ABSTRACTS 2025 #2                                  
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ENZYMATIC AND ANTIFUNGAL ACTIVITIES OF ENDOPHYTIC Streptomyces sp. BK79 ISOLATED FROM THE ROOT SYSTEM OF Artemisia herba-alba

Asso Karima BOUTI, Nadjette DJEMOUAI, Guendouz DIF, Atika MEKLAT, Sid Ahmed SAADI

Abstract. Biomolecules from microorganisms, such as Actinobacteria (Phylum Actinomycetota), have formed the foundation for numerous medical, agricultural, and biotechnological advancements. This study examined the enzymatic and antifungal activities of the endophytic actinobacterial strain BK79, isolated from the root system of Artemisia herba-alba Asso collected from an arid environment in Biskra, Algeria. Morphological traits and 16S rRNA gene sequencing identified BK79 as belonging to the genus Streptomyces, with 100% similarity to Streptomyces mutabilis NRRL 12800T and Streptomyces rochei NRRL B-2410T. The 16S rRNA gene sequence of strain BK79 has been deposited in GenBank under accession number PQ814213. Streptomyces sp. BK79 displayed a characteristic hydrolytic enzyme profile, exhibiting detectable activities for protease (1.46 ± 0.07), amylase (1.58 ± 0.08), and pectinase (1.13 ± 0.02), while cellulase activity was not observed. The strain also tested positive for esterase and chitinase activity in qualitative assays, indicating potential for the degradation of diverse biopolymers, including fungal cell wall components. Antifungal activity, assessed by the agar plug diffusion method, was notable in synthetic medium supplemented with dextrin, with a maximum inhibition zone of 30.5 ± 0.87 mm against Aspergillus carbonarius. These findings suggest that strain BK79 is a promising source of extracellular hydrolytic enzymes and antifungal compounds, with potential applications in biotechnology and agriculture.

Key words: antifungal activity; carbon source; hydrolytic enzymes; Streptomyces; taxonomy.



MANAGEMENT OF THE NEMATODE Ditylenchus destructor THORNE, 1945 TO Solanum tuberosum L. CULTURE WITH THE APPLICATION OF Bacillus cereus var. fluorescens CNMN-BB-07 BACTERIA

Olesea GLIGA, Maria MELNIC, ştefan RUSU, Valerina SLANINA

Abstract. For the first time in the Republic of Moldova, management research was conducted with the application strains of bacteria Bacillus cereus var. fluorescens CNMN-BB-07, of autochthonous origin, both in vitro and in vivo experiences to combat pests of the genus Ditylenchus - D. destructor, D. dipsaci, which parasitize potato tubers (Solanum tuberosum L.). In vitro testing demonstrated a lethal efficacy of 98.5 – 100% after 24-hours of exposure to the strain, taken in the initial concentration – 6 x 109 cells/mL. The liquid culture (LC) of the tested strain, when diluted in proportions of: 1:50 (V2); 1:100 (V3) and 1:200 (V4), also, possess nematicidal activity. Thus, after 48 hours of exposure, the lethal effect was: 50%; 40% and 27.3%, respectively. In vivo testing in which seed potatoes infested with D. destructor (100% infestation) were treated by soaking in LC diluted 1:400 for 16 hours, resulted in a drastic reduction of infestation at harvest - down to 1-4%, compared to 40.42% in the untreated control. Additionally, the treatment with LC eliminated rot incidence (0%) both at harvest and during potato storage, and greatly reduced (just 10.4%) the attack of mole crickets (Gryllotalpa gryllotalpa). The given procedure represents an effective biological approach for combating phytoparasitic nematodes with a high growth-promoting effect on agricultural crops.

Key words: Bacillus cereus var. fluorescens CNMN-BB-07; cultural liquid; Ditylenchus destructor; lethal effectiveness; Solanum tuberosum; Roko variety.



