核苷酸转移酶HESO1调节拟南芥耐盐胁迫的机理研究

核苷酸转移酶是一类催化核苷酸残基从一个分子转移到另一个分子的转移酶类。拟南芥HEN1 SUPPRESSOR1（HESO1）是尿苷化修饰pre-miRNAs、miRNAs及其靶基因5′端剪切产物的主要核苷酸转移酶。前期研究表明，HESO1受盐胁迫诱导表达，而HESO1突变导致植株对盐胁迫耐受性下降。通过高通量测序发现，pre-miRNAs的尿苷化水平显著上升，暗示HESO1很可能通过尿苷化修饰pre-miRNAs来调节拟南芥的盐胁迫反应。为了证明上述假设，本项目拟通过反向遗传学、分子生物学等手段，分析HESO1在盐胁迫下的调控模式，明确HESO1在盐胁迫下的生化与分子机制，探索盐胁迫与pre-miRNAs、miRNAs及其靶基因5′端剪切产物尿苷化修饰之间的因果关系，开拓小分子RNA在表观遗传修饰层面上对耐盐胁迫新机制的认识。

Nucleotidyl transferase protein (NTP) is a class of transferases that can transfer nucleotide residues from one molecule to another. Arabidopsis HESO1 is the major nucleotidyl transferase that uridylates miRNAs, pre-miRNAs and 5′ cleavage products of target mRNAs. Previous studies have shown that the expression of the HESO1 gene was induced by salt stress, and that the heso1 mutant had reduced tolerance to salt stress. High-throughput sequencing revealed a significant increase in the uridylation level of pre-miRNAs. These preliminary results suggest that HESO1 may regulate the salt stress response through uridylating pre-miRNAs in Arabidopsis. In order to prove the above assumptions, this project intends to analyze the regulatory role of HESO1 under salt stress, to clarify the biochemistry and molecular mechanism of HESO1 under salt stress, and to explore the relationship between salt stress and uridylation of pre-miRNAs / miRNAs / 5′ cleavage products of target mRNAs through reverse genetics, molecular biology and other means. It is hoped to realize a new understanding of the salt stress on the epigenetic level of small RNA.