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1.
PLoS Genet ; 12(10): e1006348, 2016 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-27736883

RESUMO

Ectomycorrhizal fungi (EMF) represent one of the major guilds of symbiotic fungi associated with roots of forest trees, where they function to improve plant nutrition and fitness in exchange for plant carbon. Many groups of EMF exhibit preference or specificity for different plant host genera; a good example is the genus Suillus, which grows in association with the conifer family Pinaceae. We investigated genetics of EMF host-specificity by cross-inoculating basidiospores of five species of Suillus onto ten species of Pinus, and screened them for their ability to form ectomycorrhizae. Several Suillus spp. including S. granulatus, S. spraguei, and S. americanus readily formed ectomycorrhizae (compatible reaction) with white pine hosts (subgenus Strobus), but were incompatible with other pine hosts (subgenus Pinus). Metatranscriptomic analysis of inoculated roots reveals that plant and fungus each express unique gene sets during incompatible vs. compatible pairings. The Suillus-Pinus metatranscriptomes utilize highly conserved gene regulatory pathways, including fungal G-protein signaling, secretory pathways, leucine-rich repeat and pathogen resistance proteins that are similar to those associated with host-pathogen interactions in other plant-fungal systems. Metatranscriptomic study of the combined Suillus-Pinus transcriptome has provided new insight into mechanisms of adaptation and coevolution of forest trees with their microbial community, and revealed that genetic regulation of ectomycorrhizal symbiosis utilizes universal gene regulatory pathways used by other types of fungal-plant interactions including pathogenic fungal-host interactions.


Assuntos
Interações Hospedeiro-Patógeno/genética , Micorrizas/genética , Pinus/genética , Transcriptoma/genética , Ecossistema , Proteínas Fúngicas/biossíntese , Proteínas Fúngicas/genética , Regulação Fúngica da Expressão Gênica , Metagenoma/genética , Micorrizas/patogenicidade , Pinus/microbiologia , Raízes de Plantas/microbiologia , Simbiose/genética
2.
Int J Mol Sci ; 20(23)2019 Dec 03.
Artigo em Inglês | MEDLINE | ID: mdl-31816938

RESUMO

Protein acetylation affects gene expression, as well as other processes in cells, and it might be dependent on the availability of the metals. However, whether iron chelating compounds (siderophores) can have an effect on the acetylation process in plant roots is largely unknown. In the present study, western blotting and confocal microscopy was used to examine the degree of acetylation of histone H3 and alpha tubulin in Pinus sylvestris root cells in the presence of structurally different siderophores. The effect of metabolites that were produced by pathogenic and mycorrhizal fungi was also assessed. No effect was observed on histone acetylation. By contrast, the metabolites of the pathogenic fungus were able to decrease the level of microtubule acetylation, whereas treatment with iron-free ferrioxamine (DFO) was able to increase it. This latter was not observed when ferrioxamine-iron complexes were used. The pathogen metabolites induced important modifications of cytoskeleton organization. Siderophores also induced changes in the tubulin skeleton and these changes were iron-dependent. The effect of siderophores on the microtubule network was dependent on the presence of iron. More root cells with a depolymerized cytoskeleton were observed when the roots were exposed to iron-free siderophores and the metabolites of pathogenic fungi; whereas, the metabolites from mycorrhizal fungi and iron-enriched forms of siderophores slightly altered the cytoskeleton network of root cells. Collectively, these data indicated that the metabolites of pathogenic fungi mirror siderophore action, and iron limitation can lead to enhanced alternations in cell structure and physiology.


Assuntos
Histonas/metabolismo , Ácidos Hidroxâmicos/química , Pinus sylvestris/citologia , Raízes de Plantas/citologia , Raízes de Plantas/metabolismo , Sideróforos/química , Tubulina (Proteína)/metabolismo , Acetilação , Morte Celular , Metaboloma , Microtúbulos/metabolismo , Micorrizas/metabolismo , Micorrizas/patogenicidade , Raízes de Plantas/microbiologia
3.
J Exp Bot ; 65(18): 5231-41, 2014 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-25200735

