共查询到20条相似文献,搜索用时 31 毫秒
1.
L. J. Escote-Carlson S. Gabay-Laughnan J. R. Laughnan 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1988,75(4):659-667
Summary Cytoplasmic reversion to fertility in cms-S maize has been previously correlated with changes in mitochondrial genome organization, specifically with loss of the autonomously replicating linear plasmid-like DNAs, S1 and S2, and with accompanying alterations in the high molecular weight mtDNA (main genome) that specifically involved S1 and S2 sequences. These studies, however, dealt with cytoplasmic revertants occurring in the cms-VG M825 inbred line and in the cms-VG M825/Oh07 F1 hybrid. This paper deals principally with patterns of mitochondrial DNA reorganization accompanying cytoplasmic reversion to fertility in the WF9 inbred line nuclear background. Here the free S1 and S2 plasmid-like DNAs are retained in the revertants. Mitochondrial DNA analysis by Southern hybridization using cloned fragments of S1 and S2 shows altered organization around S-homologous regions in the main mitochondrial genome of revertants as compared with that of the male-sterile parental controls, but the pattern of main genome changes involving these regions differs from that of the cytoplasmic revertants that occurred in M825 and M825/Oh07 backgrounds. Similar experiments using a clone of the cytochrome oxidase I (COX I) gene of maize as a probe indicate that reorganization in this region is also involved in the changes in mtDNA that accompany cytoplasmic reversion to male fertility in cms-S WF9. The heterogeneity in patterns of reorganization of the main mtDNA genome that accompany cytoplasmic reversion in the same and different nuclear backgrounds are discussed in relation to cytoplasmic male sterility (CMS). 相似文献
2.
N. A. Dudareva S. G. Veprev A. V. Popovsky S. I. Maletsky I. P. Gileva R. I. Salganik 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1990,79(6):817-824
Summary Among the fertile sugar beet lines with nuclear sterility maintenance genes, rf, in a homozygous recessive state, sublines capable of reverting spontaneously at a high rate to sterility were identified. Of 24 related fertile sublines studied, 6 were found to spontaneously revert to sterility with a frequency of about 19%. Genetic analysis confirmed the cytoplasmic nature of spontaneously arising sterility. Reversion to sterility in these sublines was accompanied by alterations in the mitochondrial genome structure: loss of the autonomously replicating minicircle c (1.3 kb) and changes in the restriction patterns of high-molecular-weight mitochondrial DNA (mtDNA). Southern hybridixation analysis with cloned minicircle c as a probe revealed no integration of this DNA molecule into the main mitochondrial and nuclear genomes of the revertants. Comparative BamHI and EcoRI restriction analysis of the mtDNA from the sterile revertants and fertile parental subline showed that the spontaneous reversion is accompanied by extensive genomic rearrangement. Southern blot analysis with cloned -subunit of F1-ATPase (atpA) and cytochrome c oxidase subunit II (COX II) genes as probes indicated that the changes in mtDNA accompanying spontaneous reversion to sterility involved these regions. The mitochondrial genomes of the spontaneous revertants and the sterile analogue were shown to be identical. 相似文献
3.
X. Feng A. P. Kaur S. A. Mackenzie I. M. Dweikat 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2009,118(7):1361-1370
Cytoplasmic male sterility (CMS) represents an important agricultural trait in pearl millet [Pennisetum glaucum (L.) R. Br.] with a value to the seed industry in facilitating economical hybrid seed production. Among the CMS systems available
in millet, the A1 source is the most commonly used for hybrid production, but it can undergo low frequency reversion to fertility.
