Regulatory Networks of circRNAs and lncRNAs Related to Salt Stress in Populus euphratica Oliv. heteromorphic leaves

Circular RNAs (circRNAs) and long-noncoding RNAs (lncRNAs) are a class of non-protein-coding RNA, in eukaryotic genomes, that participate in the regulation of physiological and pathological processes such as stem cell maintenance, cell differentiation, cell growth, apoptosis, signal transduction, and immune response. In this study, based on RNA-Seq and competing endogenous RNAs hypothesis, 14 circRNAs and 28 lncRNAs, involved in the regulation of salt stress response were screened and identified from the RNA-Seq of Populus euphratica Oliv. heteromorphic leaves (P. hl), and their functions were predicted. We found that these circRNAs and lncRNAs may not only enhance the tolerance of plants to salt stress by participating in biological events such as ion compartmentation, oxidative stress, and cell division in plant cells but also play an important role in the occurrence of P. hl by participating in gene expression regulation, metabolism, and hormone regulation. This study provides theoretical support for studying the regulation mechanism of salt stress response of Populus euphratica Oliv., and lays an important foundation for using Populus euphratica Oliv. gene resources to cultivate new salt-resistant varieties.