编号：CDUT-2024-34

标题：Biological nitrogen fixation in barren soils of a high-vanadium region: Roles of carbon and vanadium

入藏号：WOS:001072636500001

中国科学院文献情报中心期刊分区：农林科学1区TOP（2023）

本校作者：王吉鹏；赵谦；钟怡秋；吉蜀昊；陈官锐

来源出版物：SOIL BIOLOGY & BIOCHEMISTRY  卷: 186  文献号: 109163

出版年：2023

第一地址：成都理工大学

关键词：Biological nitrogen fixation；nifH gene；Carbon availability；Complementary nitrogenase；Soil vanadium；Primary succession

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摘要：Free-living nitrogen fixation (FLNF) is a vital source of nitrogen for the initiation and development of ecosystemson bare lands. This process is catalyzed by the enzyme nitrogenase and is energy intensive. Of the three nitrogenase isoforms, molybdenum nitrogenase (Mo-Nase) is more efficient than its vanadium (V) and iron (Fe)counterparts at room temperature. However, the acquisition of Mo, one of the scarcest biometals in soils, represents a major resource investment for soil diazotrophs. In a vegetation restoration chronosequence developedon barren (low carbon and nitrogen) soils of a high-V region, we tested the following two hypotheses. First, theFLNF rate would be limited by the supply of energy. Second, high V availability would cut the cost of Vacquisition, and it would be beneficial for diazotrophs to use V-Nase as a complement of Mo-Nase. For the soilscollected along the chronosequence, the addition of a carbon cocktail remarkably stimulated the FLNF rate byrelieving the energy constraint and by enriching the diazotrophic genus Paenibacillus. Despite the high V contentin the soils, we failed to detect the vnf genes of V-Nase by metagenomic sequencing. Meanwhile, we observed alimited contribution of V-Nase activity to FLNF by checking the R ratio (ratio of FLNF rates measured by acetylene reduction and 15N2 incorporation) and the production of ethane during acetylene reduction. The reasonmight be that the Mo availability and temperature in our study area did not reach the thresholds for the onset ofV-Nase activity. Overall, our results highlight the importance of carbon supply for FLNF in barren soils, indicating that plants may effectively regulate rhizosphere diazotrophs by secreting root exudates. This may be animportant mechanism by which nonnitrogen-fixing plants survive on nitrogen-poor soils at the beginning ofprimary succession.

文章链接地址: https://www.sciencedirect.com/science/article/pii/S0038071723002250?via%3Dihub