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Raina A, Tantray YR, Khan S. Assessment of Bio-physiological damages and cytological aberrations in cowpea varieties treated with gamma rays and sodium azide. PLoS One 2023; 18:e0288590. [PMID: 37471405 PMCID: PMC10358960 DOI: 10.1371/journal.pone.0288590] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2023] [Accepted: 06/29/2023] [Indexed: 07/22/2023] Open
Abstract
The assessment of mutagen induced biological damage forms an important study in determining the mutagenic potency and genotypic sensitivity, a vital aspect in mutation breeding programs. A prior assessment of lethal dose (LD50), mutagen induced biological damage (alterations in bio-physiological traits and frequency of cytological aberrations) is a prerequisite for determining an optimum mutagen dose in a successful mutation breeding experiment. Therefore, in a multi-year project of mutation breeding, two widely cultivated varieties of cowpea viz., Gomati VU-89 and Pusa-578, were treated with gamma (γ) rays and sodium azide (SA) doses. The results reflected a proportionate increase in bio-physiological damages with the increase in mutagenic doses and caused a substantial reduction in mean seed germination and seedling height. Different cytological aberrations such as cytomixis, univalents, chromosome stickiness, precocious separation, unequal separation, bridges, laggards, disturbed polarity, dyads, triads, and polyads were observed in both varieties. All the mutagen doses induced a broader spectrum of cytological aberrations with varying frequencies.
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Affiliation(s)
- Aamir Raina
- Mutation Breeding Laboratory, Department of Botany, Aligarh Muslim University, Aligarh, India
- Botany Section, Women's College, Aligarh Muslim University, Aligarh, India
| | | | - Samiullah Khan
- Mutation Breeding Laboratory, Department of Botany, Aligarh Muslim University, Aligarh, India
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Siddiqui S, Alrumman SA. Methomyl, imbraclaobrid and clethodim induced cytomixis and syncytes behaviors in PMCs of Pisum sativum L: Causes and outcomes. Saudi J Biol Sci 2022; 29:103390. [PMID: 35935105 PMCID: PMC9352543 DOI: 10.1016/j.sjbs.2022.103390] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2022] [Revised: 06/16/2022] [Accepted: 07/17/2022] [Indexed: 11/07/2022] Open
Abstract
Cytomixis is a common phenomenon observed in meiotic cells such as anther which is influenced by various factors. Use of pesticides is a common practice in agriculture. However, it is not known whether pesticides can induce cytomixis in plant cells and induce genetic variation. To understand this, the present study was planned to assess the cytomixis and syncytes behaviors in PMCs of Pisum sativum L. Seeds of P. sativum (Family: Fabaceae) were treated with different concentrations of commonly used pesticides methomyl (ME), imbraclaobrid (IM) and clethodim (CL). Seeds were treated with various concentrations (0.1, 0.2, 0.3, 0.4 and 0.5% of ME, IM and CL prepared in water) for 1 and 3 h. Effect of pesticides on pollen fertility, frequency of cytomixis, and kind of cytomixis cells was assessed. In the cytomixis cells, the cytomictic channel (CC) and direct fusion (DF), and various stages of meiosis (PI, MI, AI and TI) with cytomixis cells were observed. In addition, frequency of syncytes cell and their various stages of meiosis I (PI, MI, AI and TI) in pollen mother cells (PMCs) was assessed. During the microsporogenesis in P. sativum, the occurrence of cytomixis and syncytes at various stages of meiosis I were seen. The formation of cytoplasmic channels and direct fusing of pollen mother cells (PMCs) were both seen to cause cytomixis, with the former being more common than the latter. The percentage of PMCs with cytomixis and syncytes cells increased with increase in the concentration of pesticides. The result of the present investigation indicates that commonly used pesticides ME, IM, and CL have a significant effect on pollen fertility, frequency of cytomixis, and kind of cytomixis cells, the cytomictic channel (CC) and direct fusion (DF), in addition, frequency of syncytes cell and their various stages of meiosis I (PI, MI, AI and TI) in pollen mother cells (PMCs) on P. sativum.