RESUMO

Arbuscular mycorrhizal (AM) fungi, important plant mutualists, provide plants with nutrients such as phosphorus (P) in return for carbon. AM fungi also enhance the attractiveness of plants to aphids via effects on emissions of plant volatiles used in aphid host location. We tested whether increased P uptake by plants is the mechanism through which AM fungi alter the volatile profile of plants and aphid behavioural responses by manipulating the availability of P and AM fungi to broad beans (Vicia faba L.) in a multi-factorial design. If AM fungi affect plant volatiles only via increased P acquisition, we predicted that the emission of volatiles and the attractiveness of mycorrhizal beans to aphids would be similar to those of non-mycorrhizal beans supplied with additional P. AM fungi and P addition increased leaf P concentrations by 40 and 24%, respectively. The production of naphthalene was less in mycorrhizal plants, regardless of P addition. By contrast, production of (S)-linalool, (E)-caryophyllene and (R)-germacrene D was less in plants colonized by AM fungi but only in the absence of P additions. The attractiveness of plants to pea aphids (Acyrthosiphon pisum Harris) was positively affected by AM fungi and correlated with the extent of root colonization; however, attractiveness was neither affected by P treatment nor correlated with leaf P concentration. These findings suggest that increased P uptake is not the main mechanism by which mycorrhiza increase the attractiveness of plants to aphids. Instead, the mechanism is likely to operate via AM fungi-induced plant systemic signalling.


Assuntos
Afídeos/fisiologia , Micorrizas/patogenicidade , Fósforo/metabolismo , Vicia faba/microbiologia , Animais
4.
Plant Cell ; 22(7): 2509-26, 2010 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-20675572

RESUMO

Legumes form symbioses with arbuscular mycorrhiza (AM) fungi and nitrogen fixing root nodule bacteria. Intracellular root infection by either endosymbiont is controlled by the activation of the calcium and calmodulin-dependent kinase (CCaMK), a central regulatory component of the plant's common symbiosis signaling network. We performed a microscopy screen for Lotus japonicus mutants defective in AM development and isolated a mutant, nena, that aborted fungal infection in the rhizodermis. NENA encodes a WD40 repeat protein related to the nucleoporins Sec13 and Seh1. Localization of NENA to the nuclear rim and yeast two-hybrid experiments indicated a role for NENA in a conserved subcomplex of the nuclear pore scaffold. Although nena mutants were able to form pink nodules in symbiosis with Mesorhizobium loti, root hair infection was not observed. Moreover, Nod factor induction of the symbiotic genes NIN, SbtM4, and SbtS, as well as perinuclear calcium spiking, were impaired. Detailed phenotypic analyses of nena mutants revealed a rhizobial infection mode that overcame the lack of rhizodermal responsiveness and carried the hallmarks of crack entry, including a requirement for ethylene. CCaMK-dependent processes were only abolished in the rhizodermis but not in the cortex of nena mutants. These data support the concept of tissue-specific components for the activation of CCaMK.


Assuntos
Lotus/metabolismo , Micorrizas/patogenicidade , Proteínas de Plantas/fisiologia , Rhizobium/patogenicidade , Simbiose , Clonagem Molecular , Teste de Complementação Genética , Dados de Sequência Molecular , Mutação , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Técnicas do Sistema de Duplo-Híbrido
5.
Sci Rep ; 11(1): 18468, 2021 09 16.
Artigo em Inglês | MEDLINE | ID: mdl-34531432

RESUMO

Zinc (Zn) deficiency can severely inhibit plant growth, yield, and enzymatic activities. Zn plays a vital role in various enzymatic activities in plants. Arbuscular mycorrhizal fungi (AMF) play a crucial role in improving the plant's Zn nutrition and mitigating Zn stress effects on plants. The current study was conducted to compare the response of inoculated and non-inoculated maize (YH 1898) in the presence of different levels of zinc under greenhouse conditions under a Zn deficient condition. There were two mycorrhizal levels (i.e., M + with mycorrhizae, M- without mycorrhizae) and five Zn levels (i.e., 0, 1.5, 3, 6, and 12 mg kg-1), with three replicates following completely randomized design. At the vegetative stage (before tillering), biochemical, physiological, and agronomic attributes were measured. The results showed that maize plants previously inoculated with AMF had higher gaseous exchange traits, i.e., a higher stomatal conductance rate, favoring an increased photosynthetic rate. Improvement in antioxidant enzyme activity was also observed in inoculated compared to non-inoculated maize plants. Moreover, AMF inoculation also played a beneficial role in nutrients availability and its uptake by plants. Higher Zn12 (12 mg Zn kg-1 soil) treatment accumulated a higher Zn concentration in soil, root, and shoot in AMF-inoculated than in non-inoculated maize plants. These results are consistent with mycorrhizal symbiosis beneficial role for maize physiological functioning in Zn deficient soil conditions. Additionally, AMF inoculation mitigated the stress conditions and assisted nutrient uptake by maize.


