Abstract

Poplars are important woody plants, and the ability to form adventitious roots (ARs) is the key factor for their cultivation because most poplars are propagated by cloning. In previous studies, Ca²⁺ was confirmed to regulate AR formation in poplar. In this study, wild-type poplar cuttings grown in 1.0 mM Ca²⁺ solution showed the best visible performance of AR development. Coexpression analysis of a large-scale RNA-Seq transcriptome was conducted to identify Ca²⁺-related genes that regulate AR development in poplar. A total of 15 coexpression modules (CMs) were identified, and two CMs showed high association with AR development. Functional analysis identified a number of biological pathways, including ‘oxidation-reduction process’, ‘response to biotic stimulus’ and ‘metabolic process’, in tissues of AR development. The Ca²⁺-related pathway was specifically selected, and its regulation in poplar AR development was predicted. A Ca²⁺ sensor, PdeCML23-1, which is a member of the calmodulin-like protein (CML) family, was found to promote AR development by phenotypic assay of overexpressed PdeCML23-1 transgenic lines at various growing conditions. By measuring cytosolic Ca²⁺ in AR tips, PdeCML23-1 seemed to play a role in decreasing cytosolic Ca²⁺ concentration. Additionally, the expression profiles of some genes and phytohormone indole acetic acid (IAA) were also changed in the overexpressed PdeCML23-1 transgenic lines. According to this study, we were able to provide a global view of gene regulation for poplar AR development. Moreover, we also observed the regulation of cytosolic Ca²⁺ concentration by PdeCML23-1, and this regulation was involved in AR development in poplar. We also predicted that PdeCML23-1 possibly regulates AR development by modulating IAA content in poplar.

中文翻译：

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大规模转录组的共表达分析确定了调节杨树不定根发育的钙调蛋白样蛋白。

摘要

杨树是重要的木本植物，形成不定根（ARs）的能力是其栽培的关键因素，因为大多数杨树都是通过克隆繁殖的。在先前的研究中，Ca ²⁺被证实可以调节杨树中AR的形成。在这项研究中，在1.0 mM Ca ²⁺溶液中生长的野生型杨木插条表现出AR发育的最佳可见性能。进行大规模RNA-Seq转录组的共表达分析以鉴定Ca ²⁺相关基因调控杨树AR发育。总共鉴定出15个共表达模块（CM），其中两个CM与AR的发展高度相关。功能分析确定了AR发展组织中的许多生物学途径，包括“氧化还原过程”，“对生物刺激的反应”和“代谢过程”。专门选择了Ca ²⁺相关途径，并预测了其在杨树AR发育中的调控作用。Ca ²⁺传感器PdeCML23-1是钙调蛋白样蛋白（CML）家族的成员，通过在各种生长条件下过表达的PdeCML23-1转基因品系的表型分析，发现它促进了AR的发展。通过测量胞质Ca ²⁺在AR提示中，PdeCML23-1似乎在降低胞质Ca ²⁺浓度中起作用。此外，在过表达的PdeCML23-1转基因株系中，某些基因和植物激素吲哚乙酸（IAA）的表达谱也发生了变化。根据这项研究，我们能够为杨树AR发育提供基因调控的全球视野。此外，我们还观察到PdeCML23-1对胞质Ca ²⁺浓度的调节，并且该调节与杨树AR的发育有关。我们还预测PdeCML23-1可能通过调节白杨中IAA含量来调节AR的发育。