Elimination of chromosomes in <i>Hordeum vulgare</i> × <i>H. bulbosum</i> crosses at mitosis and interphase involves micronucleus formation and progressive heterochromatinization

Abstract

Uniparental chromosome elimination occurs in several interspecific hybrids of plants. We studied the mechanism underlying selective elimination of the paternal chromosomes during the development of Hordeum vulgare × H. bulbosum hybrid embryos that is restricted to an early stage of development. In almost all embryos most of the H. bulbosum chromatin undergoes a fast rate of elimination within nine days after pollination. There are differences in the mitotic behaviour between the parental chromosomes, with H. bulbosum chromatids segregating asymmetrically at anaphase. We provide evidence for a chromosome elimination pathway that involves the formation of nuclear extrusions during interphase in addition to postmitotically formed micronuclei. The chromatin structure of nuclei and micronuclei differs and heterochromatinization and disintegration of the nuclear envelope of micronuclei are the final steps of chromosome elimination.

Chromosome elimination and in vivo haploid production induced by Stock 6-derived inducer line in maize (Zea mays L.)

“…Complete and partial elimination of chromosomes from one parent was documented in plant wide crosses (Kasha and Kao 1970;Laurie 1989;Laurie and Bennett 1989;Mochida et al 2004;Riera-Lizarazu et al 1996;Gernand et al 2005Gernand et al , 2006. Chromosome elimination was generally attributed to the unbalanced chromosome sets (Kasha and Kao 1970).…”

Loss of centromeric histone H3 (CENH3) from centromeres precedes uniparental chromosome elimination in interspecific barley hybrids

“…Elimination of H. bulbosum chromosomes is completed by 5-9 d after pollination (3)(4)(5). Because CENH3 is a stable protein (22), sperm-derived centromere-incorporated CENH3 proteins are likely to provide a residual kinetochore function of H. bulbosum until it falls below a level critical for correct chromosome segregation, resulting in chromosome elimination.…”

“…Chromosomes of H. bulbosum are eliminated several days after pollination (1,(3)(4)(5)(6) independent of the crossing direction (1), but hybrids combining both sets of parental chromosomes can be obtained (7). Chromosome elimination is known to depend on genetic factors (7) and temperature after fertilization (8).…”

“…Other hypotheses that have been put forward are the formation of multipolar spindles (5), spatial separation of genomes during interphase (11,12), and genome elimination by nuclear extrusions (4,13). In addition, degradation of alien chromosomes by host-specific nucleases (14), uniparental nondisjunction of anaphase chromosomes (15), and parent-specific inactivation of centromeres (11,(16)(17)(18)(19) have been suggested.…”

Mitotic and meiotic behavior of rye chromosomes in wheat - Psathyrostachys huashanica amphiploid x triticale progeny

“…(Komeda et al, 2007), Hordeum vulgare L. (Barclay, 1975), Pennisetum glaucum (L.) R. Br. (Gernand et al, 2005), and between P. glaucum and T. spelta L., T. durum Desf., T. monococcum L., Secale cereale L. (Ishii et al, 2010), as well as between Hordeum species (LindeLaursen and von Bothmer, 1999;Gernand et al, 2006;Sanei et al, 2011). There is a classical model for explaining preferential chromosome elimination, which is closely associated with the formation of laggard chromosomes and micronuclei within the first few days of embryogenesis (Kasha and Kao, 1970;Davies, 1974).…”