DNA sequence-based mapping and comparative genomics of theStgenome ofPseudoroegneria spicata(Pursh) Á. Löve versus wheat (Triticum aestivumL.) and barley (Hordeum vulgareL.)

Abstract

Bluebunch wheatgrass (referred to as BBWG) [Pseudoroegneria spicata (Pursh) Á. Löve] is an important rangeland Triticeae grass used for forage, conservation, and restoration. This diploid has the basic St genome that occurs also in many polyploid Triticeae species, which serve as a gene reservoir for wheat improvement. Until now, the St genome in diploid species of Pseudoroegneria has not been mapped. Using a double-cross mapping populations, we mapped 230 expressed sequence tag derived simple sequence repeat (EST-SSR) and 3468 genotyping-by-sequencing (GBS) markers to 14 linkage groups (LGs), two each for the seven homologous groups of the St genome. The 227 GBS markers of BBWG that matched those in a previous study helped identify the unclassified seven LGs of the St sub-genome among 21 LGs of Thinopyrum intermedium (Host) Barkworth & D.R. Dewey. Comparisons of GBS sequences in BBWG to whole-genome sequences in bread wheat (Triticum aestivum L.) and barley (Hordeum vulgare L.) revealed that the St genome shared a homology of 35% and 24%, a synteny of 86% and 84%, and a collinearity of 0.85 and 0.86, with ABD and H, respectively. This first-draft molecular map of the St genome will be useful in breeding cereal and forage crops.

Development of Sequence-Tagged Site Marker Set for Identification of J, JS, and St Sub-genomes of Thinopyrum intermedium in Wheat Background

“…Therefore, Thi -LGs 1, 6, 7, 10, 14, 18, and 20 can be confidently assigned to Thi -HGs 1, 2, 3, 4, 5, 6, and 7 of the J sub-genome, respectively ( Table 2 ). Because Thi -LGs 2, 4, 8, 11, 13, 17, and 21 were reported as Thi -HGs 1, 2, 3, 4, 5, 6, and 7 of the St sub-genome (Wang R. R. C. et al, 2020 ), respectively, the remaining seven Thi -LGs 3, 5, 9, 12, 15, 16, and 19 were presumed to be the 1J S −7J S sub-genomes.…”

“…The method used to distinguish sub-genomes in Thi -LGs was described by Wang R. R. C. et al ( 2020 ). The 10,029 Thi -GBS sequences mapped to Thi -LG1~21 (Kantarski et al, 2017 ) were aligned with the annotated CDSs of Th.…”

“…However, the sub-genome information corresponding to each Thi -LG remains unknown. Subsequently, Wang R. R. C. et al ( 2020 ) compared the GBS sequences of Ps. spicata with the previously released Thi -GBS sequences and identified Thi -LG2, 4, 8, 11, 13, 17, and 21 as the St sub-genome.…”

Molecular cytogenetics and St-chromosome-specific molecular markers development of novel stripe rust resistant wheat–Thinopyrum intermedium as well as wheat–Thinopyrum ponticum substitution lines

“…During the past several decades, it was convinced that the set of St chromosomes contained in Th. intermedium were probably derived from P. spicata [51],…”

“…During the past several decades, it was convinced that the set of St chromosomes contained in Th. intermedium were probably derived from P. spicata [51], whereas it has been still unde ned that whether the St genome is one of the sets of chromosomes of Th. ponticum [11,52].…”