Aphid feeding response and microsatellite-based genetic diversity among diploid Brachypodium distachyon (L.) Beauv accessions

2009 ◽  
Vol 7 (1) ◽  
pp. 72-79 ◽  
Author(s):  
Perumal Azhaguvel ◽  
Wanlong Li ◽  
Jackie C. Rudd ◽  
Bikram S. Gill ◽  
G. J. Michels ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Common Wheat ◽  
Dna Sequences ◽  
Expressed Sequence Tag ◽  
Brachypodium Distachyon ◽  
Aegilops Tauschii ◽  
Cereal Aphid ◽  
D Genome ◽  
Geographical Distances ◽  
Brome Grass

False brome grass, Brachypodium distachyon (L.) Beauv, has been proposed as a new model species to bridge rice and temperate cereal crops for genomics research. However, much basic information for this species is still lacking. In this study, six diploid B. distachyon (2n = 2x = 10) accessions (Bd1-1, Bd2-3, Bd3-1, Bd18-1, Bd21 and BD29) were evaluated for their response to infestation by two cereal aphid pests of common wheat (Triticum aestivum L.): the greenbug, Schizaphis graminum Rondani, and the Russian wheat aphid (RWA), Diuraphis noxia Mordvilko. Through database mining of B. distachyon expressed sequence tag (EST) and genomic DNA sequences, 160 EST- and 21 genomic microsatellite markers were developed and used to evaluate genetic diversity among the B. distachyon accessions. All six accessions were resistant to RWA biotype RWA1 but showed distinct responses to feeding by greenbug biotypes C and E, as well as RWA2 RWAs. Although microsatellite-based genetic diversity among different accessions was generally low, Bd1-1 and BD29 were the most diverged from the other four lines. The genetic divergence was correlated with geographical distances between the Brachypodium accessions. Comparison of simple sequence repeat polymorphisms in three inbred lines (Bd2-3, Bd3-1 and Bd18-1) with their respective original parental lines revealed no effect of inbreeding on genetic diversity. Phylogenetic analysis suggested that Aegilops tauschii (Coss.) Schmal., the D genome donor of common wheat, was closer to B. distachyon than to rice. The greenbug - B. distachyon system seems to be a model of choice for plant–aphid interaction studies in the grass genome.

scholarly journals Systematic Comparisons of Orthologous Selenocysteine Methyltransferase and Homocysteine Methyltransferase Genes from Seven Monocots Species

2015 ◽  
Vol 7 (2) ◽  
pp. 210-216 ◽  
Author(s):  
De-yong ZHAO ◽  
Fu-lai SUN ◽  
Bo ZHANG ◽  
Zhi-qiang ZHANG ◽  
Long-quan YIN
Keyword(s):  
Common Wheat ◽  
Brachypodium Distachyon ◽  
Aegilops Tauschii ◽  
Selenium Deficiency ◽  
D Genome ◽  
Genome Donor ◽  
A Genome ◽  
Selenocysteine Methyltransferase ◽  
Homocysteine Methyltransferase ◽  
Plant Arabidopsis Thaliana

Identifying and manipulating genes underlying selenium metabolism could be helpful for increasing selenium content in crop grain, which is an important way to overcome diseases resulted from selenium deficiency. A reciprocal smallest distance algorithm (RSD) approach was applied using two experimentally confirmed Homocysteine S-Methyltransferases genes (HMT1 and HMT2) and a putative Selenocysteine Methyltransferase (SMT) from dicots plant Arabidopsis thaliana, to explore their orthologs in seven sequenced diploid monocot species: Oryza sativa, Zea mays, Sorghum bicolor, Brachypodium distachyon, Hordeum vulgare, Aegilops tauschii (the D-genome donor of common wheat) and Triticum urartu (the A-genome donor of common wheat). HMT1 was apparently diverged from HMT2 and most of SMT orthologs were the same with that of HMT2 in this study, leading to the hypothesis that SMT and HMT originate from one common ancestor gene. Identifying orthologs provide candidates for further experimental confirmation; also it could be helpful in designing primers to clone SMT or HMT orthologs in other crops.

scholarly journals Empirical verification of heterogeneous DNA fragments generated from wheat genome-specific SSR primers

