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Arbuscular mycorrhizal and dark septate endophytic fungi in roots of weeds in Brazil. A-Arbuscule (ar) in Amaranthus retroflexus; B-Vesicle (vs) and hyphae (hy) in Sinapis arvensis; C-Leonurus sibiricus; D-Leonotis nepetaefolia; E-Spores (sp.) in Panicum maximum; F-Hyphal coils (hc) in Sorghum arundinaceum; G-Auxiliary vesicles (av) in Eupatorium urticaefolium; H-Microesclerotia (me) in Bidens pilosa and I-Conyza bonariensis. 

Arbuscular mycorrhizal and dark septate endophytic fungi in roots of weeds in Brazil. A-Arbuscule (ar) in Amaranthus retroflexus; B-Vesicle (vs) and hyphae (hy) in Sinapis arvensis; C-Leonurus sibiricus; D-Leonotis nepetaefolia; E-Spores (sp.) in Panicum maximum; F-Hyphal coils (hc) in Sorghum arundinaceum; G-Auxiliary vesicles (av) in Eupatorium urticaefolium; H-Microesclerotia (me) in Bidens pilosa and I-Conyza bonariensis. 

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Article
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Studies on the ecology of the organisms involved in the production process are necessary for the development of sustainable agriculture, and sustainability is currently closely linked to the profitability of production. The objective of this study was to verify the occurrence of arbuscular mycorrhizal fungi in weeds infesting Brazilian crops and to...

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... Sinapis arvensis L., a species of the Brassicaceae family, vesicles, hyphae, arbuscules and Arum-type mycorrhizal colonization were observed. The presence of DSEs was observed in 33% of the analyzed plant species, belonging to the following families: Amaranthaceae, Asteraceae, Convolvulaceae, Labiatae, Malvaceae, Solanaceae and Verbenaceae (Figure 1 and Table 1). According to , the Arum arbuscular mycorrhizae are found in most angiosperms, whereas the Paris type is prevalent in gymnosperms. ...
Context 2
... and Guan (2007) reported a close relationship between DSEs and AMFs, suggesting competition or even cooperation between them. Confirming the association of the studied weeds with EDS, the biggest difficulty in the presentation of our results can be explained by the presence of certain components in the cell walls of those fungi that hinder their visualization in some plant species (BARROW; AALTONEN, 2001). ...

Citations

... Also, Microbial genomics is suddenly advancing, including substantial collections concerning isolated rhizosphere strains and mutant libraries award current insights among the metabolic mechanisms concerning root colonization (Jacoby and Kopriva, 2018). Rhizospheric microbiomes affect plant life thru a range concerning mechanisms consisting of production of siderophores, phytohormones (as gibberlins and acid -3-indole acetic), phosphates solubilization, bacteriocins, lytic enzymes (proteases, lypases, Chitinase, B-glucanase), antibiotics and volatile compounds (like Hydrogen cyanide) (Khamna et al., 2009;Gutiérrez-Mañero et al., 2001Majeed et al., 2015Santos et al., 2013;Subramanian and Smith, 2015;Verma et al., 2016;Mazurier et al., 2009;Rijavec and Lapanje, 2016). In return, plant existence deposit theirs photosynthetically regular carbon within theirs direct surroundings, that is, spermosphere, phyllosphere, rhizosphere, and mycorrhizosphere, thereby maintenance the microbial community and influencing their composition and activities (Mendes et al., 2013). ...
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The extinction of species and reducing of biodiversity is a global problem increasingly threatening food chain, balance, and life on earth. This problem also concerns underground life in the soil and more particularly the microorganisms in the plant rhizosphere. The rhizospheric region is undoubtedly among the most populated natural microenvironment in terms of microorganisms. This is due to the particular composition of these areas and the specific integrations between soil, microorganisms, and plants. Rhizospheric microbiomes are endowed with interactive metabolism and function. On the other hand, many researches are being focused on the impact of rhizospheric microbial biodiversity on plant health. The study of the biodiversity of rhizospheric soil microorganisms is currently developing many applications including agricultural, therapeutical, environmental, human and animal health, and industrial.
