Genomic Imprinting in Plants

Seeds-An evolutionary innovation underlying reproductive success in flowering plants

"Seeds nourish, seeds unite, seeds endure, seeds defend, seeds travel," explains the science writer Thor Hanson in his book The Triumph of Seeds (2015). The seed is an ultimate product of land plant evolution. The nursing and protective organization of the seed enable a unique parental care of the progeny that has fueled seed plant radiation. Seeds promote dispersal and optimize offspring production and thus reproductive fitness through biological adaptations that integrate environmental and developmental cues. The composite structure of seeds, uniting tissues that originate from three distinct organisms, enables the partitioning of tasks during development, maturation, and storage, while a sophisticated interplay between the compartments allows the fine-tuning of embryonic growth, as well as seed maturation, dormancy, and germination. In this review, we will highlight peculiarities in the development and evolution of the different seed compartments and focus on the molecular mechanisms underlying the interactions between them.

Systems biology of seeds: decoding the secret of biochemical seed factories for nutritional security

Seeds serve as biochemical factories of nutrition, processing, bio-energy and storage related important bio-molecules and act as a delivery system to transmit the genetic information to the next generation. The research pertaining towards delineating the complex system of regulation of genes and pathways related to seed biology and nutrient partitioning is still under infancy. To understand these, it is important to know the genes and pathway(s) involved in the homeostasis of bio-molecules. In recent past with the advent and advancement of modern tools of genomics and genetic engineering, multi-layered 'omics' approaches and high-throughput platforms are being used to discern the genes and proteins involved in various metabolic, and signaling pathways and their regulations for understanding the molecular genetics of biosynthesis and homeostasis of bio-molecules. This can be possible by exploring systems biology approaches via the integration of omics data for understanding the intricacy of seed development and nutrient partitioning. These information can be exploited for the improvement of biologically important chemicals for large-scale production of nutrients and nutraceuticals through pathway engineering and biotechnology. This review article thus describes different omics tools and other branches that are merged to build the most attractive area of research towards establishing the seeds as biochemical factories for human health and nutrition.

EARLY FLOWERING IN SHORT DAYS (EFS) regulates the seed size in Arabidopsis

Post-transcriptional modifications, including histone modifications and DNA methylation, alter the chromatin landscape to regulate gene expression, thus control various cellular processes in plants. EARLY FLOWERING IN SHORT DAYS (EFS) is the major contributor for H3K36 methylation in Arabidopsis and is important for plant development. Here, we find that EFS is expressed in different stages of embryo morphogenesis, and the efs mutant produces larger embryo that results in enlarged seeds. Further analysis reveals that an imprinted gene MOP9.5 is hypomethylated at the promoter region and its expression is derepressed in efs mutant. MOP9.5 promoter is marked by various epigenetic modifications, and we find that following the increase of H3K36me3, H3K27me3 and H3K9me2 levels are reduced in efs mutant. This data indicates an antagonistic regulation between H3K36me3 and DNA methylation, and/or H3K27me3 at MOP9.5. Our results further show that both maternal and paternal EFS alleles are responsible for the seed size regulation, which unraveled a novel function of EFS in plant development.