Institute for Biological Research "Siniša Stanković"-National Institute of Republic of Serbia, University of Belgrade, Bulevar despota Stefana 142, 11060, Belgrade, Serbia.
Institute of Experimental Botany of the Czech Academy of Sciences, Rozvojová 263, 16502, Prague 6, Czech Republic.
Sci Rep. 2021 Mar 22;11(1):6494. doi: 10.1038/s41598-021-85932-w.
Cross-talk between phytohormones and sugars is intensely involved in plant metabolism, growth and regeneration. We documented alterations in cytokinin (CK) homeostasis in four developmental stages during de novo shoot organogenesis (DNSO) of kohlrabi (Brassica oleracea var. gongylodes cv. Vienna Purple) seedlings induced by exogenous CKs, trans-zeatin (transZ) and thidiazuron (TDZ), added together with elevated sucrose concentration (6% and 9%). Significant impact of CK and sucrose treatment and their interaction was recorded in all investigated stages, including plantlet development before calli formation (T1 and T2), calli formation (T3) and shoot regeneration (T4). Results showed remarkable increase in total CK levels for transZ treatment, particularly with 9% sucrose. This trend was observed for all physiological and structural groups of CKs. Application of TDZ contributed to little or no increase in CK levels regardless of sucrose concentration. Analysis of expression profiles of organogenesis-related genes involved in auxin transport, CK response, shoot apical meristem formation and cell division revealed that higher sugar concentration significantly downregulated the analysed genes, particularly in T3. This continued on TDZ, but transZ induced an opposite effect with 9% sucrose in T4, increasing gene activity. Our results demonstrated that phytohormone metabolism might be triggered by sucrose signalling in kohlrabi DNSO.
植物激素和糖之间的串扰强烈参与植物代谢、生长和再生。我们记录了外源细胞分裂素 (CK) 处理，包括玉米素 (transZ) 和噻二唑隆 (TDZ) ，以及高浓度蔗糖 (6%和 9%) ，在拟南芥幼苗从头芽器官发生 (DNSO) 的四个发育阶段中 CK 稳态的变化。CK 和蔗糖处理及其相互作用在所有研究阶段都有显著影响，包括在愈伤组织形成之前的植株发育阶段 (T1 和 T2)、愈伤组织形成阶段 (T3) 和芽再生阶段 (T4)。结果表明，transZ 处理的总 CK 水平显著增加，特别是在 9%蔗糖的情况下。所有 CK 的生理和结构组都观察到了这种趋势。无论蔗糖浓度如何，TDZ 的应用对 CK 水平的增加贡献很小或没有。对涉及生长素运输、CK 反应、茎尖分生组织形成和细胞分裂的器官发生相关基因的表达谱进行分析后发现，较高的糖浓度显著下调了所分析的基因，特别是在 T3 中。在 TDZ 中也可以看到这种情况，但 transZ 在 T4 中用 9%蔗糖诱导了相反的效果，增加了基因活性。我们的结果表明，在 Kohlrabi DNSO 中，蔗糖信号可能触发植物激素代谢。
