Manipulation of crossover frequency and distribution for plant breeding

Blary, Aurélien; Jenczewski, Eric

doi:10.1007/s00122-018-3240-1

Cited by 52 publications

(49 citation statements)

References 173 publications

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“…Although 25-30% of flowering plants are extant polyploids [ 9 ], the meiotic mechanisms responsible for their stabilisation remain poorly understood. An exception is hexaploid wheat ( Triticum aestivum L.), where there is now better understanding of these processes [ 17 ]. Despite possessing multiple related genomes, durum wheat, a tetraploid (AABB) and bread wheat, a hexaploid (AABBDD) behave as diploids during meiosis.…”

Section: Introductionmentioning

confidence: 99%

A co-expression network in hexaploid wheat reveals mostly balanced expression and lack of significant gene loss of homeologous meiotic genes upon polyploidization

Alabdullah

Borrill

Martín

et al. 2019

Preprint

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14Polyploidization has played an important role in plant evolution. However, upon polyploidization the 15 process of meiosis must adapt to ensure the proper segregation of increased numbers of chromosomes 16 to produce balanced gametes. It has been suggested that meiotic gene (MG) duplicates return to a 17 single copy following whole genome duplication to stabilise the polyploid genome. Therefore, upon 18 the polyploidization of wheat, a hexaploid species with three related (homeologous) genomes, the 19 stabilization process may have involved rapid changes in content and expression of MGs on 20 homeologous chromosomes (homeologs). To examine this hypothesis, sets of candidate MGs were 21 identified in wheat using co-expression network analysis and orthology informed approaches. In total, 22 130 RNA-Seq samples from a range of tissues including wheat meiotic anthers were used to define 23 co-expressed modules of genes. Three modules were significantly correlated with meiotic tissue 24 samples but not with other tissue types. These modules were enriched for GO terms related to cell 25 cycle, DNA replication and chromatin modification, and contained orthologs of known MGs. Overall 26 74.4 % of genes within these meiosis-related modules had three homeologous copies which was 27 similar to other tissue-related modules. Amongst wheat MGs identified by orthology, rather than co-28 expression, the majority (93.7 %) were either retained in hexaploid wheat at the same number of 29 copies (78.4 %) or increased in copy number (15.3%) compared to ancestral wheat species. 30 Furthermore, genes within meiosis-related modules showed more balanced expression levels between 31 homeologs than genes in non-meiosis-related modules. Taken together our results do not support 32 extensive gene loss nor changes in homeolog expression of MGs upon wheat polyploidization. The 33 construction of the MG co-expression network allowed identification of hub genes and provided key 34 targets for future studies. 35 36 Author summary 37 All flowering plants have undergone a polyploidization event(s) during their evolutionary history. One 38of the biggest challenges faced by a newly-formed polyploid is meiosis, an essential event for sexual 39 reproduction and fertility. This process must adapt to discriminate between multiple related 40 chromosomes and to ensure their proper segregation to produce fertile gametes. The meiotic 41 mechanisms responsible for the stabilisation of the extant polyploids remain poorly understood except 42 in wheat, where there is now a better understanding of these processes. It has been proposed that 43 meiotic adaptation in established polyploids could involve meiotic gene loss following the event of 44 polyploidization. To test this hypothesis in hexaploid wheat, we have computationally predicted sets 45 of hexaploid wheat meiotic genes based on expression data from different tissue types, including 46 meiotic anther tissue, and orthology informed approaches. We have calculated homeolog expression 47 patterns and numbe...

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Section: Introductionmentioning

confidence: 99%

A co-expression network in hexaploid wheat reveals mostly balanced expression and lack of significant gene loss of homeologous meiotic genes upon polyploidization

Alabdullah

Borrill

Martín

et al. 2019

Preprint

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“…Initial steps of recombination are to some extent responsible for the CO distribution, but it is not clear whether the CO landscape mirrors the non-uniform DSBs' positioning [105]. High-resolution maps of recombination events in plants show COs located in regions close to gene promoters and terminators [106]. While the DSB and CO maps are rather similar in Arabidopsis [107], they are very different in maize [108].…”

Section: An Overview On Meiotic Recombination In Plantsmentioning

confidence: 99%

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

Naranjo

2019

Agronomy

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The tribe Triticeae contains about 500 diploid and polyploid taxa, among which are important crops, such as wheat, barley and rye. The phylogenetic relationships, genome compo-sition and chromosomal architecture, were already reported in the pioneer genetic studies on these species, given their implications in breeding-related programs. Hexaploid wheat, driven by its high capacity to develop cytogenetic stocks, has always been at the forefront of these studies. Cytogenetic stocks have been widely used in the identification of homoeologous relationships between the chromosomes of wheat and related species, which has provided valuable information on genome evolution with implications in the transfer of useful agronomical traits into crops. Meiotic recombination is non-randomly distributed in the Triticeae species, and crossovers are formed in the distal half of the chromosomes. Also of interest for crops improvement is the possibility of being able to modulate the intraspecific and interspecific recombination landscape to increase its frequency in crossover-poor regions. Structural changes may help in this task. In fact, chromosome truncation increases the recombination frequency in the adjacent intercalary region. However, structural changes also have a negative effect upon recombination. Gross chromosome rearrangements produced in the evolution usually suppress meiotic recombination between non-syntenic homoeologs. Thus, the chromosome structural organization of related genomes is of great interest in designing strategies of the introgression of useful genes into crops.

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“…These arise as differences between male and female meiosis (for instance as shown by Giraut et al 2011 in A. thaliana and Phillips et al 2015 in barley), as differences due to genetic backgrounds (Salomé et al 2012 and Bauer et al 2013) or as responses to different environmental conditions (Lloyd et al , 2017, Modliszewski and Copenhaver 2017). Blary and Jenczewski (2019) provide a review of all these cases. In Arabidopsis thaliana , one of the double-mutants of anti-crossovers genes increased the recombination rate 7.8-fold (Fernandes et al 2018) via the production of additional non-interfering crossovers.…”

Section: Introductionmentioning

confidence: 99%