SUMMARYDehydrin proteins (late embryogenesis abundant (LEA) Dll family) are produced in a wide variety of plant species in response to environmental stimuli with a dehydrative component, including drought, low temperature, salinity, and developmental stages such as seed and pollen maturation. Despite their widespread occurrence and abundance in cells under dehydrative conditions, the biochemical role of dehydrins remains elusive. The subcellular location of dehydrins is consistent with a biochemical role as an intracellular stabilizer, possibly with surfactant characteristics, acting upon targets in both the nucleus and cytoplasm. In some species, dehydrin loci are located within quantitative trait loci (QTL) intervals for important phenotypic traits including winter hardiness in barley {Hordeum vulgare L.) and an thesis-silking interval in maize {Zea mays L.). Dehydrin loci tend to be multigenic and occur in clusters on more than one chromosome. Investigations are currently under way in our laboratory and others' to move beyond protein accumulation studies and correlations with QTL to uncover direct cause-and-efTect relationships between dehydrin {dhn) genes and phenotypes associated with physiological responses to stress.

Differences between sexes contribute to variation in the levels of fasting glucose and insulin. Epidemiological studies established a higher prevalence of impaired fasting glucose in men and impaired glucose tolerance in women, however, the genetic component underlying this phenomenon is not established. We assess sex-dimorphic (73,089/50,404 women and 67,506/47,806 men) and sex-combined (151,188/105,056 individuals) fasting glucose/fasting insulin genetic effects via genome-wide association study meta-analyses in individuals of European descent without diabetes. Here we report sex dimorphism in allelic effects on fasting insulin at IRS1 and ZNF12 loci, the latter showing higher RNA expression in whole blood in women compared to men. We also observe sex-homogeneous effects on fasting glucose at seven novel loci. Fasting insulin in women shows stronger genetic correlations than in men with waist-to-hip ratio and anorexia nervosa. Furthermore, waist-to-hip ratio is causally related to insulin resistance in women, but not in men. These results position dissection of metabolic and glycemic health sex dimorphism as a steppingstone for understanding differences in genetic effects between women and men in related phenotypes.

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