Abstract

Wild Iris plants are usually found in spontaneous flora, but due to their ornamental characteristics, they can also be used for ornamental purposes, which means that it is very important to find the perfect conditions for plant growth. This research aimed to evaluate the ornamental value and adaptive behavior of wild Iris aphylla L. in ex situ conditions. Plants from wild flora were cultivated experimentally in the Floriculture field at the Faculty of Horticulture, IULS, Iasi, Romania. The biometric determinations revealed the significantly higher ornamental value of conserved plants grown in ex situ conditions compared to wild plants. In ex situ conditions, the plants displayed more vigorous growth (similar to 100%) and had a higher number of flowers per stem (5-9 flowers), whereas, in wild conditions, this species has from two to a maximum of five flowers. Given the absence of anatomical studies in the literature, detailed anatomical investigations of the leaf structure were performed, complemented by analyses of the photosynthetic pigment content to assess the plant's physiological performance. Additionally, the molecular phylogenetic analyses conducted using two plastid markers (rbcL and trnL-F) confirmed the taxonomic classification of the native I. aphylla L. species. To the best of our knowledge, this is the first report on the molecular phylogeny of the wild Iridaceae species in Romania. These findings provide insights into the taxonomy, morphology, cultivation potential, and ornamental value of the species, supporting future conservation and horticulture development programs.

Abstract

Wild Iris plants are usually found in spontaneous flora, but due to their ornamental characteristics, they can also be used for ornamental purposes, which means that it is very important to find the perfect conditions for plant growth. This research aimed to evaluate the ornamental value and adaptive behavior of wild Iris aphylla L. in “ex situ” conditions. Plants from wild flora were cultivated experimentally in the Floriculture field at the Faculty of Horticulture, IULS, Iași, Romania. The biometric determinations revealed the significantly higher ornamental value of conserved plants grown in “ex situ” conditions compared to wild plants. In “ex situ” conditions, the plants displayed more vigorous growth (~100%) and had a higher number of flowers per stem (5–9 flowers), whereas, in wild conditions, this species has from two to a maximum of five flowers. Given the absence of anatomical studies in the literature, detailed anatomical investigations of the leaf structure were performed, complemented by analyses of the photosynthetic pigment content to assess the plant’s physiological performance. Additionally, the molecular phylogenetic analyses conducted using two plastid markers (rbcL and trnL-F) confirmed the taxonomic classification of the native I. aphylla L. species. To the best of our knowledge, this is the first report on the molecular phylogeny of the wild Iridaceae species in Romania. These findings provide insights into the taxonomy, morphology, cultivation potential, and ornamental value of the species, supporting future conservation and horticulture development programs. © 2024 by the authors.

Abstract

Biological nitrogen fixation by rhizobia-nodulated legumes reduces the dependence on synthetic nitrogen fertilizers. Identification of locally adapted rhizobia may uncover economically valuable strains for sustainable agriculture. This study investigated the diversity and symbiotic potential of rhizobia associated with three Medicago species from Eastern Romania's ecosystems. Phenotypic screening ensured that only rhizobial species were retained for molecular characterization. 16S rDNA sequencing clustered the isolates into four distinct groups: Sinorhizobium meliloti, Sinorhizobium medicae, Rhizobium leguminosarum, and Mesorhizobium spp. The chromosomal genes (atpD, glnII, recA) and nifH phylogenies were congruent, while the nodA phylogeny grouped the Mesorhizobium spp. isolates with R. leguminosarum. Medicago sativa was the most sampled plant species, and only S. meliloti and R. leguminosarum were found in its nodules, while Medicago falcata nodules hosted S. meliloti and Mesorhizobium spp. Medicago lupulina was the only species that hosted all four identified rhizobial groups, including S. medicae. This study provides the first report on the Mesorhizobium spp. associated with M. falcata nodules. Additionally, R. leguminosarum and two Mesorhizobium genospecies were identified as novel symbionts for Medicago spp. Comparative analysis of Medicago-associated rhizobia from other studies revealed that differences in 16S rDNA sequence type composition were influenced by Medicago species identity rather than geographic region.

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Abstract

Abstract

The identification and conservation of indigenous rhizobia associated with legume plants and their application as biofertilizers is becoming an agricultural worldwide priority. However, little is known about the genetic diversity and phylogeny of rhizobia in Romania. In the present study, the genetic diversity and population composition of Rhizobium leguminosarum symbiovar trifolii isolates from 12 clover plants populations located across two regions in Romania were analyzed. Red clover isolates were phenotypically evaluated and genotyped by sequencing 16S rRNA gene, 16S-23S intergenic spacer, three chromosomal genes (atpD, glnll and recA) and two plasmid genes (nifH and nodA). Multilocus sequence typing (MLST) analysis revealed that red clover plants are nodulated by a wide genetic diversity of R. leguminosarum symbiovar trifolii sequence types (STs), highly similar to the ones previously found in white clover. Rhizobial genetic variation was found mainly within the two clover populations for both chromosomal and plasmid types. Many STs appear to be unique for this region and the genetic composition of rhizobia differs significantly among the clover populations. Furthermore, our results showed that both soil pH and altitude contributed to plasmid sequence type composition while differences in chromosomal composition were affected by the altitude and were strongly correlated with distance. (C) 2018 Elsevier GmbH. All rights reserved.