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Clo J, Padilla-García N, Kolář F. Polyploidization as an opportunistic mutation: The role of unreduced gametes formation and genetic drift in polyploid establishment. J Evol Biol 2022; 35:1099-1109. [PMID: 35770884 DOI: 10.1111/jeb.14055] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2022] [Accepted: 06/07/2022] [Indexed: 01/17/2023]
Abstract
It is broadly assumed that polyploidy success reflects an increase in fitness associated with whole-genome duplication (WGD), due to higher tolerance to stressful conditions. Nevertheless, WGD also arises with several costs in neo-polyploid lineages, like genomic instability, or cellular mis-management. In addition to these costs, neo-polyploid individuals also face frequency dependent selection because of frequent low-fitness triploids formed by cross-ploidy pollinations when tetraploids are primarily rare in the population. Interestingly, the idea that polyploidy can be fixed by genetic drift as a neutral or deleterious mutation is currently underexplored in the literature. To test how and when polyploidy can fix in a population by chance, we built a theoretical model in which autopolyploidization occurs through the production of unreduced gametes, a trait modelled as a quantitative trait that is allowed to vary through time. We found that when tetraploid individuals are less or as fit as their diploid progenitors, fixation of polyploidy is only possible when genetic drift is stronger than natural selection. The necessity of drift for tetraploid fixation holds even when polyploidy confers a selective advantage, except for scenarios where tetraploids are much fitter than diploids. Finally, we found that self-fertilization is less beneficial for tetraploid establishment than previously thought, notably when polyploids harbour an initial decrease in fitness. Our results bring a novel, non-exclusive explanation for the unequal temporal and spatial distribution of polyploid species.
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Affiliation(s)
- Josselin Clo
- Department of Botany, Faculty of Science, Charles University in Prague, Prague, Czech Republic
| | - Nélida Padilla-García
- Department of Botany, Faculty of Science, Charles University in Prague, Prague, Czech Republic
| | - Filip Kolář
- Department of Botany, Faculty of Science, Charles University in Prague, Prague, Czech Republic.,Institute of Botany of the Czech Academy of Sciences, Prague, Czech Republic
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Chromosome numbers and meiotic behavior in some species of Asteraceae from high altitudinal regions of Kashmir Himalayas. JOURNAL OF ASIA-PACIFIC BIODIVERSITY 2021. [DOI: 10.1016/j.japb.2021.07.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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A case of intraspecific euploidy (2x, 4x) and secondary chromosomal associations in wild accessions of Geranium pratense L. from cold deserts of Ladakh (India). THE NUCLEUS 2019. [DOI: 10.1007/s13237-019-00299-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022] Open
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Kaur D, Singhal VK. Meiotic abnormalities affect genetic constitution and pollen viability in dicots from Indian cold deserts. BMC PLANT BIOLOGY 2019; 19:10. [PMID: 30616590 PMCID: PMC6323802 DOI: 10.1186/s12870-018-1596-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2018] [Accepted: 12/07/2018] [Indexed: 05/27/2023]
Abstract
BACKGROUND Meiotic abnormalities lead to morphological and genetic variations which caused not only to evolution but also intraspecific reproductive barriers. During present study of detailed meiotic course in dicotyledonous plants sampled from Indian cold deserts, various meiotic abnormalities have been detected. For this, the plant materials fixed in Carnoy's fixative and studied detailed meiotic course by standard squash method in 1% acetocarmine. RESULTS Meiotic abnormalities have been presently detected in 71 species which include multiple associations in diploids (Achillea millefolium L.), multivalents and univalents in polyploids (4 species), cytomixis (40 species), chromosome stickiness (20 species), nonsynchronous disjunction of bivalents (32 species), interbivalent connections (15 species), synaptic mutants (2 species), syncyte meiocytes (2 species), abnormal spindles (7 species), and fusion of pollen grains (1 species), laggards and chromatin bridges, hypo-, hyperploid PMCs, monads, dyads, triads, tetrads with micronuclei and polyads. CONCLUSIONS Consequently, variable sized apparently fertile pollen grains and considerable amount of sterile pollen grains are resulted as end products which lead to different genetic constitution (aneuploids and polyploids) and curtailed sexual reproductive success in these species.
