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Genetická determinance dormance druhu Prunus armeniaca (L.)
Čechová, Jana
As achieving higher frost resistance is one of the apricot breeding goals in the Czech Republic, it is important to obtain a deeper understanding of the genetic background of the exit from endogenous dormancy for apricot flower buds. The reason is that frost resistance of flower buds is significantly reduced after exit from endogenous dormancy. The aim of this work was to contribute to the understanding of the process of exit of various plant tissues from dormancy, as the problem is very complex and containing a number of physiological processes that are controlled by the function and regulation of many various substances and corresponding genes. The time of exit of flower buds from endogenous dormancy was established by counting of flowering buds on sampled twigs after their transport to laboratory conditions. Furthermore, the production of ethylene, ethane, and CO2 was monitored for sampled twigs with flower and leaf buds. Other physiological parameters monitored during the course of this study were the level of abscisic acid in flower buds and their weigh during the sampling close to the period of exit from endogenous dormancy. An analysis of transcriptome using the cDNA-AFLP method was carried out on four apricot variants ('Sundrop', SEO, 'Vestra' a 'Betinka') to achieve a deeper understanding of the genetic background of exit of flower buds from endogenous dormancy. The transcription profiles obtained from this experiment were evaluated for changes in the expression profiles and fragments of genes with modified expression during the monitored period were sequenced identified. Obtained sequences were compared with sequences in electronic databases (NCBI and TIGR). The results of this comparison led to the identification of a number of the sequenced genes. The results of this study confirmed the suitability of use of the cDNA-AFLP method for the identification of gene candidates and getting a preliminary picture of the main molecular mechanisms taking place during the time of exit of flower buds from endogenous dormancy. The suitability of the used procedure was confirmed by the match between the genes identified from the sequencing and genes already described in the literature as being linked to the exit of plants from endogenous dormancy (e.g. gene coding for acquaporin, GTP-binding proteins, elongation factor 1 alpha, ubiquitin, and xyloglucan endotransglycosylase hydrolase). Measurements of concentration of selected substances during exit from endogenous dormancy do not allow definite conclusions about their influence on this process. On the other hand were identified several genes that might be candidates for markers identifying the output timing of endogenous dormancy of buds and provide a good starting point for further scientific research in this field.
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