Plant mitochondrial genomes are highly recombinogenic, becoming unstable and prone to ectopic recombination under conditions
of tissue culture, somatic hybridization, or interspecific crossing. Similarly, CMS systems prone to spontaneous fertility
reversion experience sporadic mitochondrial genome instability. We compared mitochondrial genome configurations between the
male-sterile A1 line and fertile revertants of pearl millet to develop a model for millet mitochondrial genome reorganization
upon reversion. Relative copy number of a subgenomic molecule containing the CoxI-1-2 junction region, a component of the recombination process for reversion, is amplified tenfold following reversion, relative
to the CMS A1 line. We propose that increased copy number of this molecule in a small number of cells or at low frequency
triggers a recombination cascade, likely during reproductive development. The proposed recombination process initiates with
ectopic recombination through a 7-bp repeat to produce a novel CoxI-3-2 junction molecule and an unstable recombination intermediate. Subsequent intra-molecular recombination stabilizes the intermediate
to form a new copy of CoxI accompanied by a deletion. This study furthers the argument that substoichiometric shifting within the plant mitochondrial
genome plays an important role in the evolution of the mitochondrial genome and plant reproductive dynamics. 相似文献
4.
Fertile revertants from S-type male-sterile maize grown in vitro 总被引:3,自引:0,他引:3
E. D. Earle V. E. Gracen V. M. Best L. A. Batts M. E. Smith 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1987,74(5):601-609
Summary Plants were regenerated from callus cultures of maize inbred W182BN with the S(USDA) type of cytoplasmic male sterility (cms). Some regenerates from 16 of 18 separate cultures had fertile tassels. Many other regenerates, whose fertility could not be scored accurately because of abnormal plant morphology, produced fertile progeny after pollination with N cytoplasm W182BN. Revertant plants and/or progeny were obtained from all 18 cultures, which included the CA, D, LBN, and S sources of cmsS. More revertants were recovered from cultures maintained as callus for 12 months than from 3–4 month old cultures. Several types of evidence (absence of segregation for fertility after selfing or pollination of revertants with standard W182BN, pollen viability counts, failure of revertants to restore sterile cmsS lines to fertility, mitochondrial DNA analyses) indicated that the reversion to fertility involved cytoplasmic rather than nuclear alterations. All revertants examined lacked the S1 and S2 plasmid-like DNAs characteristic of the mitochondrial genome of sterile cmsS lines. Most callus cultures lost S1 and S2 after 13–20 months in vitro. No revertants were seen among thousands of W182BN cmsS plants grown from seed in the field or among plants from tissue cultures of W182BN with the C or T types of cms. The cytoplasmic revertants recovered from culture may be useful for the molecular analysis of cmsS. 相似文献
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Loida J. Escote-Carlson Susan Gabay-Laughnan John R. Laughnan 《Molecular & general genetics : MGG》1990,223(3):457-464
Summary A WF9 strain of maize with the RD subtype of the S male-sterile cytoplasm (CMS-S) was converted to the inbred M825 nuclear background by recurrent backcrossing. The organization of the mitochondrial genomes of the F1 and succeeding backcross progenies was analyzed and compared with the progenitor RD-WF9 using probes derived from the S1 and S2 mitochondrial episomes, and probes containing the genes for cytochrome c oxidase subunit I (coxI), cytochrome c oxidase subunit II (coxII) and apocytochrome b (cob). Changes in mitochondrial DNA (mtDNA) organization were observed for S1-, S2-, and coxI-homologous sequences that involve loss of homologous restriction enzyme fragments present in the RD-WF9 progenitor. With the coxI probe, the loss of certain fragments was accompanied by the appearance of a fragment not detectable in the progenitor. The changes observed indicate the effect of the nuclear genome on the differential replication of specific mitochondrial subgenomic entities. 相似文献
8.
9.
