The storage root of alligatorweed [Alternanthera philoxeroides (Mart.) Griseb.] growing in terrestrial habitats is an important metamorphic organ for its propagation, overwintering, and spread. However, the regulatory mechanism adventitious root expansion to form storage roots is still unclear. To reveal the changes accompanying the root-swelling process, we quantified sugar, soluble protein, and phytohormone content in adventitious and storage roots. Results demonstrated that sucrose, fructose, and soluble protein increased in storage roots, whereas abscisic acid (ABA), indoleacetic acid (IAA), brassinosteroid (BR), gibberellin, jasmonic acid, and cytokinin (trans-zeatin [tZ] and isopentenyladenine [iP] and the corresponding ribosides tZR and iPR). tZ-type (tZR and tZ) content decreased, suggesting the involvement of sugars and hormones in the formation of storage roots. To further reveal the molecular basis of A. philoxeroides’s ability to form storage roots and provide candidate genes for molecular function analyses, we assembled a de novo transcriptome of A. philoxeroides based on four sets of RNA-sequencing data. According to functional annotation and expression profiling, 42 unigenes involved in sucrose synthesis and hydrolysis were identified, in addition to 70, 58, and 78 unigenes in ABA, BR, and IAA signal transduction, respectively. The quantitative reverse transcriptase polymerase chain reaction analysis revealed 21 unigenes involved in sugar metabolism and hormone signal transduction were differentially expressed during the formation of storage roots. These results revealed metabolic changes during the formation of storage roots and provide candidate genes involved in sugar and phytohormone metabolism in A. philoxeroides.

中文翻译：

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短吻鳄（Alternanthera philoxeroides）贮藏根形成过程中的碳水化合物、植物激素和相关转录组变化

鳄鱼草的贮藏根[空心莲子草(Mart.) Griseb.]生长于陆地生境，是其繁殖、越冬、传播的重要变质器官。然而，不定根扩张形成贮藏根的调控机制仍不清楚。为了揭示伴随根肿胀过程的变化，我们量化了不定根和贮藏根中的糖、可溶性蛋白质和植物激素含量。结果表明，贮藏根中蔗糖、果糖和可溶性蛋白增加，而脱落酸（ABA）、吲哚乙酸（IAA）、油菜素内酯（BR）、赤霉素、茉莉酸和细胞分裂素（反式-玉米素[吨Z] 和异戊烯基腺嘌呤 [iP] 和相应的核苷吨ZR 和 iPR)。吨Z型（吨ZR 和吨Z) 含量下降，表明糖和激素参与了贮藏根的形成。进一步揭示分子基础一种.空心莲的能力形成储存根并为分子功能分析提供候选基因，我们组装了一个从头转录组一种.空心莲基于四组RNA测序数据。根据功能注释和表达谱，除了 ABA、BR 和 IAA 信号转导中的 70、58 和 78 个 unigene 外，还分别鉴定了 42 个参与蔗糖合成和水解的 unigenes。定量逆转录酶聚合酶链反应分析显示，21个参与糖代谢和激素信号转导的unigenes在贮藏根形成过程中差异表达。这些结果揭示了贮藏根形成过程中的代谢变化，并提供了参与糖和植物激素代谢的候选基因。空心莲子.