... Bidens pilosa grown in monoculture in the soil with microbiota reconstitution showed a decrease in P content, which reinforces the hypothesis of negative interactions with the soil microbiota. Amaranthus retroflexus and B. pilosa grown individually increased soil phosphate solubilization (Santos et al. 2013). Bidens pilosa shows a high ability to take up and accumulate phosphorus (Santos and Cury 2011). ...
Article
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Aims Despite the importance of the soil microbiota to plant growth, the role of soil microorganisms in crop-weed competition remains largely unexplored. Here, we investigated the influence of soil microbial communities and weed species on the outcome of maize-weed interactions. Methods The relationships between soil bacterial and fungal communities and plant growth under different cultivation managements (plant monocultures and coexistence between Bidens pilosa L. and Amaranthus viridis L. and maize) and soil conditions (sterilized soil and sterilized soil with microbiota reconstitution) were studied. Plant dry matter and soil microbial diversity were analyzed after 43 days of cultivation. Results Maize grew better in the presence of the weeds, indicating the occurrence of facilitation under the cultivation conditions tested. Plant cultivation led to different soil microbial communities after soil sterilization and microbiota reconstitution. In sterilized soil, the colonizing microbiota led to higher maize growth in the presence of B. pilosa. The opposite was observed in the soils with microbiota reconstitution, where maize grew better with A. viridis. Conclusions Soil microbial communities are involved in the facilitation of maize growth by B. pilosa and A. viridis. Facilitation intensity depends on the weed species and the way coexisting plants shape the soil microbial communities.
... The weed rhizosphere is a natural habitat for many microorganisms, including PSM [81]. Various weed species have demonstrated different potentials for P solubilisation in the rhizosphere [82]. Weed-microbe interactions usually promote weed competitiveness against crop plants [81]. ...
Article
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Facing phosphate rock scarcity, growing food requirements and pollution problems with phosphorus (P)-containing waste, re-using P as fertiliser is becoming a real need. Innovative fertilisers from sewage sludge ash, animal bones and blood, activated by phosphorus solubilising microorganisms (PSM), were tested in field experiments with winter or spring wheat and compared with commercial fertilisers (superphosphate, phosphorite). Three levels of P doses were established (17.6, 26.4 and 35.2 kg/ha). This paper discusses the fertilisers’ impact on total soil P content and on the P content and P accumulation in wheat grain and straw, weeds and post-harvest residues. Recycled fertilisers maintained soil P stocks and supplied plants with P in the same way as traditional fertilisers, and ensured a comparable P pool in the post-harvest residues to traditional fertilisers. They also did not favour weeds during competitive crop-weed interactions. The PSM included in waste-fertilisers did not exert an evident effect on the soil P content or on the P content and P accumulation in plant biomass. The findings show the potential of recycled fertilisers to act as a substitute to fertilisers from primary sources. Further field research is needed to settle the question of the reasonability of PSM inclusion into fertilisers.
... The competitive capacity of a given species reflects its ability to acquire and/or make the best use of limiting resources and/or its ability to cope with low levels of resources or reduce their availability to its competitors (Gioria and Osborne, 2014). Additionally, the interactions with the soil microbiota may be important for competitive relations (Kulmatiski et al., 2006;Santos et al., 2013;Massenssini et al., 2014a;Fialho et al., 2016). Some competition models among plants seek to explain plant diversity by identifying the circumstances under which competitors can coexist (Gurevitch et al., 2002). ...
... Plant-soil microorganism associations may promote increased plant growth, pathogen resistance, and tolerance to environmental stresses (Rodriguez et al., 2009). Weeds are able to associate, for instance, with arbuscular mycorrhizal fungi (AMF) and dark septate endophytes (Santos et al., 2013;Massenssini et al., 2014b). Plants that establish these types of association can gain a competitive advantage over others (Massenssini et al., 2014a). ...
