Nuclear genome size and cytotype analysis inAgave parvifloraTorr. subsp.flexifloraGentry (Asparagales, Asparagaceae)

Abstract

This study presents the cytogenetic characterization by karyotyping and a determination of the DNA content by flow cytometry of wild adult plants, plants grown from seeds of wild plants and bulbils of Agave parviflora subsp. flexiflora from Bacadehuachi to Nacori Town, Sonora, Mexico. The analyzed plants were diploids (2n = 2x = 60) and had three different structural cytotypes. The cytotype observed in wild adult plants was 44m + 4sm + 10st + 2t, the cytotype found in plants grown from seeds was 48m + 8st + 4t and the cytotype displayed by bulbils was 44m + 2sm + 14st. Agave parviflora subsp. flexiflora showed a bimodal karyotype of 10 large + 50 small chromosomes. All diploid plants had a secondary constriction in one pair of the large chromosomes. The arm ratio, the proportion of different types of large and small chromosomes, the mean of genome length and the asymmetry index of karyotypes clearly varied among all three diploid cytotypes. The pattern of variation among all the types of plants is probably due to rearrangements in the large and small chromosomes of the complement. Differences in the amount of nuclear 2C DNA = 8.20 pg in diploid wild adult plants and 8.21 pg in bulbils were significantly different when compared to 2C DNA = 8.07 pg of diploid plants grown from seeds. The different types of plants displayed 1.7% variation in the 2C DNA content and the mean 2C DNA content was 8.16 pg; 1Cx value = 4.08 pg. The results here reported consist of basic and useful information to set conservation strategies and breeding approaches for Agave parviflora subsp. flexiflora.

Cytological and Hybridization Studies in Three Cultivars of Tuberose (<i>Polianthes tuberosa</i> L.)

“…The details of karyotype, comprising 10 long chromosomes bearing centromeres in terminal or subterminal regions and 50 short chromosomes with centromeres in median or submedian regions, also agree with some of the previous reports (Vij et al 1982, Satô 1938, Jayasree et al 2001. In these features and the presence of a secondary constriction on the long arms of a long pair, the karyotype of P. tuberosa matches closely with that of other members of Agavoideae such as Agave and Yucca species (Satô 1938, Vij et al 1982, Jyothilekshmi et al 2015, Palomino et al 2015.…”

Review and in silico analysis of fermentation, bioenergy, fiber, and biopolymer genes of biotechnological interest inAgaveL. for genetic improvement and biocatalysis

“…Polyploidy is a little explored fundamental biological phenomenon in Agave . The genus is of possible allopolyploid origin having a basic chromosome number of n = 30, a bimodal karyotype with 5 long acrocentric and 25 small metacentric or submetacentric chromosomes, and ploidy level of its species varies from diploid (2 n = 2 x = 60) to octoploid (2 n = 8 x = 240) . Table summarizing the biotechnological applications of polyploids species of Agave shows most such species are currently used for fiber production, but maybe polyploid species of the genus should be applied for other biotechnological purposes in the short term; unfortunately, most work made in polyploid Agave species has been limited to cytological characterization.…”

“…The genus is of possible allopolyploid origin having a basic chromosome number of n = 30, a bimodal karyotype with 5 long acrocentric and 25 small metacentric or submetacentric chromosomes, and ploidy level of its species varies from diploid (2n = 2x = 60) to octoploid (2n = 8x = 240). 16,[80][81][82][83] Table 1 summarizing the biotechnological applications of polyploids species of Agave shows most such species are currently used for fiber production, but maybe polyploid species of the genus should be applied for other biotechnological purposes in the short term; unfortunately, most work made in polyploid Agave species has been limited to cytological characterization. The majority of implemented biotechnological applications have being based on empirical observations of morphological characteristics or of commercial interest product concentration, many times without clarifying the roles played by molecular and biochemical factors in plant performance or the physiological adaptations of polyploid species conferring them tolerance to environmental stress.…”

Chromatid Abnormalities in Meiosis: A Brief Review and a Case Study in the Genus Agave (Asparagales, Asparagaceae)

“…This genus has a bimodal complement of 10 large and 50 small chromosomes with a monoploid number of x = 30, and with varieties and species from diploid to hexaploid [5,[28][29][30]. Cave [31] reported regular meiosis in ive diploid, two tetraploid and one hexaploid species, and irregular meiosis in two polyploids, with bridges and fragments at anaphase I.…”