Soybean (Glycine max L.) is a very important legume in the human diet as well as fodder crop. Previous studies have reported that co-inoculation with PGPR (plant growth-promoting bacteria) and ...rhizobia promotes symbiotic nitrogen fixation efficiency, increases plant nitrogen content and reduces the occurrence of soybean diseases, thus reducing pesticide use, and protecting the environment. The aim of this study was to determine the impact of co-inoculation of soybean seeds with different strains of nodule bacteria Bradyrhizobium japonicum as well as PGPR (Pseudomonas fluorescens). Indigenous strains of beneficial bacteria used in this research were isolated from different locations in Croatia. Isolates were identified by performing 16S rRNA gene sequencing. The application of different strains of nodule bacteria resulted in a statistically justified effect on all investigated properties, with the exception of root length. A positive influence of P. fluorescens on the increase in shoot dry weight was observed with the co-inoculation with the reference strain B. japonicum and two indigenous strains. The application of P. fluorescens did not show statistically justified differences in any of the investigated properties. Co-inoculation of nodules and PGPR bacteria is a very important biotechnological tool in agriculture, which is why research in this area should definitely be continued and expanded to a larger number of P. fluorescens strains.
The strains of nodule bacteria differ greatly in their symbiotic properties and efficiency in nitrogen fixation and therefore, the selection of highly effective strains is of great importance when ...attempting to achieve a successful pre-sowing inoculation of common bean. The aim of this study was to determine the nodulation ability of indigenous rhizobial strains and to evaluate their compatibility and symbiotic efficacy with two common bean cultivars. A two-factorial pot experiment (12 indigenous rhizobial strains and two common bean cultivars) was set up in the greenhouse. In the full blossom phase, dry nodule biomass, shoot dry weight and N content in dry shoot was determined. The research revealed significant differences depending on the strain of nodule bacteria and common bean cultivars. The compatibility of indigenous and reference strains on the examined common bean cultivars was also observed. The cultivar Tresnjevac was significantly better than Slavonski zeleni in all measured parameters. The results revealed that the indigenous common bean rhizobial strains considerable differ in their symbiotic efficiency. The highest dry nodule biomass was determined when strain HO12 was applied, and the highest shoot dry weight with strains MB1 and DE7. The application of strain DE7 revealed the highest N content in dry shoot. The results indicate that these indigenous strains of common bean nodulating bacteria are characterized by the highest symbiotic efficiency and could be used for the pre-sowing inoculation of common bean after testing in field scale experiment.
Nodule bacteria (rhizobia) in symbiotic associations with legumes enable considerable entries of biologically fixed nitrogen into soil. Efforts are therefore made to intensify the natural process of ...symbiotic nitrogen fixation by legume inoculation. Studies of field populations of rhizobia open up the possibility to preserve and probably exploit some indigenous strains with hidden symbiotic or ecological potentials. The main aim of the present study is to determine genetic diversity of common bean rhizobia isolated from different field sites in central Croatia and to evaluate their symbiotic efficiency and compatibility with host plants. The isolation procedure revealed that most soil samples contained no indigenous common bean rhizobia. The results indicate that the cropping history had a significant impact on the presence of indigenous strains. Although all isolates were found to belong to species
, significant genetic diversity at the strain level was determined. Application of both random amplification of polymorphic DNA (RAPD) and enterobacterial repetitive intergenic consensus-polymerase chain reaction (ERIC- -PCR) methods resulted in similar grouping of strains. Symbiotic efficiency of indigenous rhizobia as well as their compatibility with two commonly grown bean varieties were tested in field experiments. Application of indigenous rhizobial strains as inoculants resulted in significantly different values of nodulation, seed yield as well as plant nitrogen and seed protein contents. The most abundant nodulation and the highest plant nitrogen and protein contents were determined in plants inoculated with
strains S
and S
. Although, in general, the inoculation had a positive impact on seed yield, differences depending on the applied strain were not determined. The overall results show the high degree of symbiotic efficiency of the specific indigenous strain S
. These results indicate different symbiotic potential of indigenous strains and confirmed the importance of rhizobial strain selection. These are the first studies of indigenous common bean rhizobia in Croatia that provide the basis for further characterization and selection of highly efficient indigenous strains and their potential use in agricultural practice and future research.