Assuntos
Micorrizas/patogenicidade , Solo/química , Zea mays/microbiologia , Zinco/deficiência , Micorrizas/metabolismo , Fotossíntese , Estômatos de Plantas/metabolismo , Zea mays/metabolismo , Zinco/análise
6.
Sci Rep ; 11(1): 6501, 2021 03 22.
Artigo em Inglês | MEDLINE | ID: mdl-33753844

RESUMO

In this work, the effects of co-inoculation between an arbuscular mycorrhizal fungus (AMF) and a phosphate solubilizing bacteria (PSB) to promote the growth and production of sunchoke under field condition were investigated during 2016 and 2017. Four treatments were set up as follows: plants without inoculation, with AMF inoculation, with PSB inoculation and with co-inoculation of PSB and AMF. The results showed the presence of PSB and AMF colonization at the harvest stage in both years. This suggested the survival of PSB and successful AMF colonization throughout the experiments. According to correlation analysis, PSB positively affected AMF spore density and colonization rate. Also, both AMF and PSB positively correlated with growth and production of sunchoke. Co-inoculation could enhance various plant parameters. However, better results in 2016 were found in co-inoculation treatment, while AMF inoculation performed the best in 2017. All of these results suggested that our AMF and PSB could effectively promote growth and production of sunchoke under field conditions. Such effects were varied due to different environmental conditions each year. Note that this is the first study showing successful co-inoculation of AMF and PSB for promoting growth and yield of sunchoke in the real cultivation fields.


Assuntos
Produção Agrícola/métodos , Helianthus/microbiologia , Micorrizas/patogenicidade , Rizosfera , Fungos/metabolismo , Fungos/patogenicidade , Helianthus/crescimento & desenvolvimento , Micorrizas/metabolismo , Fosfatos/metabolismo
7.
Sci Rep ; 11(1): 4362, 2021 02 23.
Artigo em Inglês | MEDLINE | ID: mdl-33623081

RESUMO

Soil salinity affects soil quality and reduces plant performance. Arbuscular mycorrhizal fungi (AMF) can enhance the tolerance of plants under salinity stress. Cultivation of eucalyptus (Eucalyptus camaldulensis), which exhibits high water use efficiency, is possible in saline areas to produce raw materials for the pulp industry. We determined the effects of arbuscular mycorrhizal fungi (AMF) on the growth and survival of eucalyptus seedlings under saline conditions. Three different clones of eucalyptus seedlings were pre-inoculated with three salt-tolerant AMF species, namely Glomus sp.2, Gigaspora albida and G. decipiens, and without pre-inoculation. The seedlings were grown in a greenhouse for 45 days. They were then transferred to individual pots, filled with field soil and subsequently treated with NaCl solution until electro-conductivity (EC) reached 10, 15 and 20 dS m-1. They were watered for 90 days under nursery conditions. The results show that increased salinity levels reduced plant performance, fractional AMF root colonization, spore number, and eucalypt K/Na ratio. AMF significantly increased chlorophyll and decreased leaf proline concentrations by more than 50% and 20% respectively and increased the K/Na ratio three- to six-fold compared with non-inoculated plants. Pre-inoculation with AMF before outplanting also improved plant performance by more than 30% under salinity stress compared to non-inoculated plants. We conclude that AMF can alleviate the negative impacts of salinity on plant physiological and biochemical parameters.