2008 ◽  
Vol 88 (6) ◽  
pp. 1065-1071 ◽  
Author(s):  
Qijiao Chen ◽  
Lianquan Zhang ◽  
Zhongwei Yuan ◽  
Zehong Yan ◽  
Youliang Zheng ◽  
...  
Keyword(s):  
Common Wheat ◽  
Hexaploid Wheat ◽  
Chinese Spring ◽  
Triticum Turgidum ◽  
Sequence Data ◽  
Aegilops Tauschii ◽  
Single Locus ◽  
Synthetic Hexaploid Wheat ◽  
D Genome ◽  
Synthetic Hexaploid

Due to the high polymorphisms between synthetic hexaploid wheat (SHW) and common wheat, SHW has been widely used in genetic studies. The transferability of simple sequence repeats (SSR) among common wheat and its donor species, Triticum turgidum and Aegilops tauschii, and their SHW suggested the possibility that some SSRs, specific for a single locus in common wheat, might appear in two or more loci in SHWs. This is an important genetic issue when using synthetic hexaploid wheat population and SSR for mapping. However, it is largely ignored and never empirically well verified. The present study addressed this issue by using the well-studied SSR marker Xgwm261 as an example. The Xgwm261 produced a 192 bp fragment specific to chromosome 2D in common wheat Chinese Spring, but generated a 176 bp fragment in the D genome of Ae. tauschii AS60. Chromosomal location and DNA sequence data revealed that the176 bp fragment also donated by 2B chromosome of durum wheat Langdon. These results indicated that although a single 176 bp fragment was appeared in synthetic hexaploid wheat Syn-SAU-5 between Langdon and AS60, the fragment contained two different loci, one from chromosome 2D of AS60 and the other from 2B of Langdon which were confirmed by the segregating analysis of SSR Xgwm261 in 185 plants from a F2 population between Syn-SAU-5 and Chinese Spring. If Xgwm261 in Syn-SAU-5 was considered as a single locus in genetic analysis, distorted segregation or incorrect conclusions would be yielded. A proposed strategy to avoid this problem is to include SHW’s parental T. turgidum and Ae. tauschii in SSR analysis as control for polymorphism detection. Key words: Synthetic hexaploid wheat, microsatellite, segregation distortion, Xgwm261, transferability

Comparative assessment of SCoT and ISSR markers for analysis of genetic diversity and population structure in some Aegilops tauschii Coss. accessions

2021 ◽  
pp. 1-9
Author(s):  
Atefeh Nouri ◽  
Maryam Golabadi ◽  
Alireza Etminan ◽  
Abdolmajid Rezaei ◽  
Ali Ashraf Mehrabi
Keyword(s):  
Genetic Diversity ◽  
Population Structure ◽  
Aegilops Tauschii ◽  
Inter Simple Sequence Repeat ◽  
Issr Markers ◽  
Start Codon ◽  
D Genome ◽  
Breeding Programmes ◽  
High Level ◽  
Effective Multiplex Ratio

Abstract Aegilops tauschii, the diploid progenitor of the wheat D-genome, is a valuable genetic resource for wheat breeders. In this study, we compared the efficiency of inter-simple sequence repeat (ISSR) (as an arbitrary technique) and start codon targeted (SCoT) (as a gene-targeting technique) markers in determining the genetic diversity and population structure of 90 accessions of Ae. tauschii. SCoT markers indicated the highest values for polymorphism information content, marker index and effective multiplex ratio compared to ISSR markers. The total genetic diversity (Ht) and genetic diversity within populations (Hs) parameters were comparably modest for the two marker systems. The results of the analysis of molecular variance showed that the genetic variation within populations was significantly higher than among them (ISSR: 92 versus 8%; SCoT: 88 versus 12%). Furthermore, SCoT markers discovered a high level of genetic differentiation among populations than ISSRs (0.19 versus 0.05), while the amount of gene flow detected by ISSR was higher than SCoT (2.13 versus 8.62). Cluster analysis and population structure of SCoT and ISSR data divided all investigated accessions into two and four main clusters, respectively. Our results revealed that SCoT and ISSR fingerprinting could be used to further molecular analysis in Ae. tauschii and other wild species. The high-genetic variability found in this study also indicates the valuable genetic potential present in the investigated Ae. tauschii germplasm, which could be utilized for future genetic analysis and linkage mapping in breeding programmes.

scholarly journals Genome comparisons reveal a dominant mechanism of chromosome number reduction in grasses and accelerated genome evolution in Triticeae

