Functional analysis of zoysiagrass chitinase genes

Abstract

In this study, we isolated two full-length chitinase genes, class I chitinase (Zjchi1) and class II chitinase (Zjchi2) from zoysiagrass. Structural property and expression analysis of these genes was performed. Furthermore, the two chitinases were overexpressed in Escherichia coli and purified for assessment of their in vitro antifungal activity. Also, we generated transgenic zoysiagrass that overexpressed the class II chitinase gene (Zjchi2) via Agrobacterium-mediated transformation from zoysiagrass calluses, although its monocot and plant regeneration is normally difficult (Toyama et al. 2003; Poeaim et al. 2005). Southern blot hybridization and polymerase chain reaction (PCR) were performed to confirm the transgenes insertion in the transgenic zoysiagrass. Furthermore, the antifungal activity was investigated to examine the disease resistance of transgenic zoysiagrass to R. solani AG2-2 (IV). To our knowledge, this study is the first to verify the antifungal activity of a class II chitinase in transgenic zoysiagrass.