Identification of chromosomal deficiency by flow cytometry and cytogenetics in mutant tomato (Solanum lycopersicum, Solanaceae) plants

Abstract

Structural chromosomal aberrations can occur spontaneously in plant karyotypes as a result of both intrinsic and extrinsic factors. These aberrations may affect sporophyte fitness because fundamental genes involved with distinct morphogenic process may be lost. Inadequate development of flowers and anomalous fruits without seeds has been observed in plants of Solanum lycopersicum L. (Solanaceae) ‘BHG 160’ of the tomato germplasm bank (Universidade Federal de Viçosa, Brazil). The nuclear DNA content, quantified by flow cytometry, showed that mutant ‘BHG 160’ possesses 0.09 pg (4.59%) less nuclear DNA content than does the wild-type ‘BGH 160’. Improved cytogenetical preparations evidenced that this difference was due to a spontaneous terminal deficiency in the short arm of the mutant ‘BGH 160’ Chromosome 1. These results suggest that the genes encoded in the short arm of Chromosome 1 may be involved in the development of flowers and fruits in the tomato.

Cytogenetic and identification of the nucleolus organizer region in Heliconia bihai (L.) L.

“…The action of the pectinase enzyme, at 35°C for 2 h, was effective in eliminating the cell wall without damaging the structure of chromatin, so a proper staining with Giemsa at 5% and pH 7.0 was achieved. Similar results, using the inhibitor agent APM and Giemsa staining at 5% were obtained with Coffea arabica (L.) , Solanum esculentum (L.) (Karsburg et al, 2009) and Carica papaya (L.) (Araújo et al, 2010).…”

“…Identical results, regarded to the quality of mitotic metaphase, were obtained with Solanum esculentum (Karsburg et al, 2009), Capsicum annuum (L.) (Abreu et al, 2008), Jatropha curcas (L.) , Psychotria ipecacuanha [(Brot.) Stoves] (Rossi et al, 2008) and Carica papaya L. (Araújo et al, 2010).…”

“…The blocking agents, such as APM, are essential for studying the chromosomes, for preventing the formation of the spindle and accumulating sufficient number of metaphase for a proper morphometric analysis, enabling the classification and identification of homologous pairs (Singh, 1993;Araújo, 2008;Rossi et al, 2008;Karsburg et al, 2009). Using APM also results in elongated chromosomes, with adequate compression for cytogenetic analysis (Planchais et al, 2000).…”

“…The use of fixative solutions also prevents the action of endonucleases, which permits detailed characterization of the karyotype of the species under study (Sumner 1990;Sybenga, 1992), as well as increases basophilia of the chromosomes, facilitating their coloration (Sharma & Sharma, 1999cited by Araújo, 2008. Moreover, the techniques of enzymatic maceration, cell dissociation and air drying enable obtaining slides with prometaphase and metaphase chromosomes, spread with no overlaps and in the same focal plane (Carvalho, 1995;Araújo, 2008;Rossi et al, 2008;Karsburg et al, 2009).…”

Karyotype variation in cultivars and spontaneous cocoa mutants (Theobroma cacao L.)

“…The presence of univalents and other meiotic abnormalities has been reported in some T. cacao cultivars (Carletto, 1946;Opeke and Jacob, 1967). Despite the greater tolerance of plants to structural and numerical chromosomal changes such as aneuploidies (Matzke et al, 2003), aberrant morphological features and reproductive changes or losses may be related to karyotypic changes (Karsburg et al, 2009). Nevertheless, the morphological features observed in T. cacao are mostly associated with recessive genes.…”