Interspecific nuclear–cytoplasmic compatibility controlled by genes on group 1 chromosomes in durum wheat

Genome ◽  
1995 ◽  
Vol 38 (4) ◽  
pp. 803-808 ◽  
Author(s):  
J. A. Anderson ◽  
S. S. Maan

Triticum longissimum cytoplasm is incompatible with the T. turgidum nuclear genome. Two nuclear genes, scs and Vi, derived from the nuclear genome of T. timopheevii and by a spontaneous mutation, respectively, restore nuclear–cytoplasmic compatibility, normal plant vigor, and male fertility in these alloplasmic genotypes. The objectives of this study were (i) to determine the chromosomal locations of scs and Vi; (ii) to identify DNA markers for scs and Vi; and (iii) to determine the interactions involving the dosage of scs and Vi. Two populations segregating for scs and Vi were produced and scored for seedling vigor (indicating presence of scs) and degree of self-fertility (indicating presence of Vi). Four RFLP markers were mapped near scs. Aneuploid analysis revealed that these markers, and hence the scs gene, are located on the long arm of chromosome 1A. Four RFLP markers were mapped near Vi on 1BS. Results indicated that other factors may be inhibiting the expression of Vi. We determined the dosage of scs and Vi in both populations with the aid of the linked RFLP markers. Individuals with two versus one dose of scs had reduced self-fertility, while individuals with two versus one dose of Vi had similar self-fertility.Key words: scs, Vi, Triticum, nucleocytoplasmic compatibility, RFLP.


Genome ◽  
1994 ◽  
Vol 37 (6) ◽  
pp. 1056-1061 ◽  
Author(s):  
M. G. Francki ◽  
P. Langridge

The diminutive "midget" chromosome is found in plants containing a wheat nuclear genome with a substituted rye cytoplasm. This cytoplasmic substituted line arose during successive backcrossing of a wheat/rye amphiploid to wheat as the recurrent male parent. Southern and in situ hybridization with a dispersed repeat sequence specific for rye, R173, indicates that the midget chromosome originates from within the rye genome. Various DNA markers previously mapped to group 1 chromosomes of wheat and barley were used to trace the origin of the midget chromosome from within the rye genome. Ten short arm and 36 long arm probes were used and one marker was identified, which hybridizes to the midget chromosome and maps to the proximal region of the long arm of chromosome 1R. An additional marker was generated from a genomic library of the line containing the midget chromosome. This also maps to the long arm of 1R. The results indicate that the midget chromosome contains a small segment of the long arm of chromosome 1R.Key words: midget chromosome, RFLP markers, chromosome 1R, repeated DNA sequence.



Genetics ◽  
2001 ◽  
Vol 157 (4) ◽  
pp. 1735-1747 ◽  
Author(s):  
Devinder Sandhu ◽  
Julie A Champoux ◽  
Svetlana N Bondareva ◽  
Kulvinder S Gill

AbstractThe short arm of Triticeae homeologous group 1 chromosomes is known to contain many agronomically important genes. The objectives of this study were to physically localize gene-containing regions of the group 1 short arm, enrich these regions with markers, and study the distribution of genes and recombination. We focused on the major gene-rich region (“1S0.8 region”) and identified 75 useful genes along with 93 RFLP markers by comparing 35 different maps of Poaceae species. The RFLP markers were tested by gel blot DNA analysis of wheat group 1 nullisomic-tetrasomic lines, ditelosomic lines, and four single-break deletion lines for chromosome arm 1BS. Seventy-three of the 93 markers mapped to group 1 and detected 91 loci on chromosome 1B. Fifty-one of these markers mapped to two major gene-rich regions physically encompassing 14% of the short arm. Forty-one marker loci mapped to the 1S0.8 region and 10 to 1S0.5 region. Two cDNA markers mapped in the centromeric region and the remaining 24 loci were on the long arm. About 82% of short arm recombination was observed in the 1S0.8 region and 17% in the 1S0.5 region. Less than 1% recombination was observed for the remaining 85% of the physical arm length.



