Unconventional vegetables collected in Brazil: chromosome number and description of nuclear DNA content

Echeveria is a polyploid genus with a wide diversity of species and morphologies. The number of species registered for Echeveria is approximately 170; many of them are native to Mexico. This genus is of special interest in cytogenetic research because it has a variety of chromosome numbers and ploidy levels. Additionally, there are no studies concerning nuclear DNA content and the extent of endopolyploidy. This work aims to investigate the cytogenetic characteristics of 23 species of Echeveria collected in 9 states of Mexico, analyzing 2n chromosome numbers, ploidy level, nuclear DNA content, and endopolyploidy levels. Chromosome numbers were obtained from root tips. DNA content was obtained from the leaf parenchyma, which was processed according to the two-step protocol with Otto solutions and propidium iodide as fluorochrome, and then analyzed by flow cytometry. From the 23 species of Echeveria analyzed, 16 species lacked previous reports of 2n chromosome numbers. The 2n chromosome numbers found and analyzed in this research for Echeveria species ranged from 24 to 270. The range of 2C nuclear DNA amounts ranged from 1.26 pg in E. catorce to 7.70 pg in E. roseiflora, while the 1C values were 616 Mbp and 753 Mbp, respectively, for the same species. However, differences in the level of endopolyploidy nuclei were found, corresponding to 4 endocycles (8C, 16C, 32C and 64C) in E. olivacea, E. catorce, E. juarezensis and E. perezcalixii. In contrast, E. longiflora presented 3 endocycles (8C, 16C and 32C) and E. roseiflora presented 2 endocycles (8C and 16C). It has been suggested that polyploidization and diploidization processes, together with the presence of endopolyploidy, allowed Echeveria species to adapt and colonize new adverse environments.

Download Full-text

Karyotype characterization and nuclear DNA content measurement in Bromeliaceae: State of the art and future perspectives

Anais da Academia Brasileira de Ciências ◽

10.1590/0001-3765201420140224 ◽

2014 ◽

Vol 86 (4) ◽

pp. 1849-1862 ◽

Cited By ~ 1

Author(s):

ANDREI C.P. NUNES ◽

WELLINGTON R. CLARINDO

Keyword(s):

Flow Cytometry ◽

Chromosome Number ◽

Dna Content ◽

Nuclear Dna ◽

State Of The Art ◽

Nuclear Dna Content ◽

Basic Chromosome Number ◽

Basic Chromosome ◽

Content Measurement ◽

2C Dna Content

In Bromeliaceae, cytogenetic and flow cytometry analyses have been performed to clarify systematic and evolutionary aspects. Karyotyping approaches have shown the relatively high chromosome number, similar morphology and small size of the chromosomes. These facts have prevented a correct chromosome counting and characterization. Authors have established a basic chromosome number of x = 25 for Bromeliaceae. Recently, one karyomorphological analysis revealed that x = 25 is no longer the basic chromosome number, whose genome may have a polyploid origin. Besides cytogenetic characterization, the 2C DNA content of bromeliads has been measured. Nuclear DNA content has varied from 2C = 0.60 to 2C = 3.34 picograms. Thus, in relation to most angiosperms, the 2C DNA content of Bromeliaceae species as well as their chromosome size can be considered relatively small. In spite of some advances, cytogenetic and flow cytometry data are extremely scarce in this group. In this context, this review reports the state of the art in karyotype characterization and nuclear DNA content measurement in Bromeliaceae, emphasizing the main problems and suggesting prospective solutions and ideas for future research.

Download Full-text

Development of Flow Cytometric Protocol for Nuclear DNA Content Estimation and Determination of Chromosome Number in Pongamia pinnata L., a Valuable Biodiesel Plant

Applied Biochemistry and Biotechnology ◽

10.1007/s12010-013-0553-z ◽

2013 ◽

Vol 172 (1) ◽

pp. 533-548 ◽

Cited By ~ 3

Author(s):

Aadi Moolam Ramesh ◽

Supriyo Basak ◽

Rimjhim Roy Choudhury ◽

Latha Rangan

Keyword(s):

Chromosome Number ◽

Dna Content ◽

Nuclear Dna ◽

Nuclear Dna Content ◽

Pongamia Pinnata ◽

Flow Cytometric

Download Full-text

Nuclear DNA content and chromosome number in somatic hybrid allopolyploids of Solanum

Plant Cell Tissue and Organ Culture (PCTOC) ◽

10.1007/s11240-011-9932-8 ◽

2011 ◽

Vol 106 (3) ◽

pp. 373-380 ◽

Cited By ~ 4

Author(s):

Anna Szczerbakowa ◽

Justyna Tarwacka ◽

Elwira Sliwinska ◽

Bernard Wielgat

Keyword(s):

Chromosome Number ◽

Dna Content ◽

Somatic Hybrid ◽

Nuclear Dna ◽

Nuclear Dna Content

Download Full-text

Karyotype evolution in Helianthemum (Cistaceae): dysploidy, achiasmate meiosis and ecological specialization in H. squamatum, a true gypsophile

Botanical Journal of the Linnean Society ◽

10.1093/botlinnean/boz066 ◽

2019 ◽

Vol 191 (4) ◽

pp. 484-501 ◽

Cited By ~ 2

Author(s):

Abelardo Aparicio ◽

Marcial Escudero ◽

Ana Valdés-Florido ◽

Miguel Pachón ◽

Encarnación Rubio ◽

...

Keyword(s):

Chromosome Number ◽

Dna Content ◽

Nuclear Dna ◽

Karyotype Evolution ◽

Nuclear Dna Content ◽

Sister Species ◽

Ecological Specialization ◽

Genome Reorganization ◽

The Individual ◽

Stressful Environments

Abstract Helianthemum squamatum is a specialist gypsophile, the only species of a recently diverged lineage in subgenus Helianthemum characterized by having the lowest chromosome number in the genus (n = 5). With the hypothesis of great genome reorganization in the lineage of H. squamatum, we (1) modelled the evolution of the chromosome number in the genus Helianthemum, (2) analysed the karyotype and the nuclear DNA content of H. squamatum and its sister species H. syriacum (n = 10) and (3) studied in detail the meiotic process of H. squamatum. Our analyses show that: (1) the rate of chromosome losses in the lineage that gave rise to H. squamatum is 100 times higher than in the genus as a whole; (2) compared to its sister species, H. squamatum has a more symmetric karyotype composed of longer metacentric chromosomes and retains c. 80% of its nuclear DNA content and (3) achiasmatic behaviour of chromosomes occurs during microsporogenesis despite full synapsis. Our results are in agreement with previous knowledge showing that reduced chromosome numbers in determinate lineages are found in short-lived species adapted to stressful environments, and we suggest that a combination of fewer chromosomes, a smaller genome, a shorter life cycle and the suppression of meiotic recombination can together contribute to the maintenance of those advantageous allelic combinations that makes H. squamatum a true gypsophile, enabling the individual plants to cope with the harshness imposed by dry gypsum soils.

Download Full-text