Abstract

The symbiotic nitrogen fixing legumes play an essential role in sustainable agriculture. White clover (Trifolium repens L.) is one of the most valuable perennial legumes in pastures and meadows of temperate regions. Despite its great agriculture and economic importance, there is no detailed available information on phylogenetic assignation and characterization of rhizobia associated with native white clover plants in South-Eastern Europe. In the present work, the diversity of indigenous white clover rhizobia originating in 11 different natural ecosystems in North-Eastern Romania were assessed by a polyphasic approach. Initial grouping showed that, 73 rhizobial isolates, representing seven distinct phenons were distributed into 12 genotypes, indicating a wide phenotypic and genotypic diversity among the isolates. To clarify their phylogeny, 44 representative strains were used in sequence analysis of 16S rRNA gene and IGS fragments, three housekeeping genes (atpD, glnII and recA) and two symbiosis-related genes (nodA and nifH). Multilocus sequence analysis (MLSA) phylogeny based on concatenated housekeeping genes delineated the clover isolates into five putative genospecies. Despite their diverse chromosomal backgrounds, test strains shared highly similar symbiotic genes closely related to Rhizobium leguminosarum biovar trifolii. Phylogenies inferred from housekeeping genes were incongruent with those of symbiotic genes, probably due to occurrence of lateral transfer events among native strains. This is the first polyphasic taxonomic study to report on the MLSA-based phylogenetic diversity of indigenous rhizobia nodulating white clover plants grown in various soil types in South-Eastern Europe. Our results provide valuable taxonomic data on native clover rhizobia and may increase the pool of genetic material to be used as biofertilizers.

Abstract

Background: Haloalkane dehalogenases (EC 3.8.1.5, HLDs) are alpha/beta-hydrolases which catalyze the irreversible cleavage of carbon-halogen bonds of haloalkanes, producing an alcohol, a halide and a hydrogen ion. Haloalkanes are acutely toxic to animals and humans and their toxic effects are mainly observed in the liver, kidneys and central nervous system. Objective: In the present work, the haloalkane dehalogenase from Rhizobium leguminosarum bv. trifolii (DrlA) was characterized. Method: Reverse transcription polymerase chain reaction analysis and enzyme activity assays revealed that the DrlA gene expression in R. leguminosarum bv. trifolii is induced by 1,2dibromoethane (1,2-DBE) during the early exponential phase. The gene of the enzyme was isolated, cloned and expressed in E. coli Rosetta (DE3). Results: Recombinant DrlA displays its high catalytic activity towards 1,2-DBE and the long-chain haloalkane 1-iodohexane. Limited activity was observed for other aliphatic and cyclic haloalkanes, indicating that the enzyme displays restricted substrate specificity, compared to other bacterial HLDs. Homology modelling and phylogenetic analysis suggested that the enzyme belongs to the HLD-II subfamily and shares the same overall fold and domain organization as other bacterial HLDs, however major variations were identified at the hydrophobic substrate-binding cavity, the cap domain and the entrance of the main tunnel that affect the size of the active site pocket and the substrate recognition mechanism. Conclusion: This work sheds new light on the environmental fate and toxicity of 1,2-DBE and provides new knowledge on the structure, function and diversity of HLDs for developing applications in toxicology.

Abstract

It is known that the genetic diversity of conspecific rhizobia present in root nodules differs greatly among populations of a legume species, which has led to the suggestion that both dispersal limitation and the local environment affect rhizobial genotypic composition. However, it remains unclear whether rhizobial genotypes residing in root nodules are representative of the entire population of compatible symbiotic rhizobia. Since symbiotic preferences differ among legume populations, the genetic composition of rhizobia found within nodules may reflect the preferences of the local hosts, rather than the full diversity of potential nodulating rhizobia present in the soil. Here, we assessed whether Vicia cracca legume hosts of different provenances select different Rhizobium leguminosarum genotypes than sympatric V. cracca hosts, when presented a natural soil rhizobial population. Through combining V. cracca plants and rhizobia from adjacent and more distant populations, we found that V. cracca hosts are relatively randomly associated with rhizobial genotypes. This indicates that pre-infection partner choice is relatively weak in certain legume hosts when faced with a natural population of rhizobia. (C) 2016 Elsevier GmbH. All rights reserved.

Abstract

The application of commercial rhizobial inoculants to legume crops is proving to be an alternative to synthetic fertilizer use. The challenge for sustainable agriculture resides in the compatibility between crop, inoculants and environmental conditions. The evaluation of symbiotic efficiency and genetic diversity of indigenous rhizobial strains could lead to the development of better inoculants and increased crop production. The genetic variability of 32 wild indigenous rhizobial isolates was assessed by RAPD (Random Amplified Polymorphic DNA). The strains were isolated from red clover (Trifolium pratense L.) nodules from two distinct geographical regions of Northern and Eastern Romania. Three decamer primers were used to resolve the phylogenetic relationships between the investigated isolates. Cluster analysis revealed a high diversity; most strains clustered together based on their geographical location.