2009 ◽  
Vol 106 (37) ◽  
pp. 15780-15785 ◽  
Author(s):  
M. C. Luo ◽  
K. R. Deal ◽  
E. D. Akhunov ◽  
A. R. Akhunova ◽  
O. D. Anderson ◽  
...  
Keyword(s):  
Chromosome Number ◽  
Genome Evolution ◽  
Expressed Sequence Tag ◽  
Aegilops Tauschii ◽  
Basic Chromosome Number ◽  
Gene Location ◽  
D Genome ◽  
Dominant Mechanism ◽  
Basic Chromosome ◽  
Genome Comparisons

Single-nucleotide polymorphism was used in the construction of an expressed sequence tag map of Aegilops tauschii, the diploid source of the wheat D genome. Comparisons of the map with the rice and sorghum genome sequences revealed 50 inversions and translocations; 2, 8, and 40 were assigned respectively to the rice, sorghum, and Ae. tauschii lineages, showing greatly accelerated genome evolution in the large Triticeae genomes. The reduction of the basic chromosome number from 12 to 7 in the Triticeae has taken place by a process during which an entire chromosome is inserted by its telomeres into a break in the centromeric region of another chromosome. The original centromere–telomere polarity of the chromosome arms is maintained in the new chromosome. An intrachromosomal telomere–telomere fusion resulting in a pericentric translocation of a chromosome segment or an entire arm accompanied or preceded the chromosome insertion in some instances. Insertional dysploidy has been recorded in three grass subfamilies and appears to be the dominant mechanism of basic chromosome number reduction in grasses. A total of 64% and 66% of Ae. tauschii genes were syntenic with sorghum and rice genes, respectively. Synteny was reduced in the vicinity of the termini of modern Ae. tauschii chromosomes but not in the vicinity of the ancient termini embedded in the Ae. tauschii chromosomes, suggesting that the dependence of synteny erosion on gene location along the centromere–telomere axis either evolved recently in the Triticeae phylogenetic lineage or its evolution was recently accelerated.

Genetic diversity and gene-pool subdivisions of diploid D-genome Aegilops tauschii Coss. (Poaceae) in Iran as revealed by AFLP

2008 ◽  
Vol 55 (8) ◽  
pp. 1231-1238 ◽  
Author(s):  
Hojjatollah Saeidi ◽  
Badradin Ebrahim Sayed Tabatabaei ◽  
Mehdi Rahimmalek ◽  
Majid Talebi-Badaf ◽  
Mohammad Reza Rahiminejad
Keyword(s):  
Genetic Diversity ◽  
Gene Pool ◽  
Aegilops Tauschii ◽  
D Genome

The Ha locus of wheat: Identification of a polymorphic region for tracing grain hardness in crosses

Genome ◽  
1999 ◽  
Vol 42 (6) ◽  
pp. 1242-1250 ◽  
Author(s):  
M Turner ◽  
Y Mukai ◽  
P Leroy ◽  
B Charef ◽  
R Appels ◽  
...  
Keyword(s):  
Dna Sequences ◽  
Hexaploid Wheat ◽  
Aegilops Tauschii ◽  
Grain Hardness ◽  
High Sequence Identity ◽  
D Genome ◽  
Sequence Identity ◽  
Group 5 ◽  
Grain Softness ◽  
Puroindoline A

The grain softness proteins or friabilins are known to be composed of three main components: puroindoline a, puroindoline b, and GSP-1. cDNAs for GSP-1 have previously been mapped to group-5 chromosomes and their location on chromosome 5D is closely linked to the grain hardness (Ha) locus of hexaploid wheat. A genomic DNA clone containing the GSP-1 gene (wGSP1-A1) from hexaploid wheat has been identified by fluorescent in situ hybridization as having originated from the distal end of the short arm of chromosome 5A. A genomic clone containing the gene (wGSP1-D1) was also isolated from Aegilops tauschii, the donor of the D genome to bread wheat. There are no introns in the GSP-1 genes, and there is high sequence identity between wGSP1-A1 and wGSP1-D1 up to 1 kb 5' and 300 bp 3' to wGSP1-D1. However, regions further upstream and downstream of wGSP1-D1 share no significant sequence identity to corresponding sequences in wGSP1-A1. These regions therefore identified potentially valuable sequences for tracing the Ha locus through assaying polymorphic DNA sequences. The sequence from 300 to 500 bp 3' to wGSP1-D1 (wGSP1-D13) was mapped to the Ha locus in a mapping population. wGSP1-D13 was also tightly linked to genes for puroindoline a and puroindoline b which have been previously mapped to be at the Ha locus. In addition wGSP1-D13 was used to detect RFLPs between near isogenic soft and hard Falcon lines and in a random selection of soft and hard wheats.Key words: wheat, grain hardness, chromosome 5, puroindoline, GSP-1.

