Abstract

Tetrastigma hemsleyanum Diels & Gilg ex Diels is a liana plant with promising medicinal and ornamental values. Its calabash-shaped roots (CRs) are served as a traditional Chinese herb. However, it takes a long growth period to form CRs. In this study, three types of architectural roots, including fibrous roots (FRs), bar-shaped roots (BRs) and CRs, were employed as materials, and the characteristics of histo-anatomy and digital RNA-seq transcriptome profiles were analyzed. Among the three types of roots, the vascular bundles in FRs were intact, while some of the vascular bundles degenerated in BRs, and only few traces of vascular bundles existed in CRs. Meanwhile, no obvious cell inclusions were found in the cytoplasm of FRs, while a few inclusions were found in BRs, and abundant inclusions were detected in CRs, which might be the main source of medicinal components in roots. The transcriptome profiles and qRT-PCR validation indicated that seven upregulated genes, encoding xyloglucan glycosyltransferase, ACC oxidase, CYP711A1, SHORT-ROOT transcript factor, galacturonosyltransferas, WAT1 and WRKY, and two downregulated genes, encoding LRR receptor-like serine/threonine-protein kinase and CYP83B1, were probably involved in the formation and development of CRs. In addition, Gene Ontology terms of intrinsic component of membrane, integral component of membrane, cell periphery, membrane part, plasma membrane, membrane, intrinsic component of plasma membrane, cellular chemical homeostasis and plasma membrane part were probably related to the formation of CRs. Kyoto Encyclopedia of Genes and Genomes pathways related to the development of CRs probably included MAPK signaling pathway–plant, plant hormone signal transduction and circadian rhythm–plant. Our finding suggested a probable mode for the formation of CRs.

中文翻译：

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数字 RNA-seq 转录组加上组织解剖分析揭示了 Tetrastigma hemsleyanum 葫芦形根的发育机制

摘要

Tetrastigma hemsleyanum Diels & Gilg exDiels 是一种藤本植物，具有很好的药用和观赏价值。它的葫芦形根 (CRs) 是一种传统的中草药。但是，CRs 的形成需要很长的生长期。在本研究中，以须根（FRs）、条形根（BRs）和 CRs 三种类型的建筑根为材料，分析了组织解剖学和数字 RNA-seq 转录组谱的特征。三类根中，FRs的维管束完整，BRs部分维管束退化，CRs仅有少量维管束存在。同时，FRs的细胞质中未发现明显的细胞包裹体，BRs中发现少量包裹体，CRs中检测到大量包裹体，可能是根中药用成分的主要来源。转录组谱和 qRT-PCR 验证表明，7 个上调基因，编码木葡聚糖糖基转移酶、ACC 氧化酶、CYP711A1、SHORT-ROOT 转录因子、半乳糖醛酸转移酶、WAT1 和 WRKY，以及两个下调基因，编码 LRR 受体样丝氨酸/苏氨酸蛋白激酶和 CYP83B1 可能参与了 CR 的形成和发展。此外，膜内在成分、膜内在成分、细胞外围、膜部分、质膜、膜、质膜内在成分、细胞化学稳态和质膜部分等基因本体术语可能与CRs的形成有关。与 CR 发展相关的京都基因和基因组通路百科全书可能包括 MAPK 信号通路-植物、植物激素信号转导和昼夜节律-植物。我们的发现提出了形成 CR 的可能模式。