The molecular basis of genetic diversity among cytoplasms of Triticum and Aegilops

Terachi, Toru; Ogihara, Yasunari; Tsunewaki, Koichiro

doi:10.1007/bf00210074

Cited by 43 publications

(8 citation statements)

References 24 publications

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“…The proportion of variable bands differed from region to region and was the highest in the 3Ј flanking region of rbcL, in which 18 of 22 bands (81.8%) detected were variable. The high level of variation in this region was consistent with the high variation among nucleotide sequences in the same region (7,10). On the other hand, no variation was detected in the psbB region.…”

Section: Variations Detected By Sscp Analyses Of Ct and Mtdnassupporting

confidence: 80%

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Plasmon analyses of Triticum (wheat) and Aegilops : PCR–single-strand conformational polymorphism (PCR-SSCP) analyses of organellar DNAs

Wang

Miyashita

Tsunewaki

1997

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

116

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To investigate phylogenetic relationships among plasmons in Triticum and Aegilops, PCR-single-strand conformational polymorphism (PCR-SSCP) analyses were made of 14.0-kb chloroplast (ct) and 13.7-kb mitochondrial (mt)DNA regions that were isolated from 46 alloplasmic wheat lines and one euplasmic line. These plasmons represent 31 species of the two genera. The ct and mtDNA regions included 10 and 9 structural genes, respectively. A total of 177 bands were detected, of which 40.6% were variable. The proportion of variable bands in ctDNA (51.1%) was higher than that of mtDNA (28.9%). The phylogenetic trees of plasmons, derived by two different models, indicate a common picture of plasmon divergence in the two genera and suggest three major groups of plasmons (Einkorn, Triticum, and Aegilops). Because of uniparental plasmon transmission, the maternal parents of all but one polyploid species were identified. Only one Aegilops species, Ae. speltoides, was included in the Triticum group, suggesting that this species is the plasmon and B and G genome donor of all polyploid wheats. ctDNA variations were more intimately correlated with vegetative characters, whereas mtDNA variations were more closely correlated with reproductive characters. Plasmon divergence among the diploids of the two genera largely paralleled genome divergence. The relative times of origin of the polyploid species were inferred from genetic distances from their putative maternal parents.Genetic diversity among plasmons within two genera, Triticum and Aegilops, was first reported by Kihara (1). On producing alloplasmic lines of common wheat (2n ϭ 6x ϭ 42, nuclear genome AABBDD), and then tracking plasmon-specific phenotypic variations, we were able to classify the plasmons of Triticum and Aegilops species into 16 types (2). The next logical step was to identify molecular variation of their organellar DNAs. First, the discovery of RFLP (restriction fragment length polymorphism) variation among ct and mtDNAs was reported (3). Second, physical maps of common wheat ctDNA were constructed by using three restriction enzymes (4). The ctDNA maps were refined by using 13 restriction enzymes, after which we discovered that the chloroplast genomes of 33 Triticum and Aegilops species fell into 16 types (5). Eventually, RFLP analyses of mtDNAs from 17 species allowed us to distinguish their mitochondrial genomes from each other (6). Even though sequencing analyses are not as thorough as the RFLP analyses, the sequence of one chloroplast gene (rbcL, for the Rubisco large subunit) from seven Triticum and Aegilops species indicated that Ae. speltoides is the donor of both the plasmon and B genome of common wheat (7).Although RFLP and sequencing analyses have been employed, sequencing lags behind. RFLP analyses are relatively easy but are insensitive to fine-structure variation. Sequencing is the ultimate way to detect variation, but it is cumbersome when applied to large numbers of species and DNA regions. This paper reports a new technique, PCR-single-stran...

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Section: Variations Detected By Sscp Analyses Of Ct and Mtdnassupporting

confidence: 80%

“…Even though sequencing analyses are not as thorough as the RFLP analyses, the sequence of one chloroplast gene (rbcL, for the Rubisco large subunit) from seven Triticum and Aegilops species indicated that Ae. speltoides is the donor of both the plasmon and B genome of common wheat (7).…”

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confidence: 99%

Plasmon analyses of Triticum (wheat) and Aegilops : PCR–single-strand conformational polymorphism (PCR-SSCP) analyses of organellar DNAs

Wang

Miyashita

Tsunewaki

1997

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

116

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“…These characters have been extensively used in studying phylogenetic relationships (Chowdhury and Smith, 1988;Wang et al, 2000;Yang et al, 1998), exploring plant geographic distribution (Tozuka et al, 1998), and evaluating mtDNA variation and diversity (Muza et al, 1995;Terachi et al, 1990). It is distinguished from nuclear DNA by many unique characteristics, including a relatively higher mutation rate, simple structure, fast evolution, and genetic independence.…”

