Search Results (24)

The soil microbial community influences and maintains soil quality and health. Leguminous plants are widely used in forestry due to their nitrogen-fixing ability, significantly improving soil quality. However, there are few studies on the effects of woody legumes on soil microbial communities and soil quality. Here, the composition and structure of bulk soil microbial communities associated with six cultivars of Falcataria falcata (L.) Greuter & R. Rankin were analyzed using full-length 16S rRNA sequencing. Additionally, the minimum dataset approach was employed to integrate indexes of soil microbial communities and physicochemical properties, allowing the calculation of a soil quality index to evaluate the cultivars’ soil quality. Although the growth characteristics of the six cultivars were identical, there were significant differences in physiological functions. Notably, cultivar 6 demonstrated a significant advantage over the other cultivars in its overall physiological characteristics. Compared to the control sample, all cultivars clearly improved soil quality, with cultivars 8 and 16 significantly outperforming the others. The findings indicate that the different cultivars improve soil fertility by recruiting microorganisms with specific functions. The stability of soil microbial communities is a crucial biological and ecological factor that influences and sustains soil quality and health and is a key index for the evaluation of these properties. Full article

The success of growing legumes as green manure depends on their spatial and temporal integration within agroecosystems, which minimizes competition with cash crops, and on their nitrogen (N) fixation potential. This study evaluated seven legume species for biomass production, N fixation, and suitability for use in cropping systems in northern Portugal. Oats (Avena sativa L.) were grown to estimate the N fixation using the difference method, as a non-legume reference crop is required for this purpose, and oats are widely grown in the region. The study was conducted over four cropping cycles (2021–2024) in two climate zones across four land plots. The results indicated that the biomass production and N fixation varied by the species/cultivar and cropping cycle, which was significantly influenced by spring precipitation. Broad beans (Vicia faba L.) failed to develop in one cycle on highly acidic soil (pH 4.9), showing negative N fixation values when calculated by the difference method. Conversely, the lupins maintained a relatively high level of N fixation across all the conditions, demonstrating strong environmental adaptability. Thus, the N fixation values across the four cycles ranged from −5.4 to 419.4 kg ha⁻¹ for broad bean (cv. Favel), while yellow lupin (Lupinus luteus L.) exhibited average values between 204.0 and 274.0 kg ha⁻¹. The percentage of N derived from the atmosphere (%Ndfa) ranged from −13.3 to 91.6, −39.4 to 85.8, 83.8 to 94.7, 74.9 to 94.3, 72.8 to 92.2, 23.1 to 75.8, and 11.7 to 21.7 for these species/cultivars. Due to their environmental adaptability, biomass production, and N fixation capacity, these legumes could be used as green manure in inter-rows of woody crops or in summer annual crops like tomatoes and maize, grown in winter as an alternative to fallow land. The lupins showed strong promise due to their environmental resilience. Full article

Eremosparton songoricum (Litv.) Vass. is a desert legume exhibiting extreme drought tolerance and the ability to withstand various harsh environments, making it a good candidate for investigating stress tolerance mechanisms and exploring valuable stress-resistant genes. However, the absence of a genetic transformation system for E. songoricum poses significant limitations for functionally validating these stress-resistant genes in situ. In this study, we developed an Agrobacterium-mediated transient transformation system for E. songoricum utilizing the β-glucuronidase (GUS) gene as a reporter. We investigated three types of explants (seedlings, assimilated branches and callus) and the effects of different Agrobacterium strains, seedling ages, OD₆₀₀ values, acetosyringone (AS) concentrations, sucrose concentrations and infection times on the transformation efficiency. The results reveal that the optimal transformation system was infecting one-month-old regenerating assimilated branches with the Agrobacterium strain C58C1. The infection solution comprised 1/2 MS medium with 3% sucrose and 200 μM AS at an OD₆₀₀ of 0.8, infection for 3 h and then followed by 2 days of dark cultivation, which achieving a maximum transformation rate of 97%. The maximum transformation rates of the seedlings and calluses were 57.17% and 39.51%, respectively. Moreover, we successfully utilized the assimilated branch transient transformation system to confirm the role of the previously reported transcription factor EsDREB2B in E. songoricum. The overexpression of EsDREB2B enhanced drought tolerance by increasing the plant’s reactive oxygen species (ROS) scavenging capacity in situ. This study established the first transient transformation system for a desert legume woody plant, E. songoricum. This efficient system can be readily applied to investigate gene functions in E. songoricum. It will expedite the exploration of genetic resources and stress tolerance mechanisms in this species, offering valuable insights and serving as a reference for the transformation of other desert plants and woody legumes. Full article

