分类: 化学 >> 物理化学 提交时间: 2017-11-05 合作期刊: 《结构化学》
摘要: Using 4΄-methoxy-5-hydroxyisoflavone and 4΄,5-dihydroxy-7-methoxyisoflavone as leding compounds, 6-methoxy-2H-phenanthro[9,10-c]pyrazol-11-ol (1a) and 9-methoxy-2H-phenanthro [9,10-c]pyrazol-6,11-diol (1b) were synthesized by two dehydration processes in the EtOH solution. They were characterized by IR, 1H NMR and 13C NMR. The black prism crystal of 1a was grown by the slow solvent evaporation technique from 40:1 (v/v) CHCl3/MeOH, and it was determined by single-crystal X-ray diffraction. In the crystal structure, 1a was stabilized by intramolecular (O–H···N) and intermolecular (N–H···O, O–H···O, π···π, C–H···π) interactions. In addition, the fluorescence properties of 1a and 1b in the base and neutral media revealed that they possessed excited state intramolecular proton transfer phenomena (ESIPT).
分类: 生物学 >> 植物学 >> 植物生物化学、植物生物物理学 提交时间: 2016-05-04
摘要: MtPAR is a proanthocyanidin (PA) biosynthesis regulator; the mechanism underlying its promotion of PA biosynthesis is not fully understood. Here, we showed that MtPAR promotes PA production by a direct repression of biosynthesis of isoflavones, the major flavonoids in legume, and by redirecting immediate precursors, such as anthocyanidins, flux into PA pathway. Ectopic expression of MtPAR repressed isoflavonoid production by directly binding and suppressing isoflavone biosynthetic genes such as isoflavone synthase (IFS). Meanwhile, MtPAR up-regulated PA-specific genes and decreased the anthocyanin levels without altering the expression of anthocyanin biosynthetic genes. MtPAR may shift the anthocyanidin precursor flux from anthocyanin pathway to PA biosynthesis. MtPAR complemented PA-deficient phenotype of Arabidopsis tt2 mutant seeds, demonstrating their similar action on PA production. We showed the direct interactions between MtPAR, MtTT8 and MtWD40-1 proteins from Medicago truncatula and Glycine max, to form a ternary complex to trans-activate PA-specific ANR gene. Finally, MtPAR expression in alfalfa (Medicago sativa) hairy roots and whole plants only promoted the production of small amount of PAs, which was significantly enhanced by co-expression of MtPAR and MtLAP1. Transcriptomic and metabolite profiling showed an additive effect between MtPAR and MtLAP1 on the production of PAs, supporting that efficient PA production requires more anthocyanidin precursors. This study provides new insights into the role and mechanism of MtPAR in partitioning precursors from isoflavone and anthocyanin pathways into PA pathways for a specific promotion of PA production. Based on this, a strategy by combining MtPAR and MtLAP1 co-expression to effectively improve metabolic engineering performance of PA production in legume forage was developed.