Gene expression analysis revealed Hbr-miR396b as a key piece participating in reaction wood formation of Hevea brasiliensis (rubber tree)
Gene expression analysis revealed Hbr-miR396b as a key piece participating in reaction wood formation of Hevea brasiliensis (rubber tree)
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DOI：
10.1016/j.indcrop.2021.114460
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发表时间：
2022-01-10
影响因子：
5.9
通讯作者：
Tu, Zhihua
中科院分区：
文献类型：
--
作者：
Meng, Xiangxu;Kong, Lingshan;Tu, Zhihua
橡胶树（Hevea brasiliensis）是一种多年生的橡胶树，在木材工业中具有重要的应用价值。然而，H.巴西种在很大程度上是未知的。本研究以3棵3年生橡胶树为试材，通过人工弯曲7 d和100 d诱导反应木的形成，并采集受拉木、对生木和正常木木质部样品，通过小分子RNA测序鉴定参与橡胶树木材形成的microRNA（miRNAs）。我们在7天木材中鉴定了25个已知的microRNA（miRNAs），属于21个miRNAs家族;在100天木材中鉴定了24个已知的miRNAs，属于20个miRNAs家族。三种已知的miRNAs，hbr-miR 396 b，hbr-miR 6168和hbr-miR 6485，在100天的木材中积累，靶向三个转录因子家族C3 H，SQUAMOSA结合蛋白（SBP）和生长素反应因子（ARF）的基因成员。Gene Ontology分析表明，与miRNAs靶向的转录因子共表达的基因与100 d木材中的纤维素代谢、纤维素合成和纤维素合成酶相关，而与7 d木材中的纤维素合成酶无关，这可能反映了人工弯曲处理的持续时间较长。我们还构建了一个共表达网络，其中包括miRNAs，其靶转录因子基因，以及与这些基因共表达的基因，揭示了纤维素生物合成受到3个已知和13个新的miRNAs的调控，它们可能都参与了反应木材的形成。综上所述，本研究确定了橡胶树反应材形成过程中潜在的关键miRNA-transcription factor-mRNA网络，为进一步阐明橡胶树木材形成机制奠定了理论基础。
Rubber tree (Hevea brasiliensis) is a perennial tree, which is important for wood-related industrial applications. However, the molecular basis of wood formation in H. brasiliensis is largely unknown. In this study, we induced the formation of reaction wood by artificial bending three 3-year-old rubber trees for 7 or 100 days, and collected xylem samples from tension wood, opposite wood, and normal wood, and subjected them to small RNA sequencing to identify the microRNAs (miRNAs) participated in rubber tree wood formation. We identified 25 known microRNAs (miRNAs) belonging to 21 miRNA families in 7-day wood and 24 known miRNAs belonging to 20 miRNA families in 100-day wood. Three known miRNAs, hbr-miR396b, hbr-miR6168, and hbr-miR6485, that accumulated in 100-day wood targeted gene members of the three transcription factor families C3H, SQUAMOSA BINDING PROTEIN (SBP), and AUXIN RESPONSE FACTOR (ARF). Gene Ontology analysis showed genes co-expressed with transcription factor genes targeted by miRNAs were associated with cellulose metabolism, cel-lulose biosynthesis, and cellulose synthase in 100-day but not 7-day wood, likely reflecting the longer duration of artificial bending treatment. We also constructed a co-expression network that includes miRNAs, their target transcription factor genes, and the genes co-expressed with these genes, revealing that cellulose biosynthesis was regulated by 3 known and 13 novel miRNAs, which may all participate in reaction wood formation. In summary, this study identified potential key miRNA-transcription factor-mRNA networks involved in reaction wood formation of rubber tree and laid a theoretical foundation for further elucidating the mechanism of wood for-mation in this species.