The Mode and Regulation of Chromosome Pairing in Wheat–Alien Hybrids (Ph Genes, an Updated View)

Naranjo, T.; Benavente, Elena

doi:10.1007/978-3-319-23494-6_6

Cited by 13 publications

(12 citation statements)

References 154 publications

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“…Reduction of genomic redundancy converts the polyploid organism into a diploid one, which is often referred to as genetic diploidization. Thus, genetic diploidization is considered an evolutionary process of a wider time scale than that of the cytological diploidization which happens at the primitive allopolyploid stage and concerns genetic systems involved in control of meiotic pairing [ 38 , 39 ].…”

Section: Introductionmentioning

confidence: 99%

Genomic and Meiotic Changes Accompanying Polyploidization

Blasio

Prieto

Pradillo

et al. 2022

Plants

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Hybridization and polyploidy have been considered as significant evolutionary forces in adaptation and speciation, especially among plants. Interspecific gene flow generates novel genetic variants adaptable to different environments, but it is also a gene introgression mechanism in crops to increase their agronomical yield. An estimate of 9% of interspecific hybridization has been reported although the frequency varies among taxa. Homoploid hybrid speciation is rare compared to allopolyploidy. Chromosome doubling after hybridization is the result of cellular defects produced mainly during meiosis. Unreduced gametes, which are formed at an average frequency of 2.52% across species, are the result of altered spindle organization or orientation, disturbed kinetochore functioning, abnormal cytokinesis, or loss of any meiotic division. Meiotic changes and their genetic basis, leading to the cytological diploidization of allopolyploids, are just beginning to be understood especially in wheat. However, the nature and mode of action of homoeologous recombination suppressor genes are poorly understood in other allopolyploids. The merger of two independent genomes causes a deep modification of their architecture, gene expression, and molecular interactions leading to the phenotype. We provide an overview of genomic changes and transcriptomic modifications that particularly occur at the early stages of allopolyploid formation.

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Section: Introductionmentioning

confidence: 99%

Genomic and Meiotic Changes Accompanying Polyploidization

Blasio

Prieto

Pradillo

et al. 2022

Plants

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“…However, as widely documented for resynthesized allopolyploids (reviewed in Chen and Ni, 2006 and Grusz et al, 2017) and some natural autopolyploids such as Arabidopsis arenosa (Yant et al, 2013), current sugarcane cultivars are assumed to have undergone genome readjustments aimed at achieving stability and re-establishing functional pathways, including the suppression of multivalent associations by a genetic control of chromosome pairing and recombination as occurs in wheat and oat (see Naranjo and Benavente, 2015). In wheat, the locus Ph1 ensures that recombination only occurs between homologous chromosomes.…”

Section: Discussionmentioning

confidence: 99%

Revisiting Meiosis in Sugarcane: Chromosomal Irregularities and the Prevalence of Bivalent Configurations

et al. 2018

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Traditional sugarcane cultivars (Saccharum officinarum) proved highly susceptible to diseases, and this led breeders to progress to interspecific crosses resulting in disease resistance. A backcrossing program to S. officinarum was then required to boost sucrose content. Clonal selection across generations and incorporation of other germplasm into cultivated backgrounds established the (narrow) genetic base of modern cultivars (Saccharum spp.), which have a man-made genome. The genome complexity has inspired several molecular studies that have elucidated aspects of sugarcane genome constitution, architecture, and cytogenetics. However, there is a critical shortage of information on chromosome behavior throughout meiosis in modern cultivars. In this study, we examined the microsporogenesis of a contemporary variety, providing a detailed analysis of the meiotic process and chromosome association at diakinesis, using FISH with centromeric probes. Chromosomal abnormalities were documented by examining high quality preparations of pollen mother cells (700 in total). Approximately 70% of the cells showed abnormalities, such as metaphase chromosomes not lined up at the plate, lagging chromosomes and chromosomal bridges, and tetrad cells with micronuclei. Some dyads with asynchronous behavior were also observed. Due to the hybrid composition of the sugarcane genome, we suggest that bivalent incomplete pairing may occur in the first prophase leading to univalency. The presence of rod bivalents showing the lagging tendency is consistent with a reduction in chiasma frequency. Finally, the presence of chromatin bridges indicates the indirect occurrence of chromosomal inversions, although chromosome fragments were not clearly recognized. Possible reasons for such meiotic abnormalities and the large prevalence of bivalent formation are discussed.

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“…The strict pairing of homologous chromosomes in hexaploid wheat reflects a delicate balance between genes that inhibit homologous pairing, such as Ph1 and Ph2 , and genes that promote pairing, such as those located on homologous groups 2, 3, and 5 (Naranjo and Benavente, 2015 ). A similar theory was suggested for Elytrigia species.…”

Section: Discussionmentioning

confidence: 99%

Chromosome Pairing in Hybrid Progeny between Triticum aestivum and Elytrigia elongata

Xing

Bao

et al. 2017

Front. Plant Sci.

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In this study, the intergeneric hybrids F1, F2, BC1F1, BC1F2, and BC2F1 from Elytrigia elongata and Triticum aestivum crosses were produced to study their chromosome pairing behavior. The average E. elongata chromosome configuration of the two F1 hybrids agreed with the theoretical chromosome configuration of 21I+7II, indicating that the genomic constitution of this F1 hybrid was ABDStStEeEbEx. Compared with the BC1F1 generation, the BC2F1 generation showed a rapid decrease in the number of E. elongata chromosomes and the BC1F2 generation showed a more extensive distribution of E. elongata chromosomes. In addition, pairing between wheat and E. elongata chromosomes was detected in each of the wheat-E. elongata hybrid progenies, albeit rarely. Our results demonstrated that genomic in situ hybridization (GISH) using an E. elongata genomic DNA probe offers a reliable approach for characterizing chromosome pairing in wheat and E. elongata hybrid progenies.

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The Mode and Regulation of Chromosome Pairing in Wheat–Alien Hybrids (Ph Genes, an Updated View)

Cited by 13 publications

References 154 publications

Genomic and Meiotic Changes Accompanying Polyploidization

Genomic and Meiotic Changes Accompanying Polyploidization

Revisiting Meiosis in Sugarcane: Chromosomal Irregularities and the Prevalence of Bivalent Configurations

Chromosome Pairing in Hybrid Progeny between Triticum aestivum and Elytrigia elongata

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