Assuntos
Eucalyptus/microbiologia , Micorrizas/patogenicidade , Tolerância ao Sal , Clorofila/metabolismo , Eucalyptus/metabolismo , Fungos/patogenicidade , Potássio/metabolismo , Prolina/metabolismo , Plântula/metabolismo , Plântula/microbiologia , Sódio/metabolismo
8.
PLoS One ; 16(11): e0259959, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34813605

RESUMO

The role of arbuscular mycorrhizal (AM) fungus (Rhizophagus intraradices) in the amelioration of the water deficit-mediated negative influence on the growth, photosynthesis, and antioxidant system in Euonymus maackii Rupr. was examined. E. maackii seedlings were subjected to 5 water deficit levels, soil water contents of 20%, 40%, 60%, 80% and 100% field capacity (FC), and 2 inoculation treatments, with and without AM inoculation. The water deficit increasingly limited the seedling height, biomass accumulation in shoots and roots, chlorophyll content, gas exchange and chlorophyll fluorescence parameters with an increasing water deficit level. In addition, water deficit stimulated the activities of antioxidant enzymes, including superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT), in both shoots and roots, except under 20% FC conditions. E. maackii seedlings under all water deficit conditions formed symbiosis well with AM fungi, which significantly ameliorated the drought-mediated negative effect, especially under 40% and 60% FC conditions. Under 40% to 80% FC conditions, AM formation improved seedling growth and photosynthesis by significantly enhancing the biomass accumulation, chlorophyll content and assimilation. Mycorrhizal seedlings showed better tolerance and less sensitivity to a water deficit, reflected in the lower SOD activities of shoots and roots and CAT activity of shoots under 40% and 60% FC conditions. Downregulation of the antioxidant system in mycorrhizal seedlings suggested better maintenance of redox homeostasis and protection of metabolism, including biomass accumulation and assimilation. All the results advocated the positive role of R. intraradices inoculation in E. maackii against a water deficit, especially under 40% FC, which suggested the distinct AM performance in drought tolerance and the potential role of the combination of E. maackii-AM fungi in ecological restoration in arid regions.


Assuntos
Euonymus/metabolismo , Micorrizas/metabolismo , Raízes de Plantas/microbiologia , Clorofila/metabolismo , Clima Desértico , Secas , Euonymus/crescimento & desenvolvimento , Euonymus/microbiologia , Micorrizas/crescimento & desenvolvimento , Micorrizas/patogenicidade , Fotossíntese , Plântula/metabolismo , Plântula/microbiologia , Simbiose/fisiologia , Água/metabolismo
9.
PLoS One ; 15(7): e0234448, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32735565

RESUMO

Soybean root rot is a typical soil-borne disease that severely affects the yield of soybean. Funneliformis mosseae is one of the arbuscular mycorrhizal fungi(AMF) dominant strains in soybean continuous cropping soil. The aim of this study was to providing an experimental basis for the study of the molecular mechanism underlying the alleviation of the obstacles associated with the continuous cropping of soybean by AMF. In this study, F. mosseae was inoculated in soil planted with soybean infected with Fusarium oxysporum. The results showed that the incidence of soybean root rot was significantly reduced after inoculation with F. mosseae. In F. mosseae-treated samples, the significantly upregulated genes encoded transmembrane protein in fungal cell membrane. The significantly downregulated genes encoded some proteins, which took part in composition of essential component of fungal cell wall; hydrolyse cellulose and hemicellulose. The DEGs in each treatment were enriched in antigen processing and presentation, carbon fixation in photosynthetic organisms, glycolysis/gluconeogenesis, the MAPK signalling pathway, protein processing in the endoplasmic reticulum and RNA degradation. Inoculation with F. mosseae could in a variety of ways to promote the growth, development of soybean and improve disease resistance. Such as help fungal build barriers to the disease resistance of host plant and enhance their pathogenicity; damaging the structure of the pathogen; protect plant tissues and so on. This study provides an experimental basis for further research on the molecular mechanism underlying the alleviation of challenges associated with the continuous cropping of soybean by AMF.


Assuntos
Fusarium/genética , Micorrizas/genética , Transcriptoma/genética , Fusarium/metabolismo , Perfilação da Expressão Gênica/métodos , Regulação Fúngica da Expressão Gênica/genética , Micorrizas/patogenicidade , Fotossíntese , Raízes de Plantas/metabolismo , Solo , Microbiologia do Solo , Glycine max/crescimento & desenvolvimento
10.
Nat Commun ; 11(1): 2636, 2020 05 26.
Artigo em Inglês | MEDLINE | ID: mdl-32457288

RESUMO

The mechanisms regulating community composition and local dominance of trees in species-rich forests are poorly resolved, but the importance of interactions with soil microbes is increasingly acknowledged. Here, we show that tree seedlings that interact via root-associated fungal hyphae with soils beneath neighbouring adult trees grow faster and have greater survival than seedlings that are isolated from external fungal mycelia, but these effects are observed for species possessing ectomycorrhizas (ECM) and not arbuscular mycorrhizal (AM) fungi. Moreover, survival of naturally-regenerating AM seedlings over ten years is negatively related to the density of surrounding conspecific plants, while survival of ECM tree seedlings displays positive density dependence over this interval, and AM seedling roots contain greater abundance of pathogenic fungi than roots of ECM seedlings. Our findings show that neighbourhood interactions mediated by beneficial and pathogenic soil fungi regulate plant demography and community structure in hyperdiverse forests.


