The relationship between chloroplast number and genome size in Zea mays ssp. mays

Ho, InSun; Rayburn, A. Lane

doi:10.1016/0168-9452(91)90054-c

Cited by 11 publications

(5 citation statements)

References 14 publications

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“…(Rosato et al 1998). The genome size variation detected in the landraces analyzed herein is the largest among those recorded to date in populations from the American continent (Díez et al 2013;Ho and Rayburn 1991;McMurphy and Rayburn 1991;Rayburn 1990;Rayburn and Auger 1990;Rayburn et al 1985Rayburn et al , 1994Tito et al 1991). This variation could be attributed to the effect of selection acting, directly or indirectly, on nuclear and chromosomal characteristics in different environmental conditions along the altitudinal cline.…”

Section: Discussionmentioning

confidence: 67%

Are cytological parameters of maize landraces (Zea mays ssp. mays) adapted along an altitudinal cline?

et al. 2017

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The Northwestern Argentina (NWA) highland region is one of the southernmost areas of native maize cultivation. We studied variations of different cytological parameters, such as DNA contents, presence/absence of B chromosomes (Bs), and number and sequence composition of heterochromatic knobs in ten accessions of four maize landraces growing along a broad altitudinal cline in NWA. The aim of this work was to assess variations in cytological parameters and their relationship with the crop altitude of cultivation, in an adaptive context. The A-DNA content of the A chromosome complements showed 40% of difference between the lowest (4.5 pg) and the highest (6.3 pg) 2C value. This variation could be attributed to differences in number and size of heterochromatic knobs. Fluorescent in situ hybridization studies revealed the sequence composition of each knob, with a higher proportion of knobs composed of 180-bp repeats rather than TR-1 repeats, in all accessions. We also found numerical polymorphisms and the highest frequency of Bs reported in maize to this date. These results lead us to propose that the frequencies and doses of Bs are influenced by the landrace genotypical make-up. The Bs might be maintained in higher frequencies in those accessions having lower heterochromatin content, so as to preserve an optimal nucleotype. Furthermore, selective forces acting along the altitudinal gradient might be modulating the cytological parameters studied, as suggested by the significant correlations found among them.

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Section: Discussionmentioning

confidence: 67%

Are cytological parameters of maize landraces (Zea mays ssp. mays) adapted along an altitudinal cline?

et al. 2017

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“…Recently, a positive correlation was observed between genome size (nuclear DNA content) and chloroplast number per cell in diploid maize (Ho and Rayburn 1991). This correlation has also been observed in a number of species having different ploidy levels, but it is not universal.…”

Section: Anatomical Effectsmentioning

confidence: 81%

Effects of polyploidy on photosynthesis

1993

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In polyploid plants the photosynthetic rate per cell is correlated with the amount of DNA per cell. The photosynthetic rate per unit leaf area is the product of the rate per cell times the number of photosynthetic cells per unit area. Therefore, the photosynthetic rate per unit leaf area will increase if there is a less than proportional increase in cell volume at higher ploidal levels, or if cell packing is altered to allow more cells per unit leaf area. In autopolyploids (Medicago sativa, C3 species, and Pennisetum americanum, C4 species) there is a doubling of photosynthesis per cell and of cell volume in the tetraploid compared to the diploid. However, there is a proportional decrease in number of cells per unit leaf area with this increase in ploidy such that the rate of photosynthesis per leaf area does not change. There is more diversity in the relationship between ploidal level (gene dosage) and photosynthetic rates per unit leaf area in allopolyploids. This is likely to reflect the effects of natural selection on leaf anatomy, and novel genetic interactions from contributed genomes which can occur with allopolyploidy. In allopolyploid wheat (C3 species) a higher cell volume per unit DNA at the higher ploidal level is negatively correlated with photosynthesis rate per unit leaf area. Although photosynthesis per cell increases with ploidy, photosynthesis per leaf area decreases, being lowest in the allohexaploid, cultivated bread wheat (Triticum aestivum). Alternatively, doubling of photosynthetic rate per cell with doubling of DNA, with apparent natural selection for decreased cell volume per unit DNA, results in higher rates of photosynthesis per leaf area in octaploid compared to tetraploid Panicum virgatum (C4) which may be a case of allopolyploidy. Similar responses probably occur in Festuca arundinacea. Therefore, in some systems anatomical factors affecting photosynthesis are also affected by ploidal level. It is important to evaluate that component as well as determining the effect on biochemical processes. Current information on polyploidy and photosynthesis in several species is discussed with respect to anatomy, biochemistry and bases for expressing photosynthetic rates.

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“…The control of chloroplast number has previously been linked to both endoreduplication ( Butterfass, 1989 ; Ho and Rayburn, 1991 ) and cell volume ( Pyke and Leech, 1987 ). The fact that we detect significant endoreduplication in the small BS cells of C 3 A. thaliana but also the large BS cells of C 4 C. gynandra suggested that evolution of increased chloroplast number in BS cells of C 4 species is not likely to be related to enreduplication in these cells but is co-ordinated with cell expansion.…”

Section: Discussionmentioning

confidence: 99%

Endoreduplication is not involved in bundle-sheath formation in the C4 species Cleome gynandra

Aubry

Kneřová

Hibberd

2013

Journal of Experimental Botany

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There is currently significant interest in engineering the two-celled C4 photosynthesis pathway into crops such as rice in order to increase yield. This will require alterations to the biochemistry of photosynthesis in both mesophyll (M) and bundle-sheath (BS) cells, but also alterations to leaf anatomy. For example, the BS of C4 species is enlarged compared with that in C3 species. Because cell and nucleus size are often correlated, this study investigated whether nuclear endoreduplication is associated with increased differentiation and expansion of BS cells. Nuclei in the BS of C4 Cleome gynandra were tagged with green fluorescent protein. Confocal laser-scanning microscopy and flow cytometry of isolated nuclei were used to quantify size and DNA content in BS cells. The results showed a significant endoreduplication in BS cells of C. gynandra but not in additional C4 lineages from both the monocotyledonous and dicotyledenous plants. Furthermore, in the C3 species Arabidopsis thaliana, BS cells undergo endoreduplication. Due to this significant endoreduplication in the small BS cells of C3 A. thaliana, it was concluded that endoreduplication of BS nuclei in C4 plants is not linked to expansion and differentiation of BS cells, and therefore that alternative strategies to increase this compartment need to be sought in order to engineer C4 traits into C3 crops such as rice.

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The relationship between chloroplast number and genome size in Zea mays ssp. mays

Cited by 11 publications

References 14 publications

Are cytological parameters of maize landraces (Zea mays ssp. mays) adapted along an altitudinal cline?

Are cytological parameters of maize landraces (Zea mays ssp. mays) adapted along an altitudinal cline?

Effects of polyploidy on photosynthesis

Endoreduplication is not involved in bundle-sheath formation in the C4 species Cleome gynandra

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