Minichromosomes: Vectors for Crop Improvement

Cody, Jon P.; Swyers, Nathan C.; McCaw, Morgan; Graham, Nathaniel D.; Zhao, Changzeng; Birchler, James A.

doi:10.3390/agronomy5030309

Cited by 4 publications

(2 citation statements)

References 59 publications

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“…This non-disjunction property makes the maize B chromosome a powerful tool when it translocates with the A chromosomes. Maize with stable B-A translocations has wide applications in various genetic studies, including experimental mapping, chromosomal dosage studies, chromosomal behavior, and genetic engineering of minichromosomes (Beckett 1991;Birchler and Veitia 2012;Cody et al 2015;Liu et al 2015).…”

Section: Introductionmentioning

confidence: 99%

Effect of aneuploidy of a non‐essential chromosome on gene expression in maize

et al. 2022

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The non-essential supernumerary maize (Zea mays) B chromosome (B) has recently been shown to contain active genes and to be capable of impacting gene expression of the A chromosomes. However, the effect of the B chromosome on gene expression is still unclear. In addition, it is unknown whether the accumulation of the B chromosome has a cumulative effect on gene expression. To examine these questions, the global expression of genes, microRNAs (miRNAs), and transposable elements (TEs) of leaf tissue of maize W22 plants with 0-7 copies of the B chromosome was studied. All experimental genotypes with B chromosomes displayed a trend of upregulated gene expression for a subset of A-located genes compared to the control. Over 3000 A-located genes are significantly differentially expressed in all experimental genotypes with the B chromosome relative to the control. Modulations of these genes are largely determined by the presence rather than the copy number of the B chromosome. By contrast, the expression of most B-located genes is positively correlated with B copy number, showing a proportional gene dosage effect. The B chromosome also causes increased expression of A-located miRNAs. Differentially expressed miRNAs potentially regulate their targets in a cascade of effects. Furthermore, the varied copy number of the B chromosome leads to the differential expression of A-located and B-located TEs. The findings provide novel insights into the function and properties of the B chromosome.

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Section: Introductionmentioning

confidence: 99%

Effect of aneuploidy of a non‐essential chromosome on gene expression in maize

et al. 2022

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“…Centromeres are regions of the chromosome that are required for faithful separation of sister chromatids to either pole of a cell during anaphase. They are the sites of kinetochore formation and where spindle fibers bind to the chromosomes (Cody et al 2015). While centromeres are determined by specific DNA sequences in yeast, centromere determination in most eukaryotes is more complex.…”

Section: Centromeresmentioning

confidence: 99%

Development of an amenable system for site-specific addition to a maize chromosome

Swyers¹

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Currently, transgenic maize is produced by random integration of a transgenes into the plant. This works for single genes, but not as well for multiple traits. Identifying plants that contain several transgenes becomes a very difficult task. Gene stacking at a single location in the genome would make combining multiple transgenes into plants a simpler process. This project focused on the development of a system would allow for transgenes to be sequentially added to a specific site in the maize genome. The system utilizes two recombinases, Cre recombinase and _C31 Integrase, to remove a selectable marker and to integrate transgenes. An initial construct containing a selectable marker, flanked by LoxP sites, which are acted upon by Cre recombinase, and an attP site, were transformed. The selectable marker was then removed from the integrated transgene by exposure to Cre recombinase. Two amendment constructs enable modification of the integrated construct by utilizing complementary attP and attB sites, which are acted upon by _C31 Integrase. The amendment constructs contain cargo and a promoterless selectable marker which, upon successful recombination with the target site, restores expression of the selectable marker. Successful demonstration of this system simplifies generation of multi-transgene plants, and the assembly of multi-gene pathways in plants.

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Understanding and exploiting uniparental genome elimination in plants: insights from Arabidopsis thaliana

Thondehaalmath

Kulaar

Bondada

et al. 2021

Journal of Experimental Botany

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Vacuolar storage of iron (Fe) is important for Fe homeostasis in plants. When sufficient, the excess Fe could be stored in vacuoles for remobilization in case of Fe deficiency. Although the mechanism of Fe remobilization from vacuoles is critical for crop development under low Fe stress, the transporters that mediate vacuolar Fe translocation into the cytosol in rice remains unknown. Here, we showed that under higher Fe 2+ concentrations, the Δccc1 yeast mutant transformed with rice natural resistance-associated macrophage protein 2 (OsNRAMP2) became more sensitive to Fe toxicity. In rice protoplasts and transgenic plants expressing Pro35S: OsNRAMP2-GFP, OsNRAMP2 was localized to tonoplast. Vacuolar Fe contents in osnramp2 knockdown lines were higher than in the wild-type, while the growth of osnramp2 knockdown plants was significantly influenced by Fe deficiency. Furthermore, the germination of osnramp2 knockdown plants was arrested. Inversely, the vacuolar Fe contents of Pro35S: OsNRAMP2-GFP lines were significantly lower than in the wild-type, and overexpression of OsNRAMP2 increased shoot biomass under Fe deficiency. Taken together, we propose that OsNRAMP2 transports Fe from the vacuole to the cytosol and plays a pivotal role in seed germination.

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Minichromosomes: Vectors for Crop Improvement

Cited by 4 publications

References 59 publications

Effect of aneuploidy of a non‐essential chromosome on gene expression in maize

Effect of aneuploidy of a non‐essential chromosome on gene expression in maize

Development of an amenable system for site-specific addition to a maize chromosome

Understanding and exploiting uniparental genome elimination in plants: insights from Arabidopsis thaliana

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