Papers by Elda Castro Mercado
Ciencia Nicolaita
Los Benzoxazinoides (Bx) son compuestos químicos derivados de ácidos hidroxámicos, con propiedade... more Los Benzoxazinoides (Bx) son compuestos químicos derivados de ácidos hidroxámicos, con propiedadesaleloquímicas y antimicrobianas. En este estudio se reporta el efecto de Azopirillum brasilensesobre la producción de Bx en plántulas de trigo. El análisis por Cromatografía de Gasesacoplada a Espectrometría de Masas (CG/EM) de extractos de plántulas de cuatro días de germinación,identificó a la benzoxazolinona 6-metoxi-2-benzoxazolinona (MBOA). El metabolito se acumulómás en follaje que en raíz, en condiciones naturales. En follaje, su acumulación fue mayor 24h después de la inoculación con A. brasilense, y en respuesta a la concentración de inóculo. El crecimientode la bacteria en presencia de MBOA disminuyó ligeramente su crecimiento. Se discute laposible función de MBOA en relación a su papel durante la interacción de la bacteria con la plántulade trigo.
Ciencia nicolaita, 2013
Insti tu to de Inves ti ga cio nes Quí mi co-Bio ló gi cas, UMSNH. Las ri zo bac te rias pro mo t... more Insti tu to de Inves ti ga cio nes Quí mi co-Bio ló gi cas, UMSNH. Las ri zo bac te rias pro mo to ras del cre ci mien to ve ge tal (Plant-Growth Pro mo ting Rhizo bac te ria, en lo su ce si vo PGPR, por sus si glas en in glés) son un gru po de bac te rias de vida li bre aso cia das a la ri zós fe ra, con tri bu yen do a in cre men tar el cre ci mien to y la pro duc ti vi dad de un gran nú me ro de plan tas. Sin em bar go, como re sul ta do de las inte rac cio nes en tre plan tas y mi croor ga nis mos, ge ne ral men te se ha ob ser va do ge nera ción de una ex plo sión oxi da ti va que de ri va en la pro duc ción de es pe cies reac ti vas de oxí ge no (ERO). Los pro duc tos de esta res pues ta oxi da ti va pue den te ner efec tos tó xi cos so bre los mi croor ga nis mos, in clu yen do a las ri zo bac te rias. Evi den cias re cientes in di can que, ade más de las en zi mas an tio xi da ti vas, cam bios en el me ta bo lis mo de las bac te rias pue den es tar in vo lu cra dos en la res pues ta an tio xi da ti va a la pro duc ción de ERO por la plan ta hos pe de ra, sin em bar go, esto no se ha ex plo ra do en las ri zo bacte rias. Actual men te exis te es ca so co no ci mien to so bre los me ca nis mos a tra vés de los cua les las ri zo bac te rias en fren tan las ERO pro du ci das por las plan tas, du ran te las prime ras eta pas de la in te rac ción. En esta re vi sión se ana li za par te de la in for ma ción dispo ni ble so bre las res pues tas al es trés oxi da ti vo ob ser va das en bac te rias y la po si bi li dad de que una de es tas res pues tas, la re pro gra ma ción me ta bó li ca es ti mu lada por este es trés, se pre sen te en las ri zo bac te rias. Pa la bras cla ve: Bac te rias pro mo to ras del cre ci mien to ve ge tal, es pe cies reac ti vas de oxí ge no, ri zós fe ra, in te rac ción plan ta-microorganismo.