COMPATIBILITY TESTING OF BACTERIAL AND FUNGAL STRAINS FOR DEVELOPING AN EFFICIENT CONSORTIUM FOR RICE STRAW DEGRADATION

Nitu MOR, Prabhjot KAUR, Daljeet KAUR, Anjali SHARMA, Sunita DALAL

Abstract. Rice straw, a significant agricultural byproduct, poses considerable environmental challenges due to its extensive accumulation and the widespread practice of open-field burning, which exacerbates air pollution and degrades soil fertility. Microbial consortia, composed of compatible bacterial and fungal strains, offer a promising solution for the efficient biodegradation of rice straw by breaking down its complex lignocellulosic structure. This study focuses on the isolation and identification of silicate-solubilizing bacteria and fungi from soil and water samples, followed by the optimization of silicase enzyme production under controlled conditions. The optimization process involved fine-tuning key parameters such as incubation time, temperature, pH, carbon and nitrogen sources, and the incorporation of metal ions and additives for both bacterial and fungal strains. After optimization, a comprehensive compatibility assessment was conducted among the isolated strains to develop a robust microbial consortium. Compatibility between fungi–bacteria, fungi–fungi, and bacteria–bacteria was evaluated using modified cross-streak, disc, and agar diffusion methods. The results indicated full compatibility among the tested strains, suggesting the potential for forming an effective consortium. The successful development of this microbial consortium represents a significant step toward sustainable rice straw management, offering a viable alternative to burning. This approach not only reduces environmental pollution but also enhances soil health through the effective breakdown of lignin, silica, and hemicellulose in rice straw.

Keywords: biodegradation; environmental sustainability; microbial consortia; rice straw; silicase.



ASSESSMENT OF WATER STRESS TOLERANCE IN DURUM WHEAT (Triticum durum Desf.): EFFECTS ON GROWTH AND BIOCHEMICAL PARAMETERS

Meriem RICHA, Mohamed LAZALI

Abstract. Water stress represents a major limitation to crop growth and yield, particularly in semi-arid ecosystems. The objective of this research is to assess the impact of water stress (30% of field capacity) on the growth and biochemical traits of four varieties of durum wheat (Oued El Bared, Simeto, Prospero, and Vitron). The parameters examined include shoot length (SL), root length (RL), fresh shoot weight (FSW), dry shoot weight (DSW), fresh root weight (FRW), dry root weight (DRW), and the concentrations of chlorophyll, proline, and soluble sugars. The results show that the different types of plants reacted to water stress in quite different ways. Vitron and Simeto varieties exhibited enhanced tolerance, which was evidenced by increased root development and a heightened accumulation of proline and soluble sugars. Overall, this research highlights considerable intervarietal variability and gives useful information that can help breeding programs that want to make durum wheat varieties that can grow in dry conditions, thereby contributing to more sustainable agriculture in arid and semi-arid regions.

Keywords: durum wheat; drought effects; proline; Triticum durum Desf.; water stress; chlorophyll.



STUDY OF PHYSICO-CHEMICAL FACTORS INFLUENCING THE SEED BIOPRIMING AND ITS IMPACT ON THE SEED GERMINATION AND GROWTH OF Brassica oleracea var. kale

Ritu BADAL, Nikhil MEHTA, Raman SAINI

Abstract Brassica oleracea var. kale is a green leafy vegetable used in various dishes, salads, and sandwiches due to its high nutritive values. The current study aimed to assess physico-chemical parameters affecting seed biopriming and to study biopriming effect on the growth via evaluating various growth parameters such as germination percentage (GP), average shoot length and average root length of seedlings (ASL and ARL), seed vigour index (SVI), seed metabolic efficiency (SME), relative water content (RWC) at the seedling stage, and further observation of biomass, number of leaves, stem and root length at certain developmental stage. Among the optimized physico-chemical parameters, Azotobacter spp. at a concentration 108 CFU/mL suspended in 1% NaCl solution of pH 7 were used for inoculation of kale seeds up to 16 hours at 20°C to obtained the maximum growth. Following these optimized conditions, seed biopriming was performed using Azotobacter spp, Rhizobium spp. and a combined application of both the microbes. The results showed that the biopriming of kale seeds with combined application of Azotobacter spp. and Rhizobium spp. led to the highest growth parameters followed by the individual application of Azotobacter spp or Rhizobium spp. compared to untreated control seeds. Overall, biopriming with combination of Azotobacter spp. and Rhizobium spp. is a viable strategy for improving crop productivity and resilience, contributing to sustainable agriculture and global food security.