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Affiliation(s)
- Dalvir Kaur
- Department of Botany, Patel Memorial National College, Rajpura affiliated to Punjabi University, Patiala, Punjab India
| | - V. K. Singhal
- Department of Botany, Punjabi University, Patiala, Punjab India
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Male meiosis in 18 species of 07 genera of the tribe Astereae (Asteraceae) from Western Himalaya. THE NUCLEUS 2018. [DOI: 10.1007/s13237-018-0230-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022] Open
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Khan NA, Singhal VK, Kumar P, Gupta RC. Male Meiotic and Morphometric Analysis in the 2 x and 4 x Cytotypes in Arabis recta Vill. (Brassicaceae) from Cold Desert Regions of North-West Himalayas. CYTOLOGIA 2018. [DOI: 10.1508/cytologia.83.207] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
| | | | - Puneet Kumar
- Department of Botany, Faculty of Life Sciences, Punjabi University
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Gupta RC, Goyal H, Goel RK, Singh V. New and Varied Chromosome Reports in Twenty-Six Species of the Family Asteraceae from Cold Deserts of the Western Himalaya. CYTOLOGIA 2018. [DOI: 10.1508/cytologia.83.215] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
| | | | | | - Vijay Singh
- Department of Botany, Punjabi University
- Department of Botany, Mata Gujri College
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Singhal VK, Tantray YR, Kaur M, Rana PK, Gupta RC. Intraspecific Euploidy (2<i>x</i>, 4<i>x</i>) in <i>Primula denticulata</i> Sm. from North West Himalayas in India. CYTOLOGIA 2018. [DOI: 10.1508/cytologia.83.31] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Sarma S, Pandey AK, Sharma K, Ravi M, Sreelakshmi Y, Sharma R. MutS-Homolog2 silencing generates tetraploid meiocytes in tomato ( Solanum lycopersicum). PLANT DIRECT 2018; 2:e00017. [PMID: 31245679 PMCID: PMC6508528 DOI: 10.1002/pld3.17] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/13/2017] [Revised: 09/07/2017] [Accepted: 09/12/2017] [Indexed: 05/16/2023]
Abstract
MSH2 is the core protein of MutS-homolog family involved in recognition and repair of the errors in the DNA. While other members of MutS-homolog family reportedly regulate mitochondrial stability, meiosis, and fertility, MSH2 is believed to participate mainly in mismatch repair. The search for polymorphism in MSH2 sequence in tomato accessions revealed both synonymous and nonsynonymous SNPs; however, SIFT algorithm predicted that none of the SNPs influenced MSH2 protein function. The silencing of MSH2 gene expression by RNAi led to phenotypic abnormalities in highly silenced lines, particularly in the stamens with highly reduced pollen formation. MSH2 silencing exacerbated formation of UV-B-induced thymine dimers and blocked light-induced repair of the dimers. The MSH2 silencing also affected the progression of male meiosis to a varying degree with either halt of meiosis at zygotene stage or formation of diploid tetrads. The immunostaining of male meiocytes with centromere localized CENPC (centromere protein C) antibody showed the presence of 48 univalent along with 24 bivalent chromosomes suggesting abnormal tetraploid meiosis. The mitotic cells of root tips of silenced lines showed diploid nuclei but lacked intervening cell plates leading to cells with syncytial nuclei. Thus, we speculate that tetraploid pollen mother cells may have arisen due to the fusion of syncytial nuclei before the onset of meiosis. It is likely that in addition to mismatch repair (MMR), MSH2 may have an additional role in regulating ploidy stability.
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Affiliation(s)
- Supriya Sarma
- Repository of Tomato Genomics ResourcesDepartment of Plant SciencesSchool of Life SciencesUniversity of HyderabadHyderabadIndia
- Present address:
Centre for Cellular and Molecular BiologyHyderabadIndia
| | - Arun Kumar Pandey
- Repository of Tomato Genomics ResourcesDepartment of Plant SciencesSchool of Life SciencesUniversity of HyderabadHyderabadIndia
- Present address:
International Crops Research Institute for the Semi‐Arid Tropics (ICRISAT)HyderabadIndia
| | - Kapil Sharma
- Repository of Tomato Genomics ResourcesDepartment of Plant SciencesSchool of Life SciencesUniversity of HyderabadHyderabadIndia
| | - Maruthachalam Ravi
- School of BiologyIndian Institute of Science Education and ResearchThiruvananthapuramKeralaIndia
| | - Yellamaraju Sreelakshmi
- Repository of Tomato Genomics ResourcesDepartment of Plant SciencesSchool of Life SciencesUniversity of HyderabadHyderabadIndia
| | - Rameshwar Sharma
- Repository of Tomato Genomics ResourcesDepartment of Plant SciencesSchool of Life SciencesUniversity of HyderabadHyderabadIndia
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Malik RA, Gupta RC, Singh V, Bala S, Kumari S. New chromosome reports in Lamiaceae of Kashmir (Northwest Himalaya), India. PROTOPLASMA 2017; 254:971-985. [PMID: 27525411 DOI: 10.1007/s00709-016-1006-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/07/2016] [Accepted: 07/14/2016] [Indexed: 06/06/2023]
Abstract
