Search Results (7)

Alfalfa (Medicago sativa L.) is a vitally important perennial fodder legume worldwide. Given their particular traits, alfalfa crop wild relatives (CWRs) could be used to develop cultivars that can tolerate extreme environmental and climatic conditions. Until now, researchers have overlooked the composition and structure of bacterial communities in the root zone of alfalfa and its relevant CWRs and their influence on forage performance under actual field conditions. In this study, high-throughput sequencing of 16S rRNA analysis was performed to investigate the diversity and assemblies of bacterial communities in the bulk soil and in the root zone of individual field-grown Medicago plants arranged in a honeycomb selection design. The plants used in this study were M. sativa × M. arborea hybrids (Genotypes 6 and 8), the closely-related M. sativa nothosubsp. varia (Martyn) Arcang. (Genotype 13), and M. sativa ssp. sativa (Genotype 20). The bacterial communities in the root-zone samples and the assemblies in the bulk soil differed significantly. Genotype 13 was found to have distinct bacterial assemblies from the other genotypes while exhibiting the lowest forage productivity. These findings suggest that plant productivity may influence the composition of bacterial communities in the root zone. Biomarker analysis conducted using linear discriminant analysis (LDA) revealed that only members of the Rhizobiales order were enriched in the M. sativa nothosubsp. varia root zone whereas taxa belonging to Sphingomonas and various Bacteriodota were enriched in the other genotypes. Of the shared taxa identified in the root zone of the Medicago lines, the abundance of specific taxa, namely, Flavisolibacter, Stenotrophomonas, and Sphingomonas, were positively associated with forage yield. This pioneering study, in which the root zones of individual Medicago plants under actual field conditions were examined, offers evidence of differences in the bacterial composition of alfalfa genotypes with varying genetic backgrounds. Its findings indicate that particular bacterial taxa may favorably influence plant performance. This study covered the first six months of crop establishment and paves the way for further investigations to advance understanding of how shifts in bacterial assemblies in alfalfa roots affect plant performance over time. Full article

The Northern Spotted Owl (Strix occidentalis caurina) (NSO) was listed as federally threatened in 1992 due to widespread logging of its old-growth forest habitat. The NSO recovery plan in 2011 elevated competition with Barred Owls (Strix varia) (BO) and wildfires as primary NSO threats based partly on the assumption that severely burned forests were no longer NSO nesting and roosting habitat. We quantified amount of logging before and/or after wildfire and opportunistic detections of BOs within two home range scales (0.8 and 2.09 km) at 105 NSO sites that experienced severe wildfire from 2000–2017. Logging affected 87% of severely burned NSO sites, with BO recorded at 22% of burned-and-logged sites. Most (60%) severely burned NSO sites had evidence of logging both before and after fires while only 12% of severely burned sites had no logging or BO detections, indicating rarity of NSO territories subjected to severe fire without the compounding stressors of logging and invasive BOs. We recommend changes to NSO habitat modeling that assume nesting and roosting habitat is no longer viable if severely burned, and to the U.S. Fish and Wildlife Service’s practice of granting incidental take permits for NSOs in logging operations within severely burned owl sites. Full article

