Hackenberg Michael, Gustafson Perry, Langridge Peter, Shi Bu-Jun
Computational Genomics and Bioinformatics Group, Genetics Department, University of Granada, Granada, Spain.
Plant Biotechnol J. 2015 Jan;13(1):2-13. doi: 10.1111/pbi.12220. Epub 2014 Jun 29.
Drought is a major constraint to crop production, and microRNAs (miRNAs) play an important role in plant drought tolerance. Analysis of miRNAs and other classes of small RNAs (sRNAs) in barley grown under water and drought conditions reveals that drought selectively regulates expression of miRNAs and other classes of sRNAs. Low-expressed miRNAs and all repeat-associated siRNAs (rasiRNAs) tended towards down-regulation, while tRNA-derived sRNAs (tsRNAs) had the tendency to be up-regulated, under drought. Antisense sRNAs (putative siRNAs) did not have such a tendency under drought. In drought-tolerant transgenic barley overexpressing DREB transcription factor, most of the low-expressed miRNAs were also down-regulated. In contrast, tsRNAs, rasiRNAs and other classes of sRNAs were not consistently expressed between the drought-treated and transgenic plants. The differential expression of miRNAs and siRNAs was further confirmed by Northern hybridization and quantitative real-time PCR (qRT-PCR). Targets of the drought-regulated miRNAs and siRNAs were predicted, identified by degradome libraries and confirmed by qRT-PCR. Their functions are diverse, but most are involved in transcriptional regulation. Our data provide insight into the expression profiles of miRNAs and other sRNAs, and their relationship under drought, thereby helping understand how miRNAs and sRNAs respond to drought stress in cereal crops.
干旱是作物生产的主要限制因素，而微小RNA（miRNA）在植物耐旱性中发挥重要作用。对在水分充足和干旱条件下生长的大麦中的miRNA和其他类别的小RNA（sRNA）进行分析发现，干旱会选择性地调节miRNA和其他类别的sRNA的表达。在干旱条件下，低表达的miRNA和所有重复相关的小干扰RNA（rasiRNA）趋于下调，而tRNA衍生的sRNA（tsRNA）则有上调的趋势。反义sRNA（推定的小干扰RNA）在干旱条件下没有这种趋势。在过表达DREB转录因子的耐旱转基因大麦中，大多数低表达的miRNA也被下调。相比之下，tsRNA、rasiRNA和其他类别的sRNA在干旱处理的植物和转基因植物之间的表达并不一致。通过Northern杂交和定量实时PCR（qRT-PCR）进一步证实了miRNA和小干扰RNA的差异表达。对干旱调节的miRNA和小干扰RNA的靶标进行了预测，通过降解组文库进行了鉴定，并通过qRT-PCR进行了确认。它们的功能多种多样，但大多数都参与转录调控。我们的数据深入了解了miRNA和其他sRNA的表达谱及其在干旱条件下的关系，从而有助于理解miRNA和sRNA如何应对谷类作物中的干旱胁迫。
