Polyploidy: its consequences and enabling role in plant diversification and evolution

Abstract

Background Most, if not all, green plant (Virdiplantae) species including angiosperms and ferns, are polyploids themselves or have ancient polyploid or whole genome duplication signatures in their genomes. Polyploids are not only restricted to our major crop species such as wheat, maize, potato and the Brassicas, but occur frequently in wild species and natural habitats. Polyploidy has thus been viewed as major driver in evolution, and its influence on genome and chromosome evolution has been at the centre of many investigations. Mechanistic models of the newly structured genomes are being developed incorporating aspects of sequence evolution or turnover (low copy genes and regulatory sequences, as well as repetitive DNAs), modification of gene functions, the re-establishment of control of genes with multiple copies and often meiotic chromosome pairing, recombination and restoration of fertility. Scope World-wide interest in how green plants have evolved to different conditions – whether in small, isolated populations, or globally – suggests that gaining further insightful knowledge of the contribution of polyploidy to plant speciation and adaptation to environmental changes, is highly needed. Forward looking research and modelling, based on cytogenetics, expression studies and genomics or genome sequencing analyses, discussed in this issue, consider how new polyploids behave and the pathways available for genome evolution. They address fundamental questions about the advantages and disadvantages of polyploidy, consequences for evolution and speciation, and applied questions regarding the spread of polyploids in the environment and challenges in breeding and exploitation of wild relatives through introgression or resynthesis of polyploids. Conclusion Chromosome number, genome size, repetitive DNA sequences, genes and regulatory sequences and their expression evolve following polyploidy – generating diversity and possible novel traits and enabling species diversification. There is the potential for ever more polyploids in natural, managed and disturbed environments under changing climates and new stresses.

Cleave and Rescue gamete killers create conditions for gene drive in plants

“…Suppression mechanisms that require insertion of ClvR into a gene required for gamete function may be challenging for related reasons. Finally, we note that plants often have a much greater ability to hybridize across species barriers than do animals 66,68 . Thus, drive in some plants may lead to spread in wild relatives-though sequence divergence at gRNA target sites, if the gRNAs are chosen to be target species specific, can prevent this.…”

Phylogenomic analyses of Sapindales support new family relationships, rapid Mid-Cretaceous Hothouse diversification, and heterogeneous histories of gene duplication

“…Taken with evidence from cytological studies and the complex morphological patterns in these clades ( Pennington and Styles, 1975 ; Appelhans et al., 2012 ; Paetzold et al., 2018 ; Appelhans et al., 2021 ; Guimarães and Forni-Martins, 2022 ), it points to a complex evolutionary history potentially involving local gene duplication, ancient hybridization (allopolyploidization) and autopolyploidization. These processes, especially ancient hybridization, may affect our ability to reconstruct the evolution of these clades as a bifurcating tree and interpret morphology ( Morales-Briones et al., 2021 ; Nauheimer et al., 2021 ; Heslop-Harrison et al., 2022 ). Therefore, investigation of the processes responsible for these signals of gene duplication will be critical for furthering our understanding of evolutionary relationships in these clades.…”

Genome Size Variation across a Cypriot Fabeae Tribe Germplasm Collection

“…As a result, it must sustain extreme conditions, which include cold winter and hot and dry summer with annual temperatures commonly varying from 0 °C to 30 °C. Abiotic stressors have been recently implicated in genome size fluctuation and evolutionary trade-offs [ 69 , 70 , 71 , 72 ]. Recently it was also reported that genome size in plants can influence the stress tolerance of invasive and native plants via genomic plasticity [ 69 ].…”