ISOZYME STUDIES IN Brassica. I. ELECTROPHORETIC TECHNIQUES FOR LEAF ENZYMES AND COMPARISON OF B. napus, B. campestris AND B. oleracea USING PHOSPHOGLUCOMUTASE

Coulthart, Michael B.; Denford, K. E.

doi:10.4141/cjps82-092

Cited by 44 publications

(16 citation statements)

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“…For example, the C genome specific markers (pB 185, pB547, pB845, pB850, and pB870) were shared by all the C-genome basic and derived species, including the wild species classified under the B. oleracea cytodeme. The origin of the amphidiploid species in the triangle of U has been confirmed before by various approaches such as cytogenetics (Prakash and Hinata 1980), nuclear DNA content (Verma and Rees 1974), isozymes (Coulthart and Denford 1982;Quiros et al 1987), proteins (Vaughan 1977, rRNA genes (Quiros et al 1987), chloroplast DNA analysis (Palmer et al 1983;Erickson et al 1983), and artificial resynthesis of hybrids (Olsson Genome Downloaded from www.nrcresearchpress.com by University of Waterloo on 12/03/14…”

Section: Discussionmentioning

confidence: 92%

Development and chromosomal localization of genome-specific DNA markers of Brassica and the evolution of amphidiploids and n = 9 diploid species

Hosaka

Kianian

McGrath

et al. 1990

Genome

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1990. Development and chromosomal localization of genome-specific DNA markers of Brassica and the evolution of amphidiploids and n = 9 diploid species. Genome, 33: 13 1-142. Ten genome-specific probes were developed from Brassica napus and B. oleracea genomic DNA libraries. Selection was based on polymorphism between and limited variation within genomes, permitting their localization on six individual C-genome chromosomes. Chromosome assignment was accomplished by using two sets of B. campestris -oleracea alien addition lines derived from ( i ) B. napus and ( i i ) the artificially synthesized B. napus 'Hakuran'. The presence of shared fragments between A, B, and C genomes indicates partial homology of the three genomes. However, several genome-specific markers could separate these three genomes. Genome-specific clones developed in this study served to confirm the parental diploid species originating the three amphidiploids, B. napus, B. carinata, and B. juncea. At least one clone suggests that B. napus has a polyphyletic origin. These clones were also useful to confirm the close evolutionary proximity among wild species in the B. oleracea cytodeme; however, no clear trends were found to suggest specific wild ancestors for the different B. oleracea horticultural types. Brassica oxyrrhina was distinct from other n = 9 species with most clones tested.

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Section: Discussionmentioning

confidence: 92%

Development and chromosomal localization of genome-specific DNA markers of Brassica and the evolution of amphidiploids and n = 9 diploid species

Hosaka

Kianian

McGrath

et al. 1990

Genome

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“…Isozyme studies suggest that most gene loci inherited from two or more progenitor species are codominant in polyploids (38)(39)(40)(41); there are relatively few examples of redundant gene silencing (42,43). Therefore, nucleolar dominance does not appear to be part of a broader genome silencing phenomenon (10).…”

Section: Discussionmentioning

confidence: 99%

Transcriptional analysis of nucleolar dominance in polyploid plants: Biased expression/silencing of progenitor rRNA genes is developmentally regulated in Brassica

