Plant Molecular Cytogenetics and Plant Biotechnology Laboratory, Department of Botany, Centre of Advanced Studies, University of Calcutta, Kolkata, West Bengal, 700019, India.
Planta. 2021 Jul 5;254(2):23. doi: 10.1007/s00425-021-03674-5.
Greening of in vitro callus cultures and andrographolide over-accumulation was achieved by manipulating light exposure and media composition, when the biosynthetic cascade was channeled through the DXP pathway. Andrographolide, the primary biologically active compound of Andrographis paniculata, is produced through coordinated action of two pathways, the classical cytosolic mevalonate pathway and the alternative plastidial non-mevalonate pathway (Deoxy-xylulose Phosphate pathway). In vitro callus cultures of A. paniculata are useful sources of production, as well as, manipulation of andrographolide, and the present study was designed to explore the strategy of pathway inhibition for its overproduction. When the cytosolic mevalonate pathway blocker, lovastatin, was applied to callus cultures of A. paniculata, andrographolide production was enhanced in comparison to untreated control. In contrast, treatment of the callus tissue with the DXP-pathway blocker, fosmidomycin, led to depletion in andrographolide production. The present study also showed that silver nitrate, a potent elicitor of andrographolide production in in vitro callus culture, when added in combination with the pathway inhibitors resulted in alterations in andrographolide production. The highest andrographolide production was obtained in callus treated with a combination of silver nitrate and lovastatin, indicating a predominant role of the plastidial DXP pathway in andrographolide biosynthesis. A positive co-relation with chlorophyll content and andrographolide production in in vitro callus cultures (untreated and treated) observed also supported the above assumption. It could be inferred from this study that greening of callus tissue through organellar organization was a potent strategy for enhancing andrographolide accumulation in callus tissues of A. paniculata.
通过操纵光照和培养基组成，当生物合成级联通过 DXP 途径进行时，实现了体外愈伤组织培养的绿色化和穿心莲内酯的过度积累。穿心莲内酯是穿心莲的主要生物活性化合物，通过两条途径的协同作用产生，即经典的细胞质甲羟戊酸途径和替代的质体非甲羟戊酸途径（脱氧木酮糖磷酸途径）。A. paniculata 的体外愈伤组织培养物是生产以及操纵穿心莲内酯的有用来源，本研究旨在探索其过度生产的途径抑制策略。当将细胞质甲羟戊酸途径抑制剂 lovastatin 应用于 A. paniculata 的愈伤组织培养物时，与未处理的对照相比，穿心莲内酯的产生得到了增强。相比之下，用 DXP-途径抑制剂 fosmidomycin 处理愈伤组织会导致穿心莲内酯的产生减少。本研究还表明，硝酸银是体外愈伤组织培养物中穿心莲内酯生产的有效诱导剂，当与途径抑制剂一起添加时，会导致穿心莲内酯的产生发生变化。在与硝酸银和 lovastatin 组合处理的愈伤组织中获得了最高的穿心莲内酯产量，这表明质体 DXP 途径在穿心莲内酯生物合成中起主要作用。在未处理和处理的体外愈伤组织培养物中观察到的叶绿素含量与穿心莲内酯产量之间的正相关关系也支持了上述假设。可以从这项研究中推断出，通过细胞器组织化使愈伤组织变绿是增强 A. paniculata 愈伤组织中穿心莲内酯积累的有效策略。
