Genetic diversity of rhizobia nodulating Arachis hypogaea L. in diverse land use systems of humid forest zone in Cameroon

Nkot, Laurette Ngo; Krasova-Wade, Tatiana; Etoa, François–Xavier; Sylla, Samba Ndao; Nwaga, D.

doi:10.1016/j.apsoil.2008.06.007

Cited by 28 publications

(21 citation statements)

References 20 publications

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“…A history of soybean production resulted in a shift away from the dominant fingerprint strain type (cluster 30), towards a more even strain distribution, with particular increases in cluster 24 and cluster 10. These results are in contrast to a study of peanut nodulating rhizobia in Cameroon where a history of peanut cultivation decreased rhizobia diversity resulted in a single strain dominating a soil as a result of selection of a particular rhizobium taxa by the peanut host legume (Nkot et al 2008). However, a study of hairy vetch (Vicia villosa) nodulating rhizobia showed that a history of hairy vetch cultivation was the single most important driver of increasing rhizobia diversity (Mothapo et al 2013).…”

Section: Field History Effects On Rhizobia Population and Community Ccontrasting

confidence: 66%

“…As expected, soil with a history of host crop cultivation resulted in greater nodule number, most likely as a result of past host-rhizobia interaction leading to increased rhizobia population size, as seen in previous studies (Mothapo et al 2013;Nkot et al 2008;Thies et al 1991). Additionally, Native, uncultivated soil was able to produce an equal number of nodules on promiscuous soybean as soils with a history of legume cultivation.…”

Section: Field History Effects On Rhizobia Population and Community Csupporting

confidence: 50%

“…The number of nodule-forming isolates usually increases the longer a soil is exposed to a particular host-legume crop (Elkins et al 1976;Mothapo et al 2013;Nkot et al 2008). Additionally, the use of commercial inoculants can lead to an increase in diversity through the introduction of novel strains and genetic material (Loureiro et al 2007).…”

Section: Introductionmentioning

confidence: 99%

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Drivers of promiscuous soybean associated rhizobia diversity in un-inoculated soil in Malawi

2016

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Increasing legume cultivation and yields on smallholder farms is challenged by low soil rhizobia bacteria populations and limited access to rhizobia inoculants. However, by understanding the environmental drivers of rhizobia diversity in un-inoculated soils to improve nodulation success for smallholder farmers. Soils were collected from 39 smallholder farms in the Ekwendeni region of northern Malawi. Soils were categorized by cropping history and analyzed for Mehlich-3 phosphorus, calcium, magnesium, potassium, iron, particle size distribution, organic matter (OM) content and pH. Rhizobia bacteria were isolated using Tropical Glycine cross (TGx) soybean (Glycine max) variety 1740-2F as a trap crop. Genomic fingerprints of extracted rhizobia were created using rep-PCR with the BOX A1R primer and diversity indexes calculated from resulting fingerprints. Genomic fingerprinting of rhizobia resulted in 32 clusters with 70 % fingerprint similarity. Soil OM and carbon strongly influenced the presence of 6 clusters, Ca of 4 clusters, pH of 3 clusters, and Mg, K, Clay of three clusters each. Recent soybean production resulted in a greater number of nodules (16) than other histories (10), and uncultivated soils had a different rhizobia community structure than cultivated soils. Soil rhizobia are subject to a complex ecology in which plant communities as well as OM, clay, and nutrient (Mg, K, Fe and P) content select for community structure. Identifying the drivers and preferred environments of high performing rhizobia strains could improve nodulation in low-input agriculture environments.

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Section: Field History Effects On Rhizobia Population and Community Ccontrasting

confidence: 66%

Section: Field History Effects On Rhizobia Population and Community Csupporting

confidence: 50%

Section: Introductionmentioning

confidence: 99%

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Drivers of promiscuous soybean associated rhizobia diversity in un-inoculated soil in Malawi

2016

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“…However, in Cameroon, where Pueraria is grown as a cover crop, no studies have been carried out in the agricultural systems to identify its nitrogen-fixing symbionts or their potential for fixing atmospheric nitrogen. Studies of nitrogen-fixing bacteria in Cameroon have been performed groundnuts (Arachis hypogaea (L.)) (Nkot et al 2008(Nkot et al , 2011 as trap hosts. Such studies were limited to characterizing bacterial diversity based on quantitative and phenotypic observations.…”