Sulla is a biannual forage legume cultivated throughout the Mediterranean Basin. It can be severely damaged by powdery mildew, but there is little understanding on its causal species or its host range. The taxonomic characterization of Erysiphe species is mainly based on the examination of chasmothecia morphology, or on the molecular analysis of ITS1 and ITS2 sequences. However, a description of chasmothecia morphology or ITS sequences is not always available to clearly assign a given isolate to an existing or novel Erysiphe species. In an attempt to clarify the identity of the powdery mildew infecting sulla crop we studied the morphology and ITS of nine populations collected over years and countries and compared them with available ITS sequences. Phylogenetic analysis showed that the powdery mildews collected on sulla clustered together with isolates collected on Coronilla varia in an independent clade between the E. guarinonii/E. trifoliorum and E. palczewskii clades, strongly suggesting that all these sequences correspond to the same Erysiphe species. Measurements of conidia and conidial foot cells of the sulla-infecting powdery mildews partially overlap those of other Erysiphe species, although they clearly differentiate from them, supporting the assumption that powdery mildews from sulla belong to a distinct species as observed from the phylogenetic analysis. As far as we know, our study is the first to report the molecular characterization of powdery mildew isolated on plants from the Hedysarum clade. Cross-inoculations confirmed a high specialization of the powdery mildew of sulla, with the sulla’s isolates infecting only the S. coronaria accessions, and none of the accessions from the other legume genera studied. All studied S. coronaria accessions were heavily infected by the sulla isolate but not by any other isolate used. All this points to E. hedysari as the causal agent of the S. coronaria powdery mildew. Full article

This study aimed to investigate the chemical composition and the activity against Staphylococcus aureus (S. aureus) (ATCC 25923), Streptococcus pyogenes (S. pyogenes) (ATCC 19615), Escherichia coli (E. coli) (ATCC 25922), Pseudomonas aeruginosa (P. aeruginosa) (ATCC 27853), Shigella flexneri (S. flexneri) (ATCC 12022), Salmonella typhimurium (S. typhimurium) (ATCC 14028), Haemophillus influenzae (H. influenza) type B (ATCC 10211) and two fungal strains: Candida albicans (C. albicans) (ATCC 10231) and Candida parapsilopsis (C. parapsilopsis) (ATCC 22019) of the extracts obtained from Melilotus officinalis (MO), Coronilla varia (CV); Ononis spinosa (OS) and Robinia pseudoacacia (RP) (Fabaceae), and to identify the chemical compounds responsible for the antimicrobial effect against the tested strains. The extracts were obtained by conventional hydroalcoholic extraction and analyzed in terms of total polyphenols using the spectrophotometric method and by liquid chromatography (LC). The results have shown that the highest polyphenols content was recorded in the RP sample (16.21 mg gallic acid equivalent GAE/g), followed by the CV (15.06 mg GAE/g), the OS (13.17 mg GAE/g), the lowest value being recorded for the MO sample (11.94 mg GAE/g). The antimicrobial testing of plant extracts was carried out using the microdilution method. The most sensitive strains identified were: E. coli, S. typhimurium, P. aeruginosa and S. pyogenes, while protocatechuic acid, gallic acid, caffeic acid, quercetin, rutin, and kaempferol were identified as the chemical compounds responsible for the antibacterial effect. The analysis of the correlation between the chemical composition and the antimicrobial effect proved a moderate (r > 0.5) positive correlation between rosmarinic acid and S. pyogenes (r = 0.526), rosmarinic acid and S. typhimurium (r = 0.568), quercetin and C. albicans (r = 0.553), quercetin and S. pyogenes (r = 0.605). Therefore, it suggested possible antimicrobial activity generated by these chemical components. The results recommend the Fabaceae plants as promising candidates for further research to develop novel natural antimicrobial drugs. Full article

