Phenotypic and genetic diversity of Moroccan rhizobia isolated from Vicia faba and study of genes that are likely to be involved in their osmotolerance (original) (raw)
Related papers
Phylogenetic and characterization of salt-tolerant rhizobial strain nodulating faba bean plants
Improvement of faba bean production in the new reclamation land in Egypt requires isolation and selection of effective abiotic stress tolerant rhizobial strains. Three rhizobial strains were isolated from healthy faba bean plants growing in different geographic areas in Egypt. These isolates were adapted against different concentrations of NaCl (100, 150 and 200 mM) by using the enrichment method. They were evaluated by measuring the symbiotic N2-fixation parameters under greenhouse and field conditions during two seasons (2010/2011 and 2011/2012). One rhizobial strain exhibited the highest values of symbiotic N2-parameters, nitrogenase activity and proline content. Based on 16S rDNA and nifH gene sequence, this strain was shown to belong to the Rhizobium leguminosarum bv. viciae. A strong similarity was found between the 16S rDNA and nifH gene sequence of the strain E15 and R. leguminosarum bv. viciae 3841 (100% similarity for 16S rDNA and 95% similarity for nifH gene). The results show that the maximum growth of this strain was obtained at pH 7 and 30°C. This strain was tolerant to drought stress till 20% polyethylene glycol and it yielded the highest concentrations of indole-3-acetic acid (IAA) at the end of the logarithmic phase. This strain solubilized inorganic phosphorus. R. leguminosarum bv. viciae was able to survive, persist, grow and effectively nodulated faba bean plants at high salt concentrations under greenhouse and field conditions and it could be used for biofertilization to reduce the severe effects of salinity and drought stress in the new reclamation land in Egypt.
Journal of Advanced Research, 2018
A phenotypic characterization of thirteen root nodule bacteria recovered from wild legumes (Genista microcephala and Argyrolobium uniflorum) growing in arid eco-climate zones (Northeastern Algeria) was conducted using analysis of sixty-six phenotypic traits (carbohydrate and nitrogen assimilation, vitamin requirements, growth temperature, salinity/pH tolerance and enzyme production). Furthermore, SDS-PAGE profiles of total cell protein, antibiotic susceptibility and heavy metal resistance were performed. The results showed that the isolates can grow at pH 4 to 10, salt concentration (0-5%) and temperature up to 45 °C. The rhizobia associated with Genista microcephala and Argyrolobium uniflorum were able to produce different hydrolytic enzymes including cellulose, pectinase and urease, with remarkable tolerance to toxic metals such as zinc, lead, copper, and mercury. Numerical analysis of the phenotypic characteristics revealed that the rhizobial isolates formed four main distinct groups showing high levels of similarity with Gammaproteobacteria. The salt tolerant and heavy metals resistance patterns found among the indigenous rhizobial strains are reflecting the environmental stresses pressure and make the strains good candidates for plant successful inoculation in arid areas.
Emirates Journal of Food and Agriculture, 2013
The salinity tolerance of naturally occurring rhizobia, isolated from the root nodules of three leguminous plants, namely sesbania (Sesbania sesban), lablab (Lablab purpureus) and pigeonpea (Cajanus cajan), growing at a research farm in Dubai (United Arab Emirates) was studied. Eight isolates identified from colony morphology and gram staining reaction, when cultured on yeast extract-mannitol agar medium (YEMA) supplemented with different concentration of sodium chloride (NaCl), produced colonies even at salinities as high as 40 dS m-1. The rhizobial isolates were also found to be effective in nodulating 21-day old seedlings grown in potting soil and irrigated with saline water of up to 12 dS m-1 after inoculation. The tolerance to high levels of salinity and the survival and persistence in severe and harsh desert conditions make these rhizobia highly valuable inoculums to improve productivity of the leguminous plants cultivated under extreme environments.
Annals of Microbiology
We investigated the effect of residual salts from the previous summer’s irrigation on two non-irrigated cover crops—broad bean and common vetch—and on their rhizobial symbiontics. Before sowing, seeds were inoculated with a salt-tolerant strain and a salt-sensitive strain of Rhizobium leguminosarum biovar viciae. An increase in the electrical conductivity of the saturated-soil extract from 2.0 dS m−1 to 6.0 dS m−1 caused a severe reduction of broad bean biomass, while growth of common vetch was almost unaffected by the salinity level. Our results clearly indicate that common vetch as a cover crop may increase the availability of nitrogen in soil more than broad bean also in saline environments. A high ability of both inoculated strains to nodulate Vicia plants was observed under controlled conditions. In contrast, inoculated strains were not able to nodulate plants in salinized soils, showing lower competitiveness compared to natural rhizobial population. Indeed, the new isolates from nodules were salt-sensitive when tested in vitro. The complex interaction among bacteria, plant and soil determined the survival of endogenous salt sensitive rhizobial strains and limited the success of inoculation with exogenous salt resistant rhizobia.