Assuntos
Micorrizas/fisiologia , Microbiologia do Solo , Árvores/microbiologia , China , Florestas , Fungos/genética , Fungos/patogenicidade , Fungos/fisiologia , Interações entre Hospedeiro e Microrganismos/genética , Interações entre Hospedeiro e Microrganismos/fisiologia , Modelos Biológicos , Biologia Molecular , Micorrizas/genética , Micorrizas/patogenicidade , Plântula/crescimento & desenvolvimento , Plântula/microbiologia , Simbiose , Árvores/crescimento & desenvolvimento
11.
Curr Opin Plant Biol ; 10(4): 393-8, 2007 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-17658291

RESUMO

Arbuscular mycorrhizal symbioses have a significant impact on plant interactions with other organisms. Increased resistance to soil-borne pathogens has been widely described in mycorrhizal plants. By contrast, effects on shoot diseases largely rely on the lifestyle and challenge strategy of the attacker. Among the potential mechanisms involved in the resistance of mycorrhizal systems, the induction of plant defenses is the most controversial. During mycorrhiza formation, modulation of plant defense responses occurs, potentially through cross-talk between salicylic acid and jasmonate dependent signaling pathways. This modulation may impact plant responses to potential enemies by priming the tissues for a more efficient activation of defense mechanisms.


Assuntos
Micorrizas/patogenicidade , Doenças das Plantas/imunologia , Doenças das Plantas/microbiologia , Imunidade Inata , Micorrizas/fisiologia , Fenômenos Fisiológicos Vegetais , Plantas/microbiologia , Transdução de Sinais , Simbiose
12.
PLoS One ; 14(1): e0209093, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30620745

RESUMO

Agroecology aims to maintain ecosystem services by minimizing the impact of agriculture and promoting the use of biological potential. Arbuscular mycorrhizal fungi (AMF) are elements which are key to improving crop productivity and soil quality. It is pertinent to understand how agricultural management in the tropics affects the AMF spatio-temporal community composition, especially in crops of global importance, such as coffee (Coffea arabica L.). Soil and root samples were collected from three localities under three management systems (agroecological, conventional and forest fragment), during the phenological stages of coffee (flowering, grain filling, harvesting). Spores were extracted for morphological identification and molecular community analysis by PCR-DGGE. Dendrograms were prepared and the bands were sequenced and analyzed by bioinformatics. No differences were observed in the richness of morphospecies between management systems, localities and period, but little is known about tropical species. Molecular analysis showed that the agroecological management system was similar to natural forest and with a higher diversity indices than conventional management. Locality and period of sample affect AMF community composition. It is necessary to associate classical taxonomic evaluations with molecular biological techniques because different approaches can lead to different outcomes. This study contributes to the understanding of the impact of agriculture management systems on AMF and provides evidence that agroecology is a management system applicable to sustainable coffee production.


Assuntos
Ecossistema , Micorrizas/genética , Micorrizas/patogenicidade , Agricultura/métodos , Coffea/microbiologia , Biologia Computacional , Produtos Agrícolas/microbiologia , Micorrizas/classificação , Reação em Cadeia da Polimerase , Microbiologia do Solo
13.
Trends Plant Sci ; 23(7): 577-587, 2018 07.
Artigo em Inglês | MEDLINE | ID: mdl-29753631

RESUMO

The widespread symbiotic interaction between plants and arbuscular mycorrhizal (AM) fungi relies on a complex molecular dialog with reciprocal benefits in terms of nutrition, growth, and protection. Approximately 29% of all vascular plant species do not host AM symbiosis, including major crops. Under certain conditions, however, presumed non-host plants can become colonized by AM fungi and develop rudimentary AM (RAM) phenotypes. Here we zoom in on the mustard family (Brassicaceae), which harbors AM hosts, non-hosts, and presumed non-host species such as Arabidopsis thaliana, for which conditional RAM colonization has been described. We advocate that RAM phenotypes and redundant genomic elements of the symbiotic 'toolkit' are missing links that can help to unravel genetic constraints that drive the evolution of symbiotic incompatibility.


