Mahood Huda E, Sarropoulou Virginia, Tzatzani Thiresia-Teresa
Department of Horticulture, College of Agriculture, University of Al-Qadisiyah, Al Diwaniyah, 58002, Iraq.
Institute of Plant Breeding and Genetic Resources, Laboratory of Protection and Evaluation of Native and Floriculture Species, Hellenic Agricultural Organization (HAO)-DEMETER, Balkan Botanic Garden of Kroussia, Thermi, P.O. Box 60458, P.C. 570 01, Thessaloniki, Greece.
Bioresour Bioprocess. 2022 Sep 16;9(1):100. doi: 10.1186/s40643-022-00588-2.
Gazania rigens (L.) Gaertn. (Asteraceae) is a medicinal plant with high ornamental potential and use in landscaping. The therapeutic potential of sesquiterpene lactones (SLs) as plant natural products for pharmaceutical development has gained extensive interest with costunolide (chemical name: 6E,10E,11aR-6,10-dimethyl-3-methylidene-3a,4,5,8,9,11a-hexahydrocyclodeca[b]furan-2-one) used as a popular herbal remedy due to its anti-cancer, antioxidant, anti-inflammatory, anti-microbial, anti-allergic, and anti-diabetic activities, among others. In the present study, two explant types (leaf, stem) and four 2,4-dichlorophenoxy acetic acid (2,4-D) concentrations (0, 0.5, 1 and 2 mg/L) were tested for callusing potential. The results showed that stem explants treated with 1.5 mg/L 2,4-D exhibited higher callus induction percentage (90%) followed by leaf explants (80%) with 1 mg/L 2,4-D, after a 4-week period. Cell suspension cultures were established from friable callus obtained from stem explants following a sigmoid pattern of growth curve with a maximum fresh weight at 20 days of subculture and a minimum one at 5 days of subculture. In the following stage, the effects of elicitation of cell suspension cultures with either yeast extract (YE) or methyl jasmonate (MeJA), each applied in five concentrations (0, 100, 150, 200 and 250 mg/L) on cell growth (fresh and dry biomass) and costunolide accumulation were tested. After 20 days of culture, YE or MeJA suppressed cell growth as compared to the non-elicited cells, while costunolide accumulation was better enhanced under the effect of 150 mg/L MeJA followed by 200 mg/L YE, respectively. In the subsequent experiment conducted, the optimal concentration of the two elicitors (200 mg/L YE, 150 mg/L MeJA) was selected to investigate further elicitation time (0, 5, 10, 15 and 20 days). The results revealed that YE biotic elicitation stimulated cell growth and costunolide production, being maximum on day 20 for fresh biomass, on day 5 for dry biomass and on day 15 for the bioactive compound. Accordingly, cell growth parameters were maximized under the effect of abiotic elicitation with MeJA for 15 days, while highest costunolide content was achieved after 10 days. Overall, MeJA served as a better elicitor type than YE for biomass and costunolide production. Irrespective of elicitor type, elicitor concentration and elicitation time, maximal response was obtained with 150 mg/L MeJA for 10 days regarding costunolide accumulation (18.47 ppm) and 15 days for cell growth (fresh weight: 954 mg and dry weight: 76.3 mg). The application of elicitors can lead the large quantity of costunolide to encounter extensive range demand through marketable production without endangering of G. rigens.
勋章菊（学名：Gazania rigens (L.) Gaertn.，菊科）是一种具有很高观赏潜力且可用于园林绿化的药用植物。倍半萜内酯（SLs）作为用于药物开发的植物天然产物，其治疗潜力已引起广泛关注，其中木香烃内酯（化学名称：6E,10E,11aR - 6,10 - 二甲基 - 3 - 亚甲基 - 3a,4,5,8,9,11a - 六氢环癸[b]呋喃 - 2 - 酮）因其抗癌、抗氧化、抗炎、抗菌、抗过敏和抗糖尿病等活性而成为一种受欢迎的草药。在本研究中，测试了两种外植体类型（叶片、茎段）和四种2,4 - 二氯苯氧乙酸（2,4 - D）浓度（0、0.5、1和2 mg/L）的愈伤组织诱导潜力。结果表明，在4周培养期后，用1.5 mg/L 2,4 - D处理的茎段外植体愈伤组织诱导率较高（90%），其次是用1 mg/L 2,4 - D处理的叶片外植体（80%）。从茎段外植体获得的易碎愈伤组织建立了细胞悬浮培养物，其生长曲线呈S形，继代培养20天时鲜重最大，继代培养5天时鲜重最小。在接下来的阶段，测试了用酵母提取物（YE）或茉莉酸甲酯（MeJA）以五种浓度（0、100、150、200和250 mg/L）诱导细胞悬浮培养物对细胞生长（鲜重和干重）以及木香烃内酯积累的影响。培养20天后，与未诱导的细胞相比，YE或MeJA抑制了细胞生长，而在150 mg/L MeJA的作用下木香烃内酯积累得到更好的增强，其次分别是200 mg/L YE。在随后进行的实验中，选择两种诱导剂的最佳浓度（200 mg/L YE，150 mg/L MeJA）来进一步研究诱导时间（0、5、10、15和20天）。结果表明，YE生物诱导刺激了细胞生长和木香烃内酯的产生，鲜重在第20天达到最大值，干重在第5天达到最大值，生物活性化合物在第15天达到最大值。因此，在MeJA非生物诱导15天的作用下细胞生长参数达到最大值，而在10天后木香烃内酯含量最高。总体而言，对于生物量和木香烃内酯的产生，MeJA作为一种诱导剂类型比YE更好。无论诱导剂类型、诱导剂浓度和诱导时间如何，在木香烃内酯积累方面（18.47 ppm），150 mg/L MeJA处理10天以及在细胞生长方面（鲜重：954 mg，干重：76.3 mg）150 mg/L MeJA处理15天均获得了最大响应。诱导剂的应用可以通过商业化生产使大量的木香烃内酯满足广泛的市场需求，而不会危及勋章菊。
