Geographical Distribution of B Chromosomes in Aegilops Mutica Boiss., A Wild Relative of Wheat

Ohta, Souichi; Saruhashi, Yoshie

doi:10.1111/j.1601-5223.1999.00177.x

Cited by 7 publications

(7 citation statements)

References 28 publications

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“…Habitats of Ae. mutica with T and T 2 cytoplasms are overlapped mainly on slopes above irrigation ditches along the roads and abandoned or fallow fields, thus likely subjected to seasonal disturbances by irrigation water or rainfall in winter 49 . This might have some relation to submergence response exhibited by the NC hybrids with the cytoplasms of Ae.…”

Section: Discussionmentioning

confidence: 99%

Genetic diversity of submergence stress response in cytoplasms of the Triticum-Aegilops complex

Takenaka

Yamamoto

Nakamura

2018

Sci Rep

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Genetic diversity in cytoplasmic and nuclear genomes and their interaction affecting adaptive traits is an attractive research subject in plants. We addressed submergence stress response of wheat that has become increasingly important but remained largely uninvestigated. Our primary aim was to disclose cytoplasmic diversity using nucleus-cytoplasm (NC) hybrids possessing a series of heterologous cytoplasms in a common nuclear background. Effects of submergence on seedling emergence and growth from imbibed seeds were studied and compared with euplasmic lines. Marked phenotypic variabilities were observed among both lines, demonstrating divergent cytoplasmic and nuclear effects on submergence response. NC hybrids with cytoplasm of Aegilops mutica showed a less inhibition, indicative of their positive contribution to submergence tolerance, whereas cytoplasms of Aegilops umbellulata and related species caused a greater inhibition. Superoxide dismutase (SOD) activity showed a marked increase accompanied by retardation of seedling growth in a susceptible NC hybrid. The observation suggested that the elevated SOD activity was resulted from a high level of reactive oxygen species accumulated and remained in susceptible seedlings. Taken together, our results point to the usefulness of NC hybrids in further studies needed to clarify molecular mechanisms underlying the nucleus-cytoplasm interaction regulating submergence stress response in wheat.

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Section: Discussionmentioning

confidence: 99%

Genetic diversity of submergence stress response in cytoplasms of the Triticum-Aegilops complex

Takenaka

Yamamoto

Nakamura

2018

Sci Rep

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“…The following accessions were used: Aegilops speltoides from Syria (PI 487238, USDA-ARS, USA) and Israel (Katzir, TS 89; Technion, 2-36; Ramat Hanadiv, 2-46, Institute of Evolution, University of Haifa, Israel) (Belyayev & Raskina, 2013); Aegilops mutica (KU-12008, Plant Germplasm Institute, Kyoto University, Japan) (Ohta & Saruhashi, 1999); Triticum aestivum 'Chinese Spring' (TRI 12922, IPK-Gatersleben Genebank, Germany); Secale cereale inbred line 7415 (Jimenez et al, 1994) and Lolium perenne accession G7 with Bs (Taylor & Evans, 1977). Plants were cultivated under glasshouse conditions (16 h 22°C : 8 h 16°C light : dark).…”

Section: Plant Materials and Cultivationmentioning

confidence: 99%

Nondisjunction and unequal spindle organization accompany the drive of Aegilops speltoides B chromosomes

Ruban

Fuchs

et al. 2019

New Phytologist

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Summary B chromosomes (Bs) are supernumerary chromosomes, which are often preferentially inherited. When transmission rates of chromosomes are higher than 0.5, not obeying the Mendelian law of equal segregation, the resulting transmission advantage is collectively referred to as ‘chromosome drive’. Here we analysed the drive mechanism of Aegilops speltoides Bs. The repeat AesTR‐183 of A. speltoides Bs, which also can be detected on the Bs of Aegilops mutica and rye, was used to track Bs during pollen development. Nondisjunction of CENH3‐positive, tubulin interacting B sister chromatids and an asymmetric spindle during first pollen grain mitosis are key for the accumulation process. A quantitative flow cytometric approach revealed that, independent of the number of Bs present in the mother plant, Bs accumulate in the generative nuclei to > 93%. Nine out of 11 tested (peri)centromeric repeats were shared by A and B chromosomes. Our findings provide new insights into the process of chromosome drive. Quantitative flow cytometry is a useful and reliable method to study the drive frequency of Bs. Nondisjunction and unequal spindle organization accompany during first pollen mitosis the drive of A. speltoides Bs. The prerequisites for the drive process seems to be common in Poaceae.