Hydrogen Peroxide Modulates Target of Rapamycin (Tor) in Arabidopsis Thaliana Seedlings to Control Growth and Development
SSRN Electronic Journal, 2022
Frontiers in Sustainable Food Systems, 2020
While the effects of lipopolysaccharides (LPS) of plant pathogenic bacteria in induction of plant... more While the effects of lipopolysaccharides (LPS) of plant pathogenic bacteria in induction of plant defense responses have been characterized, the role of LPS of beneficial rhizobacteria on plant growth is less clear. In this study, we assessed the in vitro effects of LPS from the rhizobacterium Azospirillum brasilense Sp245 on early growth of wheat seedlings (Triticum aestivum) and on some biochemical responses related to growth, like peroxidase (POD) enzyme activity and Ca 2+ availability. Four days after treating the seedlings with various concentrations of A. brasilense LPS (10 to 1,000 µg/mL), the growth of the seedlings was enhanced as evidenced by significant increase in leaf and root lengths as well as fresh weight. These increases were similar or even higher to those resulting from inoculation with the rhizobacteria. POD enzyme activity increased significantly in roots treated with LPS and was concentration dependent. Salicylhydroxamic acid, an inhibitor of peroxidase activity, decreased POD activity and plant growth promoted by LPS. Lanthanum, an inhibitor of calcium channels, and EGTA, inhibited plant growth and POD activity promoted by LPS, while the calcium ionophore A23187 alone was able to increase plant growth and POD activity. In summary, the results suggest that isolated LPS of A. brasilense have the capacity to promote early wheat seedling growth and that POD enzyme activity and Ca 2+ levels are involved in the LPS-mediated biological activity.
Las ómicas y la generación masiva de datos biológicos
EFECTO DE LA RIZOBACTERIA PROMOTORA DEL CRECIMIENTO VEGETAL Azospirillum brasilense SP245 EN LA FOSFOLIPASA D EN PLÁNTULAS DE TRIGO
Agrociencia, 2020
Azospirillum brasilense es una rizobacteria promotora del crecimiento vegetal muy utilizada en ag... more Azospirillum brasilense es una rizobacteria promotora del crecimiento vegetal muy utilizada en agricultura. Los cambios moleculares estimulados en la planta por esta rizobacteria durante la interacción se conocen de manera parcial. Uno de los sitios primarios de contacto de la rizobacteria con la célula vegetal es la membrana plasmática. El objetivo de este estudio fue analizar el efecto de A. brasilense en la actividad de la fosfolipasa D (PLD) en raíces de plántulas de trigo (Triticum aestivum L.). La actividad de la enzima se determinó mediante la producción de ácido fosfatídico (AF), el cual es el producto de su catálisis. Plántulas inoculadas con una concentración de 106 unidades formadoras de colonias por mililitro (UFC mL-1) de la rizobacteria mostraron una reducción en la producción de AF, en un periodo de inoculación de 5 a 15 min. Esta reducción reflejó un descenso en la actividad de la PLD. La disminución se mantuvo 12 a 48 h, tiempo de duración del estudio y coincidió co...
Azospirillum brasilense Sp245 triggers cytokinin signaling in root tips and improves biomass accumulation in Arabidopsis through canonical cytokinin receptors
Physiology and Molecular Biology of Plants, 2021
The plant growth promoting rhizobacterium Azospirillum brasilense Sp245 enhances biomass producti... more The plant growth promoting rhizobacterium Azospirillum brasilense Sp245 enhances biomass production in cereals and horticultural species and is an interesting model to study the physiology of the phytostimulation program. Although auxin production by Azospirillum appears to be critical for root architectural readjustments, the role of cytokinins in the growth promoting effects of Azospirillum remains unclear. Here, Arabidopsis thaliana seedlings were co-cultivated in vitro with A. brasilense Sp245 to assess whether direct contact of roots with bacterial colonies or exposure to the bacterial volatiles using divided Petri plates would affect biomass production and root organogenesis. Both interaction types increased root and shoot fresh weight but had contrasting effects on primary root length, lateral root formation and root hair development. Cell proliferation in root meristems analyzed with the CYCB1;1::GUS reporter decreased over time with direct contact, but was augmented by plant exposure to volatiles. Noteworthy, the expression of the cytokinin-inducible reporters TCS::GFP and ARR5::GUS increased in root tips in response to bacterial contact, without being affected by the volatiles. In A. thaliana having single (cre1-12, ahk2-2, ahk3-3), double (cre1-12/ahk2-2, cre1-12/ahk3-3, ahk2-2/ahk3-3) or triple (cre1-12/ahk2-2/ahk3-3) mutations in canonical cytokinin receptors, only the triple mutant had a marked effect on plant growth in response to A. brasilense. These results show that different mechanisms are elicited by A. brasilense, which influence the cytokinin-signaling pathway.
