Effect of the Plant Probiotic Bacteria on TIA Biosynthesis Pathway Gene Expression Profiling, Vinblastine and Vincristine Content in the Root of Catharanthus Roseus

Abstract Catharanthus roseus is the sole resource of vinblastine and vincristine, which are two of the biggest concerns of TIAs because of their powerful anticancer activities. Increasing the concentration of these alkaloids in various organs of the plant is one of the important goals in C. roseus breeding programs. Plant probiotic bacteria (PBB) act as biotic elicitors and can induce the synthesis of secondary products in plants. The purpose of this research is to study the individual and combined effects of P. fluorescens and A. brasilense on expression of the TIA biosynthetic pathway genes (G10H, DAT, T16H and CrPRX) using qRT-PCR and the content of vinblastine and vincristine alkaloids using HPLC method in roots of C. roseus. P. fluorescens drastically increased the content of vinblastine and vincristine alkaloids, compared to the control in the roots, up to 174 and 589 (µg/g), respectively. According to the molecular analysis, bacterium significantly increased the expression of more genes in the TIA biosynthetic pathway compared to the control. P. fluorescens increased the expression of the final gene of the biosynthetic pathway (CrPRX) 47.9 times compared to the control. Therefore, the findings indicate the coordination of transcriptional and metabolic outcomes. The same result was also observed for A. brasilense. According to the results, it can be concluded that, the seed priming and root of the seedling treatments of probiotic bacteria can be used as a good tool in the enhancement of alkaloid contents in medicinal plants, as it provides an eco-friendly approach.