Mitochondrial DNA (mtDNA) was isolated from over 100 different maize nucleo-cytoplasmic combinations. DNA preparations were
assayed for the presence of the 1.94kb mitochondrial plasmid by agarose gel electrophoresis and hybridization to a recombinant
clone of the plasmid. The plasmid was present in all tested inbreds which carried N, male fertile, cytoplasm or the cytoplasmically
male sterile (cms) groups,cms-T andcms-C. However, members of thecms-S group differed with respect to the presence of the plasmid. Cytoplasms I, J and S possessed the plasmid, whereas cytoplasms
B, CA, D, G, H, IA, ME, ML, PS, RD and VG did not.Cms-S group lines which had spontaneously reverted to fertility (nuclear and cytoplasmic revertants) did not exhibit a concomitant
change in 1.94kb plasmid levels, although all such lines showed the previously reported alteration in levels of the linear
mtDNAs, S1 and S2. The presence or absence of the plasmid was not correlated with (i) frequency of reversion to fertility,
(ii) the degree of male sterility expressed, (iii) the presence or absence of standard nuclear restorer to fertility genes
and (iv) nuclear genotype. Latin American races carrying RU cytoplasm possessed the plasmid, as did sweet corn varieties.
The relevance of the data tocms and evolution of thecms-S group is discussed. 相似文献
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Kim S Lee ET Cho DY Han T Bang H Patil BS Ahn YK Yoon MK 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2009,118(3):433-441
A novel chimeric gene with a 5′ end containing the nearly complete sequence of the coxI gene and a 3′ end showing homology with chive orfA501 was isolated by genome walking from two cytoplasm types: CMS-S and CMS-T, both of which induce male-sterility in onion (Allium cepa L.). In addition, the normal active and variant inactive coxI genes were also isolated from onions containing the normal and CMS-S cytoplasms, respectively. The chimeric gene, designated
as orf725, was nearly undetectable in normal cytoplasm, and the copy number of the normal coxI gene was significantly reduced in CMS-S cytoplasm. RT-PCR results showed that orf725 was not transcribed in normal cytoplasm. Meanwhile, the normal coxI gene, which is essential for normal mitochondrial function, was not expressed in CMS-S cytoplasm. However, both orf725 and coxI were transcribed in CMS-T cytoplasm. The expression of orf725, a putative male-sterility-inducing gene, was not affected by the presence of nuclear restorer-of-fertility gene(s) in male-fertility
segregating populations originating from the cross between a male-sterile plant containing either CMS-T or CMS-S and a male-fertile
plant whose genotypes of nuclear restorer gene(s) might be heterozygous. The specific stoichiometry of orf725 and coxI in the mtDNA of the three cytoplasm types was consistent among diverse germplasm. Therefore, a molecular marker based on
the relative copy numbers of orf725 and coxI was designed for distinguishing among the three cytoplasm types by one simple PCR. The reliability and applicability of the
molecular marker was shown by testing diverse onion germplasm. 相似文献
12.
We present here genetic experiments with a series of Chinese hamster cell mutants defective in oxidative energy metabolism. The mutations were all shown to be recessive in intraspecies hybrids. Thirty-five mutants were sorted into eight complementation groups, but one of these mutants failed to complement representatives of two distinct complementation groups. The possibility was raised that this is a cell carrying two mutations or a deletion. Because of the greatly different frequencies with which such mutants could be isolated from two different Chinese hamster cell lines, CCL16 (DON) and V79, the stability of representatives from each cell line was examined, and it was found that revertants could be obtained after treatment with mutagens, while spontaneous revertants appeared at unmeasurable or extremely low frequencies, with one exception. The mutant with a very noticeable frequency of spontaneous reversion was defective in mitochondrial protein synthesis, and the question arose whether the mutation was on the mitochondrial genome. A detailed fluctuation analysis of reversion rate and comparison with rates for other mutations was consistent with a nuclear mutation. This conclusion was supported by experiments involving fusions with cytoplasts. 相似文献
13.
Cytoplasmic reversion to fertility in cms-S maize need not involve loss of linear mitochondrial plasmids 总被引:4,自引:0,他引:4
Cytoplasmic male sterility of the S type (cms-S) in maize is characterized by the presence of two autonomously replicating plasmid-like elements, S1 and S2. These plasmids have not been found in the mitochondrial genomes of normal (male-fertile) maize nor previously in male-fertile cytoplasmic revertants. This paper reports the discovery of spontaneous cytoplasmic reversion to fertility in cms-S maize not involving the loss of S1 and S2 plasmids. Data are presented showing that loss of the plasmids during cytoplasmic reversion is under nuclear influence and is not a characteristic of the S cytoplasm itself. 相似文献
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15.