Journal of Plant Growth Regulation, 2020
The effects of lipopolysaccharides (LPS) from Azospirillum brasilense Sp245, a plant growth-promo... more The effects of lipopolysaccharides (LPS) from Azospirillum brasilense Sp245, a plant growth-promoting rhizobacteria, and Pseudomonas aeruginosa PAO1, a pathogenic bacterium, on plant growth and peroxidase (POD) activity were assessed on wheat seedlings. A. brasilense LPS (100 µg/mL) increased total length, and total fresh weight in wheat seedlings 4 days after treatment. P. aeruginosa LPS did not show effect on plant growth. A. brasilense LPS increased root hairs length similar to whole cells, while P. aeruginosa LPS increased root hairs density and slightly root hairs length. Both LPS increased POD activity and hydrogen peroxide (H 2 O 2 ) content in root; however, the LPS from the pathogenic bacterium generated higher increments. The peroxidase inhibitor salicylhydroxamic acid (SHAM) inhibited plant growth, which was not recovered by the addition of LPS neither A. brasilense nor P. aeruginosa. POD activity stimulated by LPS was calcium-dependent as confirmed by the addition of the calcium channel blocker LaCl 3 . The results suggest that plant cells sense differentially LPS from beneficial or pathogenic bacteria and that calcium is needed to respond to the presence of both LPS.
Mexican journal of biotechnology, 2021
Azospirillum spp., one of the best studied genus of plant growth promoting rhizobacteria. These r... more Azospirillum spp., one of the best studied genus of plant growth promoting rhizobacteria. These rhizobacteria are able to colonize hundreds of plant species and improve their growth, development and productivity. The target of rapamycin (TOR) protein is a central component of the TOR signaling pathway, which regulates cell growth and metabolism in response to environment cues in eukaryotes. In this study, the TOR function was analyzed in Arabidopsis thaliana L. plants inoculated with the rhizobacteria Azospirillum brasilense. Arabidopsis seedlings tor-es, which express an interference RNA in presence of estradiol and decrease TOR expression, showed an inhibition in the growth and lateral root formation, with or without 1x102 CFU/mL of the inoculum. In addition, a morphological analysis of the root showed an inhibition in the root hair formation. The results suggest that A. brasilense controls A. thaliana growth through TOR signaling pathway.
Plant Science, 2020
This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
Acta Physiologiae Plantarum, 2019
The present study aimed to determine phospholipase C (PLC) activation status during changes promo... more The present study aimed to determine phospholipase C (PLC) activation status during changes promoted by Azospirillum brasilense Sp245 in wheat seedlings. Germinated Triticum aestivum seeds by 3 days were inoculated with different A. brasilense concentrations (1 × 10 6 and 4 × 10 6 CFU/mL) and PLC enzyme activity assayed at different times. Root and leaf length, as well as total fresh weight were assessed as growth parameters; moreover, changes in root morphology were analyzed. PLC activity was measured by molybdate assay. Neomycin and LaCI 3 treatments verified PLC-and/or Ca 2+ -dependent effects on inoculated wheat, respectively. A. brasilense increased PLC activity 15-30 min after inoculation. Ca 2+ -channel blocker LaCI 3 decreased PLC activity, and activity did not recover with A. brasilense. The A. brasilense mutant FAJ009, impaired in auxin production, showed decreased PLC activity versus wild type. PLC activity was inhibited by neomycin (PLC inhibitor), concomitant with a decrease in total fresh weight. Exogenous addition of diacylglycerol (DAG) and inositol-1,4,5-trisphosphate (IP3), secondary messengers produced by the activity of PLC, increased root hair length. The putative role of PLC enzyme activity in morphological changes promoted by A. brasilense in wheat seedlings is discussed.
