Plastid Replication and Development in the Life Cycle of Higher Plants

Possingham, J. V.

doi:10.1146/annurev.pp.31.060180.000553

Cited by 124 publications

(58 citation statements)

References 53 publications

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“…When the approximate cell number (33) in the total leaf area exposed to selection for gene transfer events is divided by the number of events selected, we obtain a frequency of approximately 1 of 5 million cells where transfer of the chloroplast nptII-containing fragment into the nuclear genome has occurred. In reality, the frequency may be even higher, because our selection scheme missed all those events where the selectable marker gene was not included in the transferred chloroplast genome fragment.…”

Section: Frequency Of Gene Transfermentioning

confidence: 99%

High-frequency gene transfer from the chloroplast genome to the nucleus

Stegemann

Hartmann²,

Ruf³

et al. 2003

Proc. Natl. Acad. Sci. U.S.A.

275

237

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Eukaryotic cells arose through endosymbiotic uptake of free-living bacteria followed by massive gene transfer from the genome of the endosymbiont to the host nuclear genome. Because this gene transfer took place over a time scale of hundreds of millions of years, direct observation and analysis of primary transfer events has remained difficult. Hence, very little is known about the evolutionary frequency of gene transfer events, the size of transferred genome fragments, the molecular mechanisms of the transfer process, or the environmental conditions favoring its occurrence. We describe here a genetic system based on transgenic chloroplasts carrying a nuclear selectable marker gene that allows the efficient selection of plants with a nuclear genome that carries pieces transferred from the chloroplast genome. We can select such gene transfer events from a surprisingly small population of plant cells, indicating that the escape of genetic material from the chloroplast to the nuclear genome occurs much more frequently than generally believed and thus may contribute significantly to intraspecific and intraorganismic genetic variation.T he evolutionary origin of eukaryotic cells is characterized by the endosymbiotic uptake of bacteria and their gradual conversion into the DNA-containing cell organelles, mitochondria, and plastids (chloroplasts) (1-3). Genetically, the evolutionary optimization of endosymbiosis was accompanied by the loss of dispensable and redundant genetic information and the large-scale translocation of genetic information from the endosymbiont to the host genome (4-6). Consequently, contemporary organellar genomes are greatly reduced and contain only a small proportion of the genes that their free-living ancestors had possessed. By using molecular methods, the origins of organelles have been traced back to specific taxa of eubacteria: Whereas cyanobacteria were identified as presumptive ancestors of plastids, ␣-proteobacteria are related most closely to mitochondria (1).Interspecific variation in the gene content of organellar genomes (7-11) suggests that gene transfer from organelles to the nucleus is an ongoing process. Moreover, pieces of chloroplast and mitochondrial DNA are often found in nuclear genomes (12-18) and commonly referred to as promiscuous DNA. These sequences lack any apparent function but may provide the raw material for converting organellar genes into functional nuclear genes, the products of which are reimported into the organelle, then allowing for subsequent loss of the genes from the organellar genome (10). In addition, promiscuous DNA of mitochondrial origin has been implicated recently in DNA repair in yeast by patching broken chromosomes (19,20).In the present study we developed an experimental system suitable for selecting and analyzing DNA transfer events from the chloroplast genome to the nuclear genome. We find that DNA escape out of the chloroplast and integration into the nuclear genome occurs much more frequently than generally believed and thus provides a mechan...

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Section: Frequency Of Gene Transfermentioning

confidence: 99%

High-frequency gene transfer from the chloroplast genome to the nucleus

Stegemann

Hartmann²,

Ruf³

et al. 2003

Proc. Natl. Acad. Sci. U.S.A.

275

237

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“…From the literature, there appear to be two major categories of research in the field, one relating to the process of multiplication of mature plastids in vegetative tissue,l) and the other relating to the process in embryos and meristems. 2) In the former, the major mode of mUltiplication is believed to involve equal division of mature plastids. However, in 1991, new information was obtained that showed the formation of things called plastid initials from mature plastids in woody perennials in midwinter, concurrent with the breaking of dormancy.…”

mentioning

confidence: 99%

“…2,19) In fact, the ultrastructure was that of a heterogeneous population in terms of the presence of micro-starch granules. 1,11,14,15) Furthermore, recent studies showed that proplastids in apexes of the stolon of potatoes and callus cells of apple contained organelles that are indistinguishable from plastid initials.…”

mentioning

confidence: 99%

Functional and Structural Differences among Proplastids, as Seen by Immunogold Staining and Electron Microscopy

Akita

Sagisaka

1995

Bioscience, Biotechnology, and Biochemistry

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“…2C). This could be attributed to nitrogen deficiency resulting in a premature senescence of leaves (Possingham, 1980). This chloroplast stage has not been observed in urea-applied trees.…”

Section: Discussionmentioning

confidence: 92%

“…The different developmental stages of chloroplast observed in the mesophyll cells of both control and urea-applied trees at 20 DAB is considered to be a consequential event related to the early stage of leaf development where differentiation of plastids occur. An interesting feature of smaller chloroplasts observed in the urea-applied trees is not to be regarded as being due to slow or non-growing chloroplasts but rather can be viewed as developing plastids which have resulted from an active division of preexisting chloroplasts triggered by the application of nitrogen (Possingham, 1980). Whereas, the control trees, which had bigger chloroplasts, can be considered as the same chloroplasts that preexisted in the cell and continued to develop but were not actively dividing unlike those of urea-applied trees.…”

Section: Discussionmentioning

confidence: 99%

Development of Chloroplast in the Mesophyll Cells of Satsuma Mandarin Foliar Sprayed with Urea

Aguja¹,

Mohammad²,

Shiraishi³

1998

Pakistan J. of Biological Sciences

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The development of chloroplasts in the mesophyll cells of control and urea-applied satsuma mandarin leaves were studied. At 20 days after budding (DAB) active differentiation of chloroplasts in urea-applied trees was evident. However, on a length times width basis, chloroplasts were small in both palisade (1.99 × 0.70 µm ) starch grains. The thylakoid layers per chloroplast were lesser (2.80) in this treatment compared to control (3.72). At 40 DAB, both control and urea-applied trees reached chloroplast maturity, but control trees had bigger chloroplast (4.87 × 2.39 µm 2 ) in the palisade layer cells which contained extremely large and numerous starch grains with few dilated thylakoid layers. Degenerating chloroplasts in the spongy layer cells of control trees were characterized by the disappearance of the outer membrane. While urea-applied trees had smaller chloroplast (4.56 × 2.39 µm 2 ) in the palisade layer. Further, few small starch grains, thylakoid-filled stroma and many lipid droplets were found. Moreover, thylakoid layers were about to dilate but outer membrane of the chloroplasts remained intact in both palisade and spongy layer cells. Compared to the palisade layer cells, chloroplasts in the spongy were bigger (5.32 x 1.95 µm 2 ).

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Plastid Replication and Development in the Life Cycle of Higher Plants

Cited by 124 publications

References 53 publications

High-frequency gene transfer from the chloroplast genome to the nucleus

High-frequency gene transfer from the chloroplast genome to the nucleus

Functional and Structural Differences among Proplastids, as Seen by Immunogold Staining and Electron Microscopy

Development of Chloroplast in the Mesophyll Cells of Satsuma Mandarin Foliar Sprayed with Urea

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