Diazotrophs diversity in soybean is a topic requiring thorough investigation since the previous researches have focused on only rice, forest, grass, water, etc. In this research, iron-only nitrogenase nifH gene was as genetic marker. PCR-RFLP was used to investigate the difference of diazotrophs community diversity in the soil from the continuous cropping (CC) (the 5-yr tilling of soybean) and the rotational cropping (RC) (soybean-corn) soils in the northeast of China. A total of 36 isolates were genetically characterized. Most of the isolates closely related to Azospirillum and Azotobacter. Eighty-six unique nifH gene sequences were obtained by cloning of the respective PCR products in two soil samples. It was found that the diversity of nifH genes in CC changed obviously compared with RC. Phylogenetic analysis indicated that most of the clones clustered together in a high homogeneity with some sequence retrieved from environmental representatives. The sequence diversity of nifH genes was high and the members of the Alphaproteobacteria were predominant in both samples. The experimental study also revealed the two non-proteobacterial diazotrophs, firmicutes and euryarchaeota. Through this study, it can be assumed that different tillage perhaps affected the nifH gene-containing population diversity.
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http://dx.doi.org/10.1002/jobm.200900317 | DOI Listing |
Microorganisms
January 2025
Department of Biology and Microbiology, South Dakota State University, Brookings, SD 57007, USA.
Nitrogen inputs for sustainable crop production for a growing population require the enhancement of biological nitrogen fixation. Efforts to increase biological nitrogen fixation include bioprospecting for more effective nitrogen-fixing bacteria. As bacterial nitrogenases are extremely sensitive to oxygen, most primary isolation methods rely on the use of semisolid agar or broth to limit oxygen exposure.
View Article and Find Full Text PDFBMC Microbiol
January 2025
College of Tobacco Science/Research Center for Tobacco Harm Reduction/Tobacco Cultivation Key Laboratory of China Tobacco, Henan Agricultural University, Zhengzhou, Henan, 450002, People's Republic of China.
Objective: This study explored green manuring effects on microecology, carbon/nitrogen levels, and enzyme activity in tobacco-growing soils.
Methods: After 30,000 kg·hm⁻² overpressure and 28 days of natural decomposition, plants (Hordeum vulgare L. (DM), Secale cereale L.
Trends Biotechnol
January 2025
College of Biological Sciences, China Agricultural University, Beijing 100193, China. Electronic address:
Engineering nitrogen fixation in cereals could reduce usage of chemical nitrogen fertilizers. Here, a nitrogenase biosynthesis pathway comprising 13 genes (nifB nifH nifD nifK nifE nifN nifX hesA nifV nifS nifU groES groEL) was introduced into rice by transforming multigene vectors and subsequently by sexual crossing between transgenic rice plants. Genome sequencing analysis revealed that 13 nif genes in F hybrid rice lines L12-13 and L8-17 were inserted at two loci on rice chromosome 1.
View Article and Find Full Text PDFJ Gen Appl Microbiol
January 2025
Department of Biotechnology, Graduate School of Agricultural and Life Sciences, The University of Tokyo.
We previously constructed an Escherichia coli strain expressing 16 nitrogen fixation (nif) and 2 nif-related genes from Azotobacter vinelandii and improved nitrogenase activity to some extent by enhancing NifH-related functions. In the present study, we analyzed the formation of dinitrogenase, a heterotetrameric NifDK, produced in E. coli, using gel-filtration chromatography and blue native PAGE to gain insight into further increases in nitrogenase activity.
View Article and Find Full Text PDFHortic Res
January 2025
College of Agriculture and Biotechnology, Zhejiang University, Hangzhou 310058, China.
The circadian clock mediates metabolic functions of plants and rhythmically shapes structure and function of microbial communities in the rhizosphere. However, it is unclear how the circadian rhythm of plant hosts regulates changes in rhizosphere bacterial and fungal communities and nutrient cycles. In the present study, we measured diel changes in the rhizosphere of bacterial and fungal communities, and in nitrogen (N) and phosphorus (P) cycling in 20-year-old tea plantations.
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