In Southwest Germany, the renaturation of quarry areas close to settlements is usually based on the planting of native species of trees and shrubs, which are then neither cultivated nor used. This study investigates whether a species-rich agroforestry system based on Ernst Goetsch’s syntropic agriculture approach would be suitable for both renaturation in the form of soil fertility improvement and diverse food crop production under temperate climate. The quarry syntropy project was launched in summer 2019. Two shallow stony sections of a spoil heap of the quarry in Ehningen, Southwest Germany were available for demonstration plots. An interdisciplinary project team was set up both to obtain the official permits from five governmental institutions and to begin the study. The demonstration plots were each divided into three broad strips, which differ in three vegetation types: trees, shrubs, and annual food crops. The tree and shrub areas are mainly used for biomass production for a continuous mulch supply on the entire cultivated area in order to rapidly increase soil fertility. The food crops and also partly the trees and shrubs were intended to provide organically produced food (vegetables, fruit, berries and herbs). Most of the trees (eleven species) were planted in November 2019. In March 2020, soil samples were taken (0–30 cm), and a solar-powered water storage system was installed. Currently, the shrub and annual food crop strips are under preparation (pre-renaturation phase). In this initial phase, the priority is fertility improvement of the topsoil through intensive mulching of the existing grassland stock dominated by top grasses and the legumes hybrid alfalfa (Medicago × varia Martyn) and common bird’s-foot trefoil (Lotus corniculatus L.). The food crop strip should then start in 2021 after one year of mulching. Depending on the success of growth, the tree strips should then also gain in importance for mulch application in the following years. The strategy is to gradually build up food crop cultivation under organic low-input agricultural practices while simultaneously enhancing the biophysical growth conditions guided by natural succession. Full article

The rate of establishment of non-native bark beetle species is accelerating in many parts of the world and is considered a serious threat to forests and forest crops. Distributional data for exotic bark beetles are urgently needed, but they must be based on sound taxonomy. Using primary literature and original records, I review for the first time the invasive bark beetle (Scolytinae) species in Chile and Argentina, and I give a short risk assessment for each. I also provide the best sources for identifying these species. The invasive pine bark beetle commonly referred to in Chilean research as Orthotomicus erosus (Wollaston) is not that species: evidence suggests that the only Orthotomicus that is or has been in Chile is O. laricis (Fabricius), which is also the Orthotomicus species reported in the most recent research from Argentina. I add new information on the distributions of two other abundant pine-breeding invasive species, Hylurgus ligniperda (F.) and Hylastes ater (Paykull), and I report that populations of Hylastes linearis Erichson have been found in Chile. This is the first known occurrence of the species in South America. Phloeotribus willei Schedl, a tiny bark beetle collected from domestic fig trees in Chile and Peru, has been considered native heretofore. I argue that it must be an introduced Neotropical species, and I present new localities for Chile. I present the first Chilean records of the Myrtaceae specialist ambrosia beetle Amasa truncata (Erichson), an Australian species recently found in southern Brazil and northeastern Uruguay, and new Argentinian records that seem to be the earliest finds of Xylosandrus crassiusculus (Motschulsky) in South America. The Canary Island palm seed specialist Dactylotrypes longicollis (Wollaston) is reported for the first time from South America, from Chile. The presence in Chile of another spermatophage, Coccotrypes dactyliperda (F.), is confirmed. New Chilean regions and new host records are given for Pagiocerus frontalis (F.), a species that breeds in Lauraceae seeds but also in stored maize. Other exotic species treated briefly include Hylastinus obscurus (Marsham), Hylesinus taranio (Danthione), Scolytus multistriatus (Marsham), S. rugulosus (Müller), Coccotrypes cyperi (Beeson), and Xyleborinus saxeseni (Ratzeburg). Finally, reports of several species from Chile or Argentina are considered unsupported by evidence: Scolytus kirschii Skalitzky, Pityokteines curvidens (Germar), Coccotrypes robustus Eichhoff, and Hypothenemus hampei (Ferrari).
La velocidad de establecimiento de especies de coleópteros descortezadores no nativos se está acelerando en muchas partes del mundo y se considera una amenaza seria a bosques y cultivos forestales. Se requiere datos distribucionales urgentemente, pero estos tienen que basarse en taxonomía sólida. Utilizando literatura primaria y registros originales, reviso por primera vez la fauna invasora de especies de descortezadores (Scolytinae) en Chile y Argentina, y ofrezco una evaluación breve del riesgo de cada una. También proporciono los mejores referencias para identificar estas especies. La especie descortezador invasora de pinos comunmente citado en investigaciones chilenas como Orthotomicus erosus (Wollaston) no es esa: la evidencia sugiere que la única especie de Orthotomicus actualmente o históricamente presente en Chile es O. laricis (Fabricius), la cual es la especie de Orthotomicus reportado en las investigaciones mas recientes de Argentina. Agrego información nueva sobre las distribuciones de otros dos especies abundantes invasoras que se reproducen en pinos, Hylurgus ligniperda (F.) y Hylastes ater (Paykull) y comunico que poblaciones de Hylastes linearis Erichson se han encontrado en Chile, siendo esta el primer hallazgo de la especie en Sudamérica. Phloeotribus willei Schedl, una especie minúscula colectado de higueras cultivadas en Chile y Peru, se ha considerado nativa hasta ahora: presento argumentos que debe de ser una especie neotropical introducida y presento nuevas localidades para Chile. Presento los primeros registros chilenos de Amasa truncata (Erichson) coleóptero ambrosial, especialista en Myrtaceae, especie australiana recientemente encontrada en el sur de Brasil y nordeste de Uruguay, y nuevos registros argentinos que parecen ser los primeros hallazgos de Xylosandrus crassiusculus (Motschulsky) en Sudamérica. Se registra la especialista en semillas de palma, Dactylotrypes longicollis (Wollaston), originario de las Islas Canárias pro primera vez de Sudamérica; se confirma la presencia en Chile de otra espermatófago, Coccotrypes dactyliperda (F.). Se presentan nuevos registros regionales de Chile y de hospederas por Pagiocerus frontalis (F.), especie que se reproduce en semillas de Lauraceae pero también en maíz almacenado. Otras especies exóticas tratadas brevemente incluyen Hylastinus obscurus (Marsham), Hylesinus taranio (Danthione), Scolytus multistriatus (Marsham), S. rugulosus (Müller), Coccotrypes cyperi (Beeson), y Xyleborinus saxeseni (Ratzeburg). Finalmente, registros de varias especies de Chile o de Argentina se consideran sin apoyo de evidencia: Scolytus kirschii Skalitzky, Pityokteines curvidens (Germar), Coccotrypes robustus Eichhoff, y Hypothenemus hampei (Ferrari). Full article

