Response of gene abundance of ammonia-oxidizing microorganisms and denitrifying microorganisms to nitrogen and phosphorus addition in subtropical forest.

We conducted a nitrogen (N) and phosphorus (P) addition experiment in Qianjiangyuan National Park in 2015, to investigate the response of ammonia-oxidizing microorganisms and denitrifying microorganisms. There were four treatments, including N addition (N), P addition (P), NP, and control (CK). Soil samples were collected in April (wet season) and November (dry season) of 2021. The abundance of amoA gene of ammonia-oxidizing microorganisms (i.e., ammonia-oxidizing archaea, AOA; ammonia-oxidizing bacteria, AOB; comammox) and denitrifying microbial genes (i.e., nirS, nirK, and nosZ) were determined using quantitative PCR approach. The results showed that soil pH was significantly decreased by long-term N addition, while soil ammonium and nitrate contents were significantly increased. Soil available P and total P contents were significantly increased with the long-term P addition. The addition of N (N and NP treatments) significantly increased the abundance of AOB-amoA gene in both seasons, and reached the highest in the N treatment around 8.30×107 copies·g-1 dry soil. The abundance of AOA-amoA gene was significantly higher in the NP treatment than that in CK, with the highest value around 1.17×109 copies·g-1 dry soil. There was no significant difference in N-related gene abundances between two seasons except for the abundance of comammox-amoA. Nitrogen addition exerted significant effect on the abundance of AOB-amoA, nirK and nosZ genes, especially in wet season. Phosphorus addition exerted significant effect on the abundance of AOA-amoA and AOB-amoA genes in both seasons, but did not affect denitrifying gene abundances. Soil pH, ammonium, nitrate, available P, and soil water contents were the main factors affecting the abundance of soil N-related functional genes. In summary, the response of soil ammonia-oxidizing microorganisms and denitrifying microorganisms was more sensitive to N addition than to P addition. These findings shed new light for evaluating soil nutrient availability as well as their response mechanism to global change in subtropical forests.

[Genomics-based Biomarkers for Diseases:A Bibliometric Analysis Based on Web of Science].

Objective To analyze the research hotspots and trends of biomarkers for diseases based on genomics and thus provide basis for the future studies in this field. Method Based on the Web of Science,we analyzed the genomics-based biomarkers for diseases in literature published between 2006 and 2018 in terms of country and institutions,knowledge base,research hotspots,and trends by using bibliometric methods and CiteSpace software. Results A total of 998 articles were retrieved.The total number of articles has shown an upward trend and reached a peak of 112 in 2017 and 2018.Most articles(n=477)were from the United States,follwed by China(n=93).Nature,P Natl Acad Sci USA,PLoS One,Science,and New Engl J Med are core journals in this field.Keywords co-occurrence analysis identified four research hotspots:disease research,research method and technology,research level,and application purpose. Conclusion Research in functional genomics,cancer immunotherapy,genome-wide association and multi-omics techniques,personalized medicine,and precision medicine are research hotspots and frontiers in this field.