Sabanci University, Molecular Biology, Genetics and Bioengineering Program, Istanbul, Turkey.
Cereal Genomics Lab, Montana State University, Department of Plant Sciences and Plant Pathology, Bozeman, MT, USA.
Sci Rep. 2017 Sep 6;7(1):10670. doi: 10.1038/s41598-017-11170-8.
There is an urgent need for the improvement of drought-tolerant bread and durum wheat. The huge and complex genome of bread wheat (BBAADD genome) stands as a vital obstruction for understanding the molecular mechanism underlying drought tolerance. However, tetraploid wheat (Triticum turgidum ssp., BBAA genome) is an ancestor of modern bread wheat and offers an important model for studying the drought response due to its less complex genome. Additionally, several wild relatives of tetraploid wheat have already shown a significant drought tolerance. We sequenced root transcriptome of three tetraploid wheat varieties with varying stress tolerance profiles, and built differential expression library of their transcripts under control and drought conditions. More than 5,000 differentially expressed transcripts were identified from each genotype. Functional characterization of transcripts specific to drought-tolerant genotype, revealed their association with osmolytes production and secondary metabolite pathways. Comparative analysis of differentially expressed genes and their non-coding RNA partners, long noncoding RNAs and microRNAs, provided valuable insight to gene expression regulation in response to drought stress. LncRNAs as well as coding transcripts share similar structural features in different tetraploid species; yet, lncRNAs slightly differ from coding transcripts. Several miRNA-lncRNA target pairs were detected as differentially expressed in drought stress. Overall, this study suggested an important pool of transcripts where their manipulations confer a better performance of wheat varieties under drought stress.
迫切需要提高耐旱面包和硬质小麦的产量。由于面包小麦（BBAADD 基因组）庞大而复杂的基因组，理解其耐旱性的分子机制成为一个重要的障碍。然而，四倍体小麦（Triticum turgidum ssp.，BBAA 基因组）是现代面包小麦的祖先，由于其基因组相对简单，是研究干旱响应的重要模型。此外，四倍体小麦的几个野生近缘种已经表现出很强的耐旱性。我们对三种具有不同耐旱性的四倍体小麦品种的根系转录组进行了测序，并构建了它们在对照和干旱条件下的差异表达文库。从每个基因型中鉴定出超过 5000 个差异表达的转录本。对耐旱基因型特有的转录本进行功能表征，揭示了它们与渗透物质产生和次生代谢途径的关系。差异表达基因及其非编码 RNA 伙伴、长非编码 RNA 和 microRNAs 的比较分析，为基因表达调控提供了有价值的见解，以响应干旱胁迫。lncRNAs 与编码转录本在不同的四倍体物种中具有相似的结构特征；然而，lncRNAs 与编码转录本略有不同。在干旱胁迫下，检测到一些 miRNA-lncRNA 靶对差异表达。总的来说，这项研究表明了一个重要的转录本库，对其进行操作可以提高小麦品种在干旱胁迫下的性能。