Assuntos
Micorrizas/patogenicidade , Arabidopsis/microbiologia , Brassicaceae/microbiologia , Plantas/microbiologia
14.
Chemosphere ; 191: 272-279, 2018 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-29040941

RESUMO

1. CONTEXT: Urban areas are often contaminated with various forms of persistent metal (loid) and emerging contaminants such as antimony (Sb). Thus, in the context of urban agriculture where sustainable practices such as biofertilizers application (arbuscular mycorrhizal fungi, AMF) could improve nutrient transfer from the soil to the vegetables, the effect of AMF on metal (loid) mobility and human bioaccessibility is still poorly known. 2. METHODS: The role of AMF in Sb uptake by lettuce and carrot grown in artificial substrate spiked with different Sb chemical species was investigated. Plants were grown under hydroponic conditions and half of the treatments received a concentrated spore solution to obtain mycorrhized and non-mycorrhized plants. Three weeks before harvest, plants were exposed to 10 mg.L-1 of either Sb2O3 or KSbO-tartrate (KSb). 3. RESULTS: The presence of AMF significantly increased its accumulation in carrots (all organs) with higher accumulation in roots. In lettuce, accumulation appeared to be dependent on the Sb chemical species. Moreover, it was observed for the first time that AMF changed the human bioaccessible fraction of Sb in edible organs. 4. IMPLICATIONS: The present results highlight a possible risk of Sb transfer from soil to edible plants cultivated in soil naturally containing AMF propagules, or when AMF are added as biofertilizers. After validating the influence of soil environment and AMF on Sb behavior in the field, these results should be considered in health risk assessments.


Assuntos
Antimônio/farmacocinética , Micorrizas/patogenicidade , Verduras/metabolismo , Agricultura/métodos , Exposição Ambiental , Jardins , Humanos , Raízes de Plantas/química , Solo/química , Microbiologia do Solo , Poluentes do Solo/análise
15.
Curr Opin Plant Biol ; 45(Pt B): 248-254, 2018 10.
Artigo em Inglês | MEDLINE | ID: mdl-29853281

RESUMO

Improving phosphorus (P)-use efficiency in legumes is a worldwide challenge in the face of an increasing world population, dwindling global rock phosphate reserves, the relatively high P demand of legumes and global change. This review focuses on P acquisition of crop legumes in response to climate change. We advocate further studies on: firstly, the response of carboxylate exudation, mycorrhizas and root morphology to climate change and their role in P acquisition as dependent on edaphic factors; secondly, developing intercropping systems with a combination of a legume and another crop species to enhance P acquisition; and thirdly, the impact of the interactions of the major climate change factors on P acquisition in the field.


Assuntos
Fabaceae/metabolismo , Nitrogênio/metabolismo , Fósforo/metabolismo , Mudança Climática , Produtos Agrícolas/metabolismo , Micorrizas/patogenicidade , Raízes de Plantas/microbiologia
16.
Ecol Lett ; 9(5): 501-15, 2006 May.
Artigo em Inglês | MEDLINE | ID: mdl-16643296

RESUMO

Advances in ecology during the past decade have led to a much more detailed understanding of the potential negative consequences of species' introductions. Moreover, recent studies of mycorrhizal symbionts have led to an increased knowledge of the potential utility of fungal inoculations in agricultural, horticultural and ecological management. The intentional movement of mycorrhizal fungal species is growing, but the concomitant potential for negative ecological consequences of invasions by mycorrhizal fungi is poorly understood. We assess the degree to which introductions of mycorrhizal fungi may lead to unintended negative, and potentially costly, consequences. Our purpose is to make recommendations regarding appropriate management guidelines and highlight top priority research needs. Given the difficulty in discerning invasive species problems associated with mycorrhizal inoculations, we recommend the following. First, careful assessment documenting the need for inoculation, and the likelihood of success, should be conducted prior to inoculation because inoculations are not universally beneficial. Second, invasive species problems are costly and often impossible to control by the time they are recognized. We recommend using local inoculum sources whenever possible. Third, non-sterile cultures of inoculum can result in the movement of saprobes and pathogens as well as mutualists. We recommend using material that has been produced through sterile culture when local inoculum is not available. Finally, life-history characteristics of inoculated fungi may provide general guidelines relative to the likelihood of establishment and spread. We recommend that, when using non-local fungi, managers choose fungal taxa that carry life-history traits that may minimize the likelihood of deleterious invasive species problems. Additional research is needed on the potential of mycorrhizal fungi to spread to non-target areas and cause ecological damage.


