有机培肥条件下红壤区稻田土壤病毒多样性及其对生物地球碳循环的影响

Paddy soil virus diversity in red soil region under organic fertilization and its effects on biogeographical carbon cycle

  • 摘要: 【目的】探究不同有机培肥条件下稻田土壤病毒多样性、群落结构特征及其差异,为揭示病毒与寄主协同进化关系,以及病毒微生态系统驱动生物地球碳循环过程提供理论基础。【方法】长期定位试验开始于1981年,试验设置6个处理,每处理3次重复,试验处理分别为:(1)CK,不施肥;(2)NPK,单施化肥;(3)M1,早稻施绿肥;(4)M2,早稻施绿肥+早稻施猪粪;(5)M3,早稻施绿肥+晚稻施猪粪;(6)M4,早稻施绿肥+晚稻秸秆还田。2020年晚稻收获后,采集耕层(0~20 cm)土壤,通过宏病毒组测序平台、土壤常规理化分析等方法测定土壤宏病毒组以及土壤养分含量。【结果】红壤区稻田土壤病毒分布于37个科,微小病毒科(Microviridae)是红壤区稻田土壤主要的病毒类群。M3处理中长尾病毒科(Siphoviridae)、肌病毒科(Myoviridae)和痘病毒科(Poxviridae)丰度显著高于其他处理(P<0.05,下同),M2处理中微小病毒科和矮化病毒科(Nanoviridae)丰度显著高于其他处理。通过稻田土壤病毒宏基因组基因注释,鉴定出143个独特碳水化合物的运输和代谢基因,46个开放阅读框属于13种病毒辅助碳水化合物活性酶(CAZyme),其中糖苷水解酶最丰富,约占61.7%,其次为糖基转移酶。土壤病毒物种丰富度可在一定程度反映土壤pH、Mg2+含量和水稻产量的高低,病毒群落结构受p H、Mg2+含量等其他因素驱动。【结论】微小病毒科是红壤区稻田土壤主要的病毒类群,施用猪粪可显著提高土壤病毒群落结构和物种组成,病毒群落结构受土壤pH和Mg2+含量的显著影响。通过稻田土壤病毒宏基因组基因注释,在病毒体中检测到丰富的碳水化合物活性酶基因,主要分别属于糖苷水解酶类和糖苷转移酶,病毒编码的辅助代谢基因或代谢基因会改变细菌代谢,间接促进农业土壤的生物地球碳化学循环。

     

    Abstract: 【Objective】To explore the diversity,community structure and differences of soil viruses in paddy fields under different organic fertilization conditions,and to provide a theoretical basis for revealing coevolutionary relationship between viruses and their host,as well as the process of viral-microecosystems-driven biogeographical carbon cycle.【Method】The long-term localization trial began in 1981 and set up 6 treatments with 3 replicates foreach.Field experiment comprised of 6 treatments:(1)CK,no fertilizer,(2)NPK,single chemical fertilizer,(3)M1,green manure at early rice,(4)M2,green manureat early rice+pig manure at early rice,(5)M3,green manure at early rice+pig manure at late rice,(6)M4,green manure at early rice+straw returning at late rice.After the late harvest of rice in 2020,the topsoil(0-20 cm)was collected to determine macro-virus groupand nutrient contentin the soil by means of the macro-virus sequencing platform and soil routine analysis.【Result】Soil viruses were distributed in 37 families in red soil region,and Microviridae was the main virus group.Abundance of Siphoviridae,Myoviridae and Poxviridae in M3 treatment was significantly higher than that in other treatments(P<0.05,the same below).Abundance of Microviridae and Nanoviridae in M2 treatment were significantly higher than that in other treatments.Through metagenomic gene annotation of the rice field soil virus,143 unique carbohydrate transport and metabolism genes were identified.46 open reading frames belonged to 13 virus-assisted carbohydrate-active enzymes(CAZyme),of which glycoside hydrolases were the most abundant,accounting for 61.7%,followed by glycosyl transfer enzyme.The study also found that abundance of soil virus species could reflect soil pH,Mg2+and rice yield to a certain extent.Virus community structure was driven by pH,Mg2+and other factors.【Conclusion】Microviridae is the main virus group in the paddy soil in the red soil area.The application of pig manure significantly changes the community structure and species composition of soil viruses,and the virus community structure is significantly affected by soil pH and Mg2+content.CAZyme genes are detected in the virions through metagenome gene annotation of paddy soil virus,belonging to carbohydrate esterase and glycosidyltransferase,respectively.Virally-encoded accessory metabolic genes or metabolic genes alter bacterial metabolism and indirectly contribute to bio-Earth carbon cycling of agricultural soils.

     

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