Heteroplasmy and paternally oriented shift of the organellar DNA composition in barley–wheat hybrids during backcrosses with wheat parents

Abstract

Mitochondrial (mt) and chloroplast (ct) genome inheritance was studied in barley-wheat hybrids, as were their progenies obtained from backcrosses with different common wheat cultivars, by monitoring the composition of 4 mtDNA (coxI, a 5'-flanking region of cob, nad3-orf156, and 5'-upstream region of 18S/5S) and 2 ctDNA (simple-sequence repeat locus downstream of trnS and a 3'-flanking region of rbcL) loci. In male sterile F1 and BC1 plants, maternal barley mtDNA fragments were mainly detected and very low levels of paternal wheat fragments were occasionally detected by PCR in coxI, a 5'-flanking region of cob and nad3-orf156, whereas a 5'-upstream region of 18S/5S showed clear heteroplasmy, containing both maternal and paternal copies, with maternal copies prevailing. Plants showing such heteroplasmic mtDNA composition remained either semisterile or became completely sterile in the later backcross generations. Only maternal ctDNA copies were detected in these plants. In 3 stable, self-fertile, and vigourous lines obtained in the advanced backcross generations and possessing recombinant wheat nuclear genome, however, only mt- and ctDNA copies of wheat parents were detected; thus, the original alloplasmic condition appeared to be lost. Our results suggest that transmission followed by selective replication of the paternal wheat organellar DNA leads to a paternally oriented shift of the organellar DNA composition in barley-wheat hybrids, which correlates with the restoration of fertility and plant vigour. These 2 processes seem to be related to nucleocytoplasmic compatibility and to be under the control of the nuclear genome composition.

Distant and intraspecific hybridization, induced mutagenesis in soft bread wheat

“…However, despite the difficulties (the sterility of hybrids and cytological instability), the literature contains information about the migration of a number of genes resistant to brown stem rust, powdery mildew by T. timopheevii to soft wheat. The published information about the compatibility of species T. aestivum and T. timopheevii is contradictory due to specific ecological zones [3,4]. Using Twell method contributed to a sharp increase in the volume and improve the pollination quality, but in general -hybridization.…”

Some results of the breeding and genetic studies of common wheat in the south-east of Kazakhstan

“…Contradictory results are explained as genetic features of parent forms and originality of specific ecological zones [3,4].…”

“…It is possible to use hybridization in selection of mutations. More important is the use of mutants in hybridization to obtain positive transgressions [4][5][6][7][8].…”

Interspecific incompatibility in wide hybridization of plants and ways to overcome

“…Так, при межпопуляционных скрещиваниях Helianthus verticillatus выявлены случаи передачи хлоропластного генома (Ellis et al, 2008), а при межпопуляционных скрещиваниях Silene vulgaris -мито-хондриального генома (Bentley et al, 2010) от отцовского генотипа. При отдаленной гибридизации пшеницы отме-чали замену передачи мтДНК по материнской линии на отцовское или двуродительское наследование (Soliman et al, 1987;Kiang et al, 1994;Kitagawa et al, 2002;Aksyonova et al, 2005).…”

“…При беккроссиро-вании отцовским видом (пшеницей) ячменно-пшеничных гибридов H. vulgare × T. aestivum, для которых характерна гетероплазмия мтДНК, наблюдали изменчивость не толь-ко ядерного, но и митохондриального генома. При этом характер изменчивости мтДНК у формирующихся алло-плазматических линий (H. vulgare)-T. aestivum ассоции-рован или с восстановлением фертильности, или с закре-плением стерильности (Aksyonova et al, 2005;Трубачеева и др., 2009. Так, при восстановлении фертильности аллоплазматических линий (H. vulgare)-T. aestivum про-исходит увеличение числа копий мтДНК пшеничного (отцовского) типа, а при закреплении стерильности пре-обладают копии материнского (ячменного) типа.…”