铁皮石斛miR168分子进化特征及响应蓝激光表达分析

笔者在关于铁皮石斛miRNA组学研究中发现较多响应蓝激光的miRNA，挑选关键且差异表达的miR168进行分子进化特征及其响应蓝激光表达分析。经对前体和成熟体分类统计、进化树构建、靶基因预测、启动子顺示作用元件及响应不同光质表达等进行分析，结果显示：miR168家族成员分布在40个植物物种中，前体和成熟体成员较少，其在植物中可能进化得不够完整；物种特异性是影响miR168前体进化特性的重要因素，而序列保守性是影响成熟体进化特性的主要因素；由3p臂上形成的miR168成熟体序列有较高特异性、5p臂形成的成熟体的序列保守性较高；Mfold和Rfam预测表明铁皮石斛miR168茎序列的保守性高于环序列，前体发卡结构较多，成熟体位置位于3p臂上，既包含茎序列也包含环序列；铁皮石斛miR168a的启动子主要包括光、激素、生物和非生物胁迫响应元件，可能通过这些顺式元件在其响应蓝激光中起调控作用；铁皮石斛响应蓝激光的靶基因主要包括ABC转运蛋白B家族成员、乙酰辅酶 A 乙酰转移酶等，主要参与植物生长发育和响应外界因素。实时荧光定量PCR结果表明，铁皮石斛miR168a与其靶基因gene-MA16_Dca006149、gene-MA16_Dca020995、gene-MA16_Dca017821参与蓝激光对铁皮石斛的影响。

Molecular Evolution Characteristics of miR168 in Dendrobium officinale and Analysis of Its Response to Blue Laser Expression

Based on the analysis of miRNAs omics in Dendrobium officinale (D.officinale),the differentially expressed miR168 were selected for further analysis and verification,as it plays a key role in regulating pathway influencing the effect of laser on D.officinale.We conducted an analysis of the distribution statistics of precursor and mature sequences,construction of phylogenetic trees,sequence alignment,prediction of the target genes,promoter sequence element,as well as expression patterns in response to laser for miR168 in this study.These results showed that the miR168 family members were widely distributed in 40 plant species,with fewer precursors and mature members,suggesting incomplete evolution in plants.Species specificity was an important factor affecting the evolution of miR168 precursors,while sequence conservation was the main factor affecting the evolution of miR168 matures.The members of miR168-3p were quite specific,whereas the members of miR168-5p were conserved.Mfold and Rfam predicted that the stem sequence of D.officinale miR168 was more conservative than the loop sequence.The precursor sequences had more hairpin structures,and the mature sequences was located on the 3p arm (contains both stem and loop sequences).Both of them contain many light-responsive elements,hormone-responsive elements,and biotic and abiotic stress responsive elements,which might play a regulatory role in the longan response to blue light through these cis-elements.In D.officinale,targets responding to laser both contain ABC transporter B family member 20 and acetyl-CoA acetyltransferase,which are involved in plant growth,and development,and response to external factors.Real-time quantitative PCR showed that miR168a and its target genes (gene-MA16_Dca006149,gene-MA16_Dca020995,gene-MA16_Dca017821) participate in the effects of blue laser on D.officinale.