Molecular cytogenetic characterization and fusarium head blight resistance of five wheat-Thinopyrum intermedium partial amphiploids

Background Partial amphiploids created by crossing octoploid tritelytrigia(2n = 8× = 56, AABBDDEE) and Thinopyrum intermedium (2n = 6× = 42, StStJJJSJS) are important intermediates in wheat breeding because of their resistance to major wheat diseases. We examined the chromosome compositions of five wheat-Th. intermedium partial amphiploids using GISH and multicolor-FISH. Results The result revealed that five lines had 10-14 J-genome chromosomes from Th. intermedium and 42 common wheat chromosomes, using the J-genomic DNA from Th. bessarabicum as GISH probe and the oligo probes pAs1-1, pAs1-3, AFA-4, (GAA) 10, and pSc119.2-1 as FISH probe. Five lines resembled their parent octoploid tritelytrigia (2n = 8× = 56, AABBDDEE) but had higher protein contents. Protein contents of two lines HS2-2 and HS2-5 were up to more than 20%. Evaluation of Fusarium head blight (FHB) resistance revealed that the percent of symptomatic spikelets (PSS) of these lines were below 30%. Lines HS2-2, HS2-4, HS2-5, and HS2-16 were less than 20% of PPS. Line HS2-5 with 14 J-genome chromosomes from Th. intermedium showed the best disease resistance, with PSS values of 10.8% and 16.6% in 2016 and 2017, respectively. Conclusions New wheat-Th. intermedium amphiploids with the J-genome chromosomes were identified and can be considered as a valuable source of FHB resistance in wheat breeding.

Characterization of chromosome constitution in three wheat - Thinopyrum intermedium amphiploids revealed frequent rearrangement of alien and wheat chromosomes

Background Thinopyrum intermedium (2n = 6x = 42) is an important wild perennial Triticeae species exhibiting many potentially favorable traits for wheat improvement. Wheat-Th. intermedium partial amphiploids serve as a bridge to transfer desirable genes from Th. intermedium into common wheat. Results Three octoploid Trititrigia accessions (TE261–1, TE266–1, and TE346–1) with good resistances to stripe rust, powdery mildew and aphids were selected from hybrid progenies between Th. intermedium and the common wheat variety ‘Yannong 15’ (YN15). Genomic in situ hybridization (GISH), fluorescence in situ hybridization (FISH) and multicolor GISH (McGISH) analyses demonstrated that the three octoploid Trititrigia possess 42 wheat chromosomes and 14 Th. intermedium chromosomes. The 14 alien (Th. intermedium) chromosomes belong to a mixed genome consisting of J-, JS- and St-genome chromosomes rather than a single J, JS or St genome. Different types of chromosomal structural variation were also detected in the 1A, 6A, 6B, 2D and 7D chromosomes via FISH, McGISH and molecular marker analysis. The identity of the alien chromosomes and the variationes in the wheat chromosomes in the three Trititrigia octoploids were also different. Conclusions The wheat-Th. intermedium partial amphiploids possess 14 alien chromosomes which belong to a mixed genome consisting of J-, JS- and St- chromosomes, and 42 wheat chromosomes with different structural variations. These accessions could be used as genetic resources in wheat breeding for the transfer of disease and pest resistance genes from Th. intermedium to common wheat.

Molecular Cytogenetic Characterization and Fusarium Head Blight Resistance of Five Wheat-Thinopyrum intermedium Partial Amphiploids

Background: Partial amphiploids created by crossing octoploid tritelytrigia（2n=8x=56, AABBDDEE） and Thinopyrum intermedium (2n=6x=42, StStJJJSJS) are important intermediates in wheat breeding because of their resistance to major wheat diseases. We examined the chromosome compositions of five wheat-Th. intermedium partial amphiploids using GISH and multicolor-FISH. Results: The result revealed that five lines had 10-14 J-genome chromosomes from Th. intermedium and 42 common wheat chromosomes, using the J-genomic DNA from Th. bessarabicum as GISH probe and the oligo probes pAs1-1, pAs1-3, AFA-4, (GAA) 10, and pSc119.2-1 as FISH probe. Five lines resembled their parent octoploid tritelytrigia （2n=8x=56, AABBDDEE） but had higher protein contents. Protein contents of two lines HS2-2 and HS2-5 were up to more than 20%. Evaluation of Fusarium head blight (FHB) resistance revealed that the percent of symptomatic spikelets (PSS) of these lines were below 30%. Lines HS2-2, HS2-4, HS2-5, and HS2-16 were less than 20%. Line HS2-5 with 14 J-genome chromosomes from Th. intermedium showed the best disease resistance, with PSS values of 10.8% and 16.6% in 2016 and 2017, respectively. Conclusions: New wheat-Th. intermedium amphiploids with the J-genome chromosomes were identified and can be considered as a valuable source of FHB resistance in wheat breeding.