Assuntos
Agricultura , Guias como Assunto , Micorrizas/crescimento & desenvolvimento , Micorrizas/patogenicidade , Classificação , Ecologia , Dinâmica Populacional , Pesquisa/tendências , Medição de Risco , Simbiose
17.
PLoS One ; 10(6): e0128841, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26102587

RESUMO

We investigated the impact of drought and arbuscular mycorrhizal (AM) fungi on the morphological structure and physiological function of shoots and roots of male and female seedlings of the dioecious plant Populus cathayana Rehder. Pot-grown seedlings were subjected to well watered or water-limiting conditions (drought) and were grown in soil that was either inoculated or not inoculated with the AM fungus Rhizophagus intraradices. No significant differences were found in the infection rates between the two sexes. Drought decreased root and shoot growth, biomass and root morphological characteristics, whereas superoxide radical (O2-) and hydrogen peroxide content, peroxidase (POD) activity, malondialdehyde (MDA) concentration and proline content were significantly enhanced in both sexes. Male plants that formed an AM fungal symbiosis showed a significant increase in shoot and root morphological growth, increased proline content of leaves and roots, and increased POD activity in roots under both watering regimes; however, MDA concentration in the roots decreased. By contrast, AM fungi either had no effect or a slight negative effect on the shoot and root growth of female plants, with lower root biomass, total biomass and root/shoot ration under drought. In females, MDA concentration increased in leaves and roots under both watering regimes, and the proline content and POD activity of roots increased under drought conditions; however, POD activity significantly decreased under well-watered conditions. These findings suggest that AM fungi enhanced the tolerance of male plants to drought by improving shoot and root growth, biomass and the antioxidant system. Further investigation is needed to unravel the complex effects of AM fungi on the growth and antioxidant system of female plants.


Assuntos
Secas , Micorrizas/patogenicidade , Populus/fisiologia , Estresse Fisiológico , Biomassa , Malondialdeído/metabolismo , Peroxidase/metabolismo , Raízes de Plantas/fisiologia , Brotos de Planta/fisiologia , Populus/microbiologia
18.
Nat Genet ; 47(4): 410-5, 2015 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-25706625

RESUMO

To elucidate the genetic bases of mycorrhizal lifestyle evolution, we sequenced new fungal genomes, including 13 ectomycorrhizal (ECM), orchid (ORM) and ericoid (ERM) species, and five saprotrophs, which we analyzed along with other fungal genomes. Ectomycorrhizal fungi have a reduced complement of genes encoding plant cell wall-degrading enzymes (PCWDEs), as compared to their ancestral wood decayers. Nevertheless, they have retained a unique array of PCWDEs, thus suggesting that they possess diverse abilities to decompose lignocellulose. Similar functional categories of nonorthologous genes are induced in symbiosis. Of induced genes, 7-38% are orphan genes, including genes that encode secreted effector-like proteins. Convergent evolution of the mycorrhizal habit in fungi occurred via the repeated evolution of a 'symbiosis toolkit', with reduced numbers of PCWDEs and lineage-specific suites of mycorrhiza-induced genes.


