Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 20 de 41
Filter
1.
Ecol Lett ; 27(6): e14462, 2024 Jun.
Article in English | MEDLINE | ID: mdl-39031813

ABSTRACT

The rhizosphere influence on the soil microbiome and function of crop wild progenitors (CWPs) remains virtually unknown, despite its relevance to develop microbiome-oriented tools in sustainable agriculture. Here, we quantified the rhizosphere influence-a comparison between rhizosphere and bulk soil samples-on bacterial, fungal, protists and invertebrate communities and on soil multifunctionality across nine CWPs at their sites of origin. Overall, rhizosphere influence was higher for abundant taxa across the four microbial groups and had a positive influence on rhizosphere soil organic C and nutrient contents compared to bulk soils. The rhizosphere influence on abundant soil microbiomes was more important for soil multifunctionality than rare taxa and environmental conditions. Our results are a starting point towards the use of CWPs for rhizosphere engineering in modern crops.


Subject(s)
Crops, Agricultural , Microbiota , Rhizosphere , Soil Microbiology , Crops, Agricultural/microbiology , Soil/chemistry , Fungi/physiology , Animals , Bacteria/classification , Bacteria/isolation & purification , Invertebrates/microbiology , Invertebrates/physiology
2.
Microorganisms ; 12(6)2024 Jun 13.
Article in English | MEDLINE | ID: mdl-38930576

ABSTRACT

Living in arid environments presents unique challenges to organisms, including limited food and water, extreme temperatures, and UV exposure. Reptiles, such as the South American leaf-toed gecko (Phyllodactylus gerrhopygus), have evolved remarkable adaptations to thrive in such harsh conditions. The gut microbiome plays a critical role in host adaptation and health, yet its composition remains poorly characterized in desert reptiles. This study aimed to characterize the composition and abundance of the gut microbiome in P. gerrhopygus inhabiting the hyperarid Atacama Desert, taking into account potential sex differences. Fecal samples from adult female and male geckos were analyzed by 16S rRNA gene amplicon sequencing. No significant differences in bacterial alpha diversity were observed between the sexes. However, the phylum Bacteroidota was more abundant in females, while males had a higher Firmicutes/Bacteroidota ratio. The core microbiome was dominated by the phyla Bacteroidota, Firmicutes, and Proteobacteria in both sexes. Analysis of bacterial composition revealed 481 amplicon sequence variants (ASVs) shared by female and male geckos. In addition, 108 unique ASVs were exclusive to females, while 244 ASVs were unique to males. Although the overall bacterial composition did not differ significantly between the sexes, certain taxa exhibited higher relative abundances in each sex group. This study provides insight into the taxonomic structure of the gut microbiome in a desert-adapted reptile and highlights potential sex-specific differences. Understanding these microbial communities is critical for elucidating the mechanisms underlying host resilience in Earth's most arid environments, and for informing conservation efforts in the face of ongoing climate change.

3.
Glob Chang Biol ; 30(5): e17295, 2024 May.
Article in English | MEDLINE | ID: mdl-38804108

ABSTRACT

Plant-soil biodiversity interactions are fundamental for the functioning of terrestrial ecosystems. Yet, the existence of a set of globally distributed topsoil microbial and small invertebrate organisms consistently associated with land plants (i.e., their consistent soil-borne microbiome), together with the environmental preferences and functional capabilities of these organisms, remains unknown. We conducted a standardized field survey under 150 species of land plants, including 58 species of bryophytes and 92 of vascular plants, across 124 locations from all continents. We found that, despite the immense biodiversity of soil organisms, the land plants evaluated only shared a small fraction (less than 1%) of all microbial and invertebrate taxa that were present across contrasting climatic and soil conditions and vegetation types. These consistent taxa were dominated by generalist decomposers and phagotrophs and their presence was positively correlated with the abundance of functional genes linked to mineralization. Finally, we showed that crossing environmental thresholds in aridity (aridity index of 0.65, i.e., the transition from mesic to dry ecosystems), soil pH (5.5; i.e., the transition from acidic to strongly acidic soils), and carbon (less than 2%, the lower limit of fertile soils) can result in drastic disruptions in the associations between land plants and soil organisms, with potential implications for the delivery of soil ecosystem processes under ongoing global environmental change.


