Fungal endophytes of Catharanthus roseus enhance vindoline content by modulating structural and regulatory genes related to terpenoid indole alkaloid biosynthesis

• Published in: Scientific reports Vol. 6; no. 1; p. 26583
• Main Authors: Pandey, Shiv S., Singh, Sucheta, Babu, C. S. Vivek, Shanker, Karuna, Srivastava, N. K., Shukla, Ashutosh K., Kalra, Alok
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 25.05.2016; Nature Publishing Group
• Subjects: 38; 38/22; 38/23; 631/326/2522; 631/449/2667; Acetyltransferase; Biomass; Biosynthesis; Carbon dioxide; Catharanthus - genetics; Catharanthus - metabolism; Catharanthus - microbiology; Endophytes; Endophytes - growth & development; Gene Expression Regulation, Plant; Genes; Host plants; Humanities and Social Sciences; Hydroxylase; Indoles; Inoculation; Metabolism; Metabolites; Methyltransferase; Mucorales - growth & development; multidisciplinary; Peroxidase; Photosystem II; Plant biomass; Plant Leaves - genetics; Plant Leaves - metabolism; Plant Leaves - microbiology; Repressors; Science; Starch; Strictosidine synthase; Transcription factors; Tryptophan; Vinblastine - analogs & derivatives; Vinblastine - metabolism; Vindoline; Zinc finger proteins
• DOI: 10.1038/srep26583
• ISSN: 2045-2322

Not much is known about the mechanism of endophyte-mediated induction of secondary metabolite production in Catharanthus roseus . In the present study two fungal endophytes, Curvularia sp. CATDLF5 and Choanephora infundibulifera CATDLF6 were isolated from the leaves of the plant that were found to enhance vindoline content by 229–403%. The isolated endophytes did not affect the primary metabolism of the plant as the maximum quantum efficiency of PSII, net CO 2 assimilation, plant biomass and starch content of endophyte-inoculated plants was similar to endophyte-free control plants. Expression of terpenoid indole alkaloid (TIA) pathway genes, geraniol 10-hydroxylase ( G10H ), tryptophan decarboxylase ( TDC ), strictosidine synthase ( STR ), 16-hydoxytabersonine- O -methyltransferase ( 16OMT ), desacetoxyvindoline-4-hydroxylase ( D4H ), deacetylvindoline-4- O -acetyltransferase ( DAT ) were upregulated in endophyte-inoculated plants. Endophyte inoculation upregulated the expression of the gene for transcriptional activator octadecanoid-responsive Catharanthus AP2-domain protein ( ORCA3 ) and downregulated the expression of Cys2/His2-type zinc finger protein family transcriptional repressors ( ZCTs ). The gene for the vacuolar class III peroxidase ( PRX1 ), responsible for coupling vindoline and catharanthine, was upregulated in endophyte-inoculated plants. These endophytes may enhance vindoline production by modulating the expression of key structural and regulatory genes of vindoline biosynthesis without affecting the primary metabolism of the host plant.