Tackling Plant Meiosis: From Model Research to Crop Improvement

Abstract

Genetic engineering and traditional plant breeding, which harnesses the natural genetic variation that arises during meiosis, will have key roles to improve crop varieties and thus deliver Food Security in the future. Meiosis, a specialized cell division producing haploid gametes to maintain somatic diploidy following their fusion, assures genetic variation by regulated genetic exchange through homologous recombination. However, meiotic recombination events are restricted in their total number and their distribution along chromosomes limiting allelic variations in breeding programs. Thus, modifying the number and distribution of meiotic recombination events has great potential to improve and accelerate plant breeding. In recent years much progress has been made in understanding meiotic progression and recombination in plants. Many genes and factors involved in these processes have been identified primarily in Arabidopsis thaliana but also more recently in crops such as Brassica, rice, barley, maize, or wheat. These advances put researchers in the position to translate acquired knowledge to various crops likely improving and accelerating breeding programs. However, although fundamental aspects of meiotic progression and recombination are conserved between species, differences in genome size and organization (due to repetitive DNA content and ploidy level) exist, particularly among plants, that likely account for differences in meiotic progression and recombination patterns found between species. Thus, tools and approaches are needed to better understand differences and similarities in meiotic progression and recombination among plants, to study fundamental aspects of meiosis in a variety of plants including crops and non-model species, and to transfer knowledge into crop species. In this article, we provide an overview of tools and approaches available to study plant meiosis, highlight new techniques, give examples of areas of future research and review distinct aspects of meiosis in non-model species.

Genome-wide transcription during early wheat meiosis is independent of synapsis, ploidy level and thePh1locus

“…Most of these meiotic PTMs have been reported in yeast and mammals, where synaptonemal complex formation and recombination are regulated through PTMs such as ubiquitination and phosphorylation. There are also similar reports of such modifications in plants (Lambing et al, 2018 and references therein). The results in the present study suggest that the role of post-transcriptional and post-translational modifications during wheat prophase is probably more important than initially thought, and that these modifications might be responsible for the control of this critical stage, rather than simple changes in the gene expression profile.…”

Wheat and barley biology: Towards new frontiers

“…As this special issue cannot be all‐encompassing, many other promising and important future research areas, for example for mitigating the agricultural footprint in the ecosystem, such as improved nutrient use efficiency (Distelfeld et al ; Hawkesford ; Avin‐Wittenberg et al ), root architecture (Salvi ), or root‐microbe interactions specifically for nitrogen‐fixing cereals (Rogers and Oldroyd ; Mus et al ), are not itemized. Similarly, the manipulation of recombination at free‐will in our cereal crops (Lambing and Heckmann ), or a better molecular understanding of heterosis (Schrag et al ; Seifert et al ) and the introduction of a cost‐effective and reliable hybrid seed production system in cereals (Muehleisen et al ; Whitford et al ; Tucker et al ) have not even been touched upon. Thus, many global and societal challenges, but also truly exciting research opportunities, still lie ahead of us.…”

The Effect of Chromosome Structure upon Meiotic Homologous and Homoeologous Recombinations in Triticeae

“…The DSBs repairing process is broadly conserved among plants, and comprehensive insights on the underlying molecular mechanism have been provided in recent reviews [98][99][100]. Only a minor fraction (5% in Arabidopis, or maize) of the homologous interactions are resolved as COs.…”

“…In addition to these two pathways that lead to the CO production, other mechanisms are involved in DSBs repairing. Three other groups of proteins are involved in the restriction of the CO number [99,100,102]: (i) FANCM and its cofactors MHF1 and MHF2 are thought to unwind post-invasion intermediates to promote NCOs through the synthesis-dependent strand annealing (SDSA) pathway, (ii) the BLM/Sgs1 helicase homologs RECQ4A/RECQ4B and the associated proteins TOP3α and RMI1, which process probably different recombination intermediates of FANCM, and (iii) FIGL1 and its partner FLIP, which may control the activity of the recombinases RAD51 and DMC1. Mutations that disrupt any of these three NCOs promoter pathways increase the frequency of class II COs dependent of MUS81 in Arabidopsis [102].…”