Agronomic Management of Indigenous Mycorrhizas

Many of the advantages conferred to plants by arbuscular mycorrhiza (AM) are associated to the ability of AM plants to explore a greater volume of soil through the extraradical mycelium. Sieverding (1991) estimates that for each centimetre of colonized root there is an increase of 15 cm3 on the volume of soil explored, this value can increase to 200 cm3 depending on the circumstances. Due to the enhancement of the volume of soil explored and the ability of the extraradical mycelium to absorb and translocate nutrients to the plant, one of the most obvious and important advantages resulting from mycorrhization is the uptake of nutrients. Among of which the ones that have immobilized forms in soil, such as P, assume particular significance. Besides this, many other benefits are recognized for AM plants (Gupta et al, 2000): water stress alleviation (Augé, 2004; Cho et al, 2006), protection from root pathogens (Graham, 2001), tolerance to toxic heavy metals and phytoremediation (Audet and Charest, 2006; Göhre and Paszkowski, 2006), tolerance to adverse conditions such as very high or low temperature, high salinity (Sannazzaro et al, 2006), high or low pH (Yano and Takaki, 2005) or better performance during transplantation shock (Subhan et al, 1998). The extraradical hyphae also stabilize soil aggregates by both enmeshing soil particles (Miller e Jastrow, 1992) and producing a glycoprotein, golmalin, which may act as a glue-like substance to adhere soil particles together (Wright and Upadhyaya, 1998). Despite the ubiquous distribution of mycorrhizal fungi (Smith and Read, 2000) and only a relative specificity between host plants and fungal isolates (McGonigle and Fitter, 1990), the obligate nature of the symbiosis implies the establishment of a plant propagation system, either under greenhouse conditions or in vitro laboratory propagation. These techniques result in high inoculum production costs, which still remains a serious problem since they are not competitive with production costs of phosphorus fertilizer. Even if farmers understand the significance of sustainable agricultural systems, the reduction of phosphorus inputs by using AM fungal inocula alone cannot be justified except, perhaps, in the case of high value crops (Saioto and Marumoto, 2002). Nurseries, high income horticulture farmers and no-agricultural application such as rehabilitation of degraded or devegetated landscapes are examples of areas where the use of commercial inoculum is current. Another serious problem is quality of commercial available products concerning guarantee of phatogene free content, storage conditions, most effective application methods and what types to use. Besides the information provided by suppliers about its inoculum can be deceiving, as from the usually referred total counts, only a fraction may be effective for a particular plant or in specific soil conditions. Gianinazzi and Vosátka (2004) assume that progress should be made towards registration procedures that stimulate the development of the mycorrhizal industry. Some on-farm inoculum production and application methods have been studied, allowing farmers to produce locally adapted isolates and generate a taxonomically diverse inoculum (Mohandas et al, 2004; Douds et al, 2005). However the inocula produced this way are not readily processed for mechanical application to the fields, being an obstacle to the utilization in large scale agriculture, especially row crops, moreover it would represent an additional mechanical operation with the corresponding economic and soil compaction costs. It is well recognized that inoculation of AM fungi has a potential significance in not only sustainable crop production, but also environmental conservation. However, the status quo of inoculation is far from practical technology that can be widely used in the field. Together a further basic understanding of the biology and diversity of AM fungi is needed (Abbott at al, 1995; Saito and Marumoto, 2002). Advances in ecology during the past decade have led to a much more detailed understanding of the potential negative consequences of species introductions and the potential for negative ecological consequences of invasions by mycorrhizal fungi is poorly understood. Schwartz et al, (2006) recommend that a careful assessment documenting the need for inoculation, and the likelihood of success, should be conducted prior to inoculation because inoculations are not universally beneficial. Agricultural practices such as crop rotation, tillage, weed control and fertilizer apllication all produce changes in the chemical, physical and biological soil variables and affect the ecological niches available for occupancy by the soil biota, influencing in different ways the symbiosis performance and consequently the inoculum development, shaping changes and upset balance of native populations. The molecular biology tools developed in the latest years have been very important for our perception of these changes, ensuing awareness of management choice implications in AM development. In this context, for extensive farming systems and regarding environmental and economic costs, the identification of agronomic management practices that allow controlled manipulation of the fungal community and capitalization of AM mutualistic effect making use of local inoculum, seem to be a wise option for mycorrhiza promotion and development of sustainable crop production