Chen

Pikaard

1997

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

239

206

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Nucleolar dominance is an epigenetic phenomenon that describes the formation of nucleoli around rRNA genes inherited from only one parent in the progeny of an interspecific hybrid. Despite numerous cytogenetic studies, little is known about nucleolar dominance at the level of rRNA gene expression in plants. We used S1 nuclease protection and primer extension assays to define nucleolar dominance at a molecular level in the plant genus Brassica. rRNA transcription start sites were mapped in three diploids and in three allotetraploids (amphidiploids) and one allohexaploid species derived from these diploid progenitors. rRNA transcripts of only one progenitor were detected in vegetative tissues of each polyploid. Dominance was independent of maternal effect, ploidy, or rRNA gene dosage. Natural and newly synthesized amphidiploids yielded the same results, arguing against substantial evolutionary effects. The hypothesis that nucleolar dominance in plants is correlated with physical characteristics of rRNA gene intergenic spacers is not supported in Brassica. Furthermore, in Brassica napus, rRNA genes silenced in vegetative tissues were found to be expressed in all f loral organs, including sepals and petals, arguing against the hypothesis that passage through meiosis is needed to reactivate suppressed genes. Instead, the transition of inf lorescence to f loral meristem appears to be a developmental stage when silenced genes can be derepressed.Ribosomal RNA genes (rRNA genes, rDNA) in eukaryotes are tandemly arrayed in hundreds (to thousands) of copies at chromosomal loci known as nucleolus organizer regions (NORs) (1). Each rRNA gene can be transcribed within the nucleolus by RNA polymerase I to produce a primary transcript that is processed to form the 18S, 5.8S, and 25-27S rRNAs (the size depends on species). To form ribosomes, these RNAs are assembled with 5S rRNA transcribed by RNA polymerase III and Ϸ80 proteins whose mRNAs are transcribed by RNA polymerase II. Because ribosome production directly affects the protein synthetic capacity of the cell, proper regulation of rRNA gene transcription is critical (2-9).The study of rRNA gene regulation in eukaryotes has focused primarily on in vitro analyses of transcriptional activation of individual rRNA genes and the biochemical characterization of transcription factors (6). However, cytogenetic evidence for rRNA gene regulation on a larger scale has accumulated for nearly 70 years on the basis of studies of nucleolar dominance. Nucleolar dominance occurs in organisms as diverse as insects, amphibians, and mammals (10) but was first described in the plant genus Crepis (11-13), followed by studies in Salix, Ribes, Solanum, Hordeum, Avena, Agropyron, Triticum, and Zea, and in intergeneric crosses such as Triticale (wheat ϫ rye; reviewed in refs. 10 and 14). In wheat, changes in the methylation status and DNase I hypersensitivity of dominant and underdominant (the term recessive is inappropriate) rRNA genes suggest that inactive genes are packaged into a transcri...

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“…This close relationship of S. arvensis and B. nigra is strongly supported by several data sets: cytological and hybridization data (Mizushima 1980;Prakash and Hinata 1980); electrophoretic data from seed proteins (Vaughan and Denford 1968); isozyme data (Coulthart and Denford 1982;Simonsen and Heneen 1995); nuclear RFLP data (Song et al 1988), chloroplast DNA restriction site data (Yanagino et al 1987;Warwick and Black 1991); combined analysis of morphological, cytogenetic and isozyme data (Takahata and Hinata 1992); differential abundance of simple repetitive DNA sequences (Poulsen et al 1994); shared presence of three pairs of active nucleolus organizer regions ; and shared presence of genome B specific family of dispersed repeat pBN-4 (Kapila et al 1996b). …”

mentioning

confidence: 82%

The biology of Canadian weeds. 8. Sinapis arvensis. L. (updated)

Warwick¹,

Beckie²,

Thomas³

et al. 2000

Can. J. Plant Sci.

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. An updated review of biological information is provided for Sinapis arvensis L. Native to the Old World, the species is widely introduced and naturalized in temperate regions around the world. The species occurs in all the provinces, the Northwest Territories, and the Yukon. It is an important weed of field crops in the Canadian prairies. A strongly persistent seedbank, competitive annual growth habit and high fecundity all contribute to its weedy nature and ensure that it will be a continuing problem. Several cases of herbicide resistance have been documented for natural populations of S. arvensis in Canada, including biotypes resistant to: i) Group 2 herbicides, which inhibit acetolactate synthase (ALS), from Manitoba in 1992 and Alberta in 1993; ii) Group 4 herbicides or synthetic auxins from Manitoba in 1991; and iii) Group 5 herbicides, which inhibit photosynthesis at photosystem II, from Ontario in 1983. The species is a close relative of Brassica nigra (L.) Koch, black mustard, and is capable of limited genetic exchange with the Brassica crop species under laboratory hybridization conditions either by conventional crossing or with the aid of ovary/embryo recovery techniques.

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ISOZYME STUDIES IN Brassica. I. ELECTROPHORETIC TECHNIQUES FOR LEAF ENZYMES AND COMPARISON OF B. napus, B. campestris AND B. oleracea USING PHOSPHOGLUCOMUTASE

Cited by 44 publications

References 4 publications

Development and chromosomal localization of genome-specific DNA markers of Brassica and the evolution of amphidiploids and n = 9 diploid species

Development and chromosomal localization of genome-specific DNA markers of Brassica and the evolution of amphidiploids and n = 9 diploid species

Transcriptional analysis of nucleolar dominance in polyploid plants: Biased expression/silencing of progenitor rRNA genes is developmentally regulated in Brassica

The biology of Canadian weeds. 8. Sinapis arvensis. L. (updated)

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