The zygotic transition, from a fertilized egg to an embryo, is central to animal and plant reproduction. Animal embryos depend upon maternally provided factors until zygotic genome activation (ZGA). In plants, the timing and parental genome contributions to ZGA are unresolved. Here, we use the flowering plant Oryza sativa (rice) to characterize transcriptomes of time-staged isogenic and hybrid zygotes following fertilization. Large-scale transcriptomic changes were observed in unicellular zygotes, including upregulation of S-phase genes, a characteristic of ZGA. The parental contributions to ZGA were highly asymmetric. Zygotic transcription was primarily from the maternal genome and included genes for basic cellular processes. Transcription of the paternal genome was highly restricted but unexpectedly included genes encoding putative pluripotency factors expressed at the onset of ZGA. Thus, distinct transcriptional activities are exhibited by the parental genomes during the initiation of embryogenesis, which presumptively derive from divergent pre-zygotic transcriptional states established in the gametes.

Stretchable alternating current electroluminescent display is an emerging form of light-emitting device by combining elasticity with optoelectronic properties. The practical implementations are currently impeded by the high operating voltages required to achieve sufficient brightness. In this study, we report the development of dielectric nanocomposites by filling surface-modified ceramic nanoparticles into polar elastomers, which exhibit a series of desirable attributes, in terms of high permittivity, mechanical deformability, and solution processability. Dielectric nanocomposite effectively concentrates electric fields onto phosphor to enable low-voltage operation of stretchable electroluminescent display, thereby alleviating safety concerns toward wearable applications. The practical feasibility is demonstrated by an epidermal stopwatch that allows intimate integration with the human body. The high-permittivity nanocomposites reported here represent an attractive building block for stretchable electronic systems, which may find broad range of applications in intrinsically stretchable transistors, sensors, light-emitting devices, and energy-harvesting devices.

Gametes constitute a critical stage of the plant life cycle during which the genome undergoes reprogramming in preparation for embryogenesis. Here, we examined genome-wide distributions of small RNAs in the sperm and egg cells of rice. We found that 24-nt siRNAs, which are a hallmark of RNA-directed DNA methylation (RdDM) in plants, were depleted from heterochromatin boundaries in both gametes relative to vegetative tissues, reminiscent of siRNA patterns in DDM1type nucleosome remodeler mutants. In sperm cells, 24-nt siRNAs were spread across heterochromatic regions, while in egg cells, 24-nt siRNAs were concentrated at a smaller number of heterochromatic loci throughout the genome, especially at loci which also produced siRNAs in other tissues. In both gametes, patterns of CHH methylation, typically a strong indicator of RdDM, were similar to vegetative tissues, although lower in magnitude. These findings indicate that the small RNA transcriptome undergoes large-scale redistribution in both male and female gametes, which is not correlated with recruitment of DNA methyltransferases in gametes and suggestive of unexplored regulatory activities of gamete small RNAs.

Vitiligo is an acquired depigmentation disorder, and reactive oxygen species have an important role in the physiology of cell damage. Reduced catalase enzyme activity and accumulation of excessive hydrogen peroxide have been observed in vitiligo. In a hospital-based case-control study of vitiligo patients (n=749) and age- and sex-matched healthy controls (n=763), we investigated three catalase (CAT) gene polymorphisms (-89A>T, 389C>T, and 419C>T) to examine whether CAT gene polymorphisms are associated with vitiligo susceptibility in the Chinese population. The case-control analysis revealed a 1.54-fold (95% confidence interval (CI) 1.25-1.91) increased risk of developing vitiligo for -89A>T genotype carriers. No evidence for any association between 389C>T and 419C>T polymorphisms in the catalase gene and vitiligo susceptibility was found. An analysis of haplotypes showed increased risk for T(-89)C(389) (odds ratio (OR) 1.90, 95% CI 1.26-2.86) and T(-89)T(389) (OR 2.80, 95% CI 1.24-6.30). Logistic regression analysis of catalase activity also showed a dose-response relationship between increased risk and decreased activity in CAT -89A>T variant genotype carriers, especially in vitiligo patients (P(trend) <0.001). Our molecular epidemiologic findings suggest that the CAT -89A>T variant genotypes were associated with a significant decrease in catalase enzyme activity and a genetic predisposition for vitiligo in Chinese people.