Water-Soluble Humic Materials Regulate Quorum Sensing in Sinorhizobium meliloti Through a Novel Repressor of expR
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 sinI, sinR, and expR in Sinorhizobium meliloti. This decreased the production of N...
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doaj-e67f94dc57414246a023d9a45be711f32020-11-25T00:04:18ZengFrontiers Media S.A.Frontiers in Microbiology1664-302X2018-12-01910.3389/fmicb.2018.03194422904Water-Soluble Humic Materials Regulate Quorum Sensing in Sinorhizobium meliloti Through a Novel Repressor of expRYuan-Yuan Xu0Jin-Shui Yang1Cong Liu2En-Tao Wang3Ruo-Nan Wang4Xiao-Qian Qiu5Bao-Zhen Li6Wen-Feng Chen7Hong-Li Yuan8State Key Laboratory of Agrobiotechnology and Key Laboratory of Soil Microbial, Ministry of Agriculture, College of Biological Sciences, China Agricultural University, Beijing, ChinaState Key Laboratory of Agrobiotechnology and Key Laboratory of Soil Microbial, Ministry of Agriculture, College of Biological Sciences, China Agricultural University, Beijing, ChinaState Key Laboratory of Agrobiotechnology and Key Laboratory of Soil Microbial, Ministry of Agriculture, College of Biological Sciences, China Agricultural University, Beijing, ChinaEscuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Mexico City, MexicoState Key Laboratory of Agrobiotechnology and Key Laboratory of Soil Microbial, Ministry of Agriculture, College of Biological Sciences, China Agricultural University, Beijing, ChinaState Key Laboratory of Agrobiotechnology and Key Laboratory of Soil Microbial, Ministry of Agriculture, College of Biological Sciences, China Agricultural University, Beijing, ChinaState Key Laboratory of Agrobiotechnology and Key Laboratory of Soil Microbial, Ministry of Agriculture, College of Biological Sciences, China Agricultural University, Beijing, ChinaState Key Laboratory of Agrobiotechnology and Key Laboratory of Soil Microbial, Ministry of Agriculture, College of Biological Sciences, China Agricultural University, Beijing, ChinaState Key Laboratory of Agrobiotechnology and Key Laboratory of Soil Microbial, Ministry of Agriculture, College of Biological Sciences, China Agricultural University, Beijing, ChinaQuorum 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 sinI, sinR, and expR in Sinorhizobium meliloti. This decreased the production of N-acetyl homoserine lactones (AHL) and exopolysaccharides (EPS), and ultimately increased S. meliloti cell density. We also identified a novel regulator, SMc03890 (renamed QsrR), which binds directly to the expR promoter. Deletion of qsrR increased expR expression. WSHM repressed the expression of expR by augmenting the interaction between QsrR and the expR promoter; this was determined by a bacterial-one-hybrid assay. These effects of WSHM on the QS system in S. meliloti may be the underlying mechanism by which WSHM increase the symbiotic nitrogen fixation of Medicago sativa inoculated with S. meliloti. 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.https://www.frontiersin.org/article/10.3389/fmicb.2018.03194/fullSinorhizobium melilotiquorum sensinghumic materialsExpR regulatorbacterial communication |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
Yuan-Yuan Xu Jin-Shui Yang Cong Liu En-Tao Wang Ruo-Nan Wang Xiao-Qian Qiu Bao-Zhen Li Wen-Feng Chen Hong-Li Yuan |
spellingShingle |
Yuan-Yuan Xu Jin-Shui Yang Cong Liu En-Tao Wang Ruo-Nan Wang Xiao-Qian Qiu Bao-Zhen Li Wen-Feng Chen Hong-Li Yuan Water-Soluble Humic Materials Regulate Quorum Sensing in Sinorhizobium meliloti Through a Novel Repressor of expR Frontiers in Microbiology Sinorhizobium meliloti quorum sensing humic materials ExpR regulator bacterial communication |
author_facet |
Yuan-Yuan Xu Jin-Shui Yang Cong Liu En-Tao Wang Ruo-Nan Wang Xiao-Qian Qiu Bao-Zhen Li Wen-Feng Chen Hong-Li Yuan |
author_sort |
Yuan-Yuan Xu |
title |
Water-Soluble Humic Materials Regulate Quorum Sensing in Sinorhizobium meliloti Through a Novel Repressor of expR |
title_short |
Water-Soluble Humic Materials Regulate Quorum Sensing in Sinorhizobium meliloti Through a Novel Repressor of expR |
title_full |
Water-Soluble Humic Materials Regulate Quorum Sensing in Sinorhizobium meliloti Through a Novel Repressor of expR |
title_fullStr |
Water-Soluble Humic Materials Regulate Quorum Sensing in Sinorhizobium meliloti Through a Novel Repressor of expR |
title_full_unstemmed |
Water-Soluble Humic Materials Regulate Quorum Sensing in Sinorhizobium meliloti Through a Novel Repressor of expR |
title_sort |
water-soluble humic materials regulate quorum sensing in sinorhizobium meliloti through a novel repressor of expr |
publisher |
Frontiers Media S.A. |
series |
Frontiers in Microbiology |
issn |
1664-302X |
publishDate |
2018-12-01 |
description |
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 sinI, sinR, and expR in Sinorhizobium meliloti. This decreased the production of N-acetyl homoserine lactones (AHL) and exopolysaccharides (EPS), and ultimately increased S. meliloti cell density. We also identified a novel regulator, SMc03890 (renamed QsrR), which binds directly to the expR promoter. Deletion of qsrR increased expR expression. WSHM repressed the expression of expR by augmenting the interaction between QsrR and the expR promoter; this was determined by a bacterial-one-hybrid assay. These effects of WSHM on the QS system in S. meliloti may be the underlying mechanism by which WSHM increase the symbiotic nitrogen fixation of Medicago sativa inoculated with S. meliloti. 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. |
topic |
Sinorhizobium meliloti quorum sensing humic materials ExpR regulator bacterial communication |
url |
https://www.frontiersin.org/article/10.3389/fmicb.2018.03194/full |
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