Characterization of Mycosphaerellaceae species associated with citrus greasy spot in Panama and Spain

[EN] Greasy spot of citrus, caused by Zasmidium citri-griseum (= Mycosphaerella citri), is widely distributed in the Caribbean Basin, inducing leaf spots, premature defoliation, and yield loss. Greasy spot-like symptoms were frequently observed in humid citrus-growing regions in Panama as well as in semi-arid areas in Spain, but disease aetiology was unknown. Citrus-growing areas in Panama and Spain were surveyed and isolates of Mycosphaerellaceae were obtained from citrus greasy spot lesions. A selection of isolates from Panama (n = 22) and Spain (n = 16) was assembled based on their geographical origin, citrus species, and affected tissue. The isolates were characterized based on multi-locus DNA (ITS and EF-1 alpha) sequence analyses, morphology, growth at different temperatures, and independent pathogenicity tests on the citrus species most affected in each country. Reference isolates and sequences were also included in the analysis. Isolates from Panama were identified as Z. citri-griseum complex, and others from Spain attributed to Amycosphaerella africana. Isolates of the Z. citri-griseum complex had a significantly higher optimal growth temperature (26.8 degrees C) than those of A. africana (19.3 degrees C), which corresponded well with their actual biogeographical range. The isolates of the Z. citri-griseum complex from Panama induced typical greasy spot symptoms in 'Valencia' sweet orange plants and the inoculated fungi were reisolated. No symptoms were observed in plants of the 'Ortanique' tangor inoculated with A. africana. These results demonstrate the presence of citrus greasy spot, caused by Z. citri-griseum complex, in Panama whereas A. africana was associated with greasy spot-like symptoms in Spain.Research was partially funded by 'Programa de Formacion de los INIA Iberoamerica' and INIA RTA2010-00105-00-00-FEDER to Vidal Aguilera Cogley.. We thank J. Martinez-Minaya (UV) for assistance with INLAAguilera-Cogley, VA.; Berbegal Martinez, M.; Català, S.; Collison Brentu, F.; Armengol Fortí, J.; Vicent Civera, A. (2017). Characterization of Mycosphaerellaceae species associated with citrus greasy spot in Panama and Spain. PLoS ONE. 12(12):1-19. https://doi.org/10.1371/journal.pone.0189585S1191212Crous, P. W., Summerell, B. A., Carnegie, A. J., Wingfield, M. J., Hunter, G. C., Burgess, T. I., … Groenewald, J. Z. (2009). Unravelling Mycosphaerella: do you believe in genera? Persoonia - Molecular Phylogeny and Evolution of Fungi, 23(1), 99-118. doi:10.3767/003158509x479487Mondal, S. N., & Timmer, L. W. (2006). Greasy Spot, a Serious Endemic Problem for Citrus Production in the Caribbean Basin. Plant Disease, 90(5), 532-538. doi:10.1094/pd-90-0532Whiteside, J. O. (1970). Etiology and Epidemiology of Citrus Greasy Spot. Phytopathology, 60(10), 1409. doi:10.1094/phyto-60-1409Huang, F., Groenewald, J. Z., Zhu, L., Crous, P. W., & Li, H. (2015). Cercosporoid diseases of Citrus. Mycologia, 107(6), 1151-1171. doi:10.3852/15-059Wellings, C. R. (1981). Pathogenicity of fungi associated with citrus greasy spot in New South Wales. Transactions of the British Mycological Society, 76(3), 495-499. doi:10.1016/s0007-1536(81)80080-0Marco, G. M. (1986). A Disease Similar to Greasy Spot but of Unknown Etiology on Citrus Leaves in Argentina. Plant Disease, 70(11), 1074a. doi:10.1094/pd-70-1074aVidal Aguilera-Cogley, & Antonio Vicent. (2015). FUNGAL DISEASES OF CITRUS IN PANAMA. Acta Horticulturae, (1065), 947-952. doi:10.17660/actahortic.2015.1065.118Honger J. Aetiology and importance of foliage diseases affecting citrus in the nursery at the Agricultural Research Station (ARS). PhD Thesis. Accra: University of Ghana; 2004.Vicent A, Álvarez A, León M, García-Jiménez J. Mycosphaerella sp. asociada a manchas foliares de cítricos en España. In: Proceedings of the 13th Congress of the Spanish Phytopathological Society. 