Pulse crops have become more important in food production and consumption systems for the transition towards sustainability. We present an agroecological dataset from 304 samples from 12 legume field ...trials in five locations across three countries in the Mediterranean. The field trials were established in the seasons 2021/22 and 2022/23 and tested different lentil or chickpea cultivars, inoculants, intercropping and weeding regimes. The dataset encompasses detailed information on wild flora diversity, grain yield, associated management practices, soil texture and weather during the growing period. Wild flora diversity was recorded by conducting a vegetation survey in 1 × 2 m sample plots. Grain yield was determined at the crop maturity stage, with full plots harvested in Spain, while samples were taken in Croatia and Tunisia. Environmental variables were via laboratory analysis or bottle testing of soil samples and analysis of local weather data. The comprehensiveness of the dataset, including all relevant agroecological information, enables other researchers to employ the dataset for various statistical analyses of agroecosystem processes, such as plant-environment interactions or biodiversity-yield trade-off analysis.
Soil bacteria, Sinorhizobium meliloti is of great agricultural importance because of its ability to fix atmospheric nitrogen in symbiosis with alfalfa very valuable forage crop. The main aim of this ...study was to evaluate tolerance of indigenous S. meliloti strains to stress environmental conditions. Twenty rhizobial strains, isolated from different regions in Croatia, were genotipically characterized to assess diversity amongst natural population. Stress tolerance assays were performed in order to select indigenous rhizobia with tolerance to unfavorable soil conditions. The growth of the strains was studied at different pH values, temperatures, NaCl and heavy metals concentrations. The results of 16S rDNA genotyping using PCR/RFLP analysis showed that 17 isolates could be assigned to S. meliloti while RAPD and ERIC-PCR fingerprints revealed significant genetic diversity among indigenous rhizobial strains. In comparison to the reference strain, higher resistance to adverse growth conditions of indigenous S. meliloti strains was determined. Most of the strains grew at temperatures higher than optimal and tolerated both acidic and alkaline environment. It was found that indigenous strains tolerate extremely high NaCl concentrations. Better understanding of rhizobial response to adverse environmental conditions is of potential value for improving rhizobial inoculants and efficiency of symbiotic nitrogen fixation.
The main aim of this study was to assess genetic diversity within the natural populations of field pea rhizobia on different field sites in Northwestern Croatia and to evaluate their symbiotic ...efficiency. Identification of related bacterial strains was carried out using RAPD and rep-PCR methods and on the basis of differences in the nodulation nodD gene region by PCR-RFLP method. Indigenous strains have been shown to differ significantly from each other as well as from the reference strains Rhizobium leguminosarum bv. viciae used in these study. Based on the nodulation genes, it was found that most isolates have the same or very similar nodulation nodD region except the isolates K22 and K23. A greenhouse studie was performed for evaluation of symbiotic efficiency of strains. The highest nodule dry weight was determined by inoculation with strains K23, K22, K17 and K20, indicating their high infectivity and nodulation ability. Significantly higher green mass and dry matter yield in abouveground plant parts were determined by inoculation with two indigenous strains K26 and K16 that showed potentially high symbiotic efficiency compared to other tested strains.
Environmental degradation and the decrease of ecosystem service provision are currently of major concern, with current agricultural systems being a major driver. To meet our future environmental and ...sustainability targets a transformation of the agro-food systems and current agricultural value chain are crucial. One approach to redesign farming systems is the concept of biodiversity-based agriculture (BBA) which relies on sustainable diversification of biological components and their natural interactions in farming systems to maximize fertility, productivity, and resilience to external perturbations. Despite minimizing anthropogenic inputs, BBA is not yet able to meet all beneficial environmental objectives. BBA applied in the Mediterranean basin requires urgent innovation in approaches, methodologies, and models for small-holder traditional farming systems to ensure a stable provision of ecosystem services and better resilience to environmental stresses linked to climate change. Legumes are the backbone of the Mediterranean agro-ecosystems from ancient times, but their unique and wide biodiversity was not sufficiently valorized, especially by North-African countries. Here, we present LEGU-MED, a three-year international project funded by PRIMA initiative 2019. An international consortium was established involving five universities, 5 research institutes, and one private company from 8 countries: Italy, Germany, Spain, Algeria, Tunisia, Turkey, Lebanon, and Croatia. The main objective of this project is to put forward an international and well-integrated plan to valorize the legume agrobiodiversity of the Mediterranean in biodiversity-based farming systems and consequently enhance agro-ecosystem functions and services in the Mediterranean basin. The successful completion of LEGU-MED will have the following impacts on Mediterranean legume-based farming systems: (1) improve water use efficiency, (2) reduce the use of anthropogenic inputs through the maintenance of soil fertility, (3) enhance pollination and improve ecological connectivity with flora and fauna, (4) protect close-by wildland ecosystems, (5) enhance other ecosystem services (e.g., pest, disease, and weed suppression), and (6) provide healthier and safer protein-rich food.