Subject(s)
Embryophyta , Microbiota , Soil Microbiology , Biodiversity , Soil/chemistry
4.
ISME J ; 18(1)2024 Jan 08.
Article in English | MEDLINE | ID: mdl-38625060

ABSTRACT

High-elevation arid regions harbor microbial communities reliant on metabolic niches and flexibility to survive under biologically stressful conditions, including nutrient limitation that necessitates the utilization of atmospheric trace gases as electron donors. Geothermal springs present "oases" of microbial activity, diversity, and abundance by delivering water and substrates, including reduced gases. However, it is unknown whether these springs exhibit a gradient of effects, increasing their impact on trace gas-oxidizers in the surrounding soils. We assessed whether proximity to Polloquere, a high-altitude geothermal spring in an Andean salt flat, alters the diversity and metabolic structure of nearby soil bacterial populations compared to the surrounding cold desert. Recovered DNA and metagenomic analyses indicate that the spring represents an oasis for microbes in this challenging environment, supporting greater biomass with more diverse metabolic functions in proximal soils that declines sharply with radial distance from the spring. Despite the sharp decrease in biomass, potential rates of atmospheric hydrogen (H2) and carbon monoxide (CO) uptake increase away from the spring. Kinetic estimates suggest this activity is due to high-affinity trace gas consumption, likely as a survival strategy for energy/carbon acquisition. These results demonstrate that Polloquere regulates a gradient of diverse microbial communities and metabolisms, culminating in increased activity of trace gas-oxidizers as the influence of the spring yields to that of the regional salt flat environment. This suggests the spring holds local importance within the context of the broader salt flat and potentially represents a model ecosystem for other geothermal systems in high-altitude desert environments.


Subject(s)
Bacteria , Desert Climate , Hot Springs , Oxidation-Reduction , Soil Microbiology , Bacteria/classification , Bacteria/genetics , Bacteria/metabolism , Bacteria/isolation & purification , Hot Springs/microbiology , Carbon Monoxide/metabolism , Hydrogen/metabolism , Microbiota , Altitude , Soil/chemistry
5.
Front Plant Sci ; 15: 1323087, 2024.
Article in English | MEDLINE | ID: mdl-38455727

ABSTRACT

Olive (Olea europaea L. subsp. europaea) is one of the most important crops of the Mediterranean Basin and temperate areas worldwide. Obtaining new olive varieties adapted to climatic changing conditions and to modern agricultural practices, as well as other traits such as biotic and abiotic stress resistance and increased oil quality, is currently required; however, the long juvenile phase, as in most woody plants, is the bottleneck in olive breeding programs. Overexpression of genes encoding the 'florigen' Flowering Locus T (FT), can cause the loss of the juvenile phase in many perennials including olives. In this investigation, further characterization of three transgenic olive lines containing an FT encoding gene from Medicago truncatula, MtFTa1, under the 35S CaMV promoter, was carried out. While all three lines flowered under in vitro conditions, one of the lines stopped flowering after acclimatisation. In soil, all three lines exhibited a modified plant architecture; e.g., a continuous branching behaviour and a dwarfing growth habit. Gene expression and hormone content in shoot tips, containing the meristems from which this phenotype emerged, were examined. Higher levels of OeTFL1, a gene encoding the flowering repressor TERMINAL FLOWER 1, correlated with lack of flowering. The branching phenotype correlated with higher content of salicylic acid, indole-3-acetic acid and isopentenyl adenosine, and lower content of abscisic acid. The results obtained confirm that heterologous expression of MtFTa1 in olive induced continuous flowering independently of environmental factors, but also modified plant architecture. These phenotypical changes could be related to the altered hormonal content in transgenic plants.

7.
Nat Commun ; 14(1): 1706, 2023 03 27.
Article in English | MEDLINE | ID: mdl-36973286

ABSTRACT

Soil contamination is one of the main threats to ecosystem health and sustainability. Yet little is known about the extent to which soil contaminants differ between urban greenspaces and natural ecosystems. Here we show that urban greenspaces and adjacent natural areas (i.e., natural/semi-natural ecosystems) shared similar levels of multiple soil contaminants (metal(loid)s, pesticides, microplastics, and antibiotic resistance genes) across the globe. We reveal that human influence explained many forms of soil contamination worldwide. Socio-economic factors were integral to explaining the occurrence of soil contaminants worldwide. We further show that increased levels of multiple soil contaminants were linked with changes in microbial traits including genes associated with environmental stress resistance, nutrient cycling, and pathogenesis. Taken together, our work demonstrates that human-driven soil contamination in nearby natural areas mirrors that in urban greenspaces globally, and highlights that soil contaminants have the potential to cause dire consequences for ecosystem sustainability and human wellbeing.