Assuntos
Genoma Fúngico/genética , Micorrizas/genética , Seleção Genética , Simbiose/genética , Virulência/genética , Sequência de Bases , Evolução Molecular , Deleção de Genes , Regulação Fúngica da Expressão Gênica/genética , Dados de Sequência Molecular , Micorrizas/patogenicidade , Filogenia , Doenças das Plantas/genética , Doenças das Plantas/microbiologia , Raízes de Plantas/microbiologia
19.
PLoS One ; 9(5): e96782, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-24804793

RESUMO

Maize (Zea mays) is the most widely grown crop species in the world and a classical model organism for plant research. The completion of a high-quality reference genome sequence and the advent of high-throughput sequencing have greatly empowered re-sequencing studies in maize. In this study, plants of maize inbred line B73 descended from two different sets of seed material grown for several generations either in the field or in the greenhouse were found to show a different growth phenotype and ionome under phosphate starvation conditions and moreover a different responsiveness towards mycorrhizal fungi of the species Glomus intraradices (syn: Rhizophagus irregularis). Whole genome re-sequencing of individuals from both sets and comparison to the B73 reference sequence revealed three cryptic introgressions on chromosomes 1, 5 and 10 in the line grown in the greenhouse summing up to a total of 5,257 single-nucleotide polymorphisms (SNPs). Transcriptome sequencing of three individuals from each set lent further support to the location of the introgression intervals and confirmed them to be fixed in all sequenced individuals. Moreover, we identified >120 genes differentially expressed between the two B73 lines. We thus have found a nearly-isogenic line (NIL) of maize inbred line B73 that is characterized by an altered growth phenotype under phosphate starvation conditions and an improved responsiveness towards symbiosis with mycorrhizal fungi. Through next-generation sequencing of the genomes and transcriptomes we were able to delineate exact introgression intervals. Putative de novo mutations appeared approximately uniformly distributed along the ten maize chromosomes mainly representing G:C -> A:T transitions. The plant material described in this study will be a valuable tool both for functional studies of genes differentially expressed in both B73 lines and for research on growth behavior especially in response to symbiosis between maize and mycorrhizal fungi.


Assuntos
Cromossomos de Plantas/genética , Genoma de Planta , Sequenciamento de Nucleotídeos em Larga Escala , Zea mays/genética , Mapeamento Cromossômico , Regulação da Expressão Gênica de Plantas , Genômica , Repetições de Microssatélites/genética , Micorrizas/genética , Micorrizas/patogenicidade , Fenótipo , Polimorfismo de Nucleotídeo Único , Zea mays/microbiologia
20.
J Environ Manage ; 87(3): 364-72, 2008 May.
Artigo em Inglês | MEDLINE | ID: mdl-17597286

RESUMO

We compared the efficacy of matrix based fertilizers (MBFs) formulated to reduce NO3-, NH4+, and total phosphorus (TP) leaching, with Osmocoate 14-14-14, a conventional commercial slow release fertilizer (SRF) and an unamended control in three different soil textures in a greenhouse column study. The MBFs covered a range of inorganic N and P in compounds that are relatively loosely bound (MBF 1) to more moderately bound (MBF 2) and more tightly bound compounds (MBF 3) mixed with Al(SO4)3H2O and/or Fe2(SO4)3 and with high ionic exchange compounds starch, chitosan and lignin. When N and P are released, the chemicals containing these nutrients in the MBF bind N and P to a Al(SO4)3H2O and/or Fe2(SO4)3 starch-chitosan-lignin matrix. One milligram (8000 spores) of Glomus intradices was added to all formulations to enhance nutrient uptake. In all three soil textures the SRF leachate contained a higher amount of NH4+, NO3- and TP than leachate from all other fertilizers. In all three soils there were no consistent differences in the amount of NH4+, NO3- and TP in the MBF leachates compared to the control leachate. Plants growing in soils receiving SRF had greater shoot, root and total biomass than all MBFs regardless of Al(SO4)3H2O or Fe2(SO4)3 additions. Arbuscular mycorrhizal infection in plant roots did not consistently differ among plants growing in soil receiving SRF, MBFs and control treatments. Although the MBFs resulted in less plant growth in this experiment they may be applied to soils growing plants in areas that are at high risk for nutrient leaching to surface waters.


Assuntos
Produtos Agrícolas/crescimento & desenvolvimento , Monitoramento Ambiental , Fertilizantes , Nitrogênio/análise , Fósforo/análise , Eliminação de Resíduos/métodos , Poluentes do Solo/análise , Compostos de Alúmen/química , Amônia/química , Quitosana/química , Produtos Agrícolas/química , Compostos de Ferro/química , Lignina/química , Micorrizas/crescimento & desenvolvimento , Micorrizas/patogenicidade , Nitratos/química , Nitrogênio/química , Fósforo/química , Raízes de Plantas/parasitologia , Poluentes do Solo/química , Amido/química
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