C. K. K. Nair 《Journal of biosciences》1993,18(3):407-422
Plant mitochondrial genomes are much larger and more complex than those of other eukaryotic organisms. They contain a very
active recombination system and have a multipartite genome organization with a master circle resolving into two or more subgenomic
circles by recombination through repeated sequences. Their protein coding capacity is very low and is comparable to that of
animal and fungal systems. Several subunits of mitochondrial functional complexes, a complete set of tRNAs and 26S, 18S and
5S rRNAs are coded by the plant mitochondrial genome. The protein coding genes contain group II introns. The organelle genome
contains stretches of DNA sequences homologous to chloroplast DNA. It also contains actively transcribed DNA sequences having
open reading frames. Plasmid like DNA molecules are found in mitochondria of some plants
Cytoplasmic male sterility in plants, characterized by failure to produce functional pollen grains, is a maternally inherited
trait. This phenomenon has been found in many species of plants and is conveniently used for hybrid plant production. The
genetic determinants for cytoplasmic male sterility reside in the mitochondrial genome. Some species of plants exhibit more
than one type of cytoplasmic male sterility. Several nuclear genes are known to control expression of cytoplasmic male sterility.
Different cytoplasmic male sterility types are distinguished by their specific nuclear genes(rfs) which restore pollen fertility. Cytoplasmic male sterility types are also characterized by mitochondrial DNA restriction
fragment length polymorphism patterns, variations in mitochondrial RNAs, differences in protein synthetic profiles, differences
in sensitivity to fungal toxins and insecticides, presence of plasmid DNAs or RNAs and also presence of certain unique sequences
in the genome. Recently nuclear male sterility systems based on (i) over expression of agrobacterialrol C gene and (ii) anther specific expression of an RNase gene have been developed in tobacco andBrassica by genetic engineering methods. 相似文献
16.
Fertility Restoration Is Associated with Loss of a Portion of the Mitochondrial Genome in Cytoplasmic Male-Sterile Common Bean 总被引:18,自引:3,他引:15 下载免费PDF全文
Restoration of pollen fertility to cytoplasmic male-sterile common bean by nuclear gene Fr is accompanied by mitochondrial (mt) DNA rearrangements within restored plants. These rearrangements are also observed upon spontaneous cytoplasmic reversion to fertility. An mtDNA fragment of at least 25 kilobases was lost from the genome upon restoration or reversion. This fragment contained DNA segments that were not repeated elsewhere in the genome and, therefore, were not detected within the genome upon fertility restoration. This result suggested that the particular mtDNA configuration absent from restored plants could not be maintained by a constant process of recombination but rather by autonomous replication. No evidence of excision of this region from the mt genome, in the form of a junction fragment associating flanking DNA regions, was detected in fertile restored plants. DNA gel blot hybridization of this mtDNA region, compared with hybridization to related regions of the mitochondrial genome that shared sequence homology, indicated that the mtDNA region associated with sterility was present in lower copy number. These observations, as well as the occurrence of similar or identical rearrangements upon spontaneous cytoplasmic reversion, indicate that the restoration of pollen fertility may be accompanied by loss of an independently replicating subgenomic DNA molecule from the mitochondrial genome. 相似文献
17.
A physical restriction map of the mitochondrial genome from one clone (TCC 854) of the sexually isolated populations (syngens) of the morphologically uniform species Pandorina morum Bory has been constructed using restriction endonucleases Ava I, Bam HI, Bgl II, Eco RI, Kpn I, and Pst I. The 20 kb linear genome can easily be separated from plastid DNA, nuclear satellite rDNA, and main band (nuclear) DNA on a Hoechst/CsCl buoyant density gradient. The Pandorina mitochondrial DNA shows sufficient similarity to the 16 kb mitochondrial genome of Chlamydomonas reinhardtii to cross-hybridize, and also hybridizes with a probe containing maize mitochondrial 18S rRNA genes. Double digests, self-probing, and Bal31 exonuclease experiments suggest that 1.8 to 3.3 kb of sequence is repeated at each end of the genome as an inverted repeat. Mitochondrial genome sizes of other P. morum syngens were found to range from ca. 20 to ca. 38 kb. The mitochondrial genome should be valuable for taxonomic studies; it can be used for comparative organellar studies; and it should be of interest to compare with that of other plant and animal mitochondrial genomes. 相似文献
18.