Science, Technology and Arts Research Journal, 2014
Article Information Faba bean is one of the legume crops commonly grown in Ethiopia. It is important source of dietary protein to the majority of population in the country. Soil acidity and related stresses are among the major yield limiting constraints for this crop. This study was conducted with the aim of evaluating acidity tolerance of Rhizobium leguminosarum bv. viciae strains isolated from faba bean growing regions of the country and their symbiotic performance under different acidic conditions. Four strains isolated from root nodules of faba bean were tested for tolerance to acidity in a defined liquid media. The results indicated that none of the tested strains was tolerant to pH 4.0 while two of them (AUFR46 and AUFR100) were found to be tolerant of pH 4.5. When tested at pH 5.0 only one isolate (AUFR58) was sensitive. The results of the present study also showed that all acid tolerant strains were recovered from highly acidic soil (4.8-5.2) and the acid sensitive strain was isolated from neutral soil. A positive correlation (r= 0.92) was observed between minimum pH tolerated in culture media and pH of origin soil of the strains. Nodulation and nitrogen fixation abilities of these strains were evaluated on sand culture. The results indicated that at pH 4.5 and 5.0 nodulation was totally inhibited and only one isolate (AUFR58) could not be able to induce nodule formation on host plant roots at pH 5.5. The results also showed that acidity (pH 5.5) reduced shoot dry weight, nodules number, total nitrogen at a highly significant level (P<0.01) compared to plants grown at pH 6.5 and 7.0. In pot experiment with soil of different pH, inoculation of the rhizobial strains improved the growth, nodulation and nitrogen content of the plants significantly over the uninoculated controls. Besides, acid tolerant strains showed better performance over acid sensitive strains in acidic soils and thus, they are highly recommended for field test in acidic soil.
Isolation and Characterization of Rhizobium Strains from Root Nodules of Faba Bean (Vicia faba L
Rhizobia are Gram-negative bacteria able to form nodules and fix nitrogen through legumes. Root nodules were collected from young and healthy plants of faba bean (Vicia faba L.) at the flowering stage from five different districts of Bangladesh to isolate effective rhizobial strains with beneficial characters for bio-fertilizer production. Thirteen rhizobial strains were isolated from root nodules of faba bean and characterized by different morpho-physiological tests. The colony size of the strains was ranged from 1.2 to 2.0 mm. All strains showed a positive result in nodulation test and also showed acid-producing fast-growing nature in bromothymol blue test suggesting that they are first growing rhizobia. Four strains (Faba-1, Faba-2, FM-4c, and FM-4f) survive at 1.7% NaCl and six strains (Faba-1, Faba-2, Faba-6, Faba-10, FM-1a, and FM-4c) were able to grow at pH 5.7. Two strains (Faba-1 and Faba-2) were able to sustain at high temperature (40 0 C), survive at a wide range of pH (5.7-11), and showed high phosphate solubilization index. The strain Faba-2 seems to be promising for future bio-fertilizer production since it had nodulation capacity, high-temperature tolerance as well as high phosphate solubilizing capacity and therefore could be used for enhancing the growth and yield of faba bean in stress-prone areas of Bangladesh with reduced chemical fertilizers.
RESPONSES OF FABA BEAN (Vicia faba L.) PLANTS TO ROOT NODULE BACTERIA UNDER SALINITY CONDITIONS
Two isolates (E1 and E2) of Rhizobium leguminosarum biovar viciae were isolated from healthy faba bean plants collected from different locations at Kafr El-Sheikh Governorate. In vitro, these strains were adapted against different concentrations of NaCl (100, 150 and 200 mM) by using the enrichment method, they were evaluated by measuring the symbiotic N2-fixation parameters under aseptic or non-aseptic conditions in two experiments which were carried out at the experimental greenhouse of Fac. of Agric. Kafr El-sheikh, during the winter seasons of 2003/2004 and 2004/2005. Results in vitro and in vivo experiments confirmed the efficiency of these salt resistance isolates (E1 and E2) under aseptic conditions. The symbiotic N2-fixation parameters were increased in comparison with the original strains under salt stress. Therefore, inoculation in the presence of salt stress with the salinity tolerant rhizobium strains did help the faba bean plants to increase dry weight and total nitrogen contents. The isolate E1 exihibited the highest values of symbiotic N2-parameters followed by E2. Seed treatment with Peat-based preparation of strain (E1) at the time of planting in sandy soil with concentration 200 mM NaCl increased the symbiotic N2-fixation parameters as well as crude protein % of dry seeds compared with non-inoculated plants (Control). The non-inoculated plants were free from nodules, indicating the necessity of using the effective salinity tolerant rhizobium isolate to achieve a good nodulation under high salinity stress to improve growth characters of faba bean plants.
FEMS Microbiology Ecology, 2020
In total 196 bacterial isolates were obtained from root nodules of lentil (Lens culinaris) and faba bean (Vicia faba) grown on soil samples collected from 10 different sites in central and southern parts of Ethiopia. All isolates were identified as members of the genus Rhizobium by using recA gene sequence analysis. In the recA phylogenetic tree 195 rhizobial strains were classified into nine genospecies. The phylogeny of symbiotic genes nodC and nifH revealed five and six distinct groups respectively, largely dominated by symbiovar viciae. A multivariate analysis showed that environmental variables of the sampling sites considered in this study had more effect on the distribution and composition of the genospecies than the host legumes of the strains. Twenty representative strains, selected based on their isolation site, host plant and nodC group, were able to nodulate all lentil, faba bean, field pea (Pisum abyssinicum) and grass pea (Lathyrus sativus) plants in a greenhouse test ...