2006; Murcia; Spain.Abdelfattah, A., Cacciola, S. O., Mosca, S., Zappia, R., & Schena, L. (2016). Analysis of the Fungal Diversity in Citrus Leaves with Greasy Spot Disease Symptoms. Microbial Ecology, 73(3), 739-749. doi:10.1007/s00248-016-0874-xQuaedvlieg, W., Binder, M., Groenewald, J. Z., Summerell, B. A., Carnegie, A. J., Burgess, T. I., & Crous, P. W. (2014). Introducing the Consolidated Species Concept to resolve species in the Teratosphaeriaceae. Persoonia - Molecular Phylogeny and Evolution of Fungi, 33(1), 1-40. doi:10.3767/003158514x681981Edgar, R. C. (2004). MUSCLE: multiple sequence alignment with high accuracy and high throughput. Nucleic Acids Research, 32(5), 1792-1797. doi:10.1093/nar/gkh340Darriba, D., Taboada, G. L., Doallo, R., & Posada, D. (2012). jModelTest 2: more models, new heuristics and parallel computing. Nature Methods, 9(8), 772-772. doi:10.1038/nmeth.2109Ronquist, F., Teslenko, M., van der Mark, P., Ayres, D. L., Darling, A., Höhna, S., … Huelsenbeck, J. P. (2012). MrBayes 3.2: Efficient Bayesian Phylogenetic Inference and Model Choice Across a Large Model Space. Systematic Biology, 61(3), 539-542. doi:10.1093/sysbio/sys029Rambaut A. FigTree v1. 4.0, a graphical viewer of phylogenetic trees. Edinburgh, Scotland: University of Edinburgh; 2016.Spiegelhalter, D. J., Best, N. G., Carlin, B. P., & van der Linde, A. (2002). Bayesian measures of model complexity and fit. Journal of the Royal Statistical Society: Series B (Statistical Methodology), 64(4), 583-639. doi:10.1111/1467-9868.00353Rue, H., Martino, S., & Chopin, N. (2009). Approximate Bayesian inference for latent Gaussian models by using integrated nested Laplace approximations. Journal of the Royal Statistical Society: Series B (Statistical Methodology), 71(2), 319-392. doi:10.1111/j.1467-9868.2008.00700.xChristensen RH. Ordinal—regression models for ordinal data. R package version 2015.1–21. 2015. http://www.cran.r-project.org/package=ordinal/ Accessed 8 May 2017.Hunter, G. C., Wingfield, B. D., Crous, P. W., & Wingfield, M. J. (2006). A multi-gene phylogeny for species of Mycosphaerella occurring on Eucalyptus leaves. Studies in Mycology, 55, 147-161. doi:10.3114/sim.55.1.147Braun, U., & Urtiaga, R. (2013). New species and new records of cercosporoid hyphomycetes from Cuba and Venezuela (Part 2). Mycosphere, 4(2), 172-214. doi:10.5943/mycosphere/4/2/3Braun, U., Crous, P. W., & Nakashima, C. (2014). Cercosporoid fungi (Mycosphaerellaceae) 2. Species on monocots (Acoraceae to Xyridaceae, excluding Poaceae). IMA Fungus, 5(2), 203-390. doi:10.5598/imafungus.2014.05.02.04Aptroot A. Mycosphaerella and its anamorphs: conspectus of Mycosphaerella CBS Biodiversity Series 5. Utrecht: CBS-KNAW Fungal Biodiversity Centre; 2006.Crous, P. W., & Wingfield, M. J. (1996). Species of Mycosphaerella and Their Anamorphs Associated with Leaf Blotch Disease of Eucalyptus in South Africa. Mycologia, 88(3), 441. doi:10.2307/3760885Aguín, O., Sainz, M. J., Ares, A., Otero, L., & Pedro Mansilla, J. (2013). Incidence, severity and causal fungal species of Mycosphaerella and Teratosphaeria diseases in Eucalyptus stands in Galicia (NW Spain). Forest Ecology and Management, 302, 379-389. doi:10.1016/j.foreco.2013.03.021Maxwell, A., Dell, B., Neumeister-Kemp, H. G., & Hardy, G. E. S. J. (2003). Mycosphaerella species associated with Eucalyptus in south-western Australia: new species, new records and a key. Mycological Research, 107(3), 351-359. doi:10.1017/s0953756203007354Otero L, Aguín O, Mansilla J, Hunter G, Wingfield M. Identificación de especies de Mycosphaerella en Eucalyptus globulus y E. nitens en Galicia. In: Proceedings of the 13th Congress of the Spanish Phytopathological Society; 2006; Murcia, Spain.ZHAN, J., & McDONALD, B. A. (2011). 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Self-Potential as a Predictor of Seawater Intrusion in Coastal Groundwater Boreholes