Subject(s)
Cities , Ecosystem , Internationality , Parks, Recreational , Soil Pollutants , Soil , Microbiota , Socioeconomic Factors , Soil/chemistry , Soil Microbiology , Soil Pollutants/analysis , Soil Pollutants/chemistry , Plastics
8.
Nat Ecol Evol ; 7(1): 113-126, 2023 01.
Article in English | MEDLINE | ID: mdl-36631668

ABSTRACT

While the contribution of biodiversity to supporting multiple ecosystem functions is well established in natural ecosystems, the relationship of the above- and below-ground diversity with ecosystem multifunctionality remains virtually unknown in urban greenspaces. Here we conducted a standardized survey of urban greenspaces from 56 municipalities across six continents, aiming to investigate the relationships of plant and soil biodiversity (diversity of bacteria, fungi, protists and invertebrates, and metagenomics-based functional diversity) with 18 surrogates of ecosystem functions from nine ecosystem services. We found that soil biodiversity across biomes was significantly and positively correlated with multiple dimensions of ecosystem functions, and contributed to key ecosystem services such as microbially driven carbon pools, organic matter decomposition, plant productivity, nutrient cycling, water regulation, plant-soil mutualism, plant pathogen control and antibiotic resistance regulation. Plant diversity only indirectly influenced multifunctionality in urban greenspaces via changes in soil conditions that were associated with soil biodiversity. These findings were maintained after controlling for climate, spatial context, soil properties, vegetation and management practices. This study provides solid evidence that conserving soil biodiversity in urban greenspaces is key to supporting multiple dimensions of ecosystem functioning, which is critical for the sustainability of urban ecosystems and human wellbeing.


Subject(s)
Ecosystem , Soil , Humans , Parks, Recreational , Biodiversity , Plants
9.
Microbiome ; 10(1): 219, 2022 Dec 12.
Article in English | MEDLINE | ID: mdl-36503688

ABSTRACT

BACKGROUND: Little is known about the global distribution and environmental drivers of key microbial functional traits such as antibiotic resistance genes (ARGs). Soils are one of Earth's largest reservoirs of ARGs, which are integral for soil microbial competition, and have potential implications for plant and human health. Yet, their diversity and global patterns remain poorly described. Here, we analyzed 285 ARGs in soils from 1012 sites across all continents and created the first global atlas with the distributions of topsoil ARGs. RESULTS: We show that ARGs peaked in high latitude cold and boreal forests. Climatic seasonality and mobile genetic elements, associated with the transmission of antibiotic resistance, were also key drivers of their global distribution. Dominant ARGs were mainly related to multidrug resistance genes and efflux pump machineries. We further pinpointed the global hotspots of the diversity and proportions of soil ARGs. CONCLUSIONS: Together, our work provides the foundation for a better understanding of the ecology and global distribution of the environmental soil antibiotic resistome. Video Abstract.


Subject(s)
Anti-Bacterial Agents , Soil , Humans , Anti-Bacterial Agents/pharmacology , Ecology , Phenotype
10.
Nature ; 610(7933): 693-698, 2022 10.
Article in English | MEDLINE | ID: mdl-36224389

ABSTRACT

Soils are the foundation of all terrestrial ecosystems1. However, unlike for plants and animals, a global assessment of hotspots for soil nature conservation is still lacking2. This hampers our ability to establish nature conservation priorities for the multiple dimensions that support the soil system: from soil biodiversity to ecosystem services. Here, to identify global hotspots for soil nature conservation, we performed a global field survey that includes observations of biodiversity (archaea, bacteria, fungi, protists and invertebrates) and functions (critical for six ecosystem services) in 615 composite samples of topsoil from a standardized survey in all continents. We found that each of the different ecological dimensions of soils-that is, species richness (alpha diversity, measured as amplicon sequence variants), community dissimilarity and ecosystem services-peaked in contrasting regions of the planet, and were associated with different environmental factors. Temperate ecosystems showed the highest species richness, whereas community dissimilarity peaked in the tropics, and colder high-latitudinal ecosystems were identified as hotspots of ecosystem services. These findings highlight the complexities that are involved in simultaneously protecting multiple ecological dimensions of soil. We further show that most of these hotspots are not adequately covered by protected areas (more than 70%), and are vulnerable in the context of several scenarios of global change. Our global estimation of priorities for soil nature conservation highlights the importance of accounting for the multidimensionality of soil biodiversity and ecosystem services to conserve soils for future generations.


