ARPEGGIO: Automated Reproducible Polyploid EpiGenetic GuIdance workflOw

Polyploidy before and after domestication of crop species

Recent advances in the genomics of polyploid species answer some of the long-standing questions about the role of polyploidy in crop species. Here, we summarize the current literature to reexamine scenarios in which polyploidy played a role both before and after domestication. The prevalence of polyploidy can help to explain environmental robustness in agroecosystems. This review also clarifies the molecular basis of some agriculturally advantageous traits of polyploid crops, including yield increments in polyploid cotton via subfunctionalization, modification of a separated sexuality to selfing in polyploid persimmon via neofunctionalization, and transition to a selfing system via nonfunctionalization combined with epistatic interaction between duplicated S-loci. The rapid progress in genomics and genetics is discussed along with how this will facilitate functional studies of understudied polyploid crop species.

Robustness and the generalist niche of polyploid species: Genome shock or gradual evolution?

The prevalence of polyploidy in wild and crop species has stimulated debate over its evolutionary advantages and disadvantages. Previous studies have focused on changes occurring at the polyploidization events, including genome-wide changes termed "genome shock," as well as ancient polyploidy. Recent bioinformatics advances and empirical studies of Arabidopsis and wheat relatives are filling a research gap: the functional evolutionary study of polyploid species using RNA-seq, DNA polymorphism, and epigenomics. Polyploid species can become generalists in natura through environmental robustness by inheriting and merging parental stress responses. Their evolvability is enhanced by mutational robustness working on inherited standing variation. The identification of key genes responsible for gradual adaptive evolution will encourage synthetic biological approaches to transfer polyploid advantages to other species.

An Epigenetic Alphabet of Crop Adaptation to Climate Change

Crop adaptation to climate change is in a part attributed to epigenetic mechanisms which are related to response to abiotic and biotic stresses. Although recent studies increased our knowledge on the nature of these mechanisms, epigenetics remains under-investigated and still poorly understood in many, especially non-model, plants, Epigenetic modifications are traditionally divided into two main groups, DNA methylation and histone modifications that lead to chromatin remodeling and the regulation of genome functioning. In this review, we outline the most recent and interesting findings on crop epigenetic responses to the environmental cues that are most relevant to climate change. In addition, we discuss a speculative point of view, in which we try to decipher the “epigenetic alphabet” that underlies crop adaptation mechanisms to climate change. The understanding of these mechanisms will pave the way to new strategies to design and implement the next generation of cultivars with a broad range of tolerance/resistance to stresses as well as balanced agronomic traits, with a limited loss of (epi)genetic variability.