Keywords: Azotobacter spp.; physico-chemical parameters; biopriming; kale; Rhizobium spp.



BEHAVIOUR OF Cupressus dupreziana A. Camus PLANTS UNDER WATER STRESS CONDITIONS

Nihal GUELLABI, Lilya BOUCELHA, Réda DJEBBAR, Mohamed GRANDI, Imene DJEMAI, Atika BENRIMA

Abstract. Cupressus dupreziana A. Camus is a critically endangered species endemic to Tassili n’Ajjer, where it survives despite extreme climatic conditions, with drought being a major limiting factor. The aim of this study is to examine the effect of water stress, induced by the cessation of irrigation, on seedlings of Tassili cypress. Although this species is adapted to aridity, its mechanisms for adaptation and tolerance to water stress have yet to be sufficiently explored. After a watering cessation of 100 days, water stress led to a significant reduction in relative water content (RWC), seedling growth, and the concentration of photosynthetic pigments. In contrast, the plants attempted to maintain their osmotic adjustment through the accumulation of proline and soluble sugars, with levels significantly increasing. This water stress also resulted in oxidative damage, as evidenced by the notable rise in hydrogen peroxide (H2O2) and malondialdehyde levels. However, despite these challenges, the plants have survived and been able to resume their growth thanks to a photo-protective system. This was facilitated by an increase in carotenoid concentration and the activation of antioxidant enzymatic defence mechanisms, as illustrated by the rise in activities of superoxide dismutase (SOD), catalase (Cat), ascorbate peroxidase (APX), and guaïacol peroxidase (GPOX). Cupressus dupreziana demonstrates significant capabilities for the rehabilitation of arid regions, thanks to its adaptation mechanisms and tolerance to water stress. This study highlights the importance of researching endemic species and their potential in combating desertification.

Keywords: antioxidant enzymes; Cupressus dupreziana; drought stress; endangered species; osmolytes; relative water content.



CHEMICAL PROFILING OF ESSENTIAL OILS FROM Ruta graveolens L. AND ASSESSING ITS LARVICIDAL PROPERTIES AGAINST Culex quinquefasciatus

Naveen DAKSHINAMOORTHY, Rajkuberan CHANDRASEKARAN, Akshay MURALIDHARA, Daniel REEGAN, Kalaiselvi AASAITHAMBI

Abstract. Mosquito borne diseases cause a severe menace to the society affecting large populations of people worldwide. Practicing the synthetic insecticides cause toxic effects to non target organism and mosquitoes adapts resistance towards synthetic insecticides. The Integrated Pest Management (IPR) aims to develop insecticides from biological sources as an alternative for chemicals based insecticides. In this context, Ruta graveolens is a well know medicinal plant bearing numerous therapeutic properties. The present study investigates the chemical profiling of essential oils and methanolic extract from the leaves of Ruta graveolens. The GC-MS analysis identified the presence of cimifugin, psolaren, chalepin, quinoxyfen, methoxsalen, nonanone, decanone, geijerene, octanone and nonanal in the oils and methanolic extract. The larvicidal activity of essential oils and methanolic extract were investigated against the Culex quinquefasciatus. The oil and methanolic extract inhibit the growth of IInd instar larvae with 100% mortality with significant LC50 value (oil 9 ppm and methanol extract 17ppm). The oil extract performed superior activity than methanol extract and the oils deteriorate the internal structures and membrane of the larvae observed by histopathological studies. Thus the preliminary studies shed light on the development of Ruta graveolens oils as an insecticide to eradicate the larvae of Culex quinquefasciatus.

Keywords: culex; diseases; insecticides; larvae; mosquitoes; oils.