Article
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The competition between weeds and crops is one of the main factors responsible for productivity losses in agricultural fields. This review aimed at presenting and discussing how the interactions between weeds and microorganisms can affect the competitive capacity of weeds and soil physicochemical properties. We also discuss how changes in the elemental stoichiometry of weeds can reflect their competitive and adaptative capacity. Although weeds are more dependent on associations with soil microorganisms than crops for growth, few studies have assessed the contribution of the soil microbiota to their competitive success in agroecosystems. When in competition, plants can change the elemental stoichiometry of their tissues in environments with varied nutrient availability. Elemental stoichiometry of plants has been particularly well studied using ecological approaches on the dynamics of weed populations in natural ecosystems, being a promising tool for understanding weed capacity to adapt to different agricultural managements. Plants control the biogeochemical cycles of carbon (C) and nitrogen (N) in the rhizosphere through a phenomenon known as the rhizosphere priming effect (RPE). Although this review has found some information in the literature that provides strong indications that the coexistence of weeds and crops may increase soil organic matter mineralization, we are not aware of studies investigating the effects of competition among these plants on RPE.
... were detected in 11 and 10 plant species, respectively. DSEs can occur in many plants from various taxa, including species of medicinal plants Muthukumar et al., 2006;Dos Santos et al., 2013;Zubek et al., 2012a), and may have a negative, neutral, or positive influence on host performance and host tissue nutrient concentrations (Andrade-Linares et al., 2011;Jumpponen, 2001;Newsham, 2011;Zhu et al., 2015). In this study, AMF coexisted with DSEs in 10 plant species. ...
... Enquanto que, no cultivo do UFLA351 entre primavera e verão houve a produção de 3,6% de arbúsculos em SSSS e 0,0% em SSBB (Tabela 1). Santos et al. (2013) [24] também observaram a ausência de arbúsculos na colonização micorrízica em Sorgum arundinaceu por FMAs nativos, mas não foi mencionada a estação do ano de cultivo. ...
... Enquanto que, no cultivo do UFLA351 entre primavera e verão houve a produção de 3,6% de arbúsculos em SSSS e 0,0% em SSBB (Tabela 1). Santos et al. (2013) [24] também observaram a ausência de arbúsculos na colonização micorrízica em Sorgum arundinaceu por FMAs nativos, mas não foi mencionada a estação do ano de cultivo. ...
Article
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Os fungos micorrízicos arbusculares (FMA) são micro-organismos endofíticos capazes de promover o crescimento de plantas de interesse econômico a depender da interação microbiana com a planta, mas poucos são os trabalhos relacionados com a produção de inoculantes. O objetivo deste trabalho foi avaliar a produção de propágulos micorrízicos em cultivo sucessivo e/ou rotacionado em sorgo e em braquiária, sem o uso de estimuladores químicos. O delineamento experimental utilizado foi inteiramente ao acaso em parcelas subdivididas, cujas parcelas foram os tratamentos (três isolados de FMAs: UFLA351 - Rhizoglomus clarum, UFLA372 - Claroideoglomus etunicatum e UFLA401 - Acaulospora morrowiae) e as subparcelas os cultivos sucessivos em sorgo/braquiária e rotacional em braquiária, com quatro repetições. O cultivo sucessivo em sorgo ou em braquiária estimula a produção de esporos micorrízicos de R. clarum, C. etunicatum e A. morrowiae. A rotação de cultura sorgo-braquiária não garante incremento na esporulação, a depender do isolado micorrízico. A produção de vesículas e de arbúsculos depende da interação do fungo com a espécie de planta e não apenas da estação do ano. As vesículas podem aumentar a produção de esporos micorrízicos, a depender da interação FMA x planta e da época do ano.