Species of the genus Colletotrichum are among the most important plant pathogens globally, as they are capable of infecting many hosts—apple (Malus spp.) and other fruit and woody plant species—but also vegetable crops, cereals, legumes, and other annual and perennial herbaceous plants. The apple (Malus spp.) is attacked by various species from the genus Colletotrichum, whereby 27 different species from this genus have been described as the causative agents of apple bitter rot (ABR) and 15 as the cause of Glomerella leaf spot (GLS). These species generally belong to one of three species complexes: Colletotrichum acutatum, Colletotrichum gloeosporioides, and Colletotrichum boninense. The largest number of apple pathogens of the genus Colletotrichum belong to the species complex C. acutatum and C. gloeosporioides. However, further data on these species and the interactions between the species complexes of the genus Colletotrichum that cause these two apple diseases is needed for the development of effective control measures, thus ensuring successful and profitable apple cultivation. To contribute to this endeavor, a comprehensive review of the causative agents of ABR and GLS from the genus Colletotrichum is provided. In addition to presenting the species’ current names, distribution, economic significance, and the symptoms they cause in apple, their development cycle, epidemiology, and molecular detection strategies are described, with a particular emphasis on control measures. Full article

Biochar (BC), which can be produced from several feedstocks, has been widely studied. However, the BC derived from highly pyrolytic shrubs, such as broom and gorse, has been less frequently used and only partially characterized. These wastes, when used for the preparation of biochar, can fix carbon and contribute to environmental conservation, helping to achieve sustainable development objectives. Eight biochars from broom and gorse were produced and fully analyzed, providing a more complete and novel description, with new insights for assessing their utilization. The aims of this study were to elucidate the effects of feedstock, pyrolysis temperature, and residence time on biochar properties and to assess the adequacy of these biochars as fuel. Elemental and proximate analyses and estimations of the lower and higher heating values were performed, and physical and chemical properties, as well as several other related energy indices, were determined. The experimental results showed that the temperature was a key factor in the properties of the biochars, while residence time was less important. The BCs obtained from the two feedstocks did not show important effects on the properties, which is consistent with the fact that they are woody legumes. These biochars had a high carbon content and were thermally stable. The BCs also had a high calorific value and suitable energetic properties. Additionally, their PAH contents were low, indicating that the use of these biochars would be safe. In conclusion, broom- and gorse-derived biochars can be considered as renewable fuels for green energy production. Full article

The biodiversity of grasslands has been shaped by long-time interaction between natural processes and human activities, such as grazing. Traditional grazing management by animals contributes to the maintenance of high biodiversity in grasslands. However, changes in land use in recent years such as the abandonment of animal husbandry or intensification of grazing, pose a threat to grasslands biodiversity. The aim of the present study was to investigate the compositional and functional diversity in semi-humid grasslands of northern Greece under different grazing intensities. Three sites with similar vegetation and composition but different grazing intensities were selected in Taxiarchis University Forest of Mountain Holomontas. The three grazing intensities were (1) ungrazed, for more than 40 years, (2) moderate grazed, and (3) highly grazed. The ungrazed area showed an increase in vegetation cover and a decrease in bare ground. In comparison to grazed areas, the ungrazed one showed lower levels of grasses and legumes but higher abundances of woody and broad-leaved species. The highest values of all the studied diversity indices (Shannon–Wiener (H), Simpson Diversity Index, Jaccard, and species abundance) were recorded at moderate grazing intensity. Differences were recorded between the grazed and ungrazed areas in all of the quantitative traits (specific leaf area, leaf dry matter content, stem dry matter content, vegetative and reproductive plant height, leaf nitrogen, and phosphorus concentration). Protecting sensitive mountainous grasslands from both overgrazing and abandonment requires a balanced and sustainable management approach. Full article