Protoplasma, 2017
This study analyzes the effects of procyanidin B2 on early wheat plant growth and plant biochemic... more This study analyzes the effects of procyanidin B2 on early wheat plant growth and plant biochemical responses promoted by lipopolysaccharides (LPS) derived from the rhizobacteria Azospirillum brasilense Sp245. Measurements of leaf, root length, fresh weight, and dry weight showed in vitro plant growth stimulation 4 days after treatment with A. brasilense as well as LPS. Superoxide anion (O 2 ) and hydrogen peroxide (H 2 O 2 ) levels increased in seedling roots treated with LPS (100 μg mL -1 ). The chlorophyll content in leaf decreased while the starch content increased 24 h after treatment in seedling roots. The LPS treatment induced a high increase in total peroxidase (POX) (EC 1.11.1.7) activity and ionically bound cell wall POX content in roots, when compared to respective controls. Early plant growth and biochemical responses observed in wheat seedlings treated with LPS were inhibited by the addition of procyanidin B2 (5 μg mL -1 ), a B type proanthocyanidin (PAC), plant-derived polyphenolic compound with binding properties of LPS. All results suggest first that the ionically bound cell wall POX enzymes could be a molecular target of A. brasilense LPS, and second that the recognition or association of LPS by plant cells is required to activate plant responses. This last event could play a critical role during plant growth regulation by A. brasilense LPS.
Superoxide anion production in the interaction of wheat roots and rhizobacteria Azospirillum brasilense Sp245
Plant and Soil, 2015
Background and aimsThe aim of this study was to test the effect of Azospirillum brasilense on the... more Background and aimsThe aim of this study was to test the effect of Azospirillum brasilense on the superoxide anion production (O2•−) and enzymes related with redox metabolism in roots of wheat (Triticum aestivum).MethodsA. brasilense Sp245 and T. aestivum seeds cv Nana F2007 were used in this study. Wheat roots were stained with nitro blue tetrazolium (NBT) to visualize and localize O2•− production. Superoxide dismutase (SOD) and peroxidase (POX) activities were assayed in native PAGE.ResultsWe found that A. brasilense application resulted in a decrease in meristem length and cell size, and in a reduction in the O2•− level in roots. The bacteria stimulated SOD and soluble POX isoenzymes, particularly in the zone of the root tip. Qualitative O2•− production in roots treated with LaCl3, a Ca2+ channel blocker, in combination with A. brasilense was comparable to inoculated roots. Similar results were observed with the Ca2+ ionophore A23187.ConclusionsOur results suggest that O2•− metabolism is important during the interaction of wheat and A. brasilense, and that the antioxidative enzymes such as SOD and POX are involved in its regulation.
Ciencia Nicolaita, Nov 10, 2012
La riboflavina (vitamina B2) se sintetiza por las plantas y muchos microorganismos y puede actuar... more La riboflavina (vitamina B2) se sintetiza por las plantas y muchos microorganismos y puede actuar como un activador de resistencia para contrarrestar el estrés biótico. En este trabajo se muestra que la aplicación exógena de riboflavina sobre la raíz de aguacate induce resistencia en contra del oomiceto Phytophthora cinnamomi. La riboflavina aplicada in vitro en una concentración de 5 mM a raíces de plántulas inhibió la colonización por P. cinnamomi, en comparación con las plántulas control, pero no tuvo efecto alguno en el crecimiento in vitro del oomiceto. Extractos de raíces tratadas con riboflavina mostraron actividad inhibitoria sobre el patógeno. Cuando diferentes concentraciones del extracto (50, 100 y 150 µl/ml) se mezclaron con zoosporas del patógeno (1x10 4 zoosporas/ml) y se analizaron al microscopio 6 días después, se observó una morfología alterada de las hifas o una disminución en la producción de clamidosporas, así como restos de hifas, sugiriendo un efecto tóxico sobre el patógeno. Estos resultados indican que los extractos de raíces de aguacate tratadas con riboflavina afectan la formación de clamidosporas y la estructura del micelio de P. cinnamomi.
Azospirillum una rizobacteria con uso potencial en la agricultura
Biologicas Revista De La Des Ciencias Biologico Agropecuarias Universidad Michoacana De San Nicolas De Hidalgo, Feb 9, 2015
El genero Azospirillum pertenece al grupo de rizobacterias promotoras del crecimiento vegetal. Es... more El genero Azospirillum pertenece al grupo de rizobacterias promotoras del crecimiento vegetal. Esta capacidad ha sido atribuida principalmente a la fijacion del nitrogeno y produccion de fitohormonas. Estas bacterias producen acido indol-3-acetico (AIA), un tipo de auxinas que inducen cambios morfologicos en el sistema radical de las plantas, y ademas pueden actuar como moleculas de senalizacion en la interaccion planta-bacteria. Sus efectos sobre el crecimiento vegetal han permitido que se utilicen en la formulacion de biofertilizantes como una alternativa en la agricultura. Sin embargo, muchos aspectos bioquimicos sobre la interaccion de esta bacteria con las plantas son aun desconocidos. Aqui se resumen algunas vias por el cual esta bacteria promueve el crecimiento vegetal asi como su importancia en la agricultura.