Securigera varia (Fabaceae) is a common herbaceous perennial plant widely growing in Europe and Asia and purposely established for erosion control, roadside planting, and soil rehabilitation. The aim of this study was to determine the radical scavenging activity of a crude methanol extract of S. varia aerial parts by using the free radical DPPH (1,1-diphenyl-2-picrylhydrazyl) and to rapidly identify the compounds involved in this activity. The crude extract was initially separated in five fractions on Diaion HP20 resin and the most active part was fractionated by Centrifugal Partition Extraction (CPE). Known compounds were directly identified by a ¹³C-NMR-based dereplication method. Semi-preparative high performance liquid chromatography purification experiments were further performed to identify unknown or minor active compounds. As a result, one new (13) and twelve known flavonoid glycosides together with three nitropropanoylglucopyranoses were isolated, including astragalin (1), kaempferol-3-O-(6-O-acetyl)-β-D-glucopyranoside (2), kaempferol-3,4′-di-O-β-D-glucopyranoside (3), trifolin (4), isoquercitrin (5), hyperoside (6), isovitexin (7), isoorientin (8), isovitexin 4′-O-β-D-glucopyranoside (9), apigenin 7-O-β-D-glucuronopyranoside (10), luteolin 7-O-β-D-glucuronopyranoside (11), apigenin 7-O-α-L-rhamnopyranosyl-(1→2)-β-D-glucuronopyranoside (12), apigenin 7-O-β-D-glucopyranosyl-(1→2)-β-D-glucuronopyranoside (13), 6-O-(3-nitropropanoyl)-β-D-glucopyranoside (14), coronillin (16) and coronarian (15). 120 mg of the most active compound isoorientin against the free radical DPPH was recovered by CPE with an HPLC purity of 99%. Full article