Subject(s)
Biodiversity , Conservation of Natural Resources , Geographic Mapping , Soil Microbiology , Soil , Animals , Conservation of Natural Resources/methods , Soil/parasitology , Invertebrates , Archaea
11.
FEMS Microbiol Ecol ; 98(11)2022 10 28.
Article in English | MEDLINE | ID: mdl-36040342

ABSTRACT

In the Antarctic Peninsula, increases in mean annual temperature are associated with the coverage and population density of the two Antarctic vascular plant species-Deschampsia antarctica and Colobanthus quitensis-potentially modifying critical soil processes. In this study, we characterized the diversity and community composition of active microorganisms inhabiting the vascular plant rhizosphere in two sites with contrasting vegetation cover in King George Island, Western Antarctic Peninsula. We assessed the interplay between soil physicochemical properties and microbial diversity and composition, evaluating the effect of an in situ experimental warming on the microbial communities of the rhizosphere from D. antarctica and C. quitensis. Bacteria and Eukarya showed different responses to warming in both sites, and the effect was more noticeable in microbial eukaryotes from the low vegetation site. Furthermore, important changes were found in the relative abundance of Tepidisphaerales (Bacteria) and Ciliophora (Eukarya) between warming and control treatments. Our results showed that rhizosphere eukaryal communities are more sensitive to in situ warming than bacterial communities. Overall, our results indicate that vegetation drives the response of the active fraction of the microbial communities from the rhizosphere of Antarctic vascular plants to soil warming.


Subject(s)
Microbiota , Rhizosphere , Soil , Antarctic Regions , Soil Microbiology , Bacteria/genetics
12.
Plant Sci ; 313: 111083, 2021 Dec.
Article in English | MEDLINE | ID: mdl-34763868

ABSTRACT

The C6 aldehydes, alcohols, and the corresponding esters are the most important compounds of virgin olive oil aroma. These C6 volatile compounds are synthesized via the 13-hydroperoxide lyase (13-HPL) branch of the lipoxygenase pathway. In this investigation, a functional analysis of the olive (Olea europaea L.) 13-HPL gene by its overexpression and silencing in olive transgenic lines was carried out. With this aim, sense and RNAi constructs of the olive 13-HPL gene were generated and used for the transformation of embryogenic olive cultures. Leaves from overexpressing lines showed a slight increase in 13-HPL gene expression, whereas RNAi lines exhibited a strong decrease in their transcript levels. Quantification of 13-HPL activity in two overexpressing and two RNAi lines showed a positive correlation with levels of transcripts. Interestingly, RNAi lines showed a high decrease in the content of C6 volatiles linked to a strong increase of C5 volatile compounds, altering the volatile profile in the leaves. In addition, the silencing of the 13-HPL gene severely affected plant growth and development. This investigation demonstrates the role of the 13-HPL gene in the biogenesis of olive volatile compounds and constitutes a functional genomics study in olive related to virgin olive oil quality.


Subject(s)
Lipoxygenase/biosynthesis , Lipoxygenase/genetics , Oils, Volatile/analysis , Oils, Volatile/metabolism , Olea/growth & development , Olea/genetics , Olive Oil/chemistry , Fruit/enzymology , Fruit/genetics , Gene Expression Regulation, Plant , Genes, Plant
13.
Plants (Basel) ; 10(6)2021 Jun 11.
Article in English | MEDLINE | ID: mdl-34208406

