MicroRNAs (miRNAs) are a class of endogenous non-coding RNAs that play a crucial role in post-transcriptional gene regulation not only in animals and land plants, but also in microalgae. Among all the microalga, Dunaliella salina (D. salina) has the highest content of beta-carotene, and a draft genome of this species was recently published. Thus far, few D. salina miRNAs have been identified. In this study, deep sequencing was performed to identify miRNAs in wild-type D. salina (Control) and in a high light and high salinity treatment group (HLS). Three small RNA (sRNA) libraries were constructed for Control and HLS, and an average of 11,542,169 and 16,877,598 clean tags were obtained, respectively. The sRNA length distribution showed that 21 nt sRNAs were the most abundant class in both Control and HLS, which is consistent with the sRNA distribution of model organism Chlamydomonas reinhardtii. Eighty-four known miRNAs and 1054 novel miRNAs were found in Control. Among them, nine known miRNAs and 39 novel miRNAs had altered levels in response to HLS treatment. The expression differences of selected miRNAs and their target genes in Control and HLS were verified by qRT-PCR, which showed that novel-m0533-3p was up-regulated and its predicted target malate dehydrogenase encoded gene was clearly down-regulated in HLS at both transcription and the protein level. Moreover, some key carotenoid pathway genes, such as PSY, PDS and LCYB were all up-regulated in HLS. These findings are providing a new insights into a miRNA-mediated beta-carotene accumulation mechanism in D. salina.

MicroRNA（miRNA）是一类内源性非编码RNA，不仅在动植物和陆地植物中，而且在微藻中，在转录后基因调控中都起着至关重要的作用。在所有微藻中，杜氏盐藻（D. salina）（D. salina）的β-胡萝卜素含量最高，该物种的基因组草图最近已发表。迄今为止，几乎没有鉴定出盐藻（D. salina） miRNA。在这项研究中，进行了深度测序以鉴定野生型D. salina中的miRNA 。（对照）和高光高盐度治疗组（HLS）。构建了三个用于Control和HLS的小RNA（sRNA）库，分别获得了平均11,542,169和16,877,598个清洁标签。sRNA的长度分布显示，在对照和HLS中，最丰富的一类是21 nt sRNA，与模型生物衣藻（Chlamydomonas reinhardtii）的sRNA分布一致。。在对照中发现八十四种已知的miRNA和1054种新颖的miRNA。其中，有9种已知的miRNA和39种新颖的miRNA响应HLS治疗而改变了水平。通过qRT-PCR验证了选定的miRNA及其靶基因在对照和HLS中的表达差异，这表明新颖的-m0533-3p在HLS中均被上调并且其预测的目标苹果酸脱氢酶编码基因在这两个位置均明显下调。转录和蛋白质水平。此外，HLS中一些关键的类胡萝卜素途径基因如PSY，PDS和LCYB均被上调。这些发现为盐沼藻中miRNA介导的β-胡萝卜素积累机制提供了新的见解。