Novel and mechanical stress-responsive microRNAs in Populus trichocarpa that are absent from Arabidopsis
Novel and mechanical stress-responsive microRNAs in Populus trichocarpa that are absent from Arabidopsis
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DOI：
10.1105/tpc.105.033456
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发表时间：
2005-08-01
期刊：
影响因子：
11.6
通讯作者：
Chiang, VL
中科院分区：
文献类型：
--
作者：
Lu, SF;Sun, YH;Chiang, VL
微小RNA（microRNAs，miRNAs）是一类小的非编码RNA，在真核生物中通过靶向mRNA沉默发挥重要的调控作用。为了验证miRNAs是否在树种木材发育中发挥作用，我们从发育中的大叶杨茎木质部中分离小RNA，并克隆了22个miRNAs。它们是21个miRNA基因家族的创始成员，48个miRNA序列，由杨树基因组中的98个位点代表。预测这些miRNA中的大多数靶向发育和应激/防御相关基因以及与细胞壁代谢物的生物合成相关的可能功能。在21个龙眼miRNA家族中，11个在拟南芥中具有序列保守性，但表现出物种特异性的发育表达模式，这表明即使是保守的miRNA也可能在不同物种中具有不同的调控作用。最出乎意料的是，剩下的10个miRNAs，其中17个预测的目标是在体内实验验证，是不存在的拟南芥基因组中，这表明在树的特定过程中可能的作用。事实上，大多数克隆的miRNA的表达在木质茎中上调或下调，其方式与针对张力和压缩应力（树木中的两种恒定机械负荷）的树木特异性矫正生长一致。我们的研究结果表明，植物miRNAs可以被机械应力诱导，并可能在结构和机械适应性的最关键的防御系统之一发挥作用。
MicroRNAs ( miRNAs) are small, noncoding RNAs that can play crucial regulatory roles in eukaryotes by targeting mRNAs for silencing. To test whether miRNAs play roles in the regulation of wood development in tree species, we isolated small RNAs from the developing xylem of Populus trichocarpa stems and cloned 22 miRNAs. They are the founding members of 21 miRNA gene families for 48 miRNA sequences, represented by 98 loci in the Populus genome. A majority of these miRNAs were predicted to target developmental- and stress/ defense- related genes and possible functions associated with the biosynthesis of cell wall metabolites. Of the 21 P. trichocarpa miRNA families, 11 have sequence conservation in Arabidopsis thaliana but exhibited species- specific developmental expression patterns, suggesting that even conserved miRNAs may have different regulatory roles in different species. Most unexpectedly, the remaining 10 miRNAs, for which 17 predicted targets were experimentally validated in vivo, are absent from the Arabidopsis genome, suggesting possible roles in tree-specific processes. In fact, the expression of a majority of the cloned miRNAs was upregulated or downregulated in woody stems in a manner consistent with tree- specific corrective growth against tension and compression stresses, two constant mechanical loads in trees. Our results show that plant miRNAs can be induced by mechanical stress and may function in one of the most critical defense systems for structural and mechanical fitness.