Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu, 610041, Sichuan, China.
University of Chinese Academy of Sciences, Beijing, 100049, China.
BMC Genomics. 2019 Jul 29;20(1):615. doi: 10.1186/s12864-019-5939-z.
Heavy metal ATPases (HMAs) are responsible for Cd translocation and play a primary role in Cd detoxification in various plant species. However, the characteristics of HMAs and the regulatory mechanisms between HMAs and microRNAs in wheat (Triticum aestivum L) remain unknown.
By comparative microRNA and transcriptome analysis, a total three known and 19 novel differentially expressed microRNAs (DEMs) and 1561 differentially expressed genes (DEGs) were found in L17 after Cd treatment. In H17, by contrast, 12 known and 57 novel DEMs, and only 297 Cd-induced DEGs were found. Functional enrichments of DEMs and DEGs indicate how genotype-specific biological processes responded to Cd stress. Processes found to be involved in microRNAs-associated Cd response include: ubiquitin mediated proteolysis, tyrosine metabolism, and carbon fixation pathways and thiamine metabolism. For the mRNA response, categories including terpenoid backbone biosynthesis and phenylalanine metabolism, and photosynthesis - antenna proteins and ABC transporters were enriched. Moreover, we identified 32 TaHMA genes in wheat. Phylogenetic trees, chromosomal locations, conserved motifs and expression levels in different tissues and roots under Cd stress are presented. Finally, we infer a microRNA-TaHMAs expression network, indicating that miRNAs can regulate TaHMAs.
Our findings suggest that microRNAs play important role in wheat under Cd stress through regulation of targets such as TaHMA2;1. Identification of these targets will be useful for screening and breeding low-Cd accumulation wheat lines.
重金属 ATP 酶（HMAs）负责 Cd 的转运，在各种植物物种中对 Cd 的解毒起着主要作用。然而，HMAs 的特征以及小麦（Triticum aestivum L）中 HMAs 和 microRNAs 之间的调控机制尚不清楚。
通过比较 microRNA 和转录组分析，在 L17 经 Cd 处理后发现了总共 3 个已知和 19 个新的差异表达 microRNAs（DEMs）和 1561 个差异表达基因（DEGs）。相比之下，在 H17 中，仅发现了 12 个已知和 57 个新的 DEMs，以及 297 个 Cd 诱导的 DEGs。DEMs 和 DEGs 的功能富集表明基因型特异性的生物过程如何对 Cd 应激做出反应。发现参与 microRNAs 相关 Cd 反应的过程包括：泛素介导的蛋白水解、酪氨酸代谢、碳固定途径和硫胺素代谢。对于 mRNA 反应，包括萜类骨架生物合成和苯丙氨酸代谢以及光合作用-天线蛋白和 ABC 转运体在内的类别得到了富集。此外，我们在小麦中鉴定了 32 个 TaHMA 基因。呈现了系统发育树、染色体位置、保守基序和不同组织及根中 Cd 胁迫下的表达水平。最后，我们推断了一个 microRNA-TaHMAs 表达网络，表明 microRNAs 通过调节 TaHMA2;1 等靶标在 Cd 胁迫下对小麦起重要作用。
我们的研究结果表明，microRNAs 通过调节 TaHMA2;1 等靶标在 Cd 胁迫下对小麦起重要作用。这些靶标的鉴定将有助于筛选和培育低 Cd 积累的小麦品系。