LARVICIDAL EFFECTS OF ESSENTIAL OILS FROM Artemisia herba-alba, Juniperus oxycedrus, AND Pelargonium graveolens AGAINST Tribolium castaneum LARVAE

Mounir KHERROUBI, Izzeddine Zakarya ZERROUK, Ahmed Diya Elhak GUETTOUCHE, Mounir SAIFI

Abstract. The chemical composition of the essential oils from Artemisia herba-alba, Juniperus oxycedrus, and Pelargonium graveolens (Geranium) and their insecticidal activity against Tribolium castaneum (Herbst) larvae were investigated. The essential oils from the aerial parts of these three plants were obtained by hydro-distillation and analyzed by gas chromatography–mass spectrometry (GC–MS). These plant species were selected because they are widely distributed in Algeria and have been traditionally used for their aromatic and medicinal properties. Previous studies have reported that their essential oils contain high levels of bioactive monoterpenoids, such as camphor, α-pinene, citronellol, and geraniol, which are known to possess insecticidal and repellent activities. The main compounds in Artemisia herba-alba EO’s were chrysanthenone (31.40%), camphor (15.97%), and alpha -thujone (14.90%), in Juniperus oxycedrus were alpha-pinene (64.80%), myrcene (5.03%), and delta- cadinene (2.62%), and the major compounds in Pelargonium graveolens EO’s were citronellol (36%), geraniol (16.63%), and isomenthone (8.82%). The insecticidal effect of EO’s extracts were evaluated by means of contact toxicity. After 24 h exposure time, it was found that the Artemisia herba-alba, Juniperus oxycedrus and Pelargonium graveolens EO’s exhibited contact activity against T. castaneum larvae (LD50 = 0.003%, LD50 = 0.095%, LD50 = 0.006%, respectively). The results showed that Artemisia herba-alba and Pelargonium graveolens oils more toxic against T. castaneum larvae and may have potential as a control agent.

Keywords: essential oil; insecticid; larvae; Tribolium castaneum.



PLANT-MICROBIAL INTERACTION IN THE SYSTEM Glycine max / ENDOPHYTIC FUNGI

Olena SHAKHOVNINA, Evgeniy KOPYLOV, Olena NADKERNYCHNA, Ivan PYSHCHUR

Abstract. Mycocenosis in sod-podzolic soil for soybeans growing had been mainly represented by Penicillium Link:Fr, Fusarium Link:Fr, Trichoderma Hers, Acremonium Link, Alternaria Nees, Cladosporium Corda, Gliocladium Corda, Rhizopus Ehrenb, Mortierella Coem, Mucor Mich. Micromycetes biodiversity was different between rhizosphere soil and root surface by its quality and quantity but in both cases the most numerous had been Fusarium genera representatives. Endophytic mycobiota of soybean plants had been formed with fungal genera Penicillium, Chaetomium, Trichoderma, Fusarium, Verticillium, Phomа. Taking into attention that representatives of genera Fusarium, Verticillium and Phomа often used to be found as agricultural crops root diseases causative agents, the object of our research were elected the fungi of genera Penicillium, Chaetomium and Trichoderma. Pre-sowing treatment of soybean seeds with spores of the studied endophytic fungi had positive effect on plants growth and symbiotic indicators. The height of inoculated plants increased on 11.9-13.3% according to the control. Above-ground dry mass increased on 12.7 and 14.3% in accordance to inoculation with Chaetomium sp. 2061 and Trichoderma sp. 2227. Dry roots mass was raised up on 10.5% using Penicillium sp. 2221 and Chaetomium sp. 2061. A trend to increase the number and mass of nodules on plant roots as well as nitrogenase activity increase on 25.2 - 56.2% using researched endophytic fungi strains has been recorded. The total phosphorus content increased from 0.281% in control to 0.297%, 0.342%, and 0.318% in variants using Penicillium sp. 2221, Chaetomium sp. 2061, and Trichoderma sp. 2227 respectively.

Keywords: endophytes; mycocenosis; phosphorus nutrition; soybean; symbiotic nitrogen fixation.