Revista Mexicana De Fitopatologia, 2008
Resumen. Las plantas responden a la infección por patógenos, al daño mecánico o herida inducida p... more Resumen. Las plantas responden a la infección por patógenos, al daño mecánico o herida inducida por herbívoros con una producción localizada de especies reactivas de oxígeno (ERO), un fenómeno referido con frecuencia como "explosión oxidativa". Si bien se han identificado algunas fuentes potenciales de ERO, no es claro cuales mecanismos predominan durante las interacciones planta patógeno. Las ERO tienen una función importante en el inicio de la respuesta hipersensible, una forma de muerte celular programada inducida por patógenos incompatibles (avirulentos), y efectos directos sobre el patógeno, el entrecruzamiento oxidativo incrementando los polímeros de pared celular y la inducción de expresión de genes que responden a patógeno. En este artículo se revisa la química y la función de estos compuestos durante una interacción planta-patógeno. Palabras clave adicionales: Antioxidantes, respuestas de defensa.
Production of reactive oxygen species during the resistance expression of plants to diseases
Revista Mexicana De Fitopatologia, 2008
Chocolate alimento y medicina
Ciencia Y Desarrollo, 2009
La inmunidad innata en las plantas: una batalla molecular entre receptores y estimuladores
Biologicas Revista De La Des Ciencias Biologico Agropecuarias Universidad Michoacana De San Nicolas De Hidalgo, Jun 22, 2013
En anos recientes se han obtenido avances significativos en el conocimiento de los mecanismosmole... more En anos recientes se han obtenido avances significativos en el conocimiento de los mecanismosmoleculares que gobiernan la resistencia a las enfermedades en las plantas. Estos conocimientoshan derivado en nuevos conceptos sobre como aparentemente tipos no relacionados de resistenciaa microorganismos en plantas estan funcional y evolutivamente ligados. Durante mucho tiempola investigacion sobre las defensas de las plantas inducidas por estimulador (no especificas paraun cultivar), y las defensas inducidas por factores de avirulencia (especificas para un cultivar)han coexistido sin formar parte de un modelo integrado para la resistencia a las enfermedadesen plantas. La informacion reciente ha modificado significativamente nuestra percepcion sobrela inmunidad de las plantas. Este articulo resalta los progresos recientes en la investigacion sobrelo que se ha denominado Patrones Moleculares Asociados a Patogenos (PMAP), con enfasisparticular en los nuevos conceptos usados en la literatura respectiva.
Oxidative and antioxidative responses in the wheat-Azospirillum brasilense interaction
Protoplasma, 2015
Azospirillum is a plant growth-promoting rhizobacteria (PGPR) able to enhance the growth of wheat... more Azospirillum is a plant growth-promoting rhizobacteria (PGPR) able to enhance the growth of wheat. The aim of this study was to test the effect of Azospirillum brasilense cell wall components on superoxide (O2·(-)) production in wheat roots and the effect of oxidative stress on A. brasilense viability. We found that inoculation with A. brasilense reduced O2·(-) levels by approx. 30 % in wheat roots. Inoculation of wheat with papain-treated A. brasilense, a Cys protease, notably increased O2·(-) production in all root tissues, as was observed by the nitro blue tetrazolium (NBT) reduction. However, a 24-h treatment with rhizobacteria lipopolysaccharides (50 and 100 μg/mL) alone did not affect the pattern of O2·(-) production. Analysis of the effect of plant cell wall components on A. brasilense oxidative enzyme activity showed no changes in catalase activity but a decrease in superoxide dismutase activity in response to polygalacturonic acid treatment. Furthermore, A. brasilense growth was only affected by high concentrations of H2O2 or paraquat, but not by sodium nitroprusside. Our results suggest that rhizobacterial cell wall components play an important role in controlling plant cell responses and developing tolerance of A. brasilense to oxidative stress produced by the plant.
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Papers by Elda Castro Mercado