Genome ◽  
1995 ◽  
Vol 38 (1) ◽  
pp. 45-59 ◽  
Author(s):  
A. E. Van Deynze ◽  
J. Dubcovsky ◽  
K. S. Gill ◽  
J. C. Nelson ◽  
M. E. Sorrells ◽  
...  

Group 1 chromosomes of the Triticeae tribe have been studied extensively because many important genes have been assigned to them. In this paper, chromosome 1 linkage maps of Triticum aestivum, T. tauschii, and T. monococcum are compared with existing barley and rye maps to develop a consensus map for Triticeae species and thus facilitate the mapping of agronomic genes in this tribe. The consensus map that was developed consists of 14 agronomically important genes, 17 DNA markers that were derived from known-function clones, and 76 DNA markers derived from anonymous clones. There are 12 inconsistencies in the order of markers among seven wheat, four barley, and two rye maps. A comparison of the Triticeae group 1 chromosome consensus map with linkage maps of homoeologous chromosomes in rice indicates that the linkage maps for the long arm and the proximal portion of the short arm of group 1 chromosomes are conserved among these species. Similarly, gene order is conserved between Triticeae chromosome 1 and its homoeologous chromosome in oat. The location of the centromere in rice and oat chromosomes is estimated from its position in homoeologous group 1 chromosomes of Triticeae.Key words: Triticeae, RFLP, consensus, comparative.



2020 ◽  
Author(s):  
Jingping Fang ◽  
Andrew Wood ◽  
Youqiang Chen ◽  
Jingjing Yue ◽  
Ray Ming

Abstract Background: The safety of genetically transformed plants remains a subject of scrutiny. Genomic variants in PRSV resistant transgenic papaya will provide evidence to rationally address such concerns. Results: In this study, a total of more than 74 million Illumina reads for progenitor ‘Sunset’ were mapped onto transgenic papaya ‘SunUp’ reference genome. 310,364 single nucleotide polymorphisms (SNPs), 34,071 small Inserts/deletions (InDels) and 1,200 large structural variations (SVs) were detected between ‘Sunset’ and ‘SunUp’. Those variations have an uneven distribution across nine chromosomes in papaya. Only 0.27% of mutations were predicted to be high-impact mutations. ATP-related categories were highly enriched among these high-impact genes. The SNP mutation rate was about 8.4×10-4 per site, comparable with the rate induced by spontaneous mutation over numerous generations. The transition-to-transversion ratio was 1.439 and the predominant mutations were C/G to T/A transitions. Spontaneous mutations were the leading cause of SNPs in transgenic papaya ‘SunUp’. A total of 3,430 nuclear plastid DNA (NUPT) and 2,764 nuclear mitochondrial DNA (NUMT) junction sites have been found in ‘SunUp’, which is proportionally higher than the predicted total NUPT and NUMT junction sites in ‘Sunset’ (3,346 and 2,745, respectively). Among all nuclear organelle DNA (norgDNA) junction sites, 96% of junction sites were shared by ‘SunUp’ and ‘Sunset’. The average identity between ‘SunUp’ specific norgDNA and corresponding organelle genomes was higher than that of norgDNA shared by ‘SunUp’ and ‘Sunset’. Six ‘SunUp’ organelle-like borders of transgenic insertions were nearly identical to corresponding sequences in organelle genomes (98.18~100%). None of the paired-end spans of mapped ‘Sunset’ reads were elongated by any ‘SunUp’ transformation plasmid derived inserts. Significant amounts of DNA were transferred from organelles to the nuclear genome during bombardment, including the six flanking sequences of the three transgenic insertions.Conclusions: Comparative whole-genome analyses between ‘SunUp’ and ‘Sunset’ provide a reliable estimate of genome-wide variations and evidence of organelle-to-nucleus transfer of DNA associated with biolistic transformation.