As the woody legume, Prosopis glandulosa (honey mesquite) has encroached into grasslands and rangelands in the southern Great Plains, USA, two grass species, C₄ shortgrass, Buchloe dactyloides (buffalograss), and C₃ mid-grass, Nassella leucotricha (Texas wintergrass), have increased in dominance. Occurrence of more productive C₄ mid-grasses and herbaceous diversity have declined. We measured effects of various combinations of spring clipping (to simulate cattle grazing) and summer and/or winter fire treatments on the stability of monoculture patches of these two grass species over an eight-year period, with the goal of reducing Nassella and increasing C₄ mid-grass cover. All fire treatments top-killed most Prosopis trees that subsequently resprouted. Buchloe cover declined in the No Clip + No Fire treatment but remained intact with clipping and/or fire. Frequent clipping reduced Nassella cover across all fire treatments. Buchloe encroachment into Nassella patches was greatest in the Clip + Alternate Season fire treatment. C₄ mid-grass cover increased to 15–25% in Nassella patches in several fire-only or Clip + Fire treatments; greatest gains were observed in treatments that included summer fire. In contrast, C₄ mid-grass gains were lower in Buchloe patches. These results suggest that C₄ mid-grass restoration was linked with treatments that reduced Nassella cover. Full article

Sclerophyllous scrub formations, the main vegetation type in many islands of the Aegean area, provide many goods and services to humans, such as biodiversity, soil protection, and forage for livestock and wildlife. Dominant shrub species of sclerophyllous formations are well adapted to dry season conditions due to various anatomical and physiological mechanisms. As a result, their biomass acts as very flammable, fine fuel, and consequently, wildfires are very common in these ecosystems. Wildfire effects on vegetation and biodiversity in the Mediterranean basin have been studied, and the results are diverse, depending mainly on the vegetation type and frequency of fires. Additionally, post-fire vegetation establishment and structure are critical factors for the implementation of grazing management. The aim of this study was to evaluate the effects of wildfire on species composition, floristic diversity, forage quality, and rangeland health indices related to ecosystem stability and function in three thermo-Mediterranean vegetation types: (1) Sarcopoterium spinosum low formations, (2) low formations of Cistus creticus, and (3) low formations of Cistus creticus in abandoned terraces. The research was conducted on the Oinousses islet, which is located northeast of Chios Island, in May 2013 (one year after the fire). Vegetation sampling was performed along five transects placed in recently burned and adjacent unburned sites of each vegetation type. The plant cover was measured, while the floristic composition, diversity, evenness, and dominance indices were determined for the vegetation data. Additionally, the forage quality was determined in terms of crude protein (CP) and fiber content. The vegetation cover was significantly lower, and the floristic diversity was significantly higher in burned areas in comparison to those in the unburned areas. Woody species, followed by grasses and forbs, dominated in both the burned and unburned areas. However, the percentage of woody species was significantly decreased in the burned areas of Sarcopoterium spinosum and Cistus creticus low formations. On the other hand, the percentage of grasses, forbs, and legumes increased in all cases except in Cistus creticus terraces. The lowest value of the Jaccard Index of similarity between the burned and unburned sites (beta diversity) was observed for Cistus creticus, indicating the effect of fire on the species composition of this vegetation type. The forage quality was found to be improved in all the burned areas, especially in those dominated by Cistus creticus. Finally, fire has a positive impact on the ecosystem’s functions, mainly for Sarcopoterium spinosum low formations. Full article

In Mexico, pasture degradation is associated with extensive pastures; additionally, under these conditions, livestock activities contribute considerably to greenhouse gas (GHG) emissions. Among the options to improve grazing systems and reduce GHG emissions, silvopastoral systems (SPS) have been recommended. The objectives of this work were to quantify the N outflow in a soil–plant–animal interface, as well as the CH₄ emissions and milk production in an SPS with woody legumes (Leucaena leucocephala) that is associated with stargrass (Cynodon nlemfuensis). This was then compared with stargrass in a monoculture system (MS) in the seasons (dry and rainy period) over a two-year period. Dung was collected from the animals of each of the grazing systems and applied fresh to the land plots. Fresh dung and urine were collected from the cows of each grazing system and were applied to the experimental plots. In addition, the soil CH₄ and N₂O contents were measured to quantify the emissions. Average milk yield by seasons was similar: MS (7.1 kg per animal unit (AU)/day⁻¹) and SPS (6.31 kg per AU/day⁻¹). Cows in the MS had a mean N intake of 171.9 g/UA day⁻¹ without seasonal variation, while the SPS animals’ mean N intake was 215.7 g/UA day⁻¹ for both seasons. For the urine applied to soil, the N₂O outflow was higher in the MS (peak value = 1623.9 μg N-N₂O m⁻² h⁻¹). The peak value for the SPS was 755.9 μg of N-N₂O m⁻² h⁻¹. The N₂O emissions were higher in the rainy season (which promotes denitrification). The values for the feces treatment were 0.05% (MS) and 0.01% (SPS). The urine treatment values were 0.52% (MS) and 0.17% (SPS). The emissions of CH₄ showed that the feces of the SPS systems resulted in a higher accumulation of gas in the rainy season (29.8 g C ha⁻¹), followed by the feces of the MS system in the dry season (26.0 g C ha⁻¹). Legumes in the SPS helped to maintain milk production, and the N₂O emissions were lower than those produced by the MS (where the pastures were fertilized with N). Full article