ANNETTE W. COLEMAN WILLIAM F. THOMPSON LYNDA J. COFF 《The Journal of eukaryotic microbiology》1991,38(2):129-135
ABSTRACT. Analysis of total DNA isolated from the Chrysophyte alga Ochromonas danica revealed, in addition to nuclear DNA, two genomes present as numerous copies per cell. The larger genome (?120 kilobase pairs or kbp) is the plastid DNA, which is identified by its hybridization to plasmids containing sequences for the photosynthesis genes rbcL, psbA, and psbC. The smaller genome (40 kbp) is the mitochondrial genome as identified by its hybridization with plasmids containing gene sequences of plant cytochrome oxidase subunits I and II. Both the 120- and 40-kbp genomes contain genes for the small and large subunits of rDNA. The mitochondrial genome is linear with terminal inverted repeats of about 1.6 kbp. Two other morphologically similar species were examined, Ochromonas minuta and Poteriochromonas malhamensis. All three species have linear mitochondrial DNA of 40 kbp. Comparisons of endonuclease restriction-fragment patterns of the mitochondrial and chloroplast DNAs as well as those of their nuclear rDNA repeats failed to reveal any fragment shared by any two of the species. Likewise, no common fragment size was detected by hybridization with plasmids containing heterologous DNA or with total mitochondrial DNA of O. danica; these observations support the taxonomic assignment of these three organisms to different species. The Ochromonas mitochondrial genomes are the first identified in the chlorophyll a/c group of algae. Combining these results with electron microscopic observations of putative mitochondrial genomes reported for other chromophytes and published molecular studies of other algal groups suggests that all classes of eukaryote algae may have mitochondrial genomes < 100 kbp in size, more like other protistans than land plants. 相似文献
19.
S. E. Wachocki A. B. Bonnema M. A. O'Connell 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1991,81(3):420-427
Summary The organization of the mitochondrial genome in somatic hybrids and cybrids regenerated following fusion of protoplasts from cultivated tomato, Lycopersicon esculentum, and the wild species, L. Pennellii, was compared to assess the role of the nuclear genotype on the inheritance of organellar genomes. No organellar-encoded traits were required for the recorvery of either somatic hybrids or cybrids. The organization of the mitochondrial genome was characterized using Southern hybridization of restriction digestions of total DNA isolated from ten cybrids and ten somatic hybrids. A bank of cosmid clones carrying tomato mitochondrial DNA was used as probes, as well as a putative repeated sequence from L. pennellii mitchondrial DNA. The seven cosmids used to characterize the mitochondrial genomes are predicted to encompass at least 60% of the genome. The frequency of nonparental organizations of the mitochondrial genome was highest with a probe derived from a putative repeat element from the L. pennellii mitochondrial DNA. There was no difference in the average frequency of rearranged mitochondrial sequences in somatic hybrids (12%) versus cybrids (10%), although there were individual cybrids with a very high frequency of novel fragments (30%). The frequency of tomato-specific mtDNA sequences was higher in cybrids (25%) versus somatic hybrids (12%), suggesting a nuclear-cytoplasmic interaction on the inheritance of tomato mitochondrial sequences. 相似文献
20.
Spontaneous and induced revertants obtained from plastome chlorophyll mutants of sunflower were subjected to genetic analysis. The mechanism of reversion (nuclear suppression, plastid suppression, true reversion, or mitochondrial suppression) of the plastid mutation was shown to affect the degree of restoration of morphological and physiological traits of sunflower plants. 相似文献