Abstract A long juvenile period limits the breeding process of fruit trees, such as pears. To understand the molecular mechanisms involved in the juvenile-adult phase change, two cDNA libraries of juvenile and adult phases from seedlings of hybrid offspring (Pyrus. pyrifolia Nakai cv.Whangkeumbae × P. bretschneideri Rehd. cv. Zaosu) were subjected to high-throughput sequencing. A total of 23,995 genes were obtained, of which 608 and 290 genes were down- and up-regulated, respectively, in the adult phase compared with the juvenile phase. Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis revealed that some differentially expressed genes were involved in hormone biosynthesis and signaling pathways. Determination of hormone contents revealed that the levels of gibberellin A4 (GA4), ethylene, and jasmonic acid (JA) were lower in the adult than in the juvenile phase, while the contents of indole-3-acetic acid (IAA), gibberellin A1 (GA1), and abscisic acid (ABA) were significantly higher in the adult than in the juvenile phase. Combining the quantitative PCR (qPCR) analysis, we suggested that JA and ethylene might play negative roles, while ABA and IAA might play positive roles in the juvenile-adult phase transition in Pyrus. Meanwhile, a series of flowering-related genes were differentially expressed between juvenile and adult phases, including SPL (Squamosa promoter binding protein-like) genes, the flowering-time integrator gene SUPPRESSOR OF OVEREXPRESSION OF CO1 (SOC1), and some floral meristem identity genes. Through qPCR analysis of SPL family members, 27 SPLs were found to participate in the phase transition in Pyrus. However, the regulatory mechanisms of hormone and SPLs require further study.

中文翻译：

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SPLs介导的开花调控和激素生物合成和信号传导伴随梨中的幼年-成体相变

摘要 较长的幼龄期限制了梨等果树的繁殖过程。为了了解幼年-成体相变所涉及的分子机制，对来自杂交后代（Pyrus. pyrifolia Nakai cv.Whangkeumbae × P. bretschneideri Rehd. cv. Zaosu）幼苗的两个幼年期和成年期 cDNA 文库进行了高-通量测序。共获得23,995个基因，其中608个基因和290个基因在成年期与幼年期分别下调和上调。京都基因和基因组百科全书（KEGG）分析表明，一些差异表达的基因参与激素生物合成和信号通路。激素含量测定表明赤霉素 A4 (GA4)、乙烯、成虫中茉莉酸（JA）含量低于幼虫期，而吲哚-3-乙酸（IAA）、赤霉素A1（GA1）和脱落酸（ABA）含量在成虫期显着高于幼虫期。在少年阶段。结合定量 PCR (qPCR) 分析，我们认为 JA 和乙烯可能起负面作用，而 ABA 和 IAA 可能在 Pyrus 的幼年-成体相变中起积极作用。同时，一系列开花相关基因在幼虫期和成虫期差异表达，包括SPL（Squamosa启动子结合蛋白样）基因、开花时间整合基因SUPPRESSOR OF OVEREXPRESSION OF CO1（SOC1）和一些花分生组织特征基因。通过对 SPL 家族成员的 qPCR 分析，发现 27 个 SPL 参与了 Pyrus 的相变。然而，