Characterization of Chromosome Constitution in Three Wheat-Thinopyrum intermedium Amphiploids Revealed Frequent Rearrangement of Alien and Wheat Chromosomes

Background: Thinopyrum intermedium (2n=6x=42) is an important wild perennial Triticeae species exhibiting many potentially favorable traits for wheat improvement. Wheat-Th. intermedium partial amphiploids serve as a bridge to transfer desirable genes from Th. intermedium into common wheat. Results: Three octoploid Trititrigia accessions (TE261-1, TE266-1, and TE346-1) with good resistances to stripe rust, powdery mildew and aphids were selected from hybrid progenies between Th. intermedium and the common wheat variety ‘Yannong 15’ (YN15). Genomic in situ hybridization (GISH), fluorescence in situ hybridization (FISH) and multicolor GISH (McGISH) analyses demonstrated that the three octoploid Trititrigia possess 42 wheat chromosomes and 14 Th. intermedium chromosomes. The 14 alien (Th. intermedium) chromosomes belong to a mixed genome consisting of J-, JS- and St-genome chromosomes rather than a single J, JS or St genome. Different types of chromosomal structural variation were also detected in the 1A, 6A, 6B, 2D and 7D chromosomes via FISH, McGISH and molecular marker analysis. The identity of the alien chromosomes and the variationes in the wheat chromosomes in the three Trititrigia octoploids were also different. Conclusions: The wheat-Th. intermedium partial amphiploids possess 14 alien chromosomes which belong to a mixed genome consisting of J-, JS- and St- chromosomes, and 42 wheat chromosomes with different structural variations. These accessions could be used as genetic resources in wheat breeding for the transfer of pest resistance genes from Th. intermedium to common wheat.

Molecular Cytogenetic Characterization and Fusarium Head Blight of Five Wheat Thinopyrum Intermedium Partial Amphiploids

Background: Partial amphiploids created by crossing octoploid tritelytrigia and Thinopyrum intermedium are important intermediates in wheat breeding because of their resistance to major wheat diseases. We examined the chromosome compositions of five wheat Th. intermedium partial amphiploids using GISH and multicolor FISH. Results: The result revealed that five lines had 10 14 J genome chromosomes from Th. intermedium and 42 common wheat chromosomes, using the J genomic DNA from Th. bessarabicum and the oligo probes pAs1 1 , pAs1 3 , AFA 4 , GAA ) 10, and pSc119.2 1 . Five lines resembled the parent Ganmai 8 but had better protein contents. P rotein contents of t wo lines HS2 2 and HS2 5 were up to more than 20%. Evaluation of Fusarium head blight (FHB) resistance revealed that the percent of symptomatic spikelets (PSS) of these lines were below 30%. Lines HS2 2, HS2 4, HS2 5, and HS2 16 were less than 20%. Line HS2 5 with 14 J genome chromosomes from Th. intermedium showed the best disease resistance, with PSS values of 10.8% and 16.6% in 2016 and 2017, respectively. Conclusions: New wheat Th. intermedium amphiploids with the J genome chromosomes were identified and can be considered as a valuable source of FHB resistance in wheat breeding.

Characterization of Chromosomal Rearrangement in New Wheat—Thinopyrum intermedium Addition Lines Carrying Thinopyrum—Specific Grain Hardness Genes

The wild species, Thinopyrum intermedium. (Genome StStJSJSJJ), serves as a valuable germplasm resource providing novel genes for wheat improvement. In the current study, non-denaturing fluorescence in situ hybridization (ND-FISH) with multiple probes and comparative molecular markers were applied to characterize two wheat-Th. intermedium chromosome additions. Sequential ND-FISH with new labeled Th. intermedium specific oligo-probes were used to precisely determine the chromosomal constitution of Th. intermedium, wheat—Th. intermedium partial amphiploids and addition lines Hy36 and Hy37. The ND-FISH results showed that the added JS-St translocated chromosomes in Hy36 had minor Oligo-5S ribosomal DNA (rDNA) signals at the short arm, while a pair of J-St chromosomes in Hy37 had major Oligo-pTa71 and minor Oligo-5S rDNA signals. The 90K SNP array and PCR-based molecular markers that mapped on wheat linkage group 5 and 3 facilitated the identification of Thinopyrum chromosome introgressions in the addition lines, and confirmed that added chromosomes in Hy36 and Hy37 were 5JSS.3StS and 5JS.3StS, respectively. Complete coding sequences at the paralogous puroindoline-a (Pina) loci from Th. intermedium were cloned and localized on the short arm of chromosome 5JS of Hy36. Line Hy36 showed a reduction in the hardness index, which suggested that Th. intermedium-specific Pina gene sequences may be associated with the softness trait in wheat background. The molecular cytogenetic identification of novel wheat—Th. intermedium derivatives indicated that the frequent chromosome rearrangement occurred in the progenies of wheat-Thinopyrum hybridization. The new wheat-Thinopyrum derived lines may increase the genetic diversity for wheat breeding.