THE COMPLETE CHLOROPLAST GENOMES OF Leonurus turkestanicus FROM THE CHATKAL AND NURATAU RIDGES (CENTRAL ASIA)

Umida TOJIBOEVA, Dilnoz AZIMOVA, Sardorbek MAMASOLIEV, Mokhistara SHARIPOVA, Ibrokhimjon ERGASHOV, Ulugbek KADIROV, Alijon ESANKULOV, Ziyoviddin YUSUPOV

Abstract. Leonurus turkestanicus (Turkestan Motherwort) is a perennial herb within the tribe Leonureae (Lamioideae, Lamiaceae), distributed mainly in Central Asia (Tien Shan, Pamir-Alay). It is a valuable herbal medicine with a calming effect on the nervous system and high blood pressure. In this study, the complete chloroplast genome of Leonurus turkestanicus from Chatkal (Tien Shan) and Nuratau (Pamir-Alai) ridges was sequenced and reported for the first time. The whole cp genome of L. turkestanicus ranged from 151,777 to 151,782 bp in length, contained a pair of inverted repeats (IR, 25,644–25,646 bp) regions separated by a small single copy (SSC, 17,653–17,654 bp) and the highest proportion is the large single copy (LSC, 82,831–82,841 bp). A total 129 genes were encoded including 87 protein-coding genes, 34 tRNA genes and 8 rRNA genes. A total of 220–226 simple sequence repeat (SSR) motifs were identified, in which A/T mononucleotide type is the most numerous. In this study, SSRs were mainly distributed in the LSC and SSC regions. A total of 40 to 42 long repeat sequences were identified in the direct, palindromic, and reverse categories, with the longest sequence being 46 base pairs. Sequence analysis indicated protein coding genes such as rps12, matK, ndhF, ndhG, rpl20, infA, rps15, psbK as hypervariable regions, which can be used as specific effective markers within Leonurus genus. The maximum-likelihood approach of phylogenetic analysis shows that L.cardiaca and L. turkestanicus are the most closely related taxa. Our study offers genetic data and provides valuable genomic resources for further investigations in valuable molecular markers suitable for identification of Leonurus species, on the phylogenetics and biodiversity of the genus Leonurus.

Keywords: chloroplast genome; Central Asia; comparative analysis; Lamiaceae; Leonurus turkestanicus; phylogenetic analysis.



SOCIAL INNOVATION: URGENT NEEDS FOR SYNERGIC ACTIONS AMONG BIODIVERSITY CONSERVATION, CIRCULAR ECONOMY AND BIOECONOMY POLICIES IN RURAL AREAS FOR SOUTHEASTERN EUROPEAN COUNTRIES

Maria Mihaela ANTOFIE, Cristian Felix BLIDAR, Ion BARBU, Mirela STANCIU

Abstract. Social innovation is a must for implementing new economic policies such as circular economy and bioeconomy. However, the need to preserve our biodiversity in the quest to new and better resources impose us to take synergic actions among different economic policies and biodiversity conservation at the national, regional and global levels. The scope of this study was to reveal that social innovation may act down to the most remote rural communities in Southeastern European countries for four case studies such as following: Bulgaria (e.g. The Valley of Roses), Hungary (e.g. Hungarian Grey Cattle), North Macedonia (e.g. Honeyland film “Half for me and half for you”) and Romania (e.g. village’ cowherds). All these case studies are related to villages positioned inside or in the border of protected areas and for all of them biodiversity conservation should be a must. In order to assess the needs for communication social innovation inside these communities a simplified Galbraith's approach was proposed and acting at four levels: (1) local communication with authorities and science, (2) organizational engagements of authorities and relevant stakeholders, (3) existing strategies on circular economy and bioeconomy that should act based on integrative approaches and synergic actions with the strategy on biodiversity conservation and (4) accessing community support for social innovation implementation. Each of the case studies revealed specific peculiarities for communication needs and each of them may have the potential to be replicated at the regional level. Our study results revealed that it is a must to become engaged in developing synergic activities for all these three policies: biodiversity conservation, circular economy and bioeconomy at the country level as well as at the region level due to fast scientific and technological achievements at the global level. We need not only to live in harmony with nature but also we need to learn to share with nature.

Keywords: biodiversity conservation; bioeconomy; circular economy; Galbraith's approach of communication assessment needs; social innovation; Southeastern European countries.



