Determination of changes in alliinase gene expression during storage in garlic

Garlic has a distinctive pungent and characteristic odor. Allicin which is one of major sulfur compounds in garlic gives garlic odor. The enzyme coded by allinase gene coverts alliin precursor to the allicin. The aims of this master thesis were to determine the allinase gene expression during storage in garlic by Real-Time PCR analysis and to compare with alliin and allicin contents. In this thesis, Kastamonu and PI515971 garlic genotypes were stored at 4ºC and 21ºC for 12 weeks. After total RNA isolation and cDNA synthesis from the samples taken at the end of the storage, changes in relative allinase gene expression were determined by Real-Time PCR analysis by using actin reference gene. According to the results of Real-Time PCR analysis, significant increases in the relative allinase gene expression were observed in Kastamonu and PI515971 samples stored at 4ºC ve 21ºC compared to pre storage samples. The relative gene expression level of Kastamonu genotype was 12,85 in pre-storage samples and increased about 2,5 times to 32,37 at 4ºC, and increased approximately 3 times to 39.15 at 21ºC. A significant difference was found between 4ºC and 21ºC treatments. In the PI515971 garlic genotype, the expression was 18,08 in pre-storage samples and it increased about 5 times to 87,9 at 4ºC and increased about 5 times to 88,9 at 21ºC. There is no significant difference between 4ºC and 21ºC treatments in PI515971 garlic genotype. In addition, significant correlations were detected between increase of allinase expression level and increase of alliin and allicin contents. In conclusion, there is no significant difference between storage temperatures in terms of effect to allinase gene expression level and the increase in relative allinase gene expression during storage at 4ºC and 21ºC occurred in parallel with increase in contents of alliin and allicin.