Quorum sensing (QS) plays an important role in the growth, nodulation, and nitrogen fixation of rhizobia. In this study, we show that water-soluble humic materials (WSHM) repress the expression of the QS related genes , and in This decreased the production of -acetyl homoserine lactones (AHL) and exopolysaccharides (EPS), and ultimately increased cell density. We also identified a novel regulator, SMc03890 (renamed QsrR), which binds directly to the promoter. Deletion of increased expression. WSHM repressed the expression of by augmenting the interaction between QsrR and the promoter; this was determined by a bacterial-one-hybrid assay. These effects of WSHM on the QS system in may be the underlying mechanism by which WSHM increase the symbiotic nitrogen fixation of inoculated with . This study provides the first evidence that humic acids regulate the QS of rhizobia and suggests that WSHM could be used as fertilizers to improve the efficiency of symbiotic nitrogen fixation.
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http://dx.doi.org/10.3389/fmicb.2018.03194 | DOI Listing |
Mol Genet Genomics
December 2024
Institute of Ecology and Earth Sciences, University of Tartu, Liivi 2, 50409, Tartu, Estonia.
Root nodule symbiosis is traditionally recognized in the Fabales, Fagales, Cucurbitales, and Rosales orders within the Rosid I clade of angiosperms. However, ambiguous root nodule formation has been reported in Zygophyllaceae and Roystonea regia (Arecaceae), although a detailed analysis has yet to be conducted. We aimed to perform morphological analyses of root structures in these plants and utilize metagenomic techniques to identify and characterize the bacterial populations within the nodule-like structures.
View Article and Find Full Text PDFSci Rep
December 2024
Graduate School of Life Sciences, Ritsumeikan University, Kusatsu, Shiga, 525-8577, Japan.
A circadian clock is reconstituted in vitro by incubating three proteins, KaiA, KaiB, and KaiC from the non-nitrogen-fixing cyanobacterium Synechococcus elongatus PCC 7942 in the presence of ATP. Leptolyngbya boryana is a filamentous cyanobacterium that grows diazotrophically under microoxic conditions. Among the aforementioned proteins, KaiC is the main clock oscillator belonging to the RecA ATPase superfamily.
View Article and Find Full Text PDFJ Environ Manage
December 2024
Centre for Invasion Biology, Department of Botany and Zoology, Stellenbosch University, Matieland, 7602, South Africa; School of Natural Sciences, Macquarie University, Sydney, 2109, Australia.
The impacts of invasive plants on ecosystem processes and functions may persist as "legacy effects" after their removal. Understanding these effects on native plant-soil interactions is critical for guiding ecological restoration efforts. This study examines the legacy effects of the invasive legume Acacia saligna (Labill.
View Article and Find Full Text PDFLangmuir
December 2024
State Key Laboratory of High-Efficiency Utilization of Coal and Green Chemical Engineering, School of Chemistry and Chemical Engineering, Ningxia University, Yinchuan, Ningxia 750021, PR China.
The challenge of achieving efficient photocatalysts for the fixation of ambient nitrogen to ammonia persists. The utilization efficiency of single-metal-atom catalysts leads to an increased number of active sites, while their distinctive geometrical and electronic characteristics contribute to enhancing the intrinsic activity of each individual site. In this study, we present a method using an organic molecule to assist in loading TiO with Mo single atoms for the purpose of photocatalytic nitrogen fixation.
View Article and Find Full Text PDFBioTech (Basel)
December 2024
Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, 32 Vavilova, 119991 Moscow, Russia.
The white poplar () is a dioecious woody plant with significant potential for the phytoremediation of soils. To realize this potential, it is necessary to utilize growth-promoting microorganisms. One potential source of such beneficial microorganisms is the rhizosphere community of wild-growing trees.
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