Мейотичні мутанти томату, які виявляють фенотип десинапсису
Aim. A comparative analysis of the cytological manifestation in the meiosis of six meiotic mutants was carried out. Methods. Buds with anthers 2–3 mm long fixed in ethanol: glacial acetic acid in a ratio of 3:1, were stored in 70 % ethanol, stained with acetocarmine. For cytology preparations prepared pressure anthers at various stages of meiosis. Pollen fertility was determined by staining with acetocarmine. Results. Meiotic mutations tomato dsm1, dsm2, dsm3, as1, as5 and asb not affect the vegetative growth of plants, but have low fertility of pollen and number of seeds in the fruit. They are similar cytological manifestation. The beginning of meiosis occurred apparently normal, as violations of premature decay bivalent observed since diplotenе. Chiasma frequencies in pollen mother cells ranged from 8.13 to dsm3 / dsm3 to 6.73 in asb / asb. All investigated mutations revealed monogenic recessive character of inheritance. Mutations as1, as5 and asb and dsm2 are not allelic to each other. The mutation dsm1 appeared allelic to mutations dsm2 and asb. Conclusions. Investigated meiotic mutations failure of chiasma maintenance in the pollen mother cells with varying degrees of desynapsis. Based on the fact that the previously published data did not reveal a reduction in the recombination frequency in marked areas of the genome, we anticipate premature removal of cohesin that hold sister chromatids distal chiasmata.
Keywords: meiosis, meiotic mutants, sister chromatids cohesion, premature separation of the bivalents, Lycopersicon esculentum Mill.