Reproductive and genetic roles of the maternal progenitor in the origin of common wheat (Triticum aestivum L.)

Abstract

Common wheat (Triticum aestivum L., AABBDD genome) is thought to have emerged through natural hybridization between Triticum turgidum L. (AABB genome) and Aegilops tauschii Coss. (DD genome). Hybridization barriers and doubling of the trihaploid F1 hybrids’ genome (ABD) via unreduced gamete fusion had key roles in the process. However, how T. turgidum, the maternal progenitor, was involved in these mechanisms remains unknown. An artificial cross‐experiment using 46 cultivated and 31 wild T. turgidum accessions and a single Ae. tauschii tester with a very short genetic distance to the common wheat D genome was conducted. Cytological and quantitative trait locus analyses of F1 hybrid genome doubling were performed. The crossability and ability to cause hybrid inviability did not greatly differ between the cultivars and wild accessions. The ability to cause hybrid genome doubling was higher in the cultivars. Three novel T. turgidum loci for hybrid genome doubling, which influenced unreduced gamete production in F1 hybrids, were identified. Cultivated T. turgidum might have increased the probability of the emergence of common wheat through its enhanced ability to cause genome doubling in F1 hybrids with Ae. tauschii. The ability enhancement might have involved alterations at a relatively small number of loci.

Phylogeographic and quantitative trait locus analysis of the ability of Aegilops tauschii Coss., the D genome progenitor of common wheat, to cause genome doubling in the F1 hybrids with Triticum turgidum L., the AB genome progenitor

“…In a previous artificial cross experiment study that used 31 accessions of wild T. turgidum (Triticum turgidum L. subsp. dicoccoides), virtually no genome doubling was observed in their F1 hybrids with KU-2103 (Matsuoka and Mori 2020). Therefore, Ae tauschii is distinctive in that its ability is genealogically and geographically widespread within the species.…”

“…The variation pattern of the small TauL3 lineage remains to be determined. Interestingly, the natural variation pattern for the ability is clearly structured in T. turgidum (Matsuoka and Mori 2020). Second, the ability to cause hybrid genome doubling is a complex trait controlled by several quantitative trait loci (QTLs) for unreduced gamete production.…”

“…Six and four QTLs have been identified in the genomes of Ae. tauschii and T. turgidum, respectively (Matsuoka et al 2013;Hao et al 2014;Matsuoka and Mori 2020). The present work aimed to further elucidate the natural variation patterns and QTLs for the ability to cause hybrid genome doubling in Ae.…”

New insights into the evolution of CAF1 family and utilization of TaCAF1Ia1 specificity to reveal the origin of the maternal progenitor for common wheat

“…6 ). In addition, it is likely that the AABB progenitors of the lineages I and II collected and domesticated by ancient people encountered the crucial opportunity to contact with the DD progenitor at one or more early agricultural areas [57] . Furthermore, it is assumed that such an origin module is difficult to take place because of the well-known hybridizability between different species of wheat for generating mutual-introgression.…”

Chromosome stability of synthetic Triticum turgidum–Aegilops umbellulata hybrids

“…The formation of unreduced gametes is mainly modulated by unreduced gamete genes [ 13 ]. Quantitative trait loci (QTLs) that contribute to unreduced gamete formation have been mapped on chromosomes 1 A, 3 A, 3 B, and 4 B of tetraploid wheat [ 14 , 15 ]. Two types of unreduced gamete formation mechanisms, namely first - division restitution (FDR) and single-division meiosis (SDM), have been discovered in monocotyledonous wheat hybrids [ 11 ].…”