Influence of alternate wetting and drying water-saving irrigation practice on the dynamics of Gallionella-related iron-oxidizing bacterial community in paddy field soil
Influence of alternate wetting and drying water-saving irrigation practice on the dynamics of Gallionella-related iron-oxidizing bacterial community in paddy field soil
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DOI：
10.1016/j.soilbio.2020.108064
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发表时间：
2021
影响因子：
9.7
通讯作者：
Takeshi Watanabe;N. Katayanagi;R. Agbisit;L. Llorca;Y. Hosen;S. Asakawa
中科院分区：
文献类型：
--
作者：
Takeshi Watanabe;N. Katayanagi;R. Agbisit;L. Llorca;Y. Hosen;S. Asakawa
铁的氧化还原循环是稻田土壤生物地球化学过程中的一个关键过程。新近发现，大蒜科(Gallionellaceae，Gallionellaceae，与Gallionella相关的FeOB)中的Fe(II)氧化菌是土壤中Fe(II)氧化的关键细菌之一。研究了干湿交替灌溉(AWD)对水稻种植3个季节(干湿湿季)稻田土壤中与Gallionella相关的FeOB群落动态的影响。与连续淹水(CF)灌溉相比，AWD灌溉降低了土壤中Fe(II)的含量，尤其是在旱季水稻栽培的后半期。相反，在AWD水稻土的水稻栽培后期，观察到与Gallionella相关的FeOB的16S rRNA基因拷贝数有增加的趋势。结果表明，16S rRNA基因拷贝数与Fe(II)含量呈显著负相关。对Gallionella相关FeOB的16S rRNA基因进行了PCR-DGGE分析，结果表明，CF和AWD水稻土的16S rRNA基因带型不同。同时，克隆文库分析结果表明，与Gallionella相关的FeOB在CF和AWD水稻土中的分类组成没有差异，表明与Gallionella相关的FeOB对AWD节水灌溉在个体菌株水平上做出了响应。根据已报道的细胞Fe(II)氧化速率，估算了研究区土壤中Fe(II)氧化活性的潜势及其对Fe(II)氧化的表观贡献率分别为2.4万×10~(−)3~1.7万×10~(−)g−1 mg Fe(II)−_1和4.6%。研究表明，田间反复干湿循环引起的Fe氧化还原状态的波动，导致了土壤中与Gallionella相关的FeOB群落结构的变化。此外，还表明与Gallionella相关的FeOB确实参与了AWD稻田土壤中Fe(II)的氧化过程。
The redox cycle of iron (Fe) is a key process in the biogeochemistry of paddy field soil. It has been recently remarked that Fe(II)-oxidizing bacteria belonging to the familyGallionellaceae(Gallionella-related FeOB) are one of the key players in the Fe(II) oxidation in the soil. The present study aimed to investigate the influence of alternate wetting and drying (AWD) irrigation for water-saving rice cultivation on the dynamics of the community ofGallionella-related FeOB in the paddy field soil over three seasons (wet-dry-wet seasons) of rice cultivation. The AWD irrigation brought about the reduction of Fe(II) contents in the soil, compared with the continuously flooding (CF) irrigation, especially in the last half of the rice cultivation period in the dry season. In contrast, a trend of higher copy number of 16S rRNA genes ofGallionella-related FeOB was observed in the last half of the rice cultivation period of the AWD paddy soil. As a result, a significant negative correlation was observed between the Fe(II) contents and the copy numbers of 16S rRNA genes. PCR-DGGE analysis of 16S rRNA genes ofGallionella-related FeOB showed that the band patterns were different between the CF and AWD paddy soils. Meanwhile, the results of clone library analysis indicated that differences in the taxonomic composition ofGallionella-related FeOB were not observed between the CF and AWD paddy soils, suggesting thatGallionella-related FeOB responded to the AWD water-saving irrigation on the individual strain levels. The potential of Fe(II)-oxidizing activity and its apparent contribution of the activity ofGallionella-related FeOB to the Fe(II) oxidation in the soil of the investigated field were estimated to be 2.4 × 10−3to 1.7 × 10−1mg Fe(II) g−1dry soil day−1and 4.6%, respectively, based on the reported Fe(II) oxidation rates of cells. The present study showed that the fluctuation of the redox status of Fe caused by the repeated cycle of wetting and drying of the field brought about the changes in the community structure ofGallionella-related FeOB in the soil. Furthermore, it was suggested thatGallionella-related FeOB were certainly involved in the Fe(II)-oxidizing process in the AWD paddy field soil.