有机物料添加对长期单施化肥土壤磷酸单酯酶基因及其转录群落的修复机制

Long-term chemical fertilizations alone would cause a significant decrease in the abundance and diversity of phosphomonoesterase genes as well as a change in genes communities, which is detrimental to P bioavailability in soils. Addition of organic materials could maintain soil productivity and crop yield. However, whether and how addition of organic materials could benefit phosphomonoesterase genes and their transcripts communities still need further investigations. In this project, we would use soils from a continuously cropped corn field with long-term (>20 years) NPK fertilization to set up pot experiments. Phosphomonoesterase genes and their transcripts would be captured in different fertilization pots (NPK alone, NPK with lime (pH 6.5), livestock manure+NPK, straw+NPK, and biochar+NPK) at different plant growth stages by high-throughput sequencing and real-time PCR. Combining bioinformatic and statistical approaches, all the sequencing data would be linked to plant P uptake, soil properties and microbial communities through partial correlation networks and structure equation models, and thereby identifying the main drivers. Based on the analyses at multiple levels, including DNA (gene), mRNA (transcription) and enzyme activity (translation), the mechanisms of modifying the phosphomonoesterase genes and their transcripts communities in long-term mineral fertilized soils through addition of organic materials would be revealed.

长期单施化肥显著降低土壤磷酸单酯酶基因丰度与多样性，改变其群落组成，不利于土壤有效P持续供应。添加有机物料可以维持土壤生产力及作物产量，但对土壤磷酸单酯酶基因及其转录群落会否产生正向影响及其作用机制如何尚待深入研究。本项目以长期（>20年）单施NPK肥试验地土壤为供试土壤，采用盆栽试验方法，应用高通量测序技术，结合生物信息学与统计学分析，以单施NPK及NPK加生石灰（pH 6.5）处理为对照，研究不同有机物料（常规粪肥，秸秆及生物炭）添加在植物不同生长时期对土壤磷酸单酯酶基因及转录丰度、群落多样性与组成的影响；通过与植物P吸收、土壤、微生物群落及组成等特征参数建立偏相关关系网络与结构方程模型等分析，探讨土壤磷酸单酯酶基因及其转录群落变化的主要驱动因子；通过DNA（基因）、mRNA（转录）与酶活性（翻译）多水平解析，揭示有机物料添加对长期化肥单施土壤磷酸单酯酶基因及转录群落的修复机制。

长期单施化肥显著降低土壤磷酸单酯酶基因丰度与多样性，改变其群落组成，不利于土壤有效P持续供应。添加有机物料可以维持土壤生产力及作物产量，但对土壤磷酸单酯酶基因及其转录群落会否产生正向影响及其作用机制如何尚待深入研究。本项目应用高通量测序技术，结合生物信息学与统计学分析，系统分析了相同秸秆量，经粉碎、堆沤以及炭化后施入长期单施化肥的农田土壤后，对磷素组成、磷酸酶活性及其编码基因群落的动态影响，从分子生物学角度探讨了土壤磷形态、磷酸酶活性功能基因群落结构等特征参数对不同有机物料添加的响应及差异。结果表明，与单施氮磷钾肥相比，配施有机物料通过缓解土壤pH的下降、提高土壤有机质和微生物量碳含量，不同程度提高了土壤磷酸单酯酶的活性，且比直接改变土壤pH作用更持久。其中配施秸秆通过显著改变功能基因丰度及其表达，对磷酸酶活性提升幅度最大；生物炭和粪肥通过改变磷酸酶编码基因群落的多样性组成，也在一定程度促进了土壤有机磷向无机磷的转化。本研究初步揭示了有机物料添加改变农田土壤中磷素保持与供应能力的酶学与微生物学机制，研究成果为全面解析磷酸酶功能基因群落与磷转化关系提供新途径和数据支撑。