Enhancing the efficiency of wide hybridization mediated chromosome engineering for high precision crop improvement with special reference to wheat × Imperata cylindrica system

Chromosome Elimination in Intergeneric Hybrid of <i>Oryza sativa</i> × <i>Luziola peruviana</i>

“…It is possible that some factors may trigger the deletion for stabilization of the newly formed genome, however, the base of the cellular mechanisms involved in the process of chromosome elimination are poorly understood [13]. Genomic conflict occurs in meiosis, possibly by asynchronism and cell cycle length of the genomes involved, time differences in replication between parental species that leads to strand breaks and genomic rearrangements and that may be of unknown signals of protein synthesis or post-translational changes in existing proteins [12].…”

“…Studies show that part of chromatin may be removed directly from the cells before and during the course of meiosis by nuclear extrusion, as in the hybrid O. sativa × L. peruviana, possibly due to the spatial separation of parental chromatin, heterochromatinization and DNA fragmentation, chromosomal elimination is also explained by differences in time during the phases of the cell cycle, asynchrony in the synthesis of nucleoproteins and inactivation of chromosomes by nucleases and suppression of the function of centromere in deleted chromosomal [12] [13]. Another mechanism of elimination is given by forming chromatin mass of little condensed respect to other chromosomes and corresponds to pycnotic bodies of chromatin that is mainly characterized by the removal of one of the poles of the cell, always accompanied by sticky chromosomes fragmentation [13]; the hybrid O. sativa × L. peruviana also exhibited apoptosis processes and pycnotic bodies characterized by the elimination of one of the cell nuclei.…”

“…Chromosome elimination is established as a dynamic process of genome stabilization that occurs during hybridization and has been well explored and investigated in wheat with different kinds of Poaceae, among other intergeneric hybrid [12] [13]. Partial or total elimination chromosomes and exchange between parental chromosomes frequently occur during early development of the progeny [14], and present a barrier to the transfer of desirable traits from wild species to cultivated, but may act in favor of crop improvement programs [15] [16].…”

“…Partial or total elimination chromosomes and exchange between parental chromosomes frequently occur during early development of the progeny [14], and present a barrier to the transfer of desirable traits from wild species to cultivated, but may act in favor of crop improvement programs [15] [16]. Chromosome elimination in hybrid is explained by asynchrony during synthesis of nucleoprotein and processes of cell division, multipolar spindles formation, chromosome degradation by specific nucleases, and inactivation of centromeres, incompatibility centromere and kinetochores proteins among parents, nondisjunction of chromosome uniparental during anaphase and micronuclei formation [13] [14] [17]. Other hypotheses pose the separation of the genomes in interphase and metaphase, and elimination nuclear by nuclear extrusion [16].…”

Dihaploid induction in tetraploid durum wheat (Triticum durum L.) using pollen of Imperata cylindrica

“…Among all these available systems of doubled haploid production in wheat, the I. cylindrica-mediated approach has shown its worth in terms of haploid embryo induction frequency not doi: 10.17221/218/2014-CJGPB only in bread wheat but also in triticale × wheat and wheat × rye derivatives Kishore et al 2011). The underlined mechanism behind all the intergeneric hybridization-mediated systems is the elimination of paternal chromosomes during the initial zygotic cell divisions (Komeda et al 2007;Chaudhary et al 2013).…”