R-loop作为一种特殊的三链核酸结构广泛地分布在基因组上，并具有各种生物学功能。我们前期发现拟南芥中大量的R-loop与异染色质修饰共定位，暗示R-loop可能与转录水平基因沉默（TGS）密切相关。然而，拟南芥中R-loop调控TGS的具体机制还有待探究。本项目利用TGS报告系统L5株系，以期通过正、反向筛选鉴定参与R-loop调控TGS过程的新因子。前期筛选已经发现，端粒长度调节因子RTEL1缺失突变会抑制TGS并影响R-loop水平。本项目将运用多种科学手段，来研究RTEL1如何通过R-loop来调控TGS。本研究将对进一步理解R-loop调控TGS的分子机制、拓宽R-loops的生物学功能具有重要意义。

R-loops, comprising three-stranded nucleic acid structures, are prevalent in genome and play plenty roles in biological processes. Our previous studies had revealed that an amount of R-loops co-localized with heterochromatin marks in Arabidopsis, suggesting that R-loops might be highly associated with transcriptional gene silencing (TGS). However, how TGS is regulated by R-loops in Arabidopsis remains unclear. Through forward and reverse genetic screening using a TGS reporter line named L5, this study will explore new factors participating in R-loop-regulated TGS. Based on previous screening, we found that disruption of RTEL1 (regulator of telomere elongation helicase 1) inhibits TGS and influences R-loop levels. In this work, we try to find out how RTEL1 regulates TGS through R-loop homeostasis. This study will provide novel insights in molecular mechanisms of how TGS is regulated by R-loops, leading to further understanding about biological significances of R-loops.