Soybean (Glycine max L) is a very important legume in the human diet as well as fodder crop. Previous studies have reported that co-inoculation with PGPR (plant growth-promoting bacteria) and ...rhizobia promotes symbiotic nitrogen fixation efficiency, increases plant nitrogen content and reduces the occurrence of soybean diseases, thus reducing pesticide use, and protecting the environment. The aim of this study was to determine the impact of co-inoculation of soybean seeds with different strains of nodule bacteria Bradyrhizobium japonicum as well as PGPR (Pseudomonas fluorescens). Indigenous strains of beneficial bacteria used in this research were isolated from different locations in Croatia. Isolates were identified by performing 16S rRNA gene sequencing. The application of different strains of nodule bacteria resulted in a statistically justified effect on all investigated properties, with the exception of root length. A positive influence of P. fluorescens on the increase in shoot dry weight was observed with the co-inoculation with the reference strain B. japonicum and two indigenous strains. The application of P. fluorescens did not show statistically justified differences in any of the investigated properties. Co-inoculation of nodules and PGPR bacteria is a very important biotechnological tool in agriculture, which is why research in this area should definitely be continued and expanded to a larger number of P. fluorescens strains. Keywords: beneficial association, symbiotic efficiency, PGP bacteria, Pseudomonas fluorescens, Bradyrhizobium japonicum Soja (Glycine max L) je vrlo vazna mahunarka u ljudskoj prehrani te kao krmna kultura. Prethodna istrazivanja pokazala su da ko-inokulacija s rizobijama i PGPR-om (bakterijama koje poticu rast bilja, engl. Plant Growth Promoting Rhizobacteria) potice ucinkovitost simbiozne fiksacije dusika, povecava sadrzaj dusika u biljkama i smanjuje pojavu bolesti soje, cime se smanjuje upotreba pesticida i stiti okolis. Cilj ovih istrazivanja bio je utvrditi utjecaj koinokulacije sjemena soje razlicitim sojevima kvrzicnih bakterija Bradyrhizobium japonicum kao i bakterijama koje poticu rast biljaka (PGPR) (Pseudomonas fluorescens). Autohtoni sojevi korisnih bakterija koristeni u ovom istrazivanju izolirani su s razlicitih lokacija u Hrvatskoj. Izolati su identificirani sekvenciranjem 16S rRNA gena. Primjena razlicitih sojeva kvrzicnih bakterija rezultirala je statisticki opravdanim ucinkom na sva ispitivana svojstva, izuzetak je bila duljina korijena. Pozitivan utjecaj P. fluorescens na povecanje mase suhe tvari nadzemnog dijela biljke uocen je kod koinokulacije s referentnim sojem B. japonicum i dva autohtona soja. Primjena P. fluorescens nije pokazala statisticki opravdane razlike ni za jedan od ispitivanih svojstava. Koinokulacija kvrzicnih i PGPR bakterija vrlo je vazan biotehnoloski alat u poljoprivredi, zbog cega istrazivanja u ovom podrucju svakako treba nastaviti i prosiriti na veci broj sojeva P. fluorescens. Kljucne rijeci: korisne asocijacije, simbiozna ucinkovitost, PGPR bakterije, Pseudomonas fluorescens, Bradyrhizobium japonicum Soybean (Glycine max L) is a very important legume used for human nutrition as well as fodder crop. Soybean-rhizobia symbiotic nitrogen fixation has been of considerable significance for improving agricultural productivity. Plant growthpromoting rhizobacteria (PGPR) are particularly important in agricultural systems, and previous studies have reported that co-inoculation with PGPR and rhizobia enhances rhizobial colonization of the legumes, increases the number of nodules, improves the nitrogen fixation efficiency and increases plant nitrogen content. The co-inoculation with PGPR and rhizobia can reduce the occurrence of soybean diseases, thus reducing pesticide use, improving yield, and protecting the environment. PGP rhizobacteria consist of numerous genera with Pseudomonas, Bacillus and Azospirillum being the most represented. The aim of this research was to determine if the co-inoculation of soybean with Bradyrhizobium japonicum and Pseudomonas fluorescens strains can additionally improve seed yield and macronutrient uptake, compared to rhizobial inoculation alone. For this purpose, soil samples were taken from the arable horizon of different locations in Croatia and chemical properties of the soils were determined. Rhizobia strains were isolated following the trap host method and 16S rRNA gene sequencing was performed in order to identify rhizobia. Two-factorial vegetation experiment was set up in a growth chamber using a random block arrangement scheme in three repetitions and factors included different strains of rhizobia and PGPR bacterium P. fluorescens. In the full flowering phase, the number of nodules per plant, nodules dry matter weight and the shoot