NEW DATA ON THE DISTRIBUTION OF Veronica linearis (Bornm.) M. M. Mart. Ort. (Plantaginaceae), LOCAL ENDEMIC OF THE FLORA OF THE REPUBLIC OF NORTH MACEDONIA

Agim HAZIRI, Sheval MEMISHI, Besnik REXHEPI, Mije REÇI

Abstract. Veronica linearis (Bornm.) Rojas-Andrés & M. M. Mart. Ort., is a rare plant endemic to the Republic of North Macedonia. According to current data, this species is widespread only in a few localities. During the floristic researches in the northwestern region of North Macedonia, another new locality of Veronica linearis (Bornm.) Rojas-Andrés & M. M. Mart. Ort., was discovered, which represents a new record of the distribution of this local endemic species in the flora of Republic of North Macedonia. Specimens examined: Dry Mountain, over the village of Sedlarevo (Sallarevë): 1368 m, 41º52'42.198″N, 21º8'6.804″E, May 2025.

Keywords: new locality; Plantaginaceae; Republic of North Macedonia; Veronica linearis.



PHYLOGENETIC DIVERSITY OF RHIZOBIAL SYMBIONTS NODULATING Vachellia karroo (HAYNE) BANFI & GALASSO IN ALGERIAN ECOSYSTEMS: IMPLICATIONS FOR AFFORESTATION AND LAND RESTORATION

Amina BOUHERAMA, Samir DJOUADI, Thinhinan KHEDIM, Said AMRANI, Abdelsalam Mohamed EID, Ahmed SHAABAN

Abstract. Despite their ecological and economic importance, the diversity of rhizobia associated with the introduced woody legumes in Algeria remains largely unexplored. The main objective of this research was to identify the rhizobial species associated with Vachellia karroo cultivated in ten seedling nurseries across different eco-climatic regions in Algeria, focusing on their diversity and distribution in relation to differing soil and climate conditions. Rhizobial strains were isolated from the root nodules of V. karroo seedlings grown in nurseries located in Saharan, sub-Saharan, and humid eco-climatic conditions. Molecular identification of 29 isolated isolates was undertaken using 16S rRNA gene sequencing to identify them and determine their phylogenetic position. Regardless of the soil and climate, the study found that V. karroo seedlings exhibited a strong ability to develop nitrogen (N)-fixing nodules. Three rhizobial genera, i.e., Sinorhizobium, Mesorhizobium, and Bradyrhizobium, were identified by molecular characterization. Of these, Sinorhizobium was the most commonly occurring genus (48%) and displayed greater diversity. Furthermore, the Sinorhizobium spp. were abundantly found in seedlings collected exclusively from the nurseries in Saharan and sub-Saharan regions, indicating a strong climatic adaptation to arid environments. These results highlight V. karroo’s broad ecological adaptation to diverse Algerian eco-climatic conditions and its potential for association with a wide range of rhizobial species. The Sinorhizobium spp. dominance in arid regions suggests its potential importance in biological N fixation under harsh environmental conditions. This research provides valuable information about the rhizobial diversity associated with V. karroo, which may help Algeria implement climate-resilient afforestation and sustainable land management strategies.

Keywords: Acacia tree; biodiversity; phylogeny; nodulation effectiveness; plant-microbe symbosis; woody legume flora.



IN VITRO PROPAGATION OF TWO COMMERCIALLY IMPORTANT INDONESIAN BANANA CULTIVARS, ‘CAVENDISH’ AND ‘BARANGAN’: THE EFFECT OF VARIOUS BIOTIN CONCENTRATIONS

