Kovtunovych G. Cloning and analysis of structure and function of exopolygalacturonase gene of endophytic bacteria Klebsiella oxytoca VN13

The thesis aims a PhD degree in molecular genetics (speciality 03.00.22) to be awarded. - Institute of Molecular Biology and Genetics of National Academy of Science of Ukraine, Kiev, 2002. This manuscript presents results of investigation of pectolytic system of K. oxytoca VN13, the endophytic bacterium, which is used for inoculant production. Correlation between the bacterial pectolytic activity value, the level of internal colonisation and the bacterial effect to plants have been detected. The pehX gene, coding for exopolygalacturonase was cloned and sequenced. Analysis of the regulatory elements of this gene was accomplished, and the presence of the regulatory sites for KdgR was shown for this bacterium. Analysis of the deduced amino acid sequence for PehX enables to predict existence of the signal sequence in the N-terminus of premature protein. The mutant, defective in PehX production has been constructed, and a role it plays in pectin catabolism and in bacterium-plant interaction was investigated. Uniqueness of the DNA sequence of pehX, was used to develop the method of K. oxytoca differentiation.