Mechanism of salicylic acid in promoting the rhizosphere benzo[a]pyrene biodegradation as revealed by DNA-stable isotope probing
Mechanism of salicylic acid in promoting the rhizosphere benzo[a]pyrene biodegradation as revealed by DNA-stable isotope probing
复制标题
DNA稳定同位素探测揭示水杨酸促进根际苯并[a]芘生物降解的机制
DOI：
10.1016/j.scitotenv.2021.152202
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发表时间：
2021-12-17
影响因子：
9.8
通讯作者：
Zhang，Gan
中科院分区：
文献类型：
--
作者：
Zhao，Xuan;Li，Jibing;Zhang，Gan
苯并[a]芘（BaP）是一种典型的高分子量多环芳烃，具有致癌性。植物根系修复技术是去除土壤苯并（a）芘的常用方法，但其作用机理尚不清楚。根分泌物中诱导物在苯并（a）芘根际修复中的作用研究较少。在这里，为了解决这个问题，我们首先调查了诱导剂水杨酸对苯并（a）芘根际修复，根际苯并（a）芘降解剂，和PAH降解相关基因的影响相结合的DNA稳定同位素探测，高通量测序，和基因功能预测。水杨酸刺激显著提高了根际BaP的去除率，并显著改变了根际BaP降解微生物群落结构。14种微生物参与了BaP的降解，其中大多数降解菌如产气微生物属（Aeromicrobium）和产菌丝菌属（Myceligenerans）首先与BaP的降解有关。所有13 C处理的重组分中多环芳烃环羟化双加氧酶（PAH-RHD）基因的富集进一步表明它们参与了BaP的生物降解，这也通过基于基因功能预测的优势多环芳烃降解相关基因（例如多环芳烃双加氧酶和原儿茶酸3，4-双加氧酶基因）的富集得到证实。研究结果表明，水杨酸可通过改变根际苯并（a）芘降解菌的群落结构和多环芳烃降解相关基因的丰度来促进根际苯并（a）芘的生物降解，为石油污染土壤中苯并（a）芘的根际修复机制提供了新的思路。
Benzo[a]pyrene (BaP) is a typical high-molecular-weight PAH with carcinogenicity. Rhizoremediation is commonly applied to remove soil BaP, but its mechanism remains unclear. The role of inducers in root exudates in BaP rhizoremediation is rarely studied. Here, to address this problem, we firstly investigated the effect of the inducer salicylic acid on BaP rhizoremediation, rhizosphere BaP degraders, and PAH degradation-related genes by combining DNA-stable-isotope-probing, high-throughput sequencing, and gene function prediction. BaP removal in the rhizosphere was significantly increased by stimulation with salicylic acid, and the rhizosphere BaP-degrading microbial community structure was significantly changed. Fourteen microbes were responsible for the BaP metabolism, and most degraders,e.g. AeromicrobiumandMyceligenerans, were firstly linked with BaP biodegradation. The enrichment of the PAH-ring hydroxylating dioxygenase (PAH-RHD) gene in the heavy fractions of all13C-treatments further indicated their involvement in the BaP biodegradation, which was also confirmed by the enrichment of dominant PAH degradation-related genes (e.g.PAH dioxygenase and protocatechuate 3,4-dioxygenase genes) based on gene function prediction. Overall, our study demonstrates that salicylic acid can enhance the rhizosphere BaP biodegradation by altering the community structure of rhizosphere BaP-degrading bacteria and the abundance of PAH degradation-related genes, which provides new insights into BaP rhizoremediation mechanisms in petroleum-contaminated sites.