Identification of introgressed segments conferring disease resistance in a tetrageneric hybrid of Triticum, Secale, Thinopyrum, and Avena

Genome ◽  
1997 ◽  
Vol 40 (1) ◽  
pp. 99-103 ◽  
Author(s):  
Shunxue Tang ◽  
Jiajun Zhuang ◽  
Yuxiang Wen ◽  
Shanjiang Abydylla Ai ◽  
Hongjie Li ◽  
...  

Using genomic in situ hybridization to chromosomes, we identified introgressed segments in a tetrageneric hybrid of Triticum, Avena, Thinopyrum, and Secale, which conferred high resistance to leaf rust, stem rust, stripe rust, powdery mildew, and root rot to wheat. The disease-resistance traits of the hybrid originated from three wild related genera of Triticum, namely Avena, Thinopyrum, and Secale. The new breeding system that combined traditional wide hybridization with anther culture was efficient and rapid in creating wheat germplasms resistant to major diseases.Key words: Triticum aestivum, Avena fatua, Thinopyrum intermedium, Secale cereale, wide hybridization, anther culture, genomic in situ hybridization, GISH.

Genome ◽  
1995 ◽  
Vol 38 (5) ◽  
pp. 946-950 ◽  
Author(s):  
Juan Zhang ◽  
Bernd Friebe ◽  
Bikram S. Gill

Genomic in situ hybridization to somatic metaphase chromosomes of hexaploid wheat cv. Chinese Spring using biotinylated maize genomic DNA as a probe revealed the existence of amplified maize DNA sequences in five pairs of chromosomes. The in situ hybridization sites were located on chromosomes 1A, 7A, 2B, 3B, and 7B. One pair of in situ hybridization sites was also observed in hexaploid oat. The locations and sizes of in situ hybridization sites varied among progenitor species.Key words: Triticum aestivum, Zea mays, shared DNA sequences, genomic in situ hybridization.


Genome ◽  
1998 ◽  
Vol 41 (4) ◽  
pp. 580-586 ◽  
Author(s):  
Qin Chen ◽  
R L Conner ◽  
A Laroche ◽  
J B Thomas

Genomic in situ hybridization (GISH) using genomic DNA probes from Thinopyrum elongatum (Host) D.R. Dewey (genome E, 2n = 14), Thinopyrum bessarabicum (Savul. & Rayss) Á. Löve (genome J, 2n = 14), and Pseudoroegneria strigosa (M. Bieb.) Á. Löve (genome S, 2n = 14), was used to examine the genomic constitution of Thinopyrum intermedium (Host) Barkworth & D.R. Dewey (2n = 6x = 42) and Thinopyrum ponticum (Podp.) Barkworth & D.R. Dewey (2n = 10x = 70). Evidence from GISH indicated that hexaploid Th. intermedium contained the J, Js, and S genomes, in which the J genome was related to the E genome of Th. elongatum and the J genome of Th. bessarabicum. The S genome was homologous to the S genome of Ps. strigosa, while the Js genome referred to modified J- or E-type chromosomes distinguished by the presence of S genome specific sequences close to the centromere. Decaploid Th. ponticum had only the two basic genomes J and Js. The Js genome present in Th. intermedium and Th. ponticum was homologous with E or J genomes, but was quite distinct at centromeric regions, which can strongly hybridize with the S genome DNA probe. Based on GISH results, the genomic formula of Th. intermedium was redesignated JJsS and that of Th. ponticum was redesignated JJJJsJs. The finding of a close relationship among S, J, and Js genomes provides valuable markers for molecular cytogenetic analyses using S genome DNA probes to monitor the transfer of useful traits from Th. intermedium and Th. ponticum to wheat.Key words: genomic in situ hybridization, GISH, Thinopyrum intermedium, Thinopyrum ponticum, genomic analysis, Js genome.


Genome ◽  
2004 ◽  
Vol 47 (1) ◽  
pp. 215-223 ◽  
Author(s):  
Hongjie Li ◽  
Robert L Conner ◽  
Qin Chen ◽  
Haiyan Li ◽  
André Laroche ◽  
...  

Common root rot, caused by Cochliobolus sativus (Ito and Kurib) Drechs. ex Dastur, is a major soil-borne disease of spring and winter wheat (Triticum aestivum L. em Thell.) on the Canadian prairies. Resistance to common root rot from Thinopyrum ponticum (Podp.) Liu and Wang was transferred into wheat via crossing with Agrotana, a resistant wheat – Th. ponticum partial amphiploid line. Evaluation of common root rot reactions showed that selected advanced lines with blue kernel color derived from a wheat × Agrotana cross expressed more resistance than the susceptible T. aestivum 'Chinese Spring' parent and other susceptible wheat check cultivars. Cytological examination revealed 41 to 44 chromosomes in the advanced lines. Genomic in situ hybridization, using total genomic DNA from Pseudoroegneria strigosa (M. Bieb) A. Löve (St genome) as a probe, demonstrated that the blue kernel plants had two pairs of spontaneously translocated J–Js and Js–J chromosomes derived from the J and Js genome of Th. ponticum. The presence of these translocated chromosomes was associated with increased resistance of wheat to common root rot. The lines with blue aleurone color always had a subcentromeric Js–J translocated chromosome. The subtelocentric J–Js translocated chromosome was not responsible for the blue kernel color. The genomic in situ hybridization analysis on meiosis revealed that the two spontaneous translocations were not reciprocal translocations.Key words: Cochliobolus sativus, genomic in situ hybridization, blue kernel color.