Analysis of relationships between Aegilops tauschii and the D genome of wheat utilizing microsatellites

Genome ◽  
2000 ◽  
Vol 43 (4) ◽  
pp. 661-668 ◽  
Author(s):  
Tamás Lelley ◽  
Maria Stachel ◽  
Heinrich Grausgruber ◽  
Johann Vollmann
Keyword(s):  
Genetic Diversity ◽  
Triticum Aestivum ◽  
Hexaploid Wheat ◽  
Aegilops Tauschii ◽  
Null Alleles ◽  
The Caspian Sea ◽  
D Genome ◽  
Wheat Varieties ◽  
Center Of Origin ◽  
Primer Sets

Sixty Aegilops tauschii accessions and 60 European hexaploid wheat varieties were analyzed with 14 wheat microsatellite (WMS) primer sets to (i) study the phylogeny of Ae. tauschii, (ii) search for a specific genotype of Ae. tauschii most closely related to the D genome of hexaploid wheat, and (iii) narrow down the presumed birthplace of the latter. An average of 6.5 and 4.0 alleles per locus was detected in Ae. tauschii and in wheat, respectively. The highest genetic diversity of Ae. tauschii was found in Transcaucasia and southeast of the Caspian Sea. Distribution of the 87 alleles (without null alleles) found in Aegilops did not allow differentiation of the species into the two subspecies strangulata and tauschii. Excluding null alleles, 41 alleles occurred parallel in wheat and in Aegilops. Data obtained in this study supports the view of the D genome of hexaploid wheat being a composite of several sources but does not support subsp. strangulata as the possible major source of the D genome. The highest number of region-specific alleles (three) in Ae. tauschii occurring also in the D genome of wheat, and therefore most indicative for its evolution was found in present-day Georgia, where subsp. strangulata is not endemic.Key words: Triticum aestivum, Aegilops tauschii, genetic distance, center of origin, evolution.

Genetic diversity of Asian and European common wheat lines assessed by fluorescence in situ hybridization

Genome ◽  
2021 ◽  
Author(s):  
Xiu Yang ◽  
Binwen Tan ◽  
Yulu Yang ◽  
Xiaohui Zhang ◽  
Wei Zhu ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
In Situ Hybridization ◽  
Fluorescence In Situ Hybridization ◽  
Common Wheat ◽  
Genetic Relationships ◽  
Structural Variations ◽  
D Genome ◽  
Western Asia ◽  
Wheat Lines

Understanding the genetic diversity of wheat is important for wheat breeding and improvement. However, there have been limited attempts to evaluate wheat diversity using fluorescence in situ hybridization (FISH). In this study, the chromosomal structures of 149 wheat accessions from 13 countries located between the latitudes of 30° and 45°N, the principal growing region for wheat, were characterized using FISH with pTa535 and pSc119.2 probes. The ranges of the numbers of FISH types in the A-, B-, and D-genomes were 2–8, 3–7, and 2–4, respectively, and the average numbers in the A- and B-genomes were greater than in the D-genome. Chromosomal translocations were detected by these probes, and previously undescribed translocations were also observed. Using the FISH, the genetic relationships among the 149 common wheat lines were divided into three groups (G1, G2, and G3). G1 mainly consisted of Southern European lines, G2 consisted of most lines from Japan and some lines from Western Asia, China, and Korea, and G3 consisted of the other lines from Southern Europe and most of the lines from Western Asia, China, and Korea. FISH karyotypes of wheat chromosomes distinguished chromosomal structural variations, revealed the genetic diversity among wheat varieties. Furthermore, these results provide valuable information for the further genetic improvement of wheat in China.

scholarly journals Using the synthetic form RS5 to obtain new introgressive lines of common wheat