Section: Introductionmentioning

confidence: 99%

Phylogeny and nitrogen fixation potential ofBradyrhizobiumspecies isolated from the legume cover cropPueraria phaseoloides(Roxb.) Benth. in Eastern Cameroon

Sarr

Araki

Begoude

et al. 2015

Soil Science and Plant Nutrition

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Pueraria is an herbaceous, perennial legume crop originating in Asia. Pueraria phaseoloides (Roxb.) Benth. (tropical kudzu) is frequently introduced into production systems and is used as green manure, a cover crop and a forage plant, making it important economically. We used P. phaseoloides as a trap crop to study and characterize soil rhizobia in Eastern Cameroon. Bacteria were isolated from fresh nodules collected from field-grown P. phaseoloides roots. The 16S-23S rRNA internal transcribed spacer (ITS) sequences from 30 bacterial isolates were amplified by polymerase chain reaction (PCR) and the reaction products were sequenced. Phylogenetic analysis revealed that all isolates were ascribed to the genus Bradyrhizobium and were grouped into three clusters of Bradyrhizobium sp. strains, one cluster of B. yuanmingense strains, and one cluster of B. elkanii strains. Acetylene reduction assay (ARA) results indicated that the B. yuanmingense strains had significantly higher nitrogen fixation potential and that they could be used as inoculants to enhance nitrogen fixation in Pueraria grown in Eastern Cameroon. ARTICLE HISTORY

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“…It is worth mentioning that Bradyrhizobium has a basal position amongst all nitrogen-fixing rhizobia, [18] and is reported to be involved in endophytic or symbiotic associations with plant roots [19]. Groundnut forms effective nodules with rhizobia belonging to genus Bradyrhizobium [20,21]. A high level of species diversity and fixation efficiency of symbionts was reported from different geographical regions by morpho-physiological and molecular methods [22].…”

Section: Diversity Among Bacterial Strains Associated With Groundnut Rnsmentioning

confidence: 99%

Molecular Basis of Root Nodule Symbiosis between Bradyrhizobium and ‘Crack-Entry’ Legume Groundnut (Arachis hypogaea L.)

Sharma

Bhattacharyya

Kumar

et al. 2020

Plants

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Nitrogen is one of the essential plant nutrients and a major factor limiting crop productivity. To meet the requirements of sustainable agriculture, there is a need to maximize biological nitrogen fixation in different crop species. Legumes are able to establish root nodule symbiosis (RNS) with nitrogen-fixing soil bacteria which are collectively called rhizobia. This mutualistic association is highly specific, and each rhizobia species/strain interacts with only a specific group of legumes, and vice versa. Nodulation involves multiple phases of interactions ranging from initial bacterial attachment and infection establishment to late nodule development, characterized by a complex molecular signalling between plants and rhizobia. Characteristically, legumes like groundnut display a bacterial invasion strategy popularly known as “crack-entry’’ mechanism, which is reported approximately in 25% of all legumes. This article accommodates critical discussions on the bacterial infection mode, dynamics of nodulation, components of symbiotic signalling pathway, and also the effects of abiotic stresses and phytohormone homeostasis related to the root nodule symbiosis of groundnut and Bradyrhizobium. These parameters can help to understand how groundnut RNS is programmed to recognize and establish symbiotic relationships with rhizobia, adjusting gene expression in response to various regulations. This review further attempts to emphasize the current understanding of advancements regarding RNS research in the groundnut and speculates on prospective improvement possibilities in addition to ways for expanding it to other crops towards achieving sustainable agriculture and overcoming environmental challenges.

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Genetic diversity of rhizobia nodulating Arachis hypogaea L. in diverse land use systems of humid forest zone in Cameroon

Cited by 28 publications

References 20 publications

Drivers of promiscuous soybean associated rhizobia diversity in un-inoculated soil in Malawi

Drivers of promiscuous soybean associated rhizobia diversity in un-inoculated soil in Malawi

Phylogeny and nitrogen fixation potential ofBradyrhizobiumspecies isolated from the legume cover cropPueraria phaseoloides(Roxb.) Benth. in Eastern Cameroon

Molecular Basis of Root Nodule Symbiosis between Bradyrhizobium and ‘Crack-Entry’ Legume Groundnut (Arachis hypogaea L.)

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