ABSTRACT

Trees have a distinctive and generally long juvenile period during which vegetative growth rate is rapid and floral organs do not differentiate. Among trees, the juvenile period can range from 1 year to 15-20 years, although with some forest tree species, it can be longer. Vegetative propagation of trees is usually much easier during the juvenile phase than with mature phase materials. Therefore, reversal of maturity is often necessary in order to obtain materials in which rooting ability has been restored. Micrografting has been developed for trees to address reinvigoration/rejuvenation of elite selections to facilitate vegetative propagation. Generally, shoots obtained after serial grafting have increased rooting competence and develop juvenile traits; in some cases, graft-derived shoots show enhanced in vitro proliferation. Recent advances in graft signaling have shown that several factors, e.g., plant hormones, proteins, and different types of RNA, could be responsible for changes in the scion. The focus of this review includes (1) a discussion of the differences between the juvenile and mature growth phases in trees, (2) successful restoration of juvenile traits through micrografting, and (3) the nature of the different signals passing through the graft union.

14.
Sci Adv ; 7(28)2021 Jul.
Article in English | MEDLINE | ID: mdl-34244148

ABSTRACT

The structure and function of the soil microbiome of urban greenspaces remain largely undetermined. We conducted a global field survey in urban greenspaces and neighboring natural ecosystems across 56 cities from six continents, and found that urban soils are important hotspots for soil bacterial, protist and functional gene diversity, but support highly homogenized microbial communities worldwide. Urban greenspaces had a greater proportion of fast-growing bacteria, algae, amoebae, and fungal pathogens, but a lower proportion of ectomycorrhizal fungi than natural ecosystems. These urban ecosystems also showed higher proportions of genes associated with human pathogens, greenhouse gas emissions, faster nutrient cycling, and more intense abiotic stress than natural environments. City affluence, management practices, and climate were fundamental drivers of urban soil communities. Our work paves the way toward a more comprehensive global-scale perspective on urban greenspaces, which is integral to managing the health of these ecosystems and the well-being of human populations.

15.
Genes (Basel) ; 12(3)2021 03 09.
Article in English | MEDLINE | ID: mdl-33803172

ABSTRACT

Olive (Olea europaea L.) is the most characteristic and important oil crop of the Mediterranean region. Traditional olive cultivation is based on few tens cultivars of ancient origin. To improve this crop, novel selections with higher tolerance to biotic and abiotic stress, adaptable to high-density planting systems and resilient to climate change are needed; however, breeding programs are hindered by the long juvenile period of this species and few improved genotypes have been released so far. Genetic transformation could be of great value, in the near future, to develop new varieties or rootstocks in a shorter time; in addition, it has currently become an essential tool for functional genomic studies. The recalcitrance of olive tissues to their in vitro manipulation has been the main bottleneck in the development of genetic transformation procedures in this species; however, some important traits such as fungal resistance, flowering or lipid composition have successfully been manipulated through the genetic transformation of somatic embryos of juvenile or adult origin, providing a proof of the potential role that this technology could have in olive improvement. However, the optimization of these protocols for explants of adult origin is a prerequisite to obtain useful materials for the olive industry. In this review, initially, factors affecting plant regeneration via somatic embryogenesis are discussed. Subsequently, the different transformation approaches explored in olive are reviewed. Finally, transgenic experiments with genes of interest undertaken to manipulate selected traits are discussed.


Subject(s)
Olea/genetics , Transformation, Genetic/genetics , Genetic Variation/genetics , Genome, Plant/genetics , Genotype , Phylogeny , Plant Breeding/methods , Regeneration/genetics
16.
Educ. med. (Ed. impr.) ; 22(1): 14-19, ene.-feb. 2021. tab, graf
Article in Spanish | IBECS | ID: ibc-202111

ABSTRACT

INTRODUCCIÓN: El interno de Medicina se encuentra sometido a múltiples factores que pueden llegar a generarle síntomas depresivos. La resiliencia es un mecanismo que permite sobrellevar y contrarrestar esta circunstancia. Existe escasa información sobre la dimensión y la relación entre estos 2 aspectos en la población descrita. OBJETIVO: Determinar la relación entre el nivel de resiliencia y la presencia de síntomas depresivos durante el internado médico en Lima, Perú. MATERIALES Y MÉTODOS: Se realizó un estudio transversal en una muestra representativa de internos de Medicina Humana de 4 hospitales de Lima, Perú. El nivel de resiliencia se midió con la Escala de Resiliencia de Wagnild y Young abreviada y la presencia de síntomas depresivos con la Escala de Autoevaluación para la Depresión de Zung abreviada. Se utilizó el modelo de regresión logística para determinar la asociación estadística. RESULTADOS: Se encuestó a 202 internos (83,5% del total de internos). El nivel de resiliencia presentó una media de 78,01±11,59, con una prevalencia de resiliencia alta del 87,1% (n=176), y la prevalencia de síntomas depresivos fue del 42,6% (n=86). Se encontró una relación inversa entre el nivel alto de resiliencia y la ausencia de síntomas depresivos (OR 13,75; IC 95% 3,9-47,6; p < 0,05). CONCLUSIÓN: Aquellos internos con un mayor nivel de resiliencia presentaron menos síntomas depresivos. El contacto con amigos y la conformidad con la sede y con el personal de trabajo se asociaron con un nivel alto de resiliencia


