Effect of the plant probiotic bacteria on terpenoid indole alkaloid biosynthesis pathway gene expression profiling, vinblastine and vincristine content in the root of Catharanthus roseus

Background Catharanthus roseus is the sole resource of vinblastine and vincristine, two TIAs of great interest for 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 effects of PBB on expression of the TIA biosynthetic pathway genes and the content of alkaloids in C. roseus. Methods and results The individual and combined effects of P. fluorescens strains 169 and A. brasilense strains Ab-101 was studied for expression of the TIA biosynthetic pathway genes (G10H, DAT, T16H and CrPRX) using qRT-PCR and the content of vinblastine and vincristine using HPLC method in roots of C. roseus. P. fluorescens. This drastically increased the content of vinblastine and vincristine alkaloids, compared to the control in the roots, to 174 and 589 (mu g/g), respectively. Molecular analysis showed 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. Our findings indicate the correlation between transcriptional and metabolic outcomes. The same was true for A. brasilense. Conclusions It can be concluded that seed treatments and seedling root treatments composed of naturally occurring probiotic bacteria are likely to be widely applicable for inducing enhanced alkaloid contents in medicinal plants.

Automated summary

This study investigated the effects of plant probiotic bacteria on the expression of TIA biosynthetic pathway genes and alkaloid content in Catharanthus roseus. The results showed that P. fluorescens and A. brasilense significantly increased the alkaloid content in roots, as well as the expression of genes in the biosynthetic pathway. The findings suggest that seed and seedling root treatments with naturally occurring probiotic bacteria could be effective in enhancing alkaloid contents in medicinal plants.