Meiotic studies and chromosome data are imperative in order to have an overall germplasm evaluation of a taxon. In the present effort, the meiotic study is carried out in 48 populations belonging to 26 species of Lamiaceae collected from their natural habitats in Kashmir Himalaya, which forms an important part of Northwest Himalaya. Chromosome counts in the five species viz. Dracocephalum nutans (2n = 10), Lycopus europaeus (2n = 22), Marrubium vulgare (2n = 54), Nepeta nervosa (2n = 18) and Salvia sclarea (2n = 22) are first time reported from India. Besides, 17 species are cytologically evaluated for the first time from the study area-Kashmir Himalaya. In Marrubium vulgare, hexaploid cytotype (2n = 6 × =54) is reported for the first time. Also, diploid and tetraploid cytomorphovariants are observed in Calamintha vulgaris (2n = 20, 40), Elsholtzia ciliata (2n = 16, 32) and Mentha longifolia (2n = 20, 40). Various meiotic abnormalities like chromatin stickiness, cytomixis, nonsynchronous disjunction, laggards, chromatin bridges, etc. leading to pollen abnormalities have been documented for the first time in some species. The worldwide status of chromosome number data in each genus is presented.
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Affiliation(s)
| | | | - Vijay Singh
- Department of Botany, Punjabi University, Patiala, 147002, India
| | - Santosh Bala
- Department of Botany, Punjabi University, Patiala, 147002, India
| | - Santosh Kumari
- Department of Botany, Punjabi University, Patiala, 147002, India
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Singhal VK, Tantray YR, Kaur D, Gupta RC. First Report of Intraspecific Polyploidy (2<i>x</i>, 4<i>x</i>) in <i>Physochlaina praealta</i> (Decne.) Miers. (Family: Solanaceae). CYTOLOGIA 2017. [DOI: 10.1508/cytologia.82.245] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Kaur M, Himshikha, Singhal VK. Occurrence of Syncytes: A Possible Mechanism Owing to the Origin of Polyploid Cytotypes in Achillea millefolium L. within Indian Himalayas. CYTOLOGIA 2017. [DOI: 10.1508/cytologia.82.375] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
| | - Himshikha
- Department of Botany, Punjabi University
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Kumar G, Chaudhary N. Induced cytomictic variations and syncyte formation during microsporogenesis in Phaseolus vulgaris L. CYTOL GENET+ 2016. [DOI: 10.3103/s0095452716020109] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Rani S, Chahota RK, Sharma TR. Cytomixis and Associated Meiotic Abnormalities during Male Meiosis in Angelica glauca Edgew. (Apiaceae) from North-Western Himalayas. CYTOLOGIA 2016. [DOI: 10.1508/cytologia.81.161] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Gupta RC, Kumari K, Kaur K, Singh V. Anomalous Chromosomal Behaviour and Chromosomal Data in Some Members of Subclass Gamopetalae from District Hamirpur (H. P.), India. CYTOLOGIA 2016. [DOI: 10.1508/cytologia.81.25] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Singhal VK, Khan NA, Gupta RC. Syncyte and ‘2 n’ Pollen Grain Formation in Heracleum pinnatum: A Possible Mechanism for the Origin of Intraspecific Polyploids. CYTOLOGIA 2016. [DOI: 10.1508/cytologia.81.335] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Gupta RC, Singh V. Cytogenetic Variation among Populations of <i>Aster thomsonii</i> C. B. Clarke from District Sirmaur, Himachal Pradesh (India). CYTOLOGIA 2015. [DOI: 10.1508/cytologia.80.81] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Malik RA, Gupta RC, Kumari S, Malik AH. Cytomictic anomalous male meiosis and 2n pollen grain formation in Mertensia echioides Benth. (Boraginaceae) from Kashmir Himalaya. ScientificWorldJournal 2014; 2014:134192. [PMID: 25544950 PMCID: PMC4269315 DOI: 10.1155/2014/134192] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2014] [Accepted: 10/16/2014] [Indexed: 11/18/2022] Open
Abstract
Presently Mertensia echioides Benth. (Boraginaceae) collected from Kashmir Himalaya, India, is cytologically analyzed for the first time revealing 2n = 2x = 24 (diploid). Interestingly we found 4.3-6.2% syncytic meiocytes/PMCs with 2n = 4x = 48 (tetraploid) in addition to normal meiocytes (2n = 24) during male meiosis. These comparatively larger PMCs (pollen mother cells) lead to the formation of fertile giant 2n pollen grains. A frequency of 6.4-13.3% PMCs shows transfer of chromatin material at prophase-I and, therefore, results in aneuploid meiocytes. Whole chromatin transfer by the process of cytomixis could also have led to the formation of tetraploid cells. Translocation heterozygosity is also evident in the form of multivalents in 12-17% diploid (2x) meiocytes at diakinesis and metaphase-I and is reported for the first time in this species. The syncytes formed depict open chain hexavalent and quadrivalent formation in the three populations with different frequencies. Moreover chromatin stickiness at metaphase-I is observed in 45% of PMCs in population-1 (P-1). Syncyte or unreduced PMC formation leading to unreduced fertile gametes is here speculated to act as a possible way out for infraspecific polyploidization in the species.