INTRODUCTION: The medical intern is susceptible to multiple factors that can lead to depressive symptoms. Resilience is a mechanism that allows them to overcome and counteract this problem. There is limited information about the scope and relationship between these 2 aspects in the population described. OBJECTIVE: To determine the relationship between the level of resilience and the presence of depressive symptoms during the medical internship in Lima, Peru. MATERIALS AND METHODS: A cross-sectional study was carried out on a representative sample of interns from four hospitals in Lima, Peru. The level of resilience was measured with the Wagnild and Young Abbreviated Resilience Questionnaire, and the presence of depressive symptoms with the abbreviated Zung Self-Rating Depression Scale. A logistic regression model was used to determine statistical relationship. RESULTS: A total of 202 interns were surveyed (83.5% of the total number of interns). The mean level of resilience was 78.01±11.59, with a high resilience prevalence of 87.1% (n=176), with the mean prevalence of depressive symptoms being 42.6% (n=86). An inverse relationship was found between a high level of resilience and the absence of depressive symptoms (OR 13.75; 95% CI 3.9-47.6; P<.05). CONCLUSION: Those with a higher level of resilience had fewer depressive symptoms. Contact with friends, and conformity with the hospital and with staff were associated with a high level of resilience


Subject(s)
Humans , Male , Female , Young Adult , Adult , Education, Medical/statistics & numerical data , Depression/epidemiology , Resilience, Psychological/classification , Internship and Residency/statistics & numerical data , Students, Medical/statistics & numerical data , Patient Health Questionnaire/statistics & numerical data , Peru/epidemiology , Cross-Sectional Studies , Psychometrics/instrumentation
17.
Nat Commun ; 11(1): 4721, 2020 09 18.
Article in English | MEDLINE | ID: mdl-32948775

ABSTRACT

The importance of soil age as an ecosystem driver across biomes remains largely unresolved. By combining a cross-biome global field survey, including data for 32 soil, plant, and microbial properties in 16 soil chronosequences, with a global meta-analysis, we show that soil age is a significant ecosystem driver, but only accounts for a relatively small proportion of the cross-biome variation in multiple ecosystem properties. Parent material, climate, vegetation and topography predict, collectively, 24 times more variation in ecosystem properties than soil age alone. Soil age is an important local-scale ecosystem driver; however, environmental context, rather than soil age, determines the rates and trajectories of ecosystem development in structure and function across biomes. Our work provides insights into the natural history of terrestrial ecosystems. We propose that, regardless of soil age, changes in the environmental context, such as those associated with global climatic and land-use changes, will have important long-term impacts on the structure and function of terrestrial ecosystems across biomes.


Subject(s)
Biota , Ecosystem , Soil/chemistry , Bacteria/classification , Biodiversity , Biomass , Climate , Fungi/classification , Microbiota , Plants/classification , Time Factors
18.
Plants (Basel) ; 9(7)2020 Jun 27.
Article in English | MEDLINE | ID: mdl-32605018

