under M8.</p

Summary statistics for desaturases from <i>Ctenopseustis</i> and <i>Planotortrix</i> species.

a<p>number of sequences.</p>b<p>number of codons.</p>c<p>tree length.</p>d<p>transition/transversion ratio.</p>e<p>ω under M0.</p>f<p>ω under M3.</p

Schematic outlining the likely biosynthetic routes of the sex pheromone components of <i>C. obliquana</i>, <i>C. herana</i>, <i>P. octo</i>, and <i>P. excessana</i>.

<p><i>Desat1</i>, <i>desat5</i> and <i>desat6</i> correspond to the desaturase genes encoding a Δ9 desaturase with a preference for 16&gt;18 carbon fatty acids, a Δ10-desaturase and a Δ9-desaturase with a preference for 18&gt;16 carbon fatty acids, respectively. <i>Desat?</i> refers to a yet to be identified Δ5-desaturase. Chain shortening by β-oxidation is indicated by ‘−2C’. The minor products of the two Δ9-desaturases in <i>P. excessana</i> (<i>desat1</i> and <i>desat6</i>) are indicated in brackets. We also note that Z10-14:OAc is a very minor (2%) component of the pheromone blend of <i>P. octo</i> (not shown).</p