engleski

Reduced fertility and meiotic abnormalities in the late generations of telomerase-deficient Arabidopsis thaliana

Here we report the consequences of telomere erosion in Arabidosis thaliana by examining seeds and polen production and the course of male meiosis through the last five generation of telomerase-deficient mutants of Arabidopsis (G5-G9). We used previously described mutant line in which the activity of the enzyme telomerase has been abolished by T-DNA insertion in the TERT gene of telomerase reverse transcriptase. Decline in fertility accompanied by morphological abnormalities occurred in the sixth generation (G6), which produced on average 35 seeds per silique (43 in wt) and worsened in the generations G7 and G8, which produced 30 and 14 seeds per silique respectively and exhibited numerous morphological abnormalities. The last generation of tert mutants, G9, did not produce the reproductive organs. Analysis of meiosis indicated that the main cause of reduced fertility in the late generation tert mutants in Arabidopsis are numerous chromosomal end-to-end fusions that lead to massive genome rearrangements in meiocytes. Fusions of meiotic chromosomes began in the G5 and they deteriorated in each of the next generations. Additionally, unpaired chromosomes (univalents) were observed in the G7 and G8. The study also points to some differences in meiotic consequences of telomere shortening between plant and animal systems.

telomere ; meiosis ; telomerase-deficient Arabidopsis thaliana ; chromosome fusions ; aneuploidy

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