ABSTRACT

Cell cultures derived from strawberry fruit at different developmental stages have been obtained to evaluate their potential use to study different aspects of strawberry ripening. Callus from leaf and cortical tissue of unripe-green, white, and mature-red strawberry fruits were induced in a medium supplemented with 11.3 µM 2,4-dichlorophenoxyacetic acid (2,4-D) under darkness. The transfer of the established callus from darkness to light induced the production of anthocyanin. The replacement of 2,4-D by abscisic acid (ABA) noticeably increased anthocyanin accumulation in green-fruit callus. Cell walls were isolated from the different fruit cell lines and from fruit receptacles at equivalent developmental stages and sequentially fractionated to obtain fractions enriched in soluble pectins, ester bound pectins, xyloglucans (XG), and matrix glycans tightly associated with cellulose microfibrils. These fractions were analyzed by cell wall carbohydrate microarrays. In fruit receptacle samples, pectins were abundant in all fractions, including those enriched in matrix glycans. The amount of pectin increased from green to white stage, and later these carbohydrates were solubilized in red fruit. Apparently, XG content was similar in white and red fruit, but the proportion of galactosylated XG increased in red fruit. Cell wall fractions from callus cultures were enriched in extensin and displayed a minor amount of pectins. Stronger signals of extensin Abs were detected in sodium carbonate fraction, suggesting that these proteins could be linked to pectins. Overall, the results obtained suggest that fruit cell lines could be used to analyze hormonal regulation of color development in strawberry but that the cell wall remodeling process associated with fruit softening might be masked by the high presence of extensin in callus cultures.

19.
Front Plant Sci ; 11: 308, 2020.
Article in English | MEDLINE | ID: mdl-32265961

ABSTRACT

The NPR1 gene encodes a key component of systemic acquired resistance (SAR) signaling mediated by salicylic acid (SA). Overexpression of NPR1 confers resistance to biotrophic and hemibiotrophic fungi in several plant species. The NPR1 gene has also been shown to be involved in the crosstalk between SAR signaling and the jasmonic acid-ethylene (JA/Et) pathway, which is involved in the response to necrotrophic fungi. The aim of this research was to generate transgenic olive plants expressing the NPR1 gene from Arabidopsis thaliana to evaluate their differential response to the hemibiotrophic fungus Verticillium dahliae and the necrotroph Rosellinia necatrix. Three transgenic lines expressing the AtNPR1 gene under the control of the constitutive promoter CaMV35S were obtained using an embryogenic line derived from a seed of cv. Picual. After maturation and germination of the transgenic somatic embryos, the plants were micropropagated and acclimated to ex vitro conditions. The level of AtNPR1 expression in the transgenic materials varied greatly among the different lines and was higher in the NPR1-780 line. The expression of AtNPR1 did not alter the growth of transgenic plants either in vitro or in the greenhouse. Different levels of transgene expression also did not affect basal endochitinase activity in the leaves, which was similar to that of control plants. Response to the hemibiotrophic pathogen V. dahliae varied with pathotype. All plants died by 50 days after inoculation with defoliating (D) pathotype V-138, but the response to non-defoliating (ND) strains differed by race: following inoculation with the V-1242 strain (ND, race 2), symptoms appeared after 44-55 days, with line NPR1-780 showing the lowest disease severity index. This line also showed good performance when inoculated with the V-1558 strain (ND, race 1), although the differences from the control were not statistically significant. In response to the necrotroph R. necatrix, all the transgenic lines showed a slight delay in disease development, with mean area under the disease progress curve (AUDPC) values 7-15% lower than that of the control.

20.
Nat Ecol Evol ; 4(2): 210-220, 2020 02.
Article in English | MEDLINE | ID: mdl-32015427

ABSTRACT

The role of soil biodiversity in regulating multiple ecosystem functions is poorly understood, limiting our ability to predict how soil biodiversity loss might affect human wellbeing and ecosystem sustainability. Here, combining a global observational study with an experimental microcosm study, we provide evidence that soil biodiversity (bacteria, fungi, protists and invertebrates) is significantly and positively associated with multiple ecosystem functions. These functions include nutrient cycling, decomposition, plant production, and reduced potential for pathogenicity and belowground biological warfare. Our findings also reveal the context dependency of such relationships and the importance of the connectedness, biodiversity and nature of the globally distributed dominant phylotypes within the soil network in maintaining multiple functions. Moreover, our results suggest that the positive association between plant diversity and multifunctionality across biomes is indirectly driven by soil biodiversity. Together, our results provide insights into the importance of soil biodiversity for maintaining soil functionality locally and across biomes, as well as providing strong support for the inclusion of soil biodiversity in conservation and management programmes.


Subject(s)
Ecosystem , Soil , Biodiversity , Fungi , Humans , Soil Microbiology
SELECTION OF CITATIONS
SEARCH DETAIL
...