Section: Genetic Diversity and Classification Of Cytoplasm Of Chinesementioning

confidence: 99%

Genetic Diversity and Classification of Cytoplasm of Chinese Elite Foxtail Millet [Setaria italica (L.) P. Beauv.] Germplasm

Liu

Ting

et al. 2014

Crop Science

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A single cytoplasmic source of foxtail millet male sterile lines has become a major limiting factor for wide utilization of heterosis in foxtail millet. To explore genetic diversity of Chinese foxtail millet cytoplasm, 23 pairs of mitochondrial DNA (mtDNA) primers that showed a high level of polymorphism among selected 14 genetically diverse foxtail millet accessions were identified after screening 34 pairs of consensus mtDNA primers that were derived from various plant species. The 23 pairs of primers were used to analyze genetic diversity of cytoplasm in 111 Chinese elite foxtail millet accessions. Genetic similarity coefficients for differentiation of cytoplasmic types were calculated based on the phylogenetic tree and female‐parent‐derived pedigree graph of all the tested accessions. The results show that the genetic diversity of foxtail millet cytoplasm is low, which makes Chinese foxtail millet germplasm vulnerable to the infection by cytoplasm‐related diseases. The 111 tested accessions can be classified into eight cytoplasmic types: Qinyuanmujizui, Huangruangu, Riben60ri, Dahuanggu, Yingsuigu, Heizhigu, MissingI, and MissingII. The eight cytoplasmic types matched with the geographic and ecological distribution pattern of the most tested accessions. The results provided a scientific foundation for rationally utilizing these germplasm lines, diversifying cytoplasmic types in male sterile lines, and further improving hybrid foxtail millet cultivars.

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“…speltoides Tausch was the most likely diploid species for the donor of BB and GG genomes. This idea was supported by RFLP analyses of chloroplast DNA (Ogiwara and Tsunewaki 1988;Miyashita et al 1994;Wang et al 1997;Yamane and Kawahara 2005), mitochondrial DNA (Terachi et al 1990) and nuclear polymorphic DNA (Dvorak and Zhang 1990;Mori et al 1995;Sasanuma et al 1996;Huang et al 2002). Previous studies suggested that T. timopheevii ssp.…”

Section: Introductionmentioning

confidence: 85%

Divergent evolution of wild and cultivated subspecies of Triticum timopheevii as revealed by the study of PolA1 gene

Takahashi

Rai

Kato

et al. 2009

Genet Resour Crop Evol

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Triticum timopheevii (genome symbol AAGG) comprises two subspecies, cultivated ssp. timopheevii, and wild ssp. armeniacum. These two subspecies are considered as allotetraploids of AA genome from Triticum diploid species and SS genome from Aegilops species. The difference in genome symbol (G vs. S) is due to wide genetic variations among four SS genome species, Ae. bicornis, Ae. longissima, Ae. searsii, and Ae. speltoides. In order to study the origin of T. timopheevii, we compared 19th intron (PI19) sequence of the PolA1 gene, encoding the largest subunit of RNA polymerase I. Two different sized DNA fragments containing PI19 sequences (PI19A and PI19G) were amplified both in ssp. timopheevii and ssp. armeniacum. Shorter PI19A (112 bp) sequences of both subspecies were identical to PI19 sequences of two AA species, T. monococcum and T. urartu. Interestingly, the longer PI19G (241-243 bp) sequences of ssp. armeniacum showed more similarity to PI19 sequences of Ae. speltoides whereas ssp. timopheevii showed more similarity to PI19 sequences of other three SS genome species. The results indicated that two subspecies of T. timopheevii, ssp. armeniacum or ssp. timopheevii, might have arisen independently by allotetraploidization of AA genome with Ae. speltoides or one of the remaining three Aegilops species, respectively.

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The molecular basis of genetic diversity among cytoplasms of Triticum and Aegilops

Cited by 43 publications

References 24 publications

Plasmon analyses of Triticum (wheat) and Aegilops : PCR–single-strand conformational polymorphism (PCR-SSCP) analyses of organellar DNAs

Plasmon analyses of Triticum (wheat) and Aegilops : PCR–single-strand conformational polymorphism (PCR-SSCP) analyses of organellar DNAs

Genetic Diversity and Classification of Cytoplasm of Chinese Elite Foxtail Millet [Setaria italica (L.) P. Beauv.] Germplasm

Divergent evolution of wild and cultivated subspecies of Triticum timopheevii as revealed by the study of PolA1 gene

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