... The population of highly metabolically active PSM's is more concentrated in the rhizospheric zone than non-rhizospheric zones (Vazquez et al. 2000). Bacteria, fungi, actinomycetes and even algae are some of the microorganisms involved in the solubilisation of insoluble phosphorus Wani et al. 2007;Chun-qiao et al. 2009;Santos et al. 2013;Sharma et al. 2013). Phosphate-solubilising microorganisms are omnipresent in rhizosphere, but their numbers vary from soil to soil. ...
Chapter
Phosphorous (P) is an essential macronutrient required for plant growth and development and comes next to Nitrogen (N). The quantity of phosphorous present in soil is huge but is unavailable to the plants due to its fixation with the other elements in soil necessitating the application of chemical phosphatic fertilisers to the soil for plant growth and development. Injudicious use of phosphatic fertiliser though has resulted in enhancement of crop yield but had left an adverse effect on the ecosystem. In the present scenario, to manage the nutritional security and the environment, sustainable agriculture holds the key which uses phosphate solubilising microorganisms (PSM’s) as an important alternative, which can solubilise soil phosphate and supply it to the plants in a more eco-friendly and sustainable manner. PSM’s are diversified in nature and are abundant in normal to stressed environments. They include bacteria, fungi, algae, actinomycetes and mycorrhizae which solubilises soil phosphate by different mechanisms including production of organic acids and enzymes, thus making phosphorous available to the plants for their growth and development. Molecular biotechnology brings out a better technique that could help researchers to understand the mechanisms responsible for solubilisation and also improve the performance of PSM’s by manipulating the genes responsible for phosphorous solubilisation for the betterment of crops and also in managing a sustainable environment system.
... AM fungal colonization was characterized by the formation of a swollen appressorium on the root surface. The fungal hyphae originating from the appressorium spread inter and/or intracellularly as linear hyphae or hyphal coils to form various types of AM morphologies in the root cortex ( Fig. 1A (2010), 6 Hemavani & Thippeswamy (2013), 7 Khade & Rodrigues (2002), 8 Kulkarni et al. (1997), 9 Kumar & Muthukumar (2014), 10 Li et al. (2004), 11 Louis (1990), 12 Muthukumar & Prabha (2013), 13 Muthukumar & Udaiyan (2000a), 14 Muthukumar & Udaiyan (2000b), 15 Muthukumar et al. (1996), 16 Muthukumar et al. (2003), 17 Muthukumar et al. (2004), 18 Muthukumar et al. (2006), 19 Muthuraja et al. (2014), 20 Peyronel (1924), 21 Ragupathy & Mahadevan (1993), 22 Raja et al. (1995), 23 Santos et al. (2013), 24 Songachan & Kayang (2011), 25 Sun et al. (2013), 26 Tahira et al. (2012), 27 Thapa et al. (2015), 28 Uma et al. (2010), 29 Wang & Jiang (2015), 30 Zhang et al. (2011), 31 Zhao (2000), 32 Zhao et al. (2006) *New records The majority of the plant species investigated (81%) had DSE fungal colonization characterized by regularly septate hyaline/melanized hyphae bearing moniliform cells or microsclerotia ( Fig. 1M-P The average percentage of root length with different AM fungal structures (except %RLA) and %RLTC was maximum in trees and minimum in herbs ( Fig. 2A). Among plants of different lifecycles, average %RLH, %RLA, %RLV was higher in annuals than in perennials (Fig. 2B). ...
Article
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Plant roots in natural ecosystems are colonized by a diverse group of fungi among which the most common and widespread are arbuscular mycorrhizal (AM) and dark septate endophyte (DSE) fungi. Though AM and DSE fungal associations are well reported for terricolous plant species, they are rather poorly known for lithophytic plant species. In this study, we examined AM and DSE fungal association in 72 non-orchidaceous vascular plant species growing as lithophytes in Siruvani Hills, Western Ghats of Tamilnadu, India. Sixty-nine plant species had AM and 58 species had DSE fungal associations. To our knowledge, we report AM fungal association in 42 and DSE fungal association in 53 plant species for the fi rst time. Th ere were signifi cant diff erences in total root length colonization and root length colonized by diff erent AM and DSE fungal structures among plant species. In contrast, the diff erences in AM and DSE fungal colonization among plants in various life-forms and lifecycles were not signifi cant. AM morphology reported for the fi rst time in 56 plant species was dominated by intermediate type AM morphology. A signifi cant negative relationship existed between total root length colonized by AM and DSE fungi. These results clearly suggest that AM and DSE fungal associations are widespread in lithophytes.
