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de Souza TB, Parteka LM, de Assis R, Vanzela ALL. Diversity of the repetitive DNA fraction in Cestrum, the genus with the largest genomes within Solanaceae. Mol Biol Rep 2022; 49:8785-8799. [PMID: 35809181 DOI: 10.1007/s11033-022-07728-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2021] [Accepted: 06/17/2022] [Indexed: 10/17/2022]
Abstract
BACKGROUND Cestrum species present large genomes (2 C = ~ 24 pg), a high occurrence of B chromosomes and great diversity in heterochromatin bands. Despite this diversity, karyotypes maintain the chromosome number 2n = 16 (except when they present B chromosomes), and a relative similarity in chromosome morphology and symmetry. To deepen our knowledge of the Cestrum genome composition, low-coverage sequencing data of C. strigilatum and C. elegans were compared, including cytogenomic analyses of seven species. METHODS AND RESULTS Bioinformatics analyses showed retrotransposons comprising more than 70% of the repetitive fraction, followed by DNA transposons (~ 17%), but FISH assays using retrotransposon probes revealed inconspicuous and scattered signals. The four satellite DNA families here analyzed represented approximately 2.48% of the C. strigilatum dataset, and these sequences were used as probes in FISH assays. Hybridization signals were colocalized with all AT- and GC-rich sequences associated with heterochromatin, including AT-rich Cold-Sensitive Regions (CSRs). Although satellite probes hybridized in almost all tested species, a satDNA family named CsSat49 was highlighted because it predominates in centromeric regions. CONCLUSIONS Data suggest that the satDNA fraction is conserved in the genus, although there is variation in the number of FISH signals between karyotypes. Except to the absence of FISH signals with probes CsSat1 and CsSat72 in two species, the other satellites occurred in species of different phylogenetic clades. Some satDNA sequences have been detected in the B chromosomes, indicating that they are rich in preexisting sequences in the chromosomes of the A complement. This comparative study provides an important advance in the knowledge on genome organization and heterochromatin composition in Cestrum, especially on the distribution of satellite fractions between species and their importance for the B chromosome composition.
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Affiliation(s)
- Thaíssa Boldieri de Souza
- Laboratório de Citogenética e Diversidade Vegetal, Departamento de Biologia Geral, Centro de Ciências Biológicas, Universidade Estadual de Londrina, Londrina, Paraná, 86097-570, Brazil.,Programa de Pós-graduação em Genética e Biologia Molecular, Centro de Ciências Biológicas, Universidade Estadual de Londrina, Londrina, Paraná, 86097-570, Brazil
| | - Letícia Maria Parteka
- Laboratório de Citogenética e Diversidade Vegetal, Departamento de Biologia Geral, Centro de Ciências Biológicas, Universidade Estadual de Londrina, Londrina, Paraná, 86097-570, Brazil.,Programa de Pós-graduação em Genética e Biologia Molecular, Centro de Ciências Biológicas, Universidade Estadual de Londrina, Londrina, Paraná, 86097-570, Brazil
| | - Rafael de Assis
- Laboratório de Citogenética e Diversidade Vegetal, Departamento de Biologia Geral, Centro de Ciências Biológicas, Universidade Estadual de Londrina, Londrina, Paraná, 86097-570, Brazil.,Programa de Pós-graduação em Genética e Biologia Molecular, Centro de Ciências Biológicas, Universidade Estadual de Londrina, Londrina, Paraná, 86097-570, Brazil
| | - André Luís Laforga Vanzela
- Laboratório de Citogenética e Diversidade Vegetal, Departamento de Biologia Geral, Centro de Ciências Biológicas, Universidade Estadual de Londrina, Londrina, Paraná, 86097-570, Brazil.
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Roggero Luque JM, Moreno EMS, Kovalsky IE, Seijo JG, Solís Neffa VG. Evidence of the occurrence of structural chromosome changes at the initial diploid diversification of the autopolyploid Turnera sidoides L. (Passifloraceae) complex. Genome 2016; 59:127-36. [PMID: 26794024 DOI: 10.1139/gen-2015-0096] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Turnera sidoides is an autopolyploid complex of obligate outcrossing perennial herbs. It includes five subspecies and five morphotypes in which diploid to octoploid cytotypes were found. Based on phenetic analyses of the complex and karyotype data of polyploid cytotypes, it has been hypothesized that morphological and chromosome differentiation of T. sidoides occurred at the diploid level. To test this hypothesis, we present the first detailed chromosome analysis of diploid populations of three subspecies and four morphotypes. CMA(+)/DAPI(-) bands were restricted to secondary constrictions (except in the andino morphotype) and varied in number and position among taxa. By contrast, DAPI staining was uniform in all the materials investigated. The number and position of 45S rDNA loci were coincident with the CMA(+)/DAPI(-) bands associated with secondary constrictions. Only one pair of 5S rDNA loci was detected in all the taxa (except in subsp. holosericea), but its position was variable. The identified chromosome markers varied among the three subspecies analyzed, but they were more conserved among the morphotypes of subsp. pinnatifida. Cluster analysis of these chromosome markers supports the current taxonomic arrangement of diploids and demonstrates that structural chromosome changes would have led or accompanied the initial differentiation of T. sidoides at the diploid level.
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Affiliation(s)
- Juan M Roggero Luque
- a Instituto de Botánica del Nordeste (UNNE-CONICET). CC 209. 3400, Corrientes, Argentina
| | - E M Sara Moreno
- a Instituto de Botánica del Nordeste (UNNE-CONICET). CC 209. 3400, Corrientes, Argentina
| | - I Evelin Kovalsky
- b Instituto de Botánica del Nordeste (UNNE-CONICET). CC 209. 3400, Corrientes, Argentina. Facultad de Ciencias Exactas y Naturales y Agrimensura (UNNE)
| | - J Guillermo Seijo
- b Instituto de Botánica del Nordeste (UNNE-CONICET). CC 209. 3400, Corrientes, Argentina. Facultad de Ciencias Exactas y Naturales y Agrimensura (UNNE)
| | - Viviana G Solís Neffa
- b Instituto de Botánica del Nordeste (UNNE-CONICET). CC 209. 3400, Corrientes, Argentina. Facultad de Ciencias Exactas y Naturales y Agrimensura (UNNE)
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