Control of Nucleolar Expression in Triticale

Gustafson, J. P.; Flavell, R. B.

doi:10.1007/978-94-009-0329-6_13

Cited by 7 publications

(3 citation statements)

References 7 publications

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“…Since it was first reported (Navashin, 1934), nucleolar dominance has been described in interspecific hybrids in numerous plant species (Pikaard, 2000a(Pikaard, , b, 2003. The same phenomenon was also noted and studied in many allopolyploids, such as Brassica (Chen and Pikaard, 1997b;Pikaard, 1999Pikaard, , 2000a, triticale (Gustafson and Flavell, 1996;Houchins et al, 1997;Neves et al, 1997), and Arabidopsis (Chen et al, 1998;Pikaard, 1999Pikaard, , 2000b. Although the mechanism of nucleolar dominance is still not clear, it is believed to be associated with epigenetic regulation (Pikaard, 2000a(Pikaard, , b, 2003.…”

Section: Altered Gene Expression In Allopolyploidsmentioning

confidence: 94%

Genome evolution of allopolyploids: a process of cytological and genetic diploidization

Ma¹,

Gustafson

2005

Cytogenet Genome Res

176

125

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Allopolyploidy is a prominent mode of speciation in higher plants. Due to the coexistence of closely related genomes, a successful allopolyploid must have the ability to invoke and maintain diploid-like behavior, both cytologically and genetically. Recent studies on natural and synthetic allopolyploids have raised many discrepancies. Most species have displayed non-Mendelian behavior in the allopolyploids, but others have not. Some species have demonstrated rapid genome changes following allopolyploid formation, while others have conserved progenitor genomes. Some have displayed directed, non-random genome changes, whereas others have shown random changes. Some of the genomic changes have appeared in the F₁ hybrids, which have been attributed to the union of gametes from different progenitors, while other changes have occurred during or after genome doubling. Although these observations provide significant novel insights into the evolution of allopolyploids, the overall mechanisms of the event are still elusive. It appears that both genetic and epigenetic operations are involved in the diploidization process of allopolyploids. Overall, genetic and epigenetic variations are often associated with the activities of repetitive sequences and transposon elements. Specifically, genomic sequence elimination and chromosome rearrangement are probably the major forces guiding cytological diploidization. Gene non-functionalization, sub-functionalization, neo-functionalization, as well as other kinds of epigenetic modifications, are likely the leading factors promoting genetic diploidization.

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Section: Altered Gene Expression In Allopolyploidsmentioning

confidence: 94%

Genome evolution of allopolyploids: a process of cytological and genetic diploidization

Ma¹,

Gustafson

2005

Cytogenet Genome Res

176

125

View full text Add to dashboard Cite

show abstract

“…However, how gene expression has been affected is still elusive. Due to its high genome complexity, molecular studies on gene expression lag behind other allopolyploid model species, but changes in gene expression in triticale, compared with parents, have been reported (Lacadena et al, 1984;Somers and Gustafson, 1994;Gustafson and Flavell, 1996;Viegas et al, 1996;Houchins et al, 1997;Neves et al, 1997;Rozynek et al, 1998;Voylokov and Tikhenko, 2002;Leonova et al, 2005). Studies showing variations in cDNA-probed RFLP banding profiles also imply changes in gene expression (Tables 1 and 2).…”

Section: Gene Expression Changes In Triticalementioning

confidence: 99%

Allopolyploidization-accommodated Genomic Sequence Changes in Triticale

Gustafson

2008

Annals of Botany

103

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Molecular studies have indicated extensive non-additive sequence changes or modifications in triticale, and the degree of variation appears to be higher than in other allopolyploid species. The data indicate that at least some sequence changes are non-random, and appear to be a function of genome relations, ploidy levels and sequence types. Specifically, the rye parental genome demonstrated a higher level of changes than the wheat genome. The frequency of lost parental bands was much higher than the frequency of gained novel bands, suggesting that sequence modification and/or elimination might be a major force causing genome variation in triticale. It was also shown that 68 % of the total changes occurred immediately following wide hybridization, but before chromosome doubling. Genome evolution following chromosome doubling occurred more slowly at a very low rate and the changes were mainly observed in the first five or so generations. The data suggest that cytoplasm and relationships between parental genomes are key factors in determining the direction, amount, timing and rate of genomic sequence variation that occurred during inter-generic allopolyploidization in this system.

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“…Cytological observations have shown that the morphology of rye chromosomes is modified when placed into a wheat background (Gustafson 1976;Alkhimova et al 1999). Furthermore, many researchers (Lacadena et al 1984;Somers and Gustafson 1994;Gustafson and Flavell 1996;Viegas et al 1996;Houchins et al 1997;Neves et al 1997;Rozynek et al 1998) have reported the changes of rye gene expression in triticale.…”

Section: Introductionmentioning

confidence: 99%

Polyploidization-induced genome variation in triticale

Ma¹,

Peng²,

Gustafson³

2004

Genome

110

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Polyploidization-induced genome variation in triticale (x Triticosecale Wittmack) was investigated using both AFLP and RFLP analyses. The AFLP analyses were implemented with both EcoRI-MseI (E-M) and PstI-MseI (P-M) primer combinations, which, because of their relative differences in sensitivity to cytosine methylation, primarily amplify repetitive and low-copy sequences, respectively. The results showed that the genomic sequences in triticale involved a great degree of variation including both repetitive and low-copy sequences. The frequency of losing parental bands was much higher than the frequency of gaining novel bands, suggesting that sequence elimination might be a major force causing genome variation in triticale. In all cases, variation in E-M primer-amplified parental bands was more frequent in triticale than that using P-M primers, suggesting that repetitive sequences were more involved in variation than low-copy sequences. The data also showed that the wheat (Triticum spp.) genomes were relatively highly conserved in triticales, especially in octoploid triticales, whereas the rye (Secale cereale L.) genome consistently demonstrated a very high level of genomic sequence variation (68%-72%) regardless of the triticale ploidy levels or primers used. In addition, when a parental AFLP band was present in both wheat and rye, the tendency of the AFLP band to be present in triticale was much higher than when it was present in only one of the progenitors. Furthermore, the cDNA-probed RFLP analyses showed that over 97% of the wheat coding sequences were maintained in triticale, whereas only about 61.6% of the rye coding sequences were maintained, suggesting that the rye genome variation in triticale also involved a high degree of rye coding sequence changes. The data also suggested that concerted evolution might occur in the genomic sequences of triticale. In addition, the observed genome variation in wheat-rye addition lines was similar to that in triticale, suggesting that wheat-rye addition lines can be used to thoroughly study the genome evolution of polyploid triticale.

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Control of Nucleolar Expression in Triticale

Cited by 7 publications

References 7 publications

Genome evolution of allopolyploids: a process of cytological and genetic diploidization

Genome evolution of allopolyploids: a process of cytological and genetic diploidization

Allopolyploidization-accommodated Genomic Sequence Changes in Triticale

Polyploidization-induced genome variation in triticale

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