Application of UV-B radiation for enhancing the accumulation of bioactive phenolic compounds in pigeon pea [Cajanus cajan (L.) Millsp.] hairy root cultures

• Published in: Journal of photochemistry and photobiology. B, Biology Biology, 2022-03, Vol.228, p.112406-112406, Article 112406
• Main Authors: Gai, Qing-Yan, Lu, Yao, Jiao, Jiao, Fu, Jin-Xian, Xu, Xiao-Jie, Yao, Lan, Fu, Yu-Jie
• Format: Article
• Language: English
• Subjects: Accumulation; Acids; Biological activity; Biosynthesis; Cajanus; Flavonoids; Flavonoids - metabolism; Gene expression; Hairy root; Metabolic competition; Metabolism; Oxidative stress; Peas; Phenolic compounds; Phenols; Phenols - metabolism; Photobiological responses; Phytochemical biosynthesis; Pigeonpeas; Pisum sativum - metabolism; Plant in vitro cultures; Plant Roots - metabolism; Salicylic acid; Signaling transduction; Strategy; Supplements; Ultraviolet radiation; UV-B radiation
• ISSN: 1011-1344; 1873-2682
• DOI: 10.1016/j.jphotobiol.2022.112406

UV-B radiation is an ideal elicitation strategy for promoting phytochemical accumulation in plant in vitro cultures, associated with various advantages of easy manipulation, cost-effectiveness, no residue, and instantaneous termination. For the first time, UV-B radiation was used to enhance the production of bioactive phenolic compounds (flavonoids and stilbenes) in pigeon pea hairy root cultures (PPHRCs). The total yield of eight flavonoids (414.95 ± 50.68 μg/g DW) in 42-day-old PPHRCs exposed to 4 h of UV-B radiation increased by 1.49-fold as against control, whereas the yield of cajaninstilbene acid (6566.01 ± 702.14 μg/g DW) in PPHRCs undergoing 10 h of UV-B radiation significantly increased by 2.31-fold over control. UV-B radiation was found to induce the oxidative stress in PPHRCs and cause the tissue damage to hairy roots, which improved the levels of endogenous salicylic acid thus triggering the expression of genes involved in phenylpropanoid biosynthesis pathway. And, a regulation competition in metabolic flow dominated by CHS and STS was responsible for the difference in accumulation trends of flavonoids and cajaninstilbene acid. Results of this study not only provide a feasible and simple UV-B supplementation strategy for the enhanced production of bioactive phenolic compounds (especially the high-value cajaninstilbene acid) in PPHRCs, but also contributed to the understanding of photobiological responses related to secondary metabolism. [Display omitted] •UV-B radiation was used for phenolic enhancement in pigeon pea hairy root cultures.•UV-B radiation could increase cajaninstilbene acid yield by 2.31-fold over control.•Accumulation of flavonoids and cajaninstilbene acid showed an inverse relationship.•UV-B radiation triggered some signaling cascades in pigeon pea hairy root cultures.•A regulation competition was found between chalcone synthase and stilbene synthase.