Molecular analysis of genes mediating T-DNA trafficking inside yeast cells

Abstract

Agrobacterium tumefaciens is a natural plant pathogen, capable of transfecting its host via a transferable genetic element termed, T-DNA once induced. The single strand T-DNA molecule is exported from the bacterium and transported to the host cell nucleus as a nucleoprotein termed the T-complex, where it becomes double stranded and in the case of planta incorporates into the genome. Little is known about the post-transfection pathway involved in trafficking the T-complex to the nucleus. This study introduces the fission yeast (Schizosaccharomyces pombe) as a novel and powerful host to study factors involved in Agrobacterium-mediated transformation. The pre-established budding yeast (Saccharomyces cerevisiae) model was exploited to corroborate findings and together provide a working model of nucleoprotein trafficking inside eukaryotic cells. By assaying an array of fission and budding yeast mutants the mechanisms involved in host cell entry, active transport through the cytoplasm and nuclear import were all examined as a function of Agrobacterium-mediated transformation efficiency. Such results present an insight into the trafficking of infecting viruses to the eukaryote host nucleus during the early stage of infection.