Heterosis and nuclear DNA content in maize

Biradar, D. P.; Rayburn, A. Lane

doi:10.1038/hdy.1993.139

Cited by 38 publications

(24 citation statements)

References 11 publications

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“…After meiosis, a loss of DNA content was seen in heart-shaped embryos developing in the periphery compared with no loss for those developing at the center, and this phenomenon occurred during the very early phase of embryo formation. Pertinent to the last observations is the following relationship between heterosis and nuclear content in maize as reported by Biradar and Lane Rayburn (1993) and Lane . The inheritance of nuclear DNA content in hybrid maize supports the idea of an unstable genome, since some hybrids have more difficulty organizing the two parental genomes, with the result of a consequent variation in DNA content.…”

Section: Discussionsupporting

confidence: 54%

Genome plasticity during the acquisition of embryogenic competence

Geri¹,

Turrini²,

Giorgetti³

et al. 1999

Genome

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Hypocotyl explants from carrot and other species experience concomitant segregation events and differentiation of homeotic structures during the first 20 days of culture on 2,4-dichlorophenoxyacetic acid (2,4-D). In addition to these cyto-morphological changes, significant amounts of nuclear DNA are lost, the molecular details of which we investigate in this paper. We have developed a slot-blot analysis assay to study the DNA content of a series of carrot samples; besides the leaves, this survey ranged over different culture timepoints: hypocotyls, cell lines, and somatic embryo stages. We carried on to study the relationship between this DNA loss and sequence complexity modulation. Results from probing sequences that correspond to different degrees of complexity, such as medium repetitive and unique sequences as well as sequences belonging to both classes (ribosomal cistrons, ubiquitin, actin, and chalcone synthase), consistently manifested a reduction in DNA levels during the acquisition of embryogenic competence. In some cases, the cultured cells would contain only 10% of the gene copies observed in the reference tissues. Modulation trends also showed that DNA levels of most sequences recover at the torpedo-plantlet stage, which again correlates DNA modulation and the acquisition of embryogenic competence. These results suggest that similar DNA variations may occur in plants in vivo during meiosis, possibly so that meiotic division may be properly completed.

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Section: Discussionsupporting

confidence: 54%

Genome plasticity during the acquisition of embryogenic competence

Geri¹,

Turrini²,

Giorgetti³

et al. 1999

Genome

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“…Species with small genome size are considered to be more evolutionarily flexible, allowing them to colonize new and more diverse environments (Leitch et al 1998b). Variation in 2C DNA content did not show significant differences with an ANOVA test (P = 0.1126), suggesting that any actual minor variations had originated during species differentiation (Biradar and Rayburn 1993). Changes in DNA content can be due to deletions, duplications or genome responses to environmental stress (Price 1976).…”

Section: Also Reportedmentioning

confidence: 99%

Nuclear genome size and chromosome analysis in Chenopodium quinoa and C. berlandieri subsp. nuttalliae

2008

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Cytogenetic characterization by karyotyping and determination of DNA content by flow cytometry of seven cultivated varieties of Chenopodium was performed. Chenopodium quinoa cultivar Barandales and C. berlandieri subsp. nuttalliae cultigens Huauzontle, Quelite and Chia roja showed 2n = 4x = 36, x = 9. Statistically insignificant genome size differences for studied varieties ranged from 2.96 pg/2C (1 Cx = 724 Mbp) in C. quinoa to 3.04 pg/2C (1 Cx = 743 Mbp) in Huauzontle. Karyotype analyses revealed the presence of nine groups of four metacentric chromosomes, including two pairs of chromosomes with satellites. The first pair of satellites was located on the largest pair of chromosomes and the second on a different pair of chromosomes in all accessions analyzed. Variation among varieties was evident in chromosome size, genome length (GL) and the position of satellites. Chia roja exhibited greatest GL (58.82 lm) and biggest chromosomes (2.04 lm). Huauzontle showed the smallest GL (45.02 lm) and shortest chromosomes (1.60 lm). Comparison of GL in studied taxa was statistically significant and allowed to define three groups according to the use given to these plants. These data indicate that they are small, very stable genomes in terms of DNA content, and they support the allotetraploid origin(s) of C. berlandieri subsp. nuttalliae and C. quinoa.

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“…Nuclear DNA content analysis was performed using flow cytometry and 2-week-old seedlings of maize (Zea mays L.) inbred line W22 (5.35 pg/2C nucleus) as a standard (Biradar and Rayburn 1993). Immediately prior to nuclei extraction, 1-2 cm 2 of leaf tissue from A. hybridus, A. rudis, hybrid, or BC 2 plants were chopped and combined with chopped tissue from a 1-cm-long maize stem segment.…”

Section: Dna Content Analysismentioning

confidence: 99%

Transmission of herbicide resistance from a monoecious to a dioecious weedy Amaranthus species

et al. 2002

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The genus Amaranthus includes several important monoecious and dioecious weed species, and several populations of these species have developed resistance to herbicides. These species are closely related and two or more species often coexist in agricultural settings. Collectively, these attributes raise the concern that herbicide resistance might transfer from one weedy Amaranthus species to another. We performed research to determine if a dominant allele encoding a herbicide-insensitive form of acetolactate synthase (ALS) could be transferred from a monoecious species, A. hybridus, to a dioecious species, A. rudis. Numerous F(1) hybrids were obtained from controlled crosses in a greenhouse between A. rudis and herbicide-resistant A. hybridus, and most (85%) of these hybrids were herbicide-resistant. Molecular analysis of the ALS gene was used to verify that herbicide-resistant hybrids contained both an A. rudis and an A. hybridus ALS allele. Although hybrids had greatly reduced fertility, 42 BC(1) plants were obtained by backcrossing 33 hybrids with male A. rudis. Fertility was greatly restored in BC(1) progeny, and numerous BC(2) progeny were obtained from a second backcross to A. rudis. The herbicide-resistance allele from A. hybridus was transmitted to 50% of the BC(1) progeny. The resistance allele was subsequently transmitted to and conferred herbicide resistance in 39 of 110 plants analyzed from four BC(2) families. Parental species, hybrids, and BC(2) progeny were compared for 2C nuclear DNA contents. The mean hybrid 2C nuclear DNA content, 1.27 pg, was equal to the average between A. rudis and A. hybridus, which had 2C DNA contents of 1.42 and 1.12 pg, respectively. The mean 2C DNA content of BC(2) plants, 1.40 pg, was significantly (alpha < 0.01) less than that of the recurring A. rudis parent and indicated that BC(2) plants were not polyploid. This report demonstrates that herbicide resistance can be acquired by A. rudis through a hybridization event with A. hybridus.

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Heterosis and nuclear DNA content in maize

Cited by 38 publications

References 11 publications

Genome plasticity during the acquisition of embryogenic competence

Genome plasticity during the acquisition of embryogenic competence

Nuclear genome size and chromosome analysis in Chenopodium quinoa and C. berlandieri subsp. nuttalliae

Transmission of herbicide resistance from a monoecious to a dioecious weedy Amaranthus species

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