Epigenetics in Plant Reproductive Development: An Overview from Flowers to Seeds

Abstract

Plant development is governed by a wide variety of genetic and epigenetic events that regulate cell fate. Flower to seed developmental transition varies greatly between plants and is of importance in research programs because of its relevance for crop production and human diet. In this chapter, we review the latest research on epigenetics regulation of flower, fruit, and seed development in crop plants. We use tomato (Solanum lycopersicum L.) as our reference crop model while referring to Arabidopsis thaliana for in-depth studies and look into additional crop model plants such as maize (Zea mays), wheat (Triticum spp.), and rice (Oryza sativa) in order to cover a wide range of flower and fruit/seed types. Tomato is an interesting biological model thanks to its fleshy fruit. Tomato has the second natural epimutation reported, the Colorless non-ripening (Cnr), as well as newly reported studies on the paramutation SLTAB2, the role of the demethylase DML2 in fruit ripening, and the identification of two long noncoding RNAs (lncRNAs) involved in the ripening process. Altogether, these works make tomato an interesting and important epigenetic model for plants. A variety of epigenetic-based regulations are involved in each stage of the tomato fruit set, development, and ripening. Four epigenetic mechanisms are proved to be involved in flower, fruit, and developmental processes: histone modifications, DNA (de)methylation, small RNA posttranscriptional locus regulation, and lncRNA-associated regulatory pathways. Epigenetic mechanisms are involved at all stages of reproductive organs development, from the flower to the mature seed.