2021 ◽  
Vol 25 (7) ◽  
pp. 770-777
Author(s):  
R. O. Davoyan ◽  
I. V. Bebyakina ◽  
E. R. Davoyan ◽  
Y. S. Zubanova ◽  
D. M. Boldakov ◽  
...  
Keyword(s):  
Leaf Rust ◽  
Common Wheat ◽  
Yellow Rust ◽  
Aegilops Tauschii ◽  
Genetic Material ◽  
Leaf Rust Resistance ◽  
Wild Relatives ◽  
Aegilops Speltoides ◽  
D Genome ◽  
Synthetic Form

The use of the gene pool of wild relatives, which have a significant reserve of genetic diversity, is of immediate interest for breeding common wheat. The creation and use of synthetic forms as “bridges” is an effective method of transferring valuable genetic material from wild relatives to cultivated wheat. For this purpose, genome addition, genome substitution and recombinant “secondary” synthetic forms have been created in the P.P. Lukyanenko National Center of Grain. The synthetic recombination form RS5 (BBAASDt ), in which the third genome consists of chromosomes of Aegilops speltoides (S) and Aegilops tauschii (Dt ), was obtained from crossing the synthetic forms Avrodes (BBAASS) and M.it./Ae. tauschii (BBAADt Dt ), in which the D genome from Ae. tauschii was added to the BBAA genomes of the durum wheat cultivar Mutico italicum. Introgression lines resistant to leaf rust, yellow rust and powdery mildew have been obtained from backcrosses with the susceptible common wheat cultivars Krasnodarskaya 99, Rostislav and Zhirovka. Twelve resistant lines that additionally have high technological characteristics of grain and flour have been selected. The cytological study (С-banding) has revealed chromosomal modifications in 6 of 8 lines under study. The rearrangements mainly affected the chromosomes of the D genome, 1D, 3D, 4D, 6D and 7D. It was found that in most cases the genetic material from the synthetic form RS5 in the studied lines was represented by substituted chromosomes from Ae. tauschii. In line 5791p17, the substitution of chromosomes 6D from Ae. tauschii and 7D from Ae. speltoides was revealed. Substitutions 4D(4Dt ), 6D(6Dt ) from Ae. tauschii and 7D(7S) from Ae. speltoides were obtained for the first time. Molecular analysis of 12 lines did not reveal effective leaf rust resistance genes, presumably present in synthetic forms of M.it./Ae. tauschii and Avrodes. It is assumed that the lines may carry previously unidentified genes for fungal disease resistance, in particular for resistance to leaf rust, from Ae. tauschii and Ae. speltoides.

Origin and dynamics of Rwt6, a wheat gene for resistance to non-adapted pathotypes of Pyricularia oryzae

2021 ◽  
Author(s):  
Soichiro Asuke ◽  
Yuta Umehara ◽  
Yoshihiro Inoue ◽  
Trinh Thi Phuong Vy ◽  
Mizuki Iwakawa ◽  
...  
Keyword(s):  
Resistance Gene ◽  
Common Wheat ◽  
Caspian Sea ◽  
Aegilops Tauschii ◽  
Coastal Region ◽  
Pyricularia Oryzae ◽  
Avirulence Gene ◽  
Avirulence Genes ◽  
The Caspian Sea ◽  
D Genome

Avirulence of Eleusine isolates of Pyricularia oryzae on common wheat is conditioned by at least five avirulence genes. One is PWT3 corresponding to resistance gene Rwt3 located on chromosome 1D. We identified a resistance gene corresponding to a second avirulence gene, PWT6, and named it Rmg9 (Rwt6). Rwt6 was closely linked to Rwt3. A survey of the population of Aegilops tauschii, the D genome donor to common wheat, revealed that some accessions from the southern coastal region of the Caspian Sea, the birthplace of common wheat, carried both genes. Rwt6 and Rwt3 carriers accounted for 65% and 80%, respectively, of accessions in a common wheat landrace collection. The most likely explanation of our results is that both resistance genes were simultaneously introduced into common wheat at the time of hybridization of Triticum turgidum and Ae. tauschii. However, a prominent difference was recognized in their geographical distributions in modern wheat; Rwt3 and Rwt6 co-occurred at high frequencies in regions to the east of the Caspian Sea, whereas Rwt6 occurred at a lower frequency than Rwt3 in regions to the west. This difference was considered to be associated with range of pathotypes to which these genes were effective. Ae. tauschii accessions carrying Rwt3 and Rwt6 also carried Rwt4, another resistance gene involved in the species specificity. We suggest that the gain of the D genome should have given an adaptive advantage to the genus Triticum by conferring disease resistance.

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