(485bl) Effects of Nitric Oxide On Growth, Terpenoid Indole Alkaloid Production and Some of the TIAs Genes Transcripts in Catharanthus Roseus Hairy Root Cultures

Nitric oxide (NO) is a signaling molecule involved in elicitor-induced defense responses of plants. Sodium nitroprusside (SNP) is a spontaneous NO donor, releasing NO upon dissolution in aqueous solvents not requiring enzymatic reduction or hydrolysis. A number of important pharmaceutically valuable terpenoid indole alkaloids (TIAs) are produced in Catharanthus roseus. We are interested in engineering C. roseus hairy roots to increase the production of the TIAs. The present work investigates the effects of feeding different concentrations of SNP in the hairy root cultures from line LBE-6-1. The alkaloid concentrations were analyzed 9, 14, 17, 20, 23, 26 and 30 days after feeding of SNP on day 0, meanwhile some of the TIA genes transcripts level were examined on 20, 23, 26 and 30 days. We also studied the transient effects of SNP feeding during the exponential phase in C. roseus hairy roots.

Analysis of the results showed that feeding 0.1 mM SNP did not affect the growth of hairy roots, while 1 mM SNP suppressed the growth significantly, and 10 mM SNP almost completely inhibited the growth of hairy roots. 0.1 mM SNP feeding on day 0 caused a significant increase in the concentration of serpentine, catharanthine, ajmalicine, lochnericine and tabersonine production. SNP feeding on day 12 stimulated the formation of serpentine, catharanthine, ajmalicine, hörhammericine, lochnericine and tabersonine by day 21. After the initial stimulation, serpentine, ajmalicine and lochnericine concentrations returned to the normal level by day 28. Feeding 0.1mM of SNP on day 0 caused significant decrease in the mRNA levels for ASA, STR, ORCA3, ZCT1 and Crgbf1 on day 23, and the mRNA levels for ASA, STR and Crgbf1 returned to the similar level of the control. Feeding 0.1mM SNP on day 12 also caused the decrease in the expression levels of STR, ORCA3, ZCT1 and Crgbf1 on day 21 and day 28.