2015 ◽  
Author(s):  
Rob W Ness ◽  
Susanne A Kraemer ◽  
Nick Colegrave ◽  
Peter D Keightley

Plastids perform crucial cellular functions, including photosynthesis, across a wide variety of eukaryotes. Since endosymbiosis, plastids have maintained independent genomes that now display a wide diversity of gene content, genome structure, gene regulation mechanisms, and transmission modes. The evolution of plastid genomes depends on an input ofde novomutation, but our knowledge of mutation in the plastid is limited to indirect inference from patterns of DNA divergence between species. Here, we use a mutation accumulation experiment, where selection acting on mutations is rendered ineffective, combined with whole-plastid genome sequencing to directly characterize de novo mutation inChlamydomonas reinhardtii. We show that the mutation rates of the plastid and nuclear genomes are similar, but that the base spectra of mutations differ significantly. We integrate our measure of the mutation rate with a population genomic dataset of 20 individuals, and show that the plastid genome is subject to substantially stronger genetic drift than the nuclear genome. We also show that high levels of linkage disequilibrium in the plastid genome are not due to restricted recombination, but are instead a consequence of increased genetic drift. One likely explanation for increased drift in the plastid genome is that there are stronger effects of genetic hitchhiking. The presence of recombination in the plastid is consistent with laboratory studies inC. reinhardtiiand demonstrates that although the plastid genome is thought to be uniparentally inherited, it recombines in nature at a rate similar to the nuclear genome.



2019 ◽  
Author(s):  
Jingping Fang ◽  
Andrew Wood ◽  
Youqiang Chen ◽  
Jingjing Yue ◽  
Ray Ming

Abstract The safety of genetically transformed plants remains a subject of scrutiny. Genomic variants in PRSV resistant transgenic papaya will provide evidence to rationally address such concerns. In this study, a total of more than 74 million Illumina reads for progenitor ‘Sunset’ were mapped onto transgenic papaya ‘SunUp’ reference genome. 310,364 single nucleotide polymorphisms (SNPs), 34,071 Small Inserts/deletions (InDels) and 1,200 large structural variations (SVs) were detected between ‘Sunset’ and ‘SunUp’. Those variations have an uneven distribution across nine chromosomes in papaya. Only 0.27% of mutations were predicted to be high-impact mutations. ATP-related categories were highly enriched among these high-impact genes. The SNP mutation rate was about 8.4×10 -4 per site, comparable with the rate induced by spontaneous mutation over numerous generations. The transition-to-transversion ratio was 1.439 and the predominant mutations were C/G to T/A transitions. Spontaneous mutations were the leading cause of SNPs in transgenic papaya ‘SunUp’. A total of 3,430 nuclear plastid DNA (NUPT) and 2,764 nuclear mitochondrial DNA (NUMT) junction sites have been found in ‘SunUp’, which is proportionally higher than the predicted total NUPT and NUMT junction sites in ‘Sunset’ (3,346 and 2,745, respectively). Among all nuclear organelle DNA (norgDNA) junction sites, 96% of junction sites were shared by ‘SunUp’ and ‘Sunset’. The average identity between ‘SunUp’ specific norgDNA and corresponding organelle genomes was higher than that of norgDNA shared by ‘SunUp’ and ‘Sunset’. Six ‘SunUp’ organelle-like borders of transgenic insertions were nearly identical to corresponding sequences in organelle genomes (98.18~100%). None of the paired-end spans of mapped ‘Sunset’ reads were elongated by any ‘SunUp’ transformation plasmid derived inserts. Significant amounts of DNA were transferred from organelles to the nuclear genome during bombardment, including the six flanking sequences of the three transgenic insertions. Comparative whole-genome analyses between ‘SunUp’ and ‘Sunset’ provide a reliable estimate of genome-wide variations and evidence of organelle-to-nucleus transfer of DNA associated with biolistic transformation.



