PI-55 is a selective cytokinin receptor antagonist with an IC₅₀ of approximately 1–5µM for receptor inhibition[1]. PI-55 targets Arabidopsis thaliana histidine kinase receptors CRE1/AHK4 and AHK3, and competitively blocks natural cytokinins such as trans-zeatin[2]. Applications of PI-55 are mainly in plant developmental biology and plant stress physiology research, including organogenesis and cadmium stress tolerance[3].
In Arabidopsis thaliana ARR5:GUS reporter assays, PI-55 competitively blocked trans-zeatin with an IC₅₀ of ~1–5µM, reducing cytokinin-induced signaling at 1–50µM for 30min to several hours[4]. In cultures of medicinal plants such as Bulbine natalensis and Rumex crispus, treatment with 0.01–10µM for 7–21 days suppressed shoot induction, promoted root growth, and under cadmium stress improved biomass and antioxidant status[5].
PI-55 at 0.1–10µM for 7–21 days in growth medium decreased ARR5:GUS reporter activity in Arabidopsis thaliana seedlings and modified root development. PI-55 at 0.01–10µM for 14–21 days in MS medium alleviated cadmium-induced growth inhibition in Eucomis autumnalis plantlets, increasing biomass and antioxidant capacity[4]. PI-55 at 0.01–10µM for 14–21 days in MS medium mitigated cadmium stress in Bulbine natalensis and Rumex crispus seedlings, maintaining higher fresh weight and balanced hormone levels[6].
References:
[1] Spíchal, Lukás et al. “The purine derivative PI-55 blocks cytokinin action via receptor inhibition.” The FEBS journal vol. 276,1 (2009): 244-53.
[2] Nisler, Jaroslav et al. “Cytokinin receptor antagonists derived from 6-benzylaminopurine.” Phytochemistry vol. 71,7 (2010): 823-30.
[3] Gemrotová, M., et al. “Seedlings of Medicinal Plants Treated with Cytokinin Antagonist PI‑55 or INCYDE Are Protected against Cadmium Stress.” Plant Growth Regulation vol. 71, 2 (2013): 137–145.
[4] Berková, Veronika et al. “Arabidopsis Response to Inhibitor of Cytokinin Degradation INCYDE: Modulations of Cytokinin Signaling and Plant Proteome.” Plants (Basel, Switzerland) vol. 9,11 1563. 13 Nov. 2020.
[5] Zahajská, Lenka et al. “Preparation, characterization and biological activity of C8-substituted cytokinins.” Phytochemistry vol. 135 (2017): 115-127.
[6] Werner, Tomás, and Thomas Schmülling. “Cytokinin action in plant development.” Current opinion in plant biology vol. 12,5 (2009): 527-38.
PI-55是一种选择性细胞分裂素受体拮抗剂，其对受体抑制的IC₅₀值约为1–5µM[1]。PI-55作用于Arabidopsis thaliana的组氨酸激酶受体CRE1/AHK4和AHK3，并能竞争性阻断天然细胞分裂素如反式玉米素[2]。PI-55主要应用于植物发育生物学和植物胁迫生理学研究，包括器官发生和镉胁迫耐受性[3]。
在Arabidopsis thaliana的ARR5:GUS报告基因检测中，PI-55以约1–5µM 的IC₅₀值竞争性阻断反式玉米素，在1–50µM处理30分钟至数小时范围内降低了细胞分裂素诱导的信号[4]。在Bulbine natalensis和Rumex crispus等药用植物的培养中，PI-55在0.01–10µM条件下处理7–21天抑制了芽的诱导，促进了根的生长，并在镉胁迫下提高了生物量和抗氧化水平[5]。
在Arabidopsis thaliana幼苗的ARR5:GUS报告基因检测中，PI-55在0.1–10µM条件下处理7–21天降低了ARR5:GUS的活性，并改变了根的发育。PI-55在0.01–10µM条件下处理14–21天并加入MS培养基，缓解了Eucomis autumnalis幼苗的镉诱导生长抑制，增加了生物量和抗氧化能力[4]。在Bulbine natalensis和Rumex crispus幼苗的培养中，PI-55在相同条件下减轻了镉胁迫，保持了较高的鲜重和激素水平的平衡[6]。