Spatial and developmental synthesis of endogenous sesquiterpene lactones supports function in growth regulation of sunflower
Spatial and developmental synthesis of endogenous sesquiterpene lactones supports function in growth regulation of sunflower
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DOI：
10.1007/s00425-020-03409-y
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发表时间：
2020-06-05
期刊：
影响因子：
4.3
通讯作者：
Frey, Maximilian
中科院分区：
文献类型：
--
作者：
Spring, Otmar;Schmauder, Katharina;Frey, Maximilian
主要结论组织特异性的发生和形成的内源性倍半萜内酯已被评估，并建议在向日葵生长素诱导的植物生长的拮抗剂的生理功能。向日葵（Helianthus annuus）在腺毛中积累高浓度的生物活性倍半萜内酯（STL），但另外，结构上不同的STL仅以痕量存在于内部组织中。在植物发育的早期阶段，这些内源性STL的空间和时间生产是广泛未知的，其生理功能作为假定的天然生长调节剂是推测性的。通过HPLC和MS分析，它表明，木香烃，脱氢木香内酯，8-表黄嘌呤和毛白杨素已经存在于干燥的种子，并可以提取少量的子叶，下胚轴和根的幼苗在萌发后的第一天。半定量和RT-qPCR实验与两个独立的途径的内源STL生物合成的关键酶的基因证实了早期和个人在这些器官中的表达，并揭示了在萌发后的第一个72-96小时逐渐下调。光照射的植物导致一个快速的，但短暂的增加STL的部分下胚轴与茎的生长迟缓。在下胚轴上单侧外部施用木香酮可降低处理侧的生长，从而导致茎向施用侧弯曲。这表明STL对植物生长的抑制作用。本文还讨论了向日葵内源STL在生长过程中作为生长素拮抗剂的可能作用。
Main conclusion Tissue-specific occurrence and formation of endogenous sesquiterpene lactones has been assessed and suggests physiological function as antagonists of auxin-induced plant growth in sunflower. Sunflower, Helianthus annuus, accumulate high concentrations of bioactive sesquiterpene lactones (STL) in glandular trichomes, but in addition, structurally different STL occur in only trace amounts in the inner tissues. The spatial and temporal production of these endogenous STL during early phases of plant development is widely unknown and their physiological function as putative natural growth regulators is yet speculative. By means of HPLC and MS analysis it was shown that costunolide, dehydrocostuslactone, 8-epixanthatin and tomentosin are already present in dry seeds and can be extracted in low amounts from cotyledons, hypocotyls and roots of seedlings during the first days after germination. Semi-quantitative and RT-qPCR experiments with genes of the key enzymes of two independent routes of the endogenous STL biosynthesis confirmed the early and individual expression in these organs and revealed a gradual down regulation during the first 72-96 h after germination. Light irradiation of the plants led to a fast, but transient increase of STL in parts of the hypocotyl which correlated with growth retardation of the stem. One-sided external application of costunolide on hypocotyls conferred reduced growth of the treated side, thus resulting in the curving of the stem towards the side of the application. This indicates the inhibiting effects of STL on plant growth. The putative function of endogenous STL in sunflower as antagonists of auxin in growth processes is discussed.