Lar O. Cloning and analysis of the structure and a character of expression of exo- pectate lyase gene of endophytic bacteria Klebsiella oxytoca VN13

3 This manuscript presents results of investigation of the pectate lyase activity of endophytic bacteria Klebsiella oxytoca VN13, which is used for inoculant production. The pelX gene of Klebsiella oxytoca VN13, coding for the pectate lyase activity, was cloned and sequenced. Coding and regulatory regions of pelX were analyzed. Two boxes for the KdgR repressor binding located in the promoter region were founded. Amino- terminal signal sequence for PelX was deduced, this indicate possible extracytoplasmatic location of PelX protein. The mutant with the defect chromosomal copy of the pelX gene has been constructed and the presence of additional pectate lyase gene (-s) in the Klebsiella oxytoca VN13 genome was revealed. Fusion of the pelX promoter part and the coding part of the lacZ gene, coding for ? - galactosidase activity, has been constructed. Constitutive character of the pelX expression and the absence of the pelX expression level elevation, when the polygalacturonate and the plant extract are added, indicate the possible role of pelX as the pectinolysis activator. The possibility of the control mechanism for pectolytic activity and the number of bacteria associated with the internal plants tissues are surmise. It is possible, that the plant is able to produce certain substances- bacteria pectinase production inhibitors.