dry weight were measured. The influence of P. fluorescens on improving the growth of soybean plants was determined by measuring the root length. Statistical analysis was performed using the software package SAS 9.4 for Windows. Regardless of the dominance of the acidic soils, rhizobial strains were isolated from all soil samples. All tested strains were able to establish a symbiotic relationship with the soybean variety used. The highest number of nodules per plant was determined using strain B4. This strain, together with B3 resulted in the most effective infection and nodulation. Applying strains B5 and B6 in combination with P. fluorescens resulted in an increase in the number of nodules, which can be attributed to the positive effect of this PGP bacterium, although the differences were not statistically significant. The nodule dry matter weight per plant was significantly higher while using strain B4 compared to the other strains. A positive influence of P. fluorescens on the increase in shoot dry weight was observed with the co-inoculation with the reference strain B. japonicum 344 and strains B5 and B6. The greatest root length was recorded with the application of strain B3, although there were no statistically justified differences in root length. In the case of some strains, co-inoculation with PGPR bacteria led to a reduction in the number of nodules, shoot dry weight and nodule dry matter weight. Such results indicate the occurrence of competition between the strains of B. japonicum and P. fluorescens. The obtained results also indicate the need for further testing with more included strains of these beneficial bacteria.
Previous work indicated that some of the new synthesized analogues of dehydroacetic acid (DHA) were inhibitory to the growth of mycotoxin producing moulds and accumulation of aflatoxin B sub(1) (AFB ...sub(1)) and ochratoxin A (OTA). The objective of this study was to determine the specific new synthesized chemical compounds that may be effective against mould growth and vomitoxin (deoxynivalenol) (DON) accumulation by Fusarium graminearum. The effect of the investigated 3-/2-aminopheoylamine-(p-toluoyl)-4-hydroxy-6-(p-tolyl)-2H-pyrane- 2-one (Schiff base) and 4-hydroxy-3-(p-toluoyl)-6-(p-tolil)-2H-pyrane-2-one (DHT) on growth and DON accumulation were studied using a mould F. graminearum ZMPBF 1244 and maize grain hybrid to determine the possible use of these compounds as a mean of controlling DON accumulation. Schiff base was inhibitory at 0.05 and 0.1 mu g/g and DHT at 0.5 mu g/g of maize grain. The inhibitory effect of these substances was judged to be the inhibition of growth rather than toxin accumulation. When growth occurred after a delay, DON accumulation occurred when the cultures reached secondary metabolism. Given sufficient time, cultures which were inhibited initially, but which subsequently inhibited their growth, produced toxin levels equivalent to the control cultures. Levels of the Schiff base above 0.2 mu g/g almost completely inhibited mould growth or permitted only a small amount of growth that never reached secondary metabolism and never produced DON during the time of this study.
The strains of nodule bacteria differ greatly in their symbiotic properties and efficiency in nitrogen fixation and therefore, the selection of highly effective strains is of great importance when ...attempting to achieve a successful presowing inoculation of common bean. The aim of this study was to determine the nodulation ability of indigenous rhizobial strains and to evaluate their compatibility and symbiotic efficacy with two common bean cultivars. A two-factorial pot experiment (12 indigenous rhizobial strains and two common bean cultivars) was set up in the greenhouse. In the full blossom phase, dry nodule biomass, shoot dry weight and N content in dry shoot was determined. The research revealed significant differences depending on the strain of nodule bacteria and common bean cultivars. The compatibility of indigenous and reference strains on the examined common bean cultivars was also observed. The cultivar Tresnjevac was significantly better than Slavonski zeleni in all measured parameters. The results revealed that the indigenous common bean rhizobial strains considerable differ in their symbiotic efficiency. The highest dry nodule biomass was determined when strain HO12 was applied, and the highest shoot dry weight with strains MB1 and DE7. The application of strain DE7 revealed the highest N content in dry shoot. The results indicate that these indigenous strains of common bean nodulating bacteria are characterized by the highest symbiotic efficiency and could be used for the pre-sowing inoculation of common bean after testing in field scale experiment.
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