The symbiosis between rhizobia and legumes is of pivotal importance in nitrogen-poor ecosystems. Furthermore, as it is a specific process (most legumes only establish a symbiosis with certain rhizobia), it is of great interest to know which rhizobia are able to nodulate key legumes in a specific habitat. This study describes the diversity of the rhizobia that are able to nodulate the shrub legume Spartocytisus supranubius in the harsh environmental conditions of the high mountain ecosystem of Teide National Park (Tenerife). The diversity of microsymbionts nodulating S. supranubius was estimated from a phylogenetic analysis of root nodule bacteria isolated from soils at three selected locations in the park. The results showed that a high diversity of species of Bradyrhizobium and two symbiovars can nodulate this legume. Phylogenies of ribosomal and housekeeping genes showed these strains distributed into three main clusters and a few isolates on separate branches. These clusters consist of strains representing three new phylogenetic lineages of the genus Bradyrhizobium. Two of these lineages belong to the B. japonicum superclade, which we refer to as B. canariense-like and B. hipponense-like, as the type strains of these species are the closest species to our isolates. The third main group was clustered within the B. elkanii superclade and is referred to as B. algeriense-like as B. algeriense is its closest species. This is the first time that bradyrhizobia of the B. elkanii superclade have been reported for the canarian genista. Furthermore, our results suggest that these three main groups might belong to potential new species of the genus Bradyrhizobium. Analysis of the soil physicochemical properties of the three study sites showed some significant differences in several parameters, which, however, did not have a major influence on the distribution of bradyrhizobial genotypes at the different locations. The B. algeriense-like group had a more restrictive distribution pattern, while the other two lineages were detected in all of the soils. This suggests that the microsymbionts are well adapted to the harsh environmental conditions of Teide National Park. Full article

Neighboring relationships among plants have been extensively reported, but little is known about the effect of waterlogging. In this study, Cleistocalyx operculatus (Roxb.) Merr. and Dalbergia odorifera T. Chen saplings were used in investigating the neighboring relationships between legumes and non-leguminous woody plants under different planting and watering regimes. Results showed that C. operculatus and D. odorifera are waterlogging-tolerant species, and C. operculatus with high proportion of adventitious roots would be at an advantage during waterlogging. The growth performance of D. odorifera was better than that of C. operculatus under well-watered single-planting conditions. However, under well-watered mixed-planting conditions, C. operculatus had an obvious inhibitory effect on the growth traits (increments in stem height and leaf number, total leaf area, and total plant fresh weight) and physiological responses (net photosynthesis rate, stomatal conductance, and transpiration) of D. odorifera, whereas the growth of C. operculatus slightly increased in the presence of D. odorifera. Under waterlogging mixed-planting conditions, the facilitative effect was more intensive; the total leaf area, underground fresh weight, and total plant fresh weight of C. operculatus significantly increased, but a negative effect was found in D. odorifer. These results showed that the neighboring relationship between these two species is predominantly favorable to C. operculatus. This research sheds new light on screening waterlogging-tolerant arbor species and species collocation during vegetation restoration and reconstruction activities in wetland systems. Full article

Global climate change is one of the major constraints limiting plant growth, production, and sustainability worldwide. Moreover, breeding efforts in the past years have focused on improving certain favorable crop traits, leading to genetic bottlenecks. The use of crop wild relatives (CWRs) to expand genetic diversity and improve crop adaptability seems to be a promising and sustainable approach for crop improvement in the context of the ongoing climate challenges. In this review, we present the progress that has been achieved towards CWRs exploitation for enhanced resilience against major abiotic stressors (e.g., water deficiency, increased salinity, and extreme temperatures) in crops of high nutritional and economic value, such as tomato, legumes, and several woody perennial crops. The advances in -omics technologies have facilitated the elucidation of the molecular mechanisms that may underlie abiotic stress tolerance. Comparative analyses of whole genome sequencing (WGS) and transcriptomic profiling (RNA-seq) data between crops and their wild relative counterparts have unraveled important information with respect to the molecular basis of tolerance to abiotic stressors. These studies have uncovered genomic regions, specific stress-responsive genes, gene networks, and biochemical pathways associated with resilience to adverse conditions, such as heat, cold, drought, and salinity, and provide useful tools for the development of molecular markers to be used in breeding programs. CWRs constitute a highly valuable resource of genetic diversity, and by exploiting the full potential of this extended allele pool, new traits conferring abiotic-stress tolerance may be introgressed into cultivated varieties leading to superior and resilient genotypes. Future breeding programs may greatly benefit from CWRs utilization for overcoming crop production challenges arising from extreme environmental conditions. Full article

