Mitotic behavior in root tips of Brachiaria genotypes with meiotic chromosome elimination during microsporogenesis

Departamento de Biologia Celular e Genética, Universidade Estadual de Maringá, Maringá, PR, Brasil.
Genetics and molecular research: GMR (Impact Factor: 0.78). 02/2008; 7(2):336-41. DOI: 10.4238/vol7-2gmr437
Source: PubMed


Three accessions of Brachiaria brizantha, three of B. humidicola, and two interspecific hybrids between B. ruziziensis and B. brizantha were analyzed with regard to their mitotic behavior in root tips. All these genotypes revealed chromosome elimination or lack of chromosome affinity in previous analyses of microsporogenesis. Analyses of root tips showed a normal mitotic division in all accessions and hybrids, reinforcing the notion that the genetic control of meiosis is totally independent of that of mitosis. The implications of these findings for the Brachiaria breeding program are discussed.

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    • "So far, plants are the only organisms known to show tripolar division as an anomaly during the meiotic division (Silva et al., 2011). A few cases of tripolar division have been reported in plant microspores (Kindiger, 1993; Boldrini et al., 2006; Felismino et al., 2008) and the same anomaly has been recorded in intoxicated plant tissues (Hervas, 1975). It should be noted here that plants typically do not have centrosomes with centrioles; instead, they create highly organized microtubule arrays in the absence of a centralized microtubule organizing center (MTOC) (Hinchcliffe, 2011). "
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    ABSTRACT: Tripolar mitosis is a specific case of cell division driven by typical molecular mechanisms of mitosis, but resulting in three daughter cells instead of the usual count of two. Other variants of multipolar mitosis show even more mitotic poles and are relatively rare. In nature, this phenomenon was frequently observed or suspected in multiple common cancers, infected cells, the placenta, and in early human embryos with impaired pregnancy-yielding potential. Artificial causes include radiation and various toxins. Here we combine several pieces of the most recent evidence for the existence of different types of multipolar mitosis in preimplantation embryos together with a detailed review of the literature. The related molecular and cellular mechanisms are discussed, including the regulation of centriole duplication, mitotic spindle biology, centromere functions, cell cycle checkpoints, mitotic autocorrection mechanisms, and the related complicating factors in healthy and affected cells, including post-mitotic cell-cell fusion often associated with multipolar cell division. Clinical relevance for oncology and embryo selection in assisted reproduction is also briefly discussed in this context. Copyright © 2014 Elsevier GmbH. All rights reserved.
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