Revisiting Pivotal-Differential Genome Evolution in Wheat. (August 2017)

• Record Type: Journal Article
• Authors: Mirzaghaderi, Ghader; Mason, Annaliese S.
• Is Part Of: Trends in plant science. Volume 22:Number 8(2017)
• Page Start: 674
• Page End: 684
• Publication Date: 2017-08
• Subjects: genome evolution -- polyploidy -- wheat -- Aegilops -- Triticum; Botany -- Periodicals; Botanique -- Périodiques; Botany; Periodicals; 580.5
• DOI: 10.1016/j.tplants.2017.06.003
• Languages: English
• ISSNs: 1360-1385

Abstract

Abstract : An interesting and possibly unique pattern of genome evolution following polyploidy can be observed among allopolyploids of the Triticum and Aegilops genera (wheat group). Most polyploids in this group are presumed to share a common unaltered (pivotal) subgenome (U, D, or A) together with one or two modified (differential) subgenomes, a status that has been referred to as 'pivotal-differential' genome evolution. In this review we discuss various mechanisms that could be responsible for this evolutionary pattern, as well as evidence for and against the putative evolutionary mechanisms involved. We suggest that, in light of recent advances in genome sequencing and related technologies in the wheat group, the time has come to reopen the investigation into pivotal-differential genome evolution. Trends: Polyploids in the wheat group have 'pivotal-differential' subgenome relationships: one subgenome appears to be conserved (the pivotal genome), while the other subgenome(s) appear to be modified (the differential genome). The cause of this pattern is unknown, although three main explanations have been proposed: (i) inheritance of variation from the progenitors, (ii) induced modifications post-allopolyploid formation, and (iii) hybridization events between allopolyploids that share a genome in common. We summarize current evidence for or against each explanation, speculate on possible underlying mechanisms, and outline how these could be tested in future. We propose that, as comprehensive genomic resources become available, the time has come to revisit the 'pivotal-differential' genome evolution concept, and to fully elucidate the evolutionary processes that gave rise to the agriculturally important wheat group.