miRNA–mRNA Integrated Analysis Reveals Roles for miRNAs in a Typical Halophyte, <i>Reaumuria soongorica</i>, during Seed Germination under Salt Stress

• Main Authors: Huilong Zhang, Xiaowei Liu, Xiuyan Yang, Haiwen Wu, Jianfeng Zhu, Huaxin Zhang
• Format: Article
• Language: English
• Published: MDPI AG 2020-03-01
• Series: Plants
• Subjects: <i>reaumuria soongorica</i>; seed germination; microrna; salt stress; high-throughput sequencing
• Online Access: https://www.mdpi.com/2223-7747/9/3/351

MicroRNAs (miRNAs) are endogenous small RNAs that play a crucial role in plant growth, development, and environmental stress responses. <i>Reaumuria soongorica</i> is a typical halophyte that is widely distributed in saline&#8722;alkali desert regions. Under salt stress, <i>R. soongorica</i> can complete germination, a critical biological process in the life cycle of seed plants. To identify miRNAs and predict target mRNAs involved in seed germination during salt stress, nine small-RNA libraries were constructed and analyzed from <i>R. soongorica</i> seeds treated with various concentrations of NaCl. We also obtained transcriptome data under the same treatment conditions. Further analysis identified 88 conserved miRNAs representing 25 defined families and discovered 13 novel miRNAs from nine libraries. A co-expression analysis was performed on the same samples to identify putative miRNA&#8722;mRNA interactions that were responsive to salt stress. A comparative analysis of expression during germination under 273 (threshold) and 43 mM (optimal) NaCl treatments identified 13 differentially expressed miRNAs and 23 corresponding target mRNAs, while a comparison between 43 mM NaCl and non-salt-stress conditions uncovered one differentially expressed miRNA and one corresponding target mRNA. These results provide basic data for further study of molecular mechanisms involved in the germination of salt-stressed <i>R. soongorica</i> seeds, and also provide a reference for the improvement of salt tolerance during plant germination.