Browsing by Subject "Yeast isolation"

Yeasts have huge agricultural, medical and economic importance, and consequently, their isolation and identification are needed for more potential microbe resources. Studies of plant-microbe interaction have revealed many molecular mechanisms using mostly filamentous fungi, bacteria and viruses. However, our knowledge of yeast-plant interactions is lagging behind and there is a lack of yeasts known to interact with the model plant Arabidopsis. There were two major aims of this study: isolating and identifying the yeasts from wild growing Arabidopsis, as well as screening possible immunity modulation patterns of the strains against Arabidopsis. More than 70 yeast strains were isolated and identified belonging to 6 genera, suggesting the huge abundance of yeast diversity on plant surface. With the help of phylogenetic analysis of sequences from the internal transcription spacer (ITS) and D1/D2 region of 28S ribosomal DNA large subunit, one strain within the genus of Protomyces is proposed to be a novel species. Further carbon assimilation tests confirmed this, demonstrating differences of assimilation patterns between the new strain and all well described species in this genus. Another interesting finding was the possible pathogenicity of several yeast strains. Significant disease-like symptoms appeared on Arabidopsis five days after infiltration. Additionally, two strains synthesized auxin or related compounds in culture. Although more infections are necessary to confirm the pathogenicity, these have potential for development of new systems to study plant-yeast interactions with the genetic model plant Arabidopsis. The mechanism of yeast pathogenesis will provide new knowledge about plant defense and further assists plant breeding to produce crops with more durable resistance.