Protection of telomeres 1b safeguards the Arabidopsis genome by regulating ROS homeostasis

作者：Ji‐Hee Min, Claudia Castillo-González, Borja Barbero Barcenilla, In-Cheol Yeo, Xiaoyuan Xie, Sreyashree Bose, Fausto Andres Ortiz-Morea, Di Liu, Eli Canal, David E. Curtis, Monisha Yerram, Joonyoung Shin, Pavel Ulianich, Chinmay Phadke, Ping He, Andrzej Wierzbicki, Junjie Zhang, Eugene V. Shakirov, Thomas Juenger, Dorothy E. Shippen · 发表于：Nature Communications · 年份：2026 · DOI：10.1038/s41467-026-70441-z · 被引用次数：1 · 研究领域：Telomeres, Telomerase, and Senescence、Nuclear Structure and Function、Plant Molecular Biology Research

Telomeres safeguard the genome, acting as sentinels of oxidative stress and preventing chromosome ends from eliciting a DNA damage response. PROTECTION OF TELOMERES 1 (POT1) is a highly conserved telomere protein, essential for chromosome integrity and telomeric DNA replication. Arabidopsis thaliana encodes two divergent POT1 paralogs: AtPOT1a stimulates telomerase activity, but AtPOT1b function is unknown. Here we show that AtPOT1b modulates reactive oxygen species (ROS) homeostasis. Oxidative stress induces AtPOT1b expression and telomeric accumulation, while AtPOT1b inactivation elevates ROS, increases telomeric and genome-wide oxidation, and causes stochastic telomere length changes. To address how AtPOT1b controls ROS, we report its localization in nuclei and peroxisomes, and association with catalases and peroxidases that enhance ROS scavenging. Impairing AtPOT1b-CAT2 interaction increases ROS accumulation and telomeric oxidation. Moss or human POT1 rescues ROS overaccumulation in Arabidopsis pot1b mutants, but not telomere deficiency in pot1a pot1b mutants, supporting a conserved role for POT1 in modulating ROS homeostasis and genome stability, distinct from canonical telomeric functions.