1,721,009 research outputs found
Prospecting algae and cyanobacteria as bioprotectans for plant disease control
No full textThe European Directive 2009/128 on sustainable use of pesticides promotes the use of alternative approaches
to synthetic products for plant disease control to reduce human, animals and environmental risks. Among
alternatives, natural products based on cyanobacteria and algae are gaining attention. Our studies demonstrated
that application of water extracts from Anabaena minutissima, Ecklonia maxima and Jania adhaerens
controlled powdery mildew caused by Podosphaera xanthii on cucumber detached cotyledons and seedlings
and induced the expression of PR genes related to plant-induced resistance. In addition, tomato seed treatment
with the same extracts increased germination, seedling dry weight, calibre, and reduced root rot caused by
Rhizoctonia solani on tomato plants. Seed treatment also increased chitinase activity and lignin compound
contents in tomato seedlings. A deeper investigation on the possible bioactive compounds of A. minutissima,
E. maxima and J. adhaerens, revealed the antifungal activity of polysaccharides against Botrytis cinerea, agent
of grey mould, in vitro and in vivo on strawberry fruits. Latest research pointed out that application of
phycobiliproteins from A. minutissima, Arthrospira platensis and Hydropuntia cornea on tomato fruits before
B. cinerea challenge reduced grey mould disease. In particular, FT-IR and FT-Raman spectroscopies have
shown that phycobiliproteins from A. minutissima preserved cutin and pectine structures of tomato fruit from
B. cinerea infection. In conclusion, our research demonstrate the potentialities of algae and cyanobacteria as a
bioprotectans for plant disease control
Activity of polysaccharides extracted from Ecklonia sp. and Jania sp. against Botrytis cinerea
No full textAntifungal activity of Ecklonia sp. and Jania sp. polysaccharides against Botrytis cinerea
No full textSeaweeds are a source of macro and microelements, amino acids, vitamins,
polysaccharides and hormones, such as auxins, auxin-like compounds and cytokinins
(Craigie, 2011). Seaweeds extracts (SE) have long been used in agriculture as soil amendment
for their beneficial properties on plants, because they stimulate both plant growth and
production (Crouch & van Staden, 1992; Arthur et. al., 2003). They also increase fruit weight,
fresh dry mass of root, leaf area, yield per plant, the chlorophyll content and minerals
(Sivasankari et al., 2006; Rayorath et al., 2008; Roussos et al., 2009). It has also been shown
that SE may help the plants to counteract abiotic and biotic stresses. Among abiotic stresses,
Ashraf & Foolad (2007) demonstrated that SE are involved in overcoming plant stress
conditions such as drought and salinaty. Several studies have shown antibiotic, antiviral and
antifungal activities of SE against a number of plant pathogens such as Penicillium spp. and
Fusarium oxysporum (Khallil et al., 2015) and Aspergillus sp. (Kosanić et al., 2015).
Seaweeds extracts are also rich in several bioactive compounds, such as polysaccharides that
are well known to be elicitors of plant defence responses. Simultaneously to the growing
consumption of agricultural products, such as strawberry, there was an increase in the use of
chemical fertilizers to improve plant yield, and of synthetic pesticides to control fungal plant
pathogens. The continuous use of chemicals during the years has affected human and animal
health and the ecosystem.
Strawberry is one of the most consumed berries and its high nutritional value and
composition have stimulated its consumption increase. A number of fungal pathogens can
affect strawberry plants such as Colletotrichum spp., and several species of the soil borne
pathogens, such as Rhizoctonia, Fusarium and Pythium causing the so-called black root rot
complex (Manici et al., 2005). Among these pathogens, Botrytis cinerea, the agent of grey
mold, cause several losses especially during shelf life. Alternative approaches to chemical
treatments are necessary to preserve the quality of strawberries during the shelf life in order to
protect health safety and limit the development of the fungus.
In this study, the antifungal activity of cationic polysaccharides extracted from two
macroalgae, Ecklonia sp. (Ochrophyta) and Jania sp. (Rhodophyta) was investigated against
B. cinerea in vitro and in vivo on strawberry. Polysaccharides were extracted by selective
precipitation with 2% (w/v) N-Cetylpyridinium bromide monohydrate (Cetavlon) (Diaz et al.,
2011). In the in vitro assay, fungal colony portions were treated for 6 hours by immersion in
three polysaccharides aqueous concentrations, 1.65, 0.82 and 0.41 mg/ml for Ecklonia sp. and
0.18, 0.09 and 0.045 mg/ml for Jania sp. The treated colony portions were inoculated in
agarized medium and daily growth was measured for a week. Ecklonia sp. polysaccharides at
0.18 mg/ml and 0.09 mg/ml significantly inhibited B. cinerea growth by 21.0% and 22.8%,
respectively, two days after treatment. Jania sp. polysaccharides did never inhibit fungal colony growth. For in vivo experiments, strawberry ripe fruits cv. Cristal were immerged
before or after harvesting in polysaccharide aqueous solutions of Ecklonia sp. at the
concentrations of 0.82 and 0.41 mg/ml, and of Jania sp., at 0.09 and 0.045 mg/ml. A spore
suspension of B. cinerea (1 × 105
spores/ml) was inoculated by spraying fruits 24 hours after
treatment. Disease symptoms over the total area inoculated of fruit were evaluated as
percentage of infected area. The pre-harvest treatment with Jania sp. showed to reduce
disease symptoms by 100% at 0.09 mg/ml and by 50% at 0.045 mg/ml and with Ecklonia sp.