... Arbuscular mycorrhizal fungi are widespread in nature, and most plants are benefited from this association. In studies conducted by Santos et al. (2013) all 36 weed species, from 14 families presented mycorrhizal fungi colonization and, morphological types of arbuscular and coiled hyphae occurred in most species. The competitive advantage of weeds over cultures can be in part, result of the interaction of these plants with several groups of soil microorganisms (Reinhart & Callaway, 2006). ...
... In this case, increase of colonization occurred by mycorrhizal fungi in soybean roots when in competition. Mycorrhized plants demonstrably have higher access to soil nutrients, mainly P (Santos et al., 2013; Brito et al., 2013). In case of soil elements limitation, it is probable that more associations between plants and mycorrhizal fungi are established, attempting to increase the volume of root exploration and to have more access to nutrients. ...
Article
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The purpose of this study was to evaluate the effects of mycorrhizal association on the interference of Bidens pilosa, Urochloa decumbens and Eleusine indica on soybean culture in two conditions: a) plants competing without contact with roots of another species; b) with contact between roots. At 60 days after planting, growth, nutrient accumulation and mycorrhizal colonization of soybean and weeds were evaluated. The contact between roots of soybean plant and weed species increased the negative interference effects for both species, with less growth and nutrient accumulation. With the individualization of roots, higher competition occurred for soil resources up to 60 days of coexistence between species. In competition with soybean, Bidens pilosa and Urochloa decumbens stood out in accumulation of most nutrients without differing from when cultivated in monocultivation. The increase of the soybean mycorrhizal colonization was 53, 40 and 33% when in competition with Urochloa decumbens, Eleusine indica and Bidens pilosa species, respectively. A positive interaction occurred for soybean mycorrhizal colonization and competing plants irrespective of weed species or root contact. © 2016, Eduem - Editora da Universidade Estadual de Maringa. All rights reserved.
... Recent studies have demonstrated that weeds are able to associate with arbuscular mycorrhizal fungi (Santos et al., 2013; and that the effects of this association may vary from positive to negative, depending on the environmental conditions . Furthermore, the presence of a competing plant may alter weed root colonization by AMF. ...
Article
Full-text available
The competition between weeds and crops is a topic of great interest, since this interaction can cause heavy losses in agriculture. Despite the existence of some studies on this subject, little is known about the importance of soil microorganisms in the modulation of weed-crop interactions. Plants compete for water and nutrients in the soil and the ability of a given species to use the available resources may be directly affected by the presence of some microbial groups commonly found in the soil. Arbuscular mycorrhizal fungi (AMF) are able to associate with plant roots and affect the ability of different species to absorb water and nutrients from the soil, promoting changes in plant growth. Other groups may promote positive or negative changes in plant growth, depending on the identity of the microbial and plant partners involved in the different interactions, changing the competitive ability of a given species. Recent studies have shown that weeds are able to associate with mycorrhizal fungi in agricultural environments, and root colonization by these fungi is affected by the presence of other weeds or crops species. In addition, weeds tend to have positive interactions with soil microorganisms while cultures may have neutral or negative interactions. Competition between weeds and crops promotes changes in the soil microbial community, which becomes different from that observed in monocultures, thus affecting the competitive ability of plants. When grown in competition, weeds and crops have different behaviors related to soil microorganisms, and the weeds seem to show greater dependence on associations with members of the soil microbiota to increase growth. These data demonstrate the importance of soil microorganisms in the modulation of the interactions between weeds and crops in agricultural environments. New perspectives and hypotheses are presented to guide future research in this area.