This work was supported by the Natural Environment Research Council in the UK, as part of the Science and Solutions for a Changing Planet Doctor Training Partnership, run by the Grantham Institute for Climate Change at Imperial College London. We thank Southern Water for access to the boreholes at Saltdean and Balsdean. We thank Southern Water and Atkins Global for funding the installation of the equipment. We also thank Dr Amadi Ijioma for providing a prototype of the electrodynamic modelling code in MATLAB, which has since been adapted for use in a coastal chalk aquifer. Three anonymous reviewers are thanked for their comments, which greatly helped to improve the manuscript. The data used in this paper are in the tables, figures and cited information. The authors have no conflicts of interest to declare.Peer reviewedPublisher PDFPublisher PD

Assessment of the proliferative, apoptotic and cellular renovation indices of the human mammary epithelium during the follicular and luteal phases of the menstrual cycle

Introduction During the menstrual cycle, the mammary gland goes through sequential waves of proliferation and apoptosis. in mammary epithelial cells, hormonal and non-hormonal factors regulate apoptosis. To determine the cyclical effects of gonadal steroids on breast homeostasis, we evaluated the apoptotic index ( AI) determined by terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling ( TUNEL) staining in human mammary epithelial cells during the spontaneous menstrual cycle and correlated it with cellular proliferation as determined by the expression of Ki-67 during the same period.Methods Normal breast tissue samples were obtained from 42 randomly selected patients in the proliferative ( n = 21) and luteal ( n = 21) phases. Menstrual cycle phase characterization was based on the date of the last and subsequent menses, and on progesterone serum levels obtained at the time of biopsy.Results the proliferation index ( PI), defined as the number of Ki-67-positive nuclei per 1,000 epithelial cells, was significantly larger in the luteal phase (30.46) than in the follicular phase (13.45; P = 0.0033). the AI was defined as the number of TUNEL-positive cells per 1,000 epithelial cells. the average AI values in both phases of the menstrual cycle were not statistically significant ( P = 0.21). However, the cell renewal index ( CRI = PI/AI) was significantly higher in the luteal phase ( P = 0.033). A significant cyclical variation of PI, AI and CRI was observed. PI and AI peaks occurred on about the 24th day of the menstrual cycle, whereas the CRI reached higher values on the 28th day.Conclusions We conclude that proliferative activity is dependent mainly on hormonal fluctuations, whereas apoptotic activity is probably regulated by hormonal and non-hormonal factors.Universidade Federal de São Paulo, Dept Gyneol, Mastol Div, São Paulo, BrazilStanford Univ, Sch Med, Dept Neurosurg, Stanford, CA 94305 USAAPC Pathol, São Paulo, BrazilUniversidade Federal de São Paulo, Dept Gyneol, Mastol Div, São Paulo, BrazilWeb of Scienc

Limits to modern contraceptive use among young women in developing countries: a systematic review of qualitative research

<p>Abstract</p> <p>Background</p> <p>Improving the reproductive health of young women in developing countries requires access to safe and effective methods of fertility control, but most rely on traditional rather than modern contraceptives such as condoms or oral/injectable hormonal methods. We conducted a systematic review of qualitative research to examine the limits to modern contraceptive use identified by young women in developing countries. Focusing on qualitative research allows the assessment of complex processes often missed in quantitative analyses.</p> <p>Methods</p> <p>Literature searches of 23 databases, including Medline, Embase and POPLINE^®, were conducted. Literature from 1970–2006 concerning the 11–24 years age group was included. Studies were critically appraised and meta-ethnography was used to synthesise the data.</p> <p>Results</p> <p>Of the 12 studies which met the inclusion criteria, seven met the quality criteria and are included in the synthesis (six from sub-Saharan Africa; one from South-East Asia). Sample sizes ranged from 16 to 149 young women (age range 13–19 years). Four of the studies were urban based, one was rural, one semi-rural, and one mixed (predominantly rural). Use of hormonal methods was limited by lack of knowledge, obstacles to access and concern over side effects, especially fear of infertility. Although often more accessible, and sometimes more attractive than hormonal methods, condom use was limited by association with disease and promiscuity, together with greater male control. As a result young women often relied on traditional methods or abortion. Although the review was limited to five countries and conditions are not homogenous for all young women in all developing countries, the overarching themes were common across different settings and contexts, supporting the potential transferability of interventions to improve reproductive health.</p> <p>Conclusion</p> <p>Increasing modern contraceptive method use requires community-wide, multifaceted interventions and the combined provision of information, life skills, support and access to youth-friendly services. Interventions should aim to counter negative perceptions of modern contraceptive methods and the dual role of condoms for contraception and STI prevention should be exploited, despite the challenges involved.</p

Active, but not passive cigarette smoking was inversely associated with mammographic density

The opposing carcinogenic and antiestrogenic properties of tobacco smoke may explain why epidemiologic studies have not consistently reported positive associations for active smoking and breast cancer risk. A negative relation between mammographic density, a strong breast cancer risk factor, and active smoking would lend support for an antiestrogenic mechanism. We used multivariable linear regression to assess the associations of active smoking and secondhand smoke (SHS) exposure with mammographic density in 799 pre- and early perimenopausal women in the Study of Women’s Health Across the Nation (SWAN). We observed that current active smoking was associated with 7.2% lower mammographic density, compared to never active smoking and no SHS exposure (p = 0.02). Starting to smoke before 18 years of age and having smoked ≥20 cigarettes/day were also associated with statistically significantly lower percent densities. Among nulliparous women having smoked ≥20 cigarettes/day was associated with 23.8% lower density, compared to having smoked ≤9 cigarettes/day (p &lt; 0.001). Our findings support the hypothesis that tobacco smoke exerts an antiestrogenic effect on breast tissue, but counters the known increased risk of breast cancer with smoking prior to first full-term birth. Thus, our data suggest that the antiestrogenic but not the carcinogenic effects of smoking may be reflected by breast density

Mammary Involution and Breast Cancer Risk: Transgenic Models and Clinical Studies

Postlactational involution is the process following weaning during which the mammary gland undergoes massive cell death and tissue remodeling as it returns to the pre-pregnant state. Lobular involution is the process by which the breast epithelial tissue is gradually lost with aging of the mammary gland. While postlactational involution and lobular involution are distinct processes, recent studies have indicated that both are related to breast cancer development. Experiments using a variety of rodent models, as well as observations in human populations, suggest that deregulation of postlactational involution may act to facilitate tumor formation. By contrast, new human studies show that completion of lobular involution protects against subsequent breast cancer incidence