Zulkarnain ZULKARNAIN, Eliyanti ELIYANTI, Budiyati ICHWAN

Abstract. The study aimed to investigate the effect of biotin on in vitro shoot and root proliferation on ‘Cavendish’ and ‘Barangan’ banana explants. Sucker of ‘Barangan’ and ‘Cavendish’ bananas were used as planting materials. Five levels of biotin (0.5, 1.0, 1.5, 2.0 and 2.5 mg‧L-1) and a control were tested on both banana cultivars. A completely randomized design with four replicates was used in this trial. There were four cultures in each experimental unit. Observed variables were the occurrence of culture browning, shoot formation and root formation. An ANOVA followed by an LSD test was employed in statistical data analysis. The results showed that both ‘Barangan’ and ‘Cavendish’ cultures experienced browning from first week of initiation in preconditioning medium. Browning was reduced when explants were subcultured onto new fresh media, and regenerated shoots within 2 weeks. Enriching culture media with biotin was proven to be beneficial for regenerating shoots and roots in both cultivars. In both 'Barangan' and 'Cavendish', applying biotin up to 1.5 mg‧L-1 encouraged shoot formation. However, this shoot formation declined when 2.0 mg‧L-1 or more biotin present in the culture medium. Meanwhile, in root formation, the application of biotin up to 2.0 mg‧L-1 produced the highest number of explants growing roots in ‘Barangan’, while in ‘Cavendish’ the highest number of explants growing roots was obtained in biotin application of 1.5 mg‧L-1. There was no root formation in ‘Cavendish’ explants without biotin. The study showed that enrichment of the culture media with biotin benefited the in vitro growth and development of both ‘Barangan’ and ‘Cavendish’ bananas. However, the ‘Barangan’ responded better than the ‘Cavendish’.

Keywords: in vitro culture; micropropagation; Musa acuminata; tissue culture; vitamins.



PREVALENCE OF EFFECTIVE FIXING NODULATION AND CHARACTERISATION OF ASSOCIATED RHIZOBIA IN Leucaena leucocephala (LAM.) De Wit SEEDLINGS FROM ALGERIAN NURSERIES

Fahima LEBBIDA, Samir DJOUADI, Amina BOUHRAMA, Said AMRANI, Fatiha AID

Abstract. This study investigates the diversity and nodulation efficiency of rhizobial endophytes associated with Leucaena leucocephala nodules across 12 nurseries located in different climatic regions of Algeria. Rhizobial trapping revealed that 82.14% of strains were able to induce nodulation, with a noticeable decline in nodulation frequency and effectiveness in southern arid regions. Environmental factors such as soil texture,pH, precipitation, and temperature were key determinants influencing symbiotic performance. Strains displayed varied growth rates and host ranges; in the north, both fast- and slow-growing rhizobia nodulated L. leucocephala, whereas in the south, only fast-growing strains were effective. Fast growing strains exhibited broader host ranges and greater tolerance to salinity and drought compared to slow-growing. Phylogenetic analysis identified four genera involved in nodulation, including Bradyrhizobium, Sinorhizobium, Mesorhizobium and Rhizobium, with Sinorhizobium predominating in harsher southern soils. These findings highlight the impact of environmental stressors on rhizobial diversity and nodulation patterns and emphasize the importance of selecting stress-tolerant symbiotic partners for successful legume inoculation in arid and semi-arid regions.

Keywords: Leucaena leucocephala; nitrogen; nurseries; rhizobium; 16S rRNA; symbiosis.






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    The traditions of higher education in Oradea, metaphorically speaking, go back to time immemorial. This year (2008) there are 228 years since the inauguration of higher education in Oradea and 44 years of continuous higher education in Oradea.
    At the end of the 18th century, "a higher institution for philosophic teaching" is founded in Oradea in 1780, which was to become in 1788 the Faculty of Law, the oldest faculty not only within the Romanian borders but also in a vast region of Eastern Europe.
    In May 1990 a decree of the Romanian Government established the Technical University of Oradea, later called the University of Oradea, and based on impressive traditions of academic life in the town. It was an act of scientific and cultural restoration long expected in the life of the Romanian society, a major gain of the people's Revolution of December 1989, one of the greatest Romanian achievements in Crisana after the Great Union on 1 December 1918. This is how the dream of several generations of scholars came true, clearly expressed by a historian of Oradea: "As regarding the future, the desire of all well-meant Romanians is to establish in Oradea a complete university, the lights of which will shine across the entire western border of Romania".
    Today, the University of Oradea is an integrated institution of higher education of this kind, comprising 18 faculties.
    The mission of the University of Oradea is to train and educate on a large scale both the students and also the high education graduates, as well as to approache certain domains of science and technology at high level.
    The structure of the University contains academic education, postgraduate education and scientific research.
    The University of Oradea expanded itself by developing new faculties and research teams, as well as by developing certain specializations inside the existing faculties.
    Education will always be the best long-term investment, as nothing is as precious as the knowledge gained during academic instruction.
     
 
 

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