Genome ◽  
2009 ◽  
Vol 52 (2) ◽  
pp. 156-165 ◽  
Author(s):  
István Molnár ◽  
Elena Benavente ◽  
Márta Molnár-Láng

The frequency and pattern of irradiation-induced intergenomic chromosome rearrangements were analysed in the mutagenized (M0) and the first selfed (M1) generations of Triticum aestivum  L. – Aegilops biuncialis Vis. amphiploids (2n = 70, AABBDDUbUbMbMb) by multicolour genomic in situ hybridization (mcGISH). mcGISH allowed the simultaneous discrimination of individual Ae. biuncialis genomes and wheat chromosomes. Dicentric chromosomes, fragments, and terminal translocations were most frequently induced by γ-irradiation, but centric fusions and internal exchanges were also more abundant in the treated plants than in control amphiploids. Rearrangements involving the Ub genome (Ub-type aberrations) were more frequent than those involving the Mb genome (Mb-type aberrations). This irradiation sensitivity of the Ub chromosomes was attributed to their centromeric or near-centromeric regions, since Ub-type centric fusions were significantly more abundant than Mb-type centric fusions at all irradiation doses. Dicentrics completely disappeared, but centric fusions and translocations were well transmitted from M0 to M1. Identification of specific chromosomes involved in some rearrangements was attempted by sequential fluorescence in situ hybridization with a mix of repeated DNA probes and GISH on the same slide. The irradiated amphiploids formed fewer seeds than untreated plants, but normal levels of fertility were recovered in their offspring. The irradiation-induced wheat – Ae. biuncialis intergenomic translocations will facilitate the successful introgression of drought tolerance and other alien traits into bread wheat.


Genome ◽  
2005 ◽  
Vol 48 (6) ◽  
pp. 1070-1082 ◽  
Author(s):  
Annamária Schneider ◽  
Gabriella Linc ◽  
István Molnár ◽  
Márta Molnár-Láng

The aim of the experiments was to produce and identify different Triticum aestivum – Aegilops biuncialis disomic addition lines. To facilitate the exact identification of the Ae. biuncialis chromosomes in these Triticum aestivum – Ae. biuncialis disomic additions, it was necessary to analyze the fluorescence in situ hybridization (FISH) pattern of Ae. biuncialis (2n = 4x = 28, UbUbMbMb), comparing it with the diploid progenitors (Aegilops umbellulata, 2n = 2x = 14, UU and Aegilops comosa, 2n = 2x = 14, MM). To identify the Ae. biuncialis chromosomes, FISH was carried out using 2 DNA clones (pSc119.2 and pAs1) on Ae. biuncialis and its 2 diploid progenitor species. Differences in the hybridization patterns of all chromosomes were observed among the 4 Ae. umbellulata accessions, the 4 Ae. comosa accessions, and the 3 Ae. biuncialis accessions analyzed. The hybridization pattern of the M genome was more variable than that of the U genome. Five different wheat – Ae. biuncialis addition lines were produced from the wheat – Ae. biuncialis amphiploids produced earlier in Martonvásár. The 2M, 3M, 7M, 3U, and 5U chromosome pairs were identified with FISH using 3 repetitive DNA clones (pSc119.2, pAs1, and pTa71) in the disomic chromosome additions produced. Genomic in situ hybridization (GISH) was used to differentiate the Ae. biuncialis chromosomes from wheat, but no chromosome rearrangements between wheat and Ae. biuncialis were detected in the addition lines.Key words: Triticum aestivum, Aegilops biuncialis, fluorescence in situ hybridization, genomic in situ hybridization, wheat – Aegilops biuncialis addition lines.


Genome ◽  
1999 ◽  
Vol 42 (6) ◽  
pp. 1217-1223 ◽  
Author(s):  
Qin Chen ◽  
R L Conner ◽  
A Laroche ◽  
W Q Ji ◽  
K C Armstrong ◽  
...  

The genomic origin of alien chromosomes present in a wheat - Thinopyrum intermedium partial amphiploid TAF46 (2n = 8x = 56) and six derived chromosome addition lines were analyzed by genomic in situ hybridization (GISH) using S genomic DNA from Pseudoroegneria strigosa (2n = 2x = 14, SS) as a probe. The GISH analysis clearly showed that the chromosome complement of the partial amphiploid TAF46 consists of an entire wheat genome plus one synthetic genome consisting of a mixture of six S genome chromosomes and eight J (=E) genome chromosomes derived from Th. intermedium (2n = 6x = 42, JJJsJsSS). There were no Js genome chromosomes present in TAF46. The J genome chromosomes present in TAF46 displayed a unique GISH hybridization pattern with the S genomic DNA probe, in which S genome DNA strongly hybridized at the terminal regions and weakly hybridized over the remaining parts of the chromosomes. This provides a diagnostic marker for distinguishing J genome chromosomes from Js or S genome or wheat ABD genome chromosomes. The genomic origin of the alien chromosomes present in the six derived chromosome addition lines were identified by their characteristic GISH hybridization patterns with S genomic DNA probe. GISH analysis showed that addition lines L1, L2, L3, and L5 carried one pair of J genome chromosomes, while addition lines L4 and L7 each carried one pair of S genome chromosomes. GISH patterns detected by the S genome probe on addition line of L1 were identical to those of the J genome chromosomes present in the partial amphiploid TAF46, suggesting that these chromosomes were not structurally altered when they were transferred from TAF46 to addition lines.Key words: GISH, genomic composition, addition lines, Thinopyrum intermedium, partial amphiploid.


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