Rhizobial Genetic Repertoire to Inhabit Legume and Nonlegume Rhizospheres

López‐Guerrero, Martha G.; Ramírez, Miguel Ángel; Martı́nez-Romero, Esperanza

doi:10.1002/9781118297674.ch46

Cited by 3 publications

(3 citation statements)

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“…Rhizobia are best known for forming nitrogen-fixing nodules in legumes, they are soil bacteria, endophytes and also successful rhizosphere colonizers of legumes and non-legumes [2]. The ancestral lifestyle of rhizobia was probably rhizospheric, and the degradative capabilities of rhizospheric bacteria have been highlighted [3].…”

Section: Introductionmentioning

confidence: 99%

Diversity of Rhizobia Nodulating Faba Bean (Vicia faba) Growing in Egypt

Hassan¹

2015

J Microb Biochem Technol

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Citation: Hassan MM, Fahmi AI, Eissa RA, Nagaty HH (2015) Diversity of Rhizobia Nodulating Faba Bean (Vicia faba) Growing in Egypt. J Microb Biochem Technol 7: 152-159. doi:10.4172/1948-5948.1000197 Copyright: © 2015 Hassan MM, et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited AbstractThe aim of this work was to characterize and to describe the diversity and phylogeny of rhizobial bacteria associated to nodules of faba bean in four different geographical regions of north Egypt. Eight rhizobial isolates from healthy faba bean roots were isolated. They were identified as Rhizobium leguminosarum morphologically. They showed sensitivity to Kanamycin, Neomycin and Sulphemethooxazole antibiotics. Mannitol was the best source of carbon source for their growth. However, two isolates Rl. 2 and Rl. 10 indicated better tolerance to high NaCl concentrations than the other isolates and their plasmid profiles contained additional large plasmid with molecular weight about 23 kb. A relationship between salt tolerance and extra plasmid was suggested. Analysis of similarity among rhizobial isolates by using the RAPD-PCR technique showed a high level of genetic polymorphism, grouping the rhizobial isolates into two different clusters. These clusters reflexed the similarity among genotype of isolates independent of their geographic locations. 16S rDNA sequences of three representing isolates were determined and were aligned and compared with the 16S rDNA sequences of other members of the family Rhizobiaceae available in the Gene Bank database. The obtained dendogram indicated that the isolates belonging to Rhizobium leguminosarum biovar viciaen.

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Section: Introductionmentioning

confidence: 99%

Diversity of Rhizobia Nodulating Faba Bean (Vicia faba) Growing in Egypt

Hassan¹

2015

J Microb Biochem Technol

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“…Rhizobia promote rice growth ( Yanni et al, 1997 ) perhaps due to nitrogen fixation, and we suppose that bradyrhizobia may contribute fixed nitrogen to plants since some bradyrhizobial strains are capable of fixing nitrogen in the free-living state. A general brief overview of the rhizobial genetic repertoire to colonize non-legumes was published ( López-Guerrero et al, 2013 ).…”

Section: Diazotrophs May Be Human Pathogensmentioning

confidence: 99%

Nitrogen Fixation in Cereals

et al. 2018

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Cereals such as maize, rice, wheat and sorghum are the most important crops for human nutrition. Like other plants, cereals associate with diverse bacteria (including nitrogen-fixing bacteria called diazotrophs) and fungi. As large amounts of chemical fertilizers are used in cereals, it has always been desirable to promote biological nitrogen fixation in such crops. The quest for nitrogen fixation in cereals started long ago with the isolation of nitrogen-fixing bacteria from different plants. The sources of diazotrophs in cereals may be seeds, soils, and even irrigation water and diazotrophs have been found on roots or as endophytes. Recently, culture-independent molecular approaches have revealed that some rhizobia are found in cereal plants and that bacterial nitrogenase genes are expressed in plants. Since the levels of nitrogen-fixation attained with nitrogen-fixing bacteria in cereals are not high enough to support the plant’s needs and never as good as those obtained with chemical fertilizers or with rhizobium in symbiosis with legumes, it has been the aim of different studies to increase nitrogen-fixation in cereals. In many cases, these efforts have not been successful. However, new diazotroph mutants with enhanced capabilities to excrete ammonium are being successfully used to promote plant growth as commensal bacteria. In addition, there are ambitious projects supported by different funding agencies that are trying to genetically modify maize and other cereals to enhance diazotroph colonization or to fix nitrogen or to form nodules with nitrogen-fixing symbiotic rhizobia.

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“…Rhizobia are soil born gram-negative bacteria, endophytes and also able to colonize rhizospheric rejoins of legumes and many other crops (López-Guerrero et al, 2013). They able to fix the atmospheric nitrogen with various leguminous plants and therefore play a significant role in plant nutritional process throw enhancing nitrogen fixation and increasing crop production (Stocker et al, 2008 andToro et al, 1997).…”

Section: Introductionmentioning

confidence: 99%

Molecular Identification and Phylogenetic Relationships of Rhizobial Strains Nodulating Some Leguminous Crops

Ismail

Soltan

2023

Scientific Journal of Agricultural Sciences

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Isolation, molecular identification and phylogenetic relationships of Rhizobial isolates nodulated some leguminous crops grown in Sohag governorate, were conducted in this present study. According to the 16S rDNA sequencing analysis, all of isolates were belong to genus Rhizobium which is commonly colonizing root nodules of different leguminous crops. Among of all the 5 bacterial isolates only EMR2 gave 100% of similarity with Rhizobium pusense strain NRCPB10 NR_116874.1 while, EMR1 isolate exhibited 99.58% of similarity with Rhizobium binae strain BLR195 NR_137242.1. The two isolates EMR4 and EMR5 showed (97.35 and 97.14%, respectively) similarity with the two bacterial strains Rhizobium aegyptiacum strain 1010 NR_137399.1 and Rhizobium bangladeshense strain BLR175 NR_137241.1. Finally the isolate EMR3 was similar to Rhizobium bangladeshense strain BLR175 NR_137241.1 with 96.88%. It was found that the 2 rhizobial species (Rhizobium bangladeshense and Rhizobium aegyptiacum) of Egyptian clover were shared the same clade. As well as it also shared Rhizobium binae of Lupine as a common ancestor. Finally, it was found that Rhizobium pusense of Peanut was the common ancestor with all other rhizobial isolates. These findings revealed that the conserved gene of these 4 Rhizobium isolates was derived from Rhizobium pusense. The obtained results showed that the genetic diversity of the rhizobial isolates that nodulate the leguminous crop at the chosen sites in the Sohag governorate is very low, which may be cause their low host specificity and ability to increase nodules formation in different leguminous crops, making them a promising bio-fertilizer for Egypt's sustainable crop production.

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Rhizobial Genetic Repertoire to Inhabit Legume and Nonlegume Rhizospheres

Cited by 3 publications

References 68 publications

Diversity of Rhizobia Nodulating Faba Bean (Vicia faba) Growing in Egypt

Diversity of Rhizobia Nodulating Faba Bean (Vicia faba) Growing in Egypt

Nitrogen Fixation in Cereals

Molecular Identification and Phylogenetic Relationships of Rhizobial Strains Nodulating Some Leguminous Crops

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