The sustainability of woody crop agroecosystems requires continued improvements to water, nutrient and soil management. In this work, the combination of resource availability or fertigation dose with soil management practices was tested in a 2 × 2 factorial design in a drip irrigated young almond orchard. The fertigation doses were: the farmer supply at 60% of crop evapotranspiration and full nutrient requirements and the half-farmer supply at 30% of crop evapotranspiration and half nutrient requirements. The soil management practices were: bare soil and cover crops in the inter-row (mixture of grasses and legumes). Tree growth, yield, water and nutrient status, and cover crop biomass and nutrient status were determined, as well as inter-row soil C and N concentration. Results showed that the effect of resource availability was independent of soil management and vice versa. The half farmer treatment reduced tree vegetative growth and yield compared to farmer treatment, due to a negative effect on the water status, without observing a decrease in the concentration of nutrients in leaves or fruit. Trees with cover crop also reduced growth and yield compared to bare soil management. This was due to a nutritional competition, mainly of Ca, Fe, Mn and Zn, rather than to a decline in tree water status. Cover crops sequester up to 1 t/ha/year of carbon but do not increase soil organic carbon, nor soil total nitrogen. Cover crops proved to be efficient in reducing soil nitrate concentration in the topsoil and therefore has potential to prevent its leaching. Deficit fertigation and the use of cover crops can be effective practices to preserve and save water and nutrient resources in Mediterranean agroecosystems, but should be established with caution so as not to compromise the profitability of the orchard. Full article

Prosopis chilensis and Prosopis tamarugo, two woody legumes adapted to the arid regions of Chile, have a declining distribution due to the lack of new seedling establishment. This study investigated the potential of both species to establish in soil collected from four locations in Chile, within and outside the species distribution, and to assess the role of the root-colonizing microbiome in seedling establishment and growth. Seedling survival, height, and water potential were measured to assess establishment success and growth. 16S and ITS2 amplicon sequencing was used to characterize the composition of microbial communities from the different soils and to assess the ability of both Prosopis species to recruit bacteria and fungi from the different soils. Both species were established on three of the four soils. P. tamarugo seedlings showed significantly higher survival in foreign soils and maintained significantly higher water potential in Mediterranean soils. Amplicon sequencing showed that the four soils harbored distinct microbial communities. Root-associated microbial composition indicated that P. chilensis preferentially recruited mycorrhizal fungal partners while P. tamarugo recruited abundant bacteria with known salt-protective functions. Our results suggest that a combination of edaphic properties and microbial soil legacy are potential factors mediating the Prosopis establishment success in different soils. Full article

The objective of the present study was to assess the impacts in time of the ski-resort infrastructure and transhumance livestock grazing on floristic composition, diversity, and rangeland health indices related to ecosystem stability and function. The study was carried out at a site under the pressure of ski resorts and livestock grazing (Ano Trikala) and a site only under the pressure of livestock grazing (Sarantapicho), both located at Mt Zireia, Southern Greece. The plant cover was measured at each site, and the floristic composition was calculated and classified into four functional groups: grasses, legumes, forbs, and woody species. Species richness, ecosystem function and stability landscape indices, diversity indices, and forage value were calculated. According to the results, the development of the ski resort in Ano Trikala had a neglectable negative impact on plant cover (reduced by 5%), while it had a minor impact on species richness and floristic diversity. Livestock grazing had a positive impact on maintaining plant cover in high values. These results suggest that livestock grazing can counterbalance the effects of ski resorts and related activities on plant cover and floristic diversity. Besides the relatively limited effects on the vegetation community, the ski resort significantly negatively impacted landscape composition, function, and stability. Forage value was 25% lower close to the ski resort, mainly due to the significantly lower percentage of legumes. Transhumance livestock grazing should be used as a management tool in ski-resort areas, as it benefits floristic diversity. Full article