【作者】 冯有智； 林先贵； 贾仲君； 朱建国；

【Author】 Feng Youzhi~(1,2),Lin Xiangui~(1,2),Jia Zhongjun~(1,2),Zhu Jianguo~(1,2) (1.State Key Laboratory of Soil and Sustainable Agriculture,Institute of Soil Science, Chinese Academy of Sciences,Nanjing 210008 Jiangsu Province,People’s Republic of China)

【机构】 中国科学院南京土壤研究所土壤与农业可持续发展国家重点实验室； 南京土壤研究所-香港浸会大学土壤与环境联合开放实验室；

【摘要】 土壤微生物是陆地生态系统地下部分物质和能量的驱动者,其响应是全面揭示全球气候变化对陆地生态系统影响不可或缺的组成部分。紫色光养细菌（Purple Phototrophic Bacteria,PPB）是光养细菌中重要的组成部分。它们是环境碳循环末端的一类重要功能微生物,对环境中碳组分和总量的变化反应敏锐,是环境变化的生物指标之一。水稻土中含有丰富的PPB资源,但是其生态功能不明。本研究基于中国FACE-CO₂和FACE-O₃平台,揭示了水稻土中PPB的功能,以及大气二氧化碳浓度升高和大气臭氧浓度升高对其多样性的影响。同时利用稳定同位素探针技术（Stable Isotope Probing,SIP）研究了PPB的生态功能,结果发现水稻土中的PPB利用有机酸代谢生长,并且驱动着自下而上的微生物食物网络（如图1所示）。通过此物质和能量的传递,水稻土土壤肥力将得以更好地保持。结合可培养技术和分子生物学方法,研究发现大气二氧化碳浓度升高增加了水稻土中PPB的丰度和丰富度（如图2所示）;与之相反,大气臭氧浓度升高下,因PPB代谢能力的下降（如图3所示）而导致其丰度、占比和丰富度的降低（如图4所示）。通过PPB驱动的微生物食物网络,全球气候变化的影响将会转移给多个微生物营养层。该研究不仅为全面理解微生物驱动下的稻田土壤养分循环过程及其调控机制提供了重要科学依据,也有助于我们更好地了解全球气候变化对稻田生态系统的影响。更多还原

【Abstract】 Soil microorganisms are indispensable constituents of soil ecosystem,and their responses make great contribution to a better understanding of global climate changes on terrestrial ecosystem.Purple Phototrophic Bacteria（PPB） are one of important functional guilds.They are sensitive to changes in environmental dissolved organic C,which makes them as a good bioindicator.There are phylogenetically diverse and numberically abundant PPB residing paddy soils.However,their ecological functions remain elusive.Based on China FACE-CO₂ and FACE-O₃ platforms,we investigate the ecological function of PPB in paddy soil,as well as their responses to elevated atmospheric CO₂ and O₃.At first,we used DNA-based Stable Isotope Probing（SIP） to investigate the ecological function of PPB in paddy soil,and found that utilizing light energy,paddy PPB assimilate organic acids to drive a bottom-up microbial food web（Figure 1）.Furthermore,we found that elevated atmospheric CO₂ can increase paddy PPB richness and abundance（Figure 2）;however,in contrast,elevated ground-level O₃ can decrease the abundance and richness of PPB,as well as their percentages in total bacterial population（Figure 3） by reducing their metabolic capability（Figure 4）.Through the PPB-driven microbial food web,the effect of global climate changes can be transferred to several microbial trophic levels.The elucidation of such a web in sustaining the carbon and energy flow and their responses to global climate changes would be of great help toward a better understanding of not only paddy soil productivity,but also the effect of global changes on paddy ecosystem.更多还原