Endophytic root fungus Piriformospora indica affects transcription of steviol biosynthesis genes and enhances production of steviol glycosides in Stevia rebaudiana

Stevia rebaudiana (Bertoni) produces low calorie sweeteners, steviol glycosides (SGs) - stevioside and rebaudioside-A. Varying spore concentrations of P. indica were applied to S. rebaudiana grown in vitro and in the greenhouse to examine the effect on plant growth and synthesis of SGs. Symbiotic association of P. indica showed plant growth promotion and higher SGs content. The transcription profiles of eight key genes of the SGs biosynthetic pathway also showed strong upregulation. The results show that the symbiotic effect of P. indica can be utilized to achieve plant growth enhancement in S. rebaudiana along with increased production of SGs.