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Affiliation(s)
- Reyaz Ahmad Malik
- Department of Botany, Faculty of Life Sciences, Punjabi University, Patiala, Punjab 147002, India
| | - Raghbir Chand Gupta
- Department of Botany, Faculty of Life Sciences, Punjabi University, Patiala, Punjab 147002, India
| | - Santosh Kumari
- Department of Botany, Faculty of Life Sciences, Punjabi University, Patiala, Punjab 147002, India
| | - Akhtar Hussain Malik
- Centre for Biodiversity and Taxonomy, Department of Botany, University of Kashmir, Hazratbal, Srinagar, Jammu & Kashmir 190006, India
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De Storme N, Geelen D. Pre-meiotic endomitosis in the cytokinesis-defective tomato mutant pmcd1 generates tetraploid meiocytes and diploid gametes. JOURNAL OF EXPERIMENTAL BOTANY 2013; 64:2345-58. [PMID: 23580753 DOI: 10.1093/jxb/ert091] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
Sexual polyploidization through the formation and functioning of 2n gametes is considered a major route for plant speciation and diversification. The cellular mechanism underlying 2n gamete formation mostly involves a restitution of the meiotic cell cycle, generating dyads and triads instead of tetrad meiotic end-products. As an alternative mechanism, the tomato mutant pmcd1 (for pre-meiotic cytokinesis defect 1), which generates diploid gametes through the ectopic induction of pre-meiotic endomitosis, is presented here. Using cytological approaches, it is demonstrated that male pmcd1 meiocyte initials exhibit clear alterations in cell cycle progression and cell plate formation, and consequently form syncytial cells that display different grades of cellular and/or nuclear fusion. In addition, it was found that other somatic tissue types (e.g. cotyledons and petals) also display occasional defects in cell wall formation and exhibit alterations in callose deposition, indicating that pmcd1 has a general defect in cell plate formation, most probably caused by alterations in callose biosynthesis. In a broader perspective, these findings demonstrate that defects in cytokinesis and cell plate formation may constitute a putative route for diplogamete formation and sexual polyploidization in plants.
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Affiliation(s)
- Nico De Storme
- In vitro Biology and Horticulture, Department of Plant Production, University of Ghent, Coupure Links 653, 9000 Ghent, Belgium
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De Storme N, Geelen D. Sexual polyploidization in plants--cytological mechanisms and molecular regulation. THE NEW PHYTOLOGIST 2013; 198:670-684. [PMID: 23421646 PMCID: PMC3744767 DOI: 10.1111/nph.12184] [Citation(s) in RCA: 129] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/01/2012] [Accepted: 01/01/2013] [Indexed: 05/18/2023]
Abstract
In the plant kingdom, events of whole genome duplication or polyploidization are generally believed to occur via alterations of the sexual reproduction process. Thereby, diploid pollen and eggs are formed that contain the somatic number of chromosomes rather than the gametophytic number. By participating in fertilization, these so-called 2n gametes generate polyploid offspring and therefore constitute the basis for the establishment of polyploidy in plants. In addition, diplogamete formation, through meiotic restitution, is an essential component of apomixis and also serves as an important mechanism for the restoration of F1 hybrid fertility. Characterization of the cytological mechanisms and molecular factors underlying 2n gamete formation is therefore not only relevant for basic plant biology and evolution, but may also provide valuable cues for agricultural and biotechnological applications (e.g. reverse breeding, clonal seeds). Recent data have provided novel insights into the process of 2n pollen and egg formation and have revealed multiple means to the same end. Here, we summarize the cytological mechanisms and molecular regulatory networks underlying 2n gamete formation, and outline important mitotic and meiotic processes involved in the ectopic induction of sexual polyploidization.
