Graduate School of Life Sciences, Toyo University, 1-1-1 Izumino, Itakura-machi, Ora-gun, Gunma, 374-0193, Japan.
Department of Applied Biosciences, Toyo University, 1-1-1 Izumino, Itakura-machi, Ora-gun, Gunma, 374-0193, Japan.
Planta. 2021 May 20;253(6):123. doi: 10.1007/s00425-021-03640-1.
SL inhibited adventitious shoot formation of ipecac, whereas the SL-related inhibitors promoted adventitious shoot formation. SL-related inhibitors might be useful as new plant growth regulators for plant propagation. In most plant species, phytohormones are required to induce adventitious shoots for propagating economically important crops and regenerating transgenic plants. In ipecac (Carapichea ipecacuanha (Brot.) L. Andersson), however, adventitious shoots can be formed without phytohormone treatment. Here we evaluated the effects of GR24 (a synthetic strigolactone, SL), SL biosynthetic inhibitors, and an SL antagonist on adventitious shoot formation during tissue culture of ipecac. We found that exogenously applied GR24 suppressed indole-3-acetic acid transport in internodal segments and decreased the number of adventitious shoots formed; in addition, the distribution of adventitious shoots changed from the apical to middle region of the internodal segments. In contrast, the SL-related inhibitors promoted adventitious shoot formation on both apical and middle regions of the segments. In particular, SL antagonist treatment increased endogenous cytokinin levels and induced multiple shoot development. These results indicate that SL inhibits adventitious shoot formation in ipecac. In ipecac, one of the shoots in each internodal segment becomes dominant and auxin derived from that shoot suppresses the other shoot growth. Here, this dominance was overcome by application of SL-related inhibitors. Therefore, SL-related inhibitors might be useful as new plant growth regulators to improve the efficiency of plant propagation in vitro.
SL 抑制吐根不定芽的形成，而 SL 相关抑制剂则促进不定芽的形成。SL 相关抑制剂可能是一种有用的植物生长调节剂，可用于植物繁殖。在大多数植物物种中，植物激素是诱导不定芽形成以繁殖经济上重要的作物和再生转基因植物所必需的。然而，在吐根（Carapichea ipecacuanha (Brot.) L. Andersson）中，不定芽的形成不需要植物激素处理。在这里，我们评估了 GR24（一种合成的独脚金内酯，SL）、SL 生物合成抑制剂和 SL 拮抗剂对吐根组织培养中不定芽形成的影响。我们发现，外源施加的 GR24 抑制了节间段中吲哚-3-乙酸的运输，并减少了形成的不定芽数量；此外，不定芽的分布从节间段的顶端区域改变到中间区域。相比之下，SL 相关抑制剂促进了节间段顶端和中间区域不定芽的形成。特别是，SL 拮抗剂处理增加了内源细胞分裂素水平并诱导了多芽发育。这些结果表明，SL 抑制了吐根不定芽的形成。在吐根中，每个节间段的一个芽成为优势芽，并且来自该芽的生长素抑制了其他芽的生长。在这里，通过应用 SL 相关抑制剂克服了这种优势。因此，SL 相关抑制剂可能是一种有用的植物生长调节剂，可用于提高离体植物繁殖的效率。
