Coimbra Carina, Morais Paula V, Branco Rita
University of Coimbra, Centre for Mechanical Engineering, Materials and Processes, ARISE, Department of Life Sciences, Coimbra, Portugal.
Front Microbiol. 2024 Oct 4;15:1467386. doi: 10.3389/fmicb.2024.1467386. eCollection 2024.
Yttrium (Y), an important rare earth element (REE), is increasingly prevalent in the environment due to industrial activities, raising concerns about its toxicity. Understanding the effects of Y on microorganisms is essential for bioremediation and biorecovery processes. This study investigates how J19, a strain with notable resistance to Y, manages iron homeostasis as a detoxifying mechanism under Y stress. Using comparative genomic and transcriptomic analyses, we explored the gene expression profile of strain J19 to identify the mechanisms underlying its high Y resistance and effective Y removal from the medium. Genome-wide transcriptional profiling revealed 127 significantly differentially expressed genes out of 6,343 under Y stress, with 36.2 % up-regulated and 63.8 % down-regulated. Notably, Y exposure significantly affects cellular iron homeostasis and activates arsenic detoxifying mechanisms. A key finding was the 7.6-fold up-regulation of a TonB transporter gene, indicating its crucial role in Y detoxification. Real-time PCR (RT-PCR) analysis of the selected gene confirmed the accuracy of RNA sequencing results. Further validation showed that iron supplementation mitigates Y-induced growth inhibition, leading to reduced ROS production in strain J19. This study elucidates the molecular mechanisms by which strain J19 adapts to Y stress, emphasizing the importance of iron in controlling ROS and protecting against Y toxicity. It also highlights critical pathways and adaptive responses involved in the strain's resilience to metal stress.
钇（Y）是一种重要的稀土元素（REE），由于工业活动，它在环境中越来越普遍，这引发了人们对其毒性的担忧。了解钇对微生物的影响对于生物修复和生物回收过程至关重要。本研究调查了对钇具有显著抗性的菌株J19如何在钇胁迫下通过维持铁稳态作为解毒机制。通过比较基因组学和转录组学分析，我们探索了菌株J19的基因表达谱，以确定其高钇抗性和从培养基中有效去除钇的潜在机制。全基因组转录谱分析显示，在钇胁迫下，6343个基因中有127个基因显著差异表达，其中36.2%上调，63.8%下调。值得注意的是，钇暴露显著影响细胞铁稳态并激活砷解毒机制。一个关键发现是一个TonB转运蛋白基因上调了7.6倍，表明其在钇解毒中起关键作用。对所选基因的实时PCR（RT-PCR）分析证实了RNA测序结果的准确性。进一步的验证表明，补充铁可减轻钇诱导的生长抑制，导致菌株J19中活性氧的产生减少。本研究阐明了菌株J19适应钇胁迫的分子机制，强调了铁在控制活性氧和防止钇毒性方面的重要性。它还突出了该菌株对金属胁迫的抗性所涉及的关键途径和适应性反应。
