Creative Research Initiatives, School of Life Sciences and Biotechnology, Korea University, Seoul 136-701, Korea.
Nucleic Acids Res. 2010 May;38(9):3081-93. doi: 10.1093/nar/gkp1240. Epub 2010 Jan 27.
Flowering is the primary trait affected by ambient temperature changes. Plant microRNAs (miRNAs) are small non-coding RNAs playing an important regulatory role in plant development. In this study, to elucidate the mechanism of flowering-time regulation by small RNAs, we identified six ambient temperature-responsive miRNAs (miR156, miR163, miR169, miR172, miR398 and miR399) in Arabidopsis via miRNA microarray and northern hybridization analyses. We also determined the expression profile of 120 unique miRNA loci in response to ambient temperature changes by miRNA northern hybridization analysis. The expression of the ambient temperature-responsive miRNAs and their target genes was largely anticorrelated at two different temperatures (16 and 23 degrees C). Interestingly, a lesion in short vegetative phase (SVP), a key regulator within the thermosensory pathway, caused alteration in the expression of miR172 and a subset of its target genes, providing a link between a thermosensory pathway gene and miR172. The miR172-overexpressing plants showed a temperature-independent early flowering phenotype, suggesting that modulation of miR172 expression leads to temperature insensitivity. Taken together, our results suggest a genetic framework for flowering-time regulation by ambient temperature-responsive miRNAs under non-stress temperature conditions.
开花是受环境温度变化影响的主要特征。植物 microRNAs（miRNAs）是在植物发育中起重要调节作用的小非编码 RNA。在这项研究中，为了阐明小 RNA 对开花时间调控的机制，我们通过 miRNA 微阵列和 northern 杂交分析鉴定了拟南芥中六个环境温度响应 miRNA（miR156、miR163、miR169、miR172、miR398 和 miR399）。我们还通过 miRNA northern 杂交分析确定了 120 个独特 miRNA 基因座对环境温度变化的表达谱。在两个不同温度（16 和 23 摄氏度）下，环境温度响应 miRNA 和其靶基因的表达呈很大的反相关。有趣的是，短营养生长期（SVP）的损伤，一个热感觉途径中的关键调节剂，导致 miR172 及其一部分靶基因的表达发生改变，为热感觉途径基因和 miR172 之间提供了联系。miR172 过表达植物表现出温度独立的早期开花表型，表明 miR172 表达的调节导致对温度不敏感。总之，我们的结果表明，在非胁迫温度条件下，环境温度响应 miRNA 对开花时间的调控有一个遗传框架。
