Reference

Inhibition of flavonoid biosynthesis by gibberellic acid in cell suspension cultures of Daucus carota L

Inhibition of flavonoid biosynthesis by gibberellic acid in cell suspension cultures of Daucus carota L. Hinderer, W.; Petersen, M.; Seitz, H. U. (Inst. Biol. I, Univ. Tuebingen, Tuebingen D-7400, Fed. Rep. Ger.). Planta, 160(6), 544-9 (English) 1984. CODEN: PLANAB. ISSN: 0032-0935. DOCUMENT TYPE: Journal CA Section: 5 (Agrochemical Bioregulators) In carrot cells (D. carota), cultured in the presence of gibberellic acid [77-06-5], anthocyanin synthesis is blocked at the level of chalcone synthase [56803-04-4]. By feeding suitable precursors for anthocyanins (naringenin [480-41-1], eriodictyol [552-58-9], dihydroquercetin [480-18-2]) biosynthesis of cyanidin glycosides can be restored. After addn. of these substrates to the culture medium in the presence of gibberellic acid, the activity of chalcone synthase remained as low as in the control without precursors. The highest increase in anthocyanin content was achieved using dihydroquercetin as the added precursor. The time course of this supplementation showed a rapid response; within 4 h a substantial increase in anthocyanin could be obsd. In contrast, the flavonol quercetin [117-39-5] is not a precursor for cyanidin. Apparently, hydroxylation in 3'-position of ring B in D. carota takes place at the flavonoid stage since naringenin was accepted for cyanidin synthesis.

Naringenin induces the nodABC promotor of Rhizobium leguminosarum as well as Tsr factor production

Naringenin induces the nodABC promotor of Rhizobium leguminosarum as well as Tsr factor production. Zaat, S. A. J.; Van Brussel, A. A. N.; Wijffelman, C. A.; Spaink, H. P.; Okker, R. H. J.; Pees, E.; Lugtenberg, B. J. J. (Dep. Plant Mol. Biol., Univ. Leiden, Leiden 2311 VJ, Neth.). Mol. Genet. Plant-Microbe Interact., Proc. Int. Symp., 3rd, Meeting Date 1986, 247-9. Edited by: Verma, Desh Pal S. 480-41-1 and 520-36-5 are also in the experiment.; Brisson, Normand. Nijhoff: Dordrecht, Neth. (English) 1987. CODEN: 55OMA2. DOCUMENT TYPE: Conference CA Section: 3 (Biochemical Genetics) Section cross-reference(s): 11 The R. leguminosarum nodulation operon nodABC promoter fused to the lacZ gene on plasmid pMP154 was used to detect nod gene inducers by monitoring b-galactosidase formation. Naringenin [480-41-1], eriodictyol [552-58-9], apigenin [520-36-5], and luteolin [491-70-3], like Vicia sativa exudate, induced enzyme formation from the nodABC promoter. Induction by naringenin was kinetically similar to that by V. sativa root exudate, and narigenin could replace exudate for Tsr-factor prodn. in Sym plasmid-contg. R. leguminosarum. Apparently, Tsr-factor is an endogenous bacterial product, or naringenin, as well as the inducer in exudate, can be converted into Tsr-factor. .