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Affiliation(s)
- Nico De Storme
- Department of Plant Production, Faculty of Bioscience Engineering, University of Ghent, Coupure Links 653, B-9000, Gent, Belgium
| | - Danny Geelen
- Department of Plant Production, Faculty of Bioscience Engineering, University of Ghent, Coupure Links 653, B-9000, Gent, Belgium
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Kaur H, Kumari S, Gupta RC. Cytomorphological studies in some members of tribe Paniceae (Poaceae) from district Kangra of Himachal Pradesh (Western Himalayas). CYTOL GENET+ 2013. [DOI: 10.3103/s0095452713020060] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Kumar P, Singhal VK. Erratic male meiosis resulting in 2n pollen grain formation in a 4x cytotype (2n = 28) of Ranunculus laetus Wall. ex Royle. ScientificWorldJournal 2012; 2012:691545. [PMID: 22629184 PMCID: PMC3353565 DOI: 10.1100/2012/691545] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2011] [Accepted: 12/07/2011] [Indexed: 11/17/2022] Open
Abstract
Two accessions were studied for male meiosis in Ranunculus laetus from the cold regions of Northwest Himalayas. One accession showed the presence of 14 bivalents at diakinesis and regular segregation of bivalents at anaphase I which lead to normal tetrad formation with four n microspores and consequently n pollen grains and 100% pollen fertility. Second accession from the same locality revealed the erratic meiosis characterized by the presence of all the 28 chromosomes as univalents in meiocytes at metaphase I. Univalent chromosomes failed to segregate during anaphases and produced restitution nuclei at meiosis I and II. These restitution nuclei resulted into dyads and triads which subsequently produced two types of apparently fertile pollen grains. On the basis of size, the two types of pollen grains were categorized as n (normal reduced) and 2n (unreduced, 1.5-times larger than the n pollen grains). The estimated frequency of 2n pollen grains from dyads and triads (61.59%) was almost the same as that of the observed one (59.90%), which indicated that 2n pollen grains in R. laetus were the result of dyads and triads. The present paper herein may provide an insight into the mechanisms of the formation of various intraspecific polyploids through sexual polyploidization in R. laetus.
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Singhal VK, Kaur M, Kumar HP, Gupta RC. High Pollen Sterility and 2 n Pollen Grains in an Asynaptic 4 x Cytotype (2 n=48) of Solanum nigrum L. CYTOLOGIA 2012. [DOI: 10.1508/cytologia.77.333] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Singhal VK, Kaur D. Cytomixis Induced Meiotic Irregularities and Pollen Malformation in Clematis graveolens Lindley from the Cold Deserts of Kinnaur District of Himachal Pradesh (India). CYTOLOGIA 2011. [DOI: 10.1508/cytologia.76.319] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Singhal VK, Kaur S, Kumar P. Aberrant Male Meiosis, Pollen Sterility and Variable Sized Pollen Grains in Clematis montana Buch.-Ham. ex DC. from Dalhousie hills, Himachal Pradesh. CYTOLOGIA 2010. [DOI: 10.1508/cytologia.75.31] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Himshikha, Kumar P, Gupta RC, Kumari S, Singhal VK. Impact of Chromatin Transfer and Spindle Abnormalities on Pollen Fertility and Pollen Size in Plantago lanceolata L. CYTOLOGIA 2010. [DOI: 10.1508/cytologia.75.421] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- Himshikha
- Department of Botany, Punjabi University
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Malik RA, Gupta RC, Kumari S. Genetic Diversity in Different Populations of Artemisia absinthium Linn. from Kashmir Himalaya. CYTOLOGIA 2010. [DOI: 10.1508/cytologia.75.273] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
| | - R. C. Gupta
- Department of Botany, Faculty of Life Sciences, Punjabi University
| | - Santosh Kumari
- Department of Botany, Faculty of Life Sciences, Punjabi University
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