Insight into universality and characteristics of nitrate reduction coupled with arsenic oxidation in different paddy soils
Insight into universality and characteristics of nitrate reduction coupled with arsenic oxidation in different paddy soils
复制标题
不同水稻土硝酸盐还原与砷氧化耦合的普遍性和特征
DOI：
10.1016/j.scitotenv.2022.161342
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发表时间：
2023
影响因子：
9.8
通讯作者：
Yingmei Huang
中科院分区：
文献类型：
--
作者：
Mi Feng;Yanhong Du;Xiaomin Li;Fangbai Li;Jiangtao Qiao;Gongning Chen;Yingmei Huang
硝酸盐还原与砷 (As) 氧化相结合，强烈影响厌氧环境中砷的生物利用度和毒性。本研究利用不同母质发育的五种代表性水稻土，研究了水稻土中硝酸盐还原与砷氧化的普遍性和特征。实验结果表明，在硝酸盐存在下，99.8%的剧毒As(III)水溶液在2-8 d内转化为溶解的As(V)和Fe结合的As(V)，这表明硝酸盐处理后As很容易以其低毒且不稳定的形式保留。此外，硝酸盐的添加还显着诱导了五种水稻土中16S rRNA和As(III)氧化酶(aioA)基因的丰度升高，特别是在紫砂土岩和第四纪红粘土发育的土壤中，添加硝酸盐后分别增加了10倍和3-5倍。此外，基于宏基因组分析，鉴定出多种假定的新型硝酸盐依赖性As(III)氧化细菌，主要包括Aromatoleum、Paenibacillus、Microvirga、Herbaspirillum、Bradyrhizobium、Azospirillum。总体而言，所有这些研究结果表明，硝酸盐还原与As（III）氧化是水稻环境中普遍存在的重要氮-砷耦合过程，并强调了开发和推广基于硝酸盐的生物技术对于控制水稻土中砷污染、降低砷危害粮食安全的重要性。
Nitrate reduction coupled with arsenic (As) oxidation strongly influences the bioavailability and toxicity of As in anaerobic environments. In the present study, five representative paddy soils developed from different parent materials were used to investigate the universality and characteristics of nitrate reduction coupled with As oxidation in paddy soils. Experimental results indicated that 99.8 % of highly toxic aqueous As(III) was transformed to dissolved As(V) and Fe-bound As(V) in the presence of nitrate within 2–8 d, suggesting that As was apt to be reserved in its low-toxic and nonlabile form after nitrate treatment. Furthermore, nitrate additions also significantly induced the higher abundance of 16S rRNA and As(III) oxidase (aioA) genes in the five paddy soils, especially in the soils developed from purple sand-earth rock and quaternary red clay, which increased by 10 and 3–5 times, respectively, after nitrate was added. Moreover, a variety of putative novel nitrate-dependent As(III)-oxidizing bacteria were identified based on metagenomic analysis, mainly includingAromatoleum, Paenibacillus,Microvirga, Herbaspirillum, Bradyrhizobium, Azospirillum. Overall, all these findings indicate that nitrate reduction coupled with As(III) oxidation is an important nitrogen-As coupling process prevalent in paddy environments and emphasize the significance of developing and popularizing nitrate-based biotechnology to control As pollution in paddy soils and reduce the risk of As compromising food security.