1988 ◽  
Vol 214 (3) ◽  
pp. 541-546 ◽  
Author(s):  
Luis Gomez ◽  
Rosa Sanchez-Monge ◽  
Gabriel Salcedo


Genome ◽  
1995 ◽  
Vol 38 (1) ◽  
pp. 75-83 ◽  
Author(s):  
Enrique Autrique ◽  
Steven D. Tanksley ◽  
Mark E. Sorrells ◽  
Ravi P. Singh

Near-isolines carrying four different genes for resistance to leaf rust were used to find linked molecular markers for these genes. Clones used to detect polymorphism were selected on the basis of the reported chromosomal location of the resistance genes. Both Lophopyron-derived resistance genes, Lr19 and Lr24, cosegregated with eight molecular markers assigned to chromosomes 7DL and 3DL, respectively. One clone cosegregated with Lr9 and two closely linked RFLP markers were found for Lr32, mapping at 3.3 ± 2.6 and 6.9 ± 3.6 cM from the resistance gene. The Lophopyron-chromatin segment in isolines carrying chromosomes 7E (Lr19) and 3E (Lr24) replaced a large portion of chromosome 7D and the distal portion of chromosome 3D, respectively. Clones assigned to these chromosomes on the basis of aneuploid analysis hybridized to 7E and 3E segments, thus confirming cytological results that these introgressed segments represent homoeologous chromosomes. The linked RFLP markers could be used to identify the resistance genes and generate new combinations in breeding populations, especially in the absence of disease in the environment or when virulence is lacking.Key words: leaf rust, RFLP, Lophopyron, gene tagging, wheat, Aegilops umbellulata, Triticum tauschii.



Genome ◽  
1996 ◽  
Vol 39 (2) ◽  
pp. 395-403 ◽  
Author(s):  
Edilberto D. Redoña ◽  
David J. Mackill

Rice (Oryza sativa L.) molecular maps have previously been constructed using interspecific crosses or crosses between the two major subspecies: indica and japonica. For japonica breeding programs, however, it would be more suitable to use intrasubspecific crosses. A linkage map of 129 random amplified polymorphic DNA (RAPD) and 18 restriction fragment length polymorphism (RFLP) markers was developed using 118 F2 plants derived from a cross between two japonica cultivars with high and low seedling vigor, Italica Livorno (IL) and Labelle (LBL), respectively. The map spanned 980.5 cM (Kosambi function) with markers on all 12 rice chromosomes and an average distance of 7.6 cM between markers. Codominant (RFLP) and coupling phase linkages (among RAPDs) accounted for 79% of total map length and 71% of all intervals. This map contained a greater percentage of markers on chromosome 10, the least marked of the 12 rice chromosomes, than other rice molecular maps, but had relatively fewer markers on chromosomes 1 and 2. We used this map to detect quantitative trait loci (QTL) for four seedling vigor related traits scored on 113 F3 families in a growth chamber slantboard test at 18 °C. Two coleoptile, five root, and five mesocotyl length QTLs, each accounting for 9–50% of the phenotypic variation, were identified by interval analysis. Single-point analysis confirmed interval mapping results and detected additional markers significantly influencing each trait. About two-thirds of alleles positive for the putative QTLs were from the high-vigor parent, IL. One RAPD marker (OPAD13720) was associated with a IL allele that accounted for 18.5% of the phenotypic variation for shoot length, the most important determinant of seedling vigor in water-seeded rice. Results indicate that RAPDs are useful for map development and QTL mapping in rice populations with narrow genetic base, such as those derived from crosses among japonica cultivars. Other potential uses of the map are discussed. Key words : QTL mapping, RAPD, RFLP, seedling vigor, japonica, Oryza sativa.



1983 ◽  
Vol 67 (1) ◽  
pp. 53-58 ◽  
Author(s):  
H. M. Stinissen ◽  
W. J. Peumans ◽  
C. N. Law ◽  
P. I. Payne


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