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“…Following accessions were used: Aegilops speltoides from Syria (PI 487238, USDA-ARS, USA) and Israel (Katzir, TS 89; Technion, 2-36; Ramat Hanadiv, 2-46, Institute of Evolution, University of Haifa, Israel) (Belyayev and Raskina, 2013); Aegilops mutica (KU-12008, Plant Germplasm Institute, Kyoto University, Japan) (Ohta and Saruhashi, 1999); Triticum aestivum ‘Chinese Spring’ (TRI 12922, IPK-Gatersleben Genebank, Germany); Secale cereale inbred line 7415 (Jimenez et al, 1994) and Lolium perenne accession G7 with Bs (Taylor and Evans, 1977). Plants were cultivated under greenhouse conditions (16 h light, 22°C day/16°C night).…”

Section: Methodsmentioning

confidence: 99%

Nondisjunction and unequal spindle organization accompany the drive ofAegilops speltoidesB chromosomes

Houben

Ruban

et al. 2019

Preprint

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18Supernumerary B chromosomes (Bs), which are often preferentially inherited, 19 deviating from usual Mendelian segregation. This chromosome drive is one of the 20 most important features of Bs. Here we analyzed the drive mechanism of Aegilops 21 speltoides Bs and provide direct insight into its cellular mechanism. Comparative 22 genomics resulted in the identification of the tandem repeat AesTR-183 of Ae. 23 speltoides Bs, which also can be found on the Bs of Ae. mutica and rye, was used to 24 track Bs during microgametogenesis. Nondisjunction of CENH3-positive, tubulin 25 interacting B sister chromatids and an asymmetric spindle during first pollen grain 26 mitosis are likely components of the accumulation process. A quantitative flow 27 cytometric approach revealed, that independent on the number of Bs present in the 28 mother plant Bs accumulate in the generative nuclei with more than 93%. Nine of 29 eleven tested (peri)centromeric repeats were shared by A and B chromosomes. A 30 common origin of the drive process in Poaceae is likely. 31 32 33 Keywords 34 supernumerary B chromosome, chromosome drive, chromosome nondisjunction, 35 centromere, pollen grain mitosis, chromosome segregation, asymmetric spindle, flow 36 cytometry, Aegilops speltoides 37 38 39 Introduction 40 Supernumerary B chromosomes (Bs) are considered as dispensable chromosomes, 41 which under standard conditions do not confer advantages on the organisms that 42 harbour them. Bs are found in thousands of fungi, plant and animal species and are 43 thought to stand for a specific type of selfish DNA (Jones and Rees, 1982). Recent 44 advances in deciphering the sequence composition of B chromosomes provided a 45 unique opportunity for the analysis of the origin and evolution of this enigmatic 46 genome component. It was shown that the Bs of several plant and animal species 47 harbour gene-derived sequences. This allowed to trace their origin from duplicated 48 fragments of multiple A chromosomes of their host species (reviewed in (Ruban et 49 al., 2017). Hence, Bs could be considered as a by-product of standard chromosome 50 (As) evolution. 51 52 Often the transmission rate of B chromosomes is higher than 0.5, not obeying the 53 Mendelian law of equal segregation. The resulting transmission advantage is 54 collectively referred to as 'drive'. The maximum number of Bs tolerated by the host 55 varies between species and depends on a balance between the B chromosome 56 drive, and the negative effects, especially on fertility and vigour, caused by B 57 chromosomes if they occur in higher numbers (Bougourd and Jones, 1997). Among 58 the relatively small number of B chromosome-positive species that have been 59 investigated, relative to the total number of known species, there is a variety of 60 mechanisms of B chromosome drive that occurs before, during or after meiosis, while 61 in some cases drive has not been found (reviewed in (Austin et al., 2009; Burt and drive, the non-Mendelian inheritance of Bs could also be affected by mitotic and 64 m...

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Geographical Distribution of B Chromosomes in Aegilops Mutica Boiss., A Wild Relative of Wheat

Cited by 7 publications

References 28 publications

Genetic diversity of submergence stress response in cytoplasms of the Triticum-Aegilops complex

Genetic diversity of submergence stress response in cytoplasms of the Triticum-Aegilops complex

Nondisjunction and unequal spindle organization accompany the drive of Aegilops speltoides B chromosomes

Nondisjunction and unequal spindle organization accompany the drive ofAegilops speltoidesB chromosomes

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