Feng Kewei, Nie Xiaojun, Cui Licao, Deng Pingchuan, Wang Mengxing, Song Weining
State Key Laboratory of Crop Stress Biology in Arid Areas, College of Agronomy and Yangling Branch of China Wheat Improvement Center, Northwest A&F University, Yangling 712100, Shaanxi, China.
Australia-China Joint Research Centre for Abiotic and Biotic Stress Management in Agriculture, Horticulture and Forestry, Yangling 712100, Shaanxi, China.
Genes (Basel). 2017 Jun 6;8(6):156. doi: 10.3390/genes8060156.
MicroRNAs (miRNAs) are a class of endogenous small noncoding RNAs which regulate diverse molecular and biochemical processes at a post-transcriptional level in plants. As the ancestor of domesticated wheat, wild emmer wheat ( ssp. ) has great genetic potential for wheat improvement. However, little is known about miRNAs and their functions on salinity stress in wild emmer. To obtain more information on miRNAs in wild emmer, we systematically investigated and characterized the salinity-responsive miRNAs using deep sequencing technology. A total of 88 conserved and 124 novel miRNAs were identified, of which 50 were proven to be salinity-responsive miRNAs, with 32 significantly up-regulated and 18 down-regulated. miR172b and miR1120a, as well as mi393a, were the most significantly differently expressed. Targets of these miRNAs were computationally predicted, then Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis found that the targets of salinity-responsive miRNAs were enriched in transcription factors and stress-related proteins. Finally, we investigated the expression profiles of seven miRNAs ranging between salt-tolerant and sensitive genotypes, and found that they played critical roles in salinity tolerance in wild emmer. Our results systematically identified the salinity-responsive miRNAs in wild emmer, not only enriching the miRNA resource but also laying the foundation for further study on the biological functions and evolution of miRNAs in wild wheat and beyond.
微小RNA（miRNA）是一类内源性小非编码RNA，在植物中可在转录后水平调控多种分子和生化过程。作为驯化小麦的祖先，野生二粒小麦（亚种）在小麦改良方面具有巨大的遗传潜力。然而，关于野生二粒小麦中miRNA及其在盐胁迫下的功能却知之甚少。为了获取更多关于野生二粒小麦中miRNA的信息，我们利用深度测序技术系统地研究并鉴定了盐胁迫响应性miRNA。共鉴定出88个保守miRNA和124个新miRNA，其中50个被证明是盐胁迫响应性miRNA，32个显著上调，18个下调。miR172b、miR1120a以及mi393a的表达差异最为显著。对这些miRNA的靶标进行了计算预测，随后基因本体论（GO）和京都基因与基因组百科全书（KEGG）分析发现，盐胁迫响应性miRNA的靶标在转录因子和胁迫相关蛋白中富集。最后，我们研究了7个miRNA在耐盐和敏感基因型之间的表达谱，发现它们在野生二粒小麦的耐盐性中起关键作用。我们的结果系统地鉴定了野生二粒小麦中的盐胁迫响应性miRNA，不仅丰富了miRNA资源，也为进一步研究野生小麦及其他植物中miRNA的生物学功能和进化奠定了基础。
