Abnormal mitosis induced by wheat-rye 1R monosomic addition lines

Octoploid triticale were derived from common wheat (Triticum aestivum L. 'Mianyang11') x rye (Secale cereale L. 'Kustro'), and some progeny were obtained by the backcrossing of triticale with 'Mianyang11' followed by self-fertilization. In situ hybridization using rye genomic DNA and repetitive sequences pAs1 and pSc119.2 as probes was used to analyze the mitotic chromosomes of these progeny. Three wheat-rye 1R monosomic addition lines and a wheat line (12FT-1685) containing a 1R and a 1BL.1RS translocation chromosome were identified. Abnormal mitosis was observed in the two lines. During mitosis of a 1R monosomic addition line (3-8-20-1R-2), lagging chromosomes, micronuclei, chromosomal bridges, and the one pole segregation of 1R chromosome were observed. Abnormal mitotic behaviour of chromosomes was also observed in some of the self-progeny plants of lines 12FT-1685 and 3-8-20-1R-2. These progeny contained 1R chromosome or 1R chromosome arm. In addition, 4B chromosomes were absent from one of the progeny of 3-8-20-1R-2. This abnormal mitotic behaviour of chromosomes was not observed in two other 1R monosomic addition lines. These results indicate that a single 1R chromosome added to wheat might cause abnormal mitotic behaviour of both wheat and rye chromosomes and different genetic variations might occurr among the sibling 1R monosomic addition lines. Key words: abnormal mitotic behaviour, monosomic addition line, wheat, rye. Des triticales octoploides ont ete derives du croisement entre le ble tendre (Triticum aestivum L. 'Mianyang11') et le seigle (Secale cereale L. 'Krusto'), tandis que d'autres ont ete obtenus au terme d'un retrocroisement des triticales avec 'Mianyang11' et d'une autofecondation. Des hybridations in situ a l'aide de sondes composees de l'ADN genomique du seigle ou des sequences repetees pAs1 et pSc119.2 ont ete realisees pour analyser le comportement des chromosomes mitotiques chez ces plantes. Les auteurs ont identifie trois lignees d'addition monosomique ble-seigle 1R et une lignee de ble (12FT-1685) contenant le 1R et une translocation 1BL.1RS. Des mitoses anormales ont ete observees chez les deux lignees. Au cours de la mitose chez une lignee d'addition monosomique 1R (3-8-20-1R-2), des chromosomes retardataires, des micronoyaux, des ponts chromosomiques et une segregation unipolaire du chromosome 1R ont ete observes. Un comportement mitotique anormal des chromosomes a egalement ete observe chez certains descendants de l'autofecondation des lignees 12FT-1685 et 3-8-20-1R-2. Ces progenitures contenaient le chromosome 1R ou un bras 1R. De plus, les chromosomes 4B etaient absents chez l'un des descendants de 3-8-20-1R-2. Ce comportement mitotique anormal des chromosomes n'a pas ete observe chez deux autres lignees d'addition monosomique 1R. Ces resultats indiquent que l'addition d'un seul chromosome 1R au genome du ble peut causer un comportement mitotique anormal tant des chromosomes du ble que du seigle et que differents changements genetiques peuvent survenir parmi des lignees d'addition monosomique 1R sceurs. [Traduit par la Redaction] Mots-cles: comportement mitotique anormal, lignee d'addition monosomique, ble, seigle.
Introduction Wide hybridization is one of the stresses that might trigger reorganization of parental genomes (McClintock 1978) and has been widely used in cereal breeding programs (Feuillet et al. 2008; [...]