Maria Julissa Ek-Ramos

Dr. Maria Julissa Ek-Ramos

0000-0002-1556-0823 Universidad Autonoma de Nuevo Leon, Facultad de Ciencias Biologicas
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Research Focus & Metrics

Academic Career Length

24Years (2003-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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5 August 2014 in PLOS ONE
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Journal Article
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DLDiana Castillo Lopez
Diana Castillo Lopez
KZKeyan Zhu-Salzman
Keyan Zhu-Salzman
Maria Julissa Ek-RamosMaria Julissa Ek-Ramos
Maria Julissa Ek-Ramos
GSGregory A. Sword
Gregory A. Sword
The effects of two entomopathogenic fungal endophytes, Beauveria bassiana and Purpureocillium lilacinum (formerly Paecilomyces lilacinus), were assessed on the reproduction of cotton aphid, Aphis gossypii Glover (Homoptera:Aphididae), through in planta feeding trials. In replicate greenhouse and field trials, cotton plants (Gossypium hirsutum) were inoculated as seed treatments with two concentrations of B. bassiana or P. lilacinum conidia. Positive colonization of cotton by the endophytes was confirmed through potato dextrose agar (PDA) media plating and PCR analysis. Inoculation and colonization of cotton by either B. bassiana or P. lilacinum negatively affected aphid reproduction over periods of seven and 14 days in a series of greenhouse trials. Field trials were conducted in the summers of 2012 and 2013 in which cotton plants inoculated as seed treatments with B. bassiana and P. lilacinum were exposed to cotton aphids for 14 days. There was a significant overall effect of endophyte treatment on the number of cotton aphids per plant. Plants inoculated with B. bassiana had significantly lower numbers of aphids across both years. The number of aphids on plants inoculated with P. lilacinum exhibited a similar, but non-significant, reduction in numbers relative to control plants. We also tested the pathogenicity of both P. lilacinum and B. bassiana strains used in the experiments against cotton aphids in a survival experiment where 60% and 57% of treated aphids, respectively, died from infection over seven days versus 10% mortality among control insects. Our results demonstrate (i) the successful establishment of P. lilacinum and B. bassiana as endophytes in cotton via seed inoculation, (ii) subsequent negative effects of the presence of both target endophytes on cotton aphid reproduction using whole plant assays, and (iii) that the P. lilacinum strain used is both endophytic and pathogenic to cotton aphids. Our results illustrate the potential of using these endophytes for the biological control of aphids and other herbivores under greenhouse and field conditions.

29 March 2019 in Frontiers in Microbiology
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Maria Julissa Ek-RamosMaria Julissa Ek-Ramos
Maria Julissa Ek-Ramos
RGRicardo Gomez-Flores
Ricardo Gomez-Flores
AOAlonso A. Orozco-Flores
Alonso A. Orozco-Flores
CRCristina Rodríguez-Padilla
Cristina Rodríguez-Padilla
GGGuadalupe Gonzalez-Ochoa
Guadalupe Gonzalez-Ochoa
PTPatricia Tamez-Guerra
Patricia Tamez-Guerra
Endophytes constitute plant-colonizing microorganisms in a mutualistic symbiosis relationship. They are found in most ecosystems reducing plant crops’ biotic and abiotic stressors by stimulating immune responses, excluding plant pathogens by niche competition, and participating in antioxidant activities and phenylpropanoid metabolism, whose activation produces plant defense, structural support, and survival molecules. In fact, metabolