Biosynthetic and biocontrol potential of endophytic yeast strains yp6 and ybs14 for improvement the growth and development of solanaceae plants

YP6 was isolated from Triticum aestivum L. seeds and YBS14 was isolated from the roots of Helichrysum italicum L. Partial sequence analysis of ITS5-5.8-ITS4 region of the nuclear ribosomal DNA with universal primers identified YP6 as Pichia fermentans and YBS14 as Saccharomyces cerevisiae. Both yeast strains produced indole-3-acetic acid when cultivated in a medium supplemented with 0.2 % L-tryptophan. The antimicrobial activity of yeast strains against plant pathogenic fungi was determined. YP6 and YBS14 were tested for endophytic colonization of Solanaceae plants by soil drenching and leaf spraying. To establish colonization in the various tissues of tested plants, samples were taken and explants were inoculated on yeast malts agar. The effect of the microbial endophytes on photosynthesis, stomatal conductivity, and transpiration intensity was analyzed by using the portable photosynthetic system for CO2 analysis in plants. In all treated plants photosynthesis was intense and growth stimulation was observed. The final aim of the present study is to evaluate endophytic yeast and demonstrate their PGP activity.