by 16.7% (0.82 mg/ml) and 11.11% (0.41 mg/ml). Post-harvest treatment did never inhibit
disease symptoms. This study showed that SE could be considered for further investigation in
control strategy against B. cinere
TOMATO SEED PRIMING WITH WATER-SOLUBLE POLYSACCHARIDES FROM JANIA ADHAERENS PROMOTES PLANT GROWTH AND INCREASES PLANT RESISTANCE TO SOILBORNE PATHOGENS
No full textMarine macroalgae are a source of natural bioactive compounds, such as polysaccharides, that deserve exploitation in the field of plant disease management. Moreover, current European regulations require that priority should be given to alternative products than synthetic pesticides. In agriculture, algae have been mostly used for their beneficial properties on plant development. In this study, we showed that tomato seed biopriming with water-soluble polysaccharides (WSPs) from the alga Jania adhaerens protects seedlings and adult plants from the soilborne pathogens Fusarium oxysporum f.sp. lycopersici, Pythium ultimum and Rhizoctonia solani artificially inoculated in a growing substrate.
First, WSPs were characterized by FT-IR spectroscopy and seedling emergence, disease severity, and expression of genes related to phenylpropanoid, chlorogenic acid, SAR and ISR pathways, and chitinase and β-1,3 glucanase activities were investigated after seed priming. WSPs FT-IR spectra showed typical bands assigned to alduronic acids and glycosidic linkage formation in polysaccharides. Depending on the WSPs dose, seed treatment enhanced seedling emergence, reduced disease severity and increased plant growth. Moreover, HQT, HCT, PAL, PR1 and PR2 genes were significantly upregulated together with β-1,3 glucanase activity. These results show that algal WSPs have the potential for being considered as natural compounds for soilborne pathogens control in sustainable agriculture
Determinación del contenido lipídico en "Crypthecodinium cohnii" por citometría de flujo
No full textSuficiencia investigador
Desarrollo de la metodología para cuantificar la actividad de OCT, arginasa y arginina deaminasa en las células de "Nostoc" PCC 73101
No full textUniversidad de Las Palmas de Gran Canaria. Suficiencia investigador
Enzimas reguladoras del metabolismo diazotrófico y del potencial osmótico en cianobacterias
No full textDoctorado en Ciencias del Mar. Programa de Biotecnologí
Cyanoprokariotes from Azuaje (Gran Canaria, Canary Islands) : Microphototrophes in moist fluctuant environments of subtropical regions
No full textEs un resumen
Isolation and Characterization of The Microbial Mats Associated to a Hydroponic Culture of Halophytic Pants
No full textPrograma de Doctorado: Ecología y Gestión de los Recursos Vivos MarinosLos tapetes microbianos, formados principalmente por microalgas, generan una matriz de polisacáridos que contribuye a la fertilización, estabilización y retención de agua en el suelo. Los tapetes microbianos pueden ser empleados como herramienta en el acondicionamiento de suelos y estimuladores del crecimiento en plantas superiores (como las halófitas), en regiones áridas o semiáridas. Se plantea la agrobiotecnología como una aproximación realista e innovadora para la bioremediación de suelos degradados y la repoblación de zonas áridas y semiáridasMicrobial mats are composed mainly of microalgae embebed in a polysaccharide matrix that contribute to soil fertilization, stabilization and water retention. Microbial mats promote the growth of higher plants, such as halophytes, and could be used as a tool in the soil conditioning of arid and semiarid areas. The present study proposes a concrete approach from the agrobiotechnology into the bioremediation of degraded soils and reforestation of arid and semiarid area
Algae Production and Their Potential Contribution to a Nutritional Sustainability
No full textSustainable diets are defined as those that present low impacts both on the environment and the biodiversity, contributing to food and nutrition security and to a healthy life for present and future generations. Algae (macroalgae and microalgae, including cyanobacteria) have recently taken an increased interest as valuable products, being used as ingredients or condiments in the modern diversifying occidental cuisine. Moreover, nutritional research has confirmed algae as rich sources of potentially valuable, health-promoting compounds in a scenario where consumers are increasingly aware of the relationship between diet, health and disease prevention. Combining both ideas, nutritional needs vs. health promotion and disease risk reduction, algae are shown as a very interesting source of functional ingredients for being considered as a component of our day-to-day diet and related food products. Sustainability contribution of cultivation systems and techniques to biomass increasing in quality, security and control, so reducing effects on the environment and biodiversity, makes algae production a promising activity to be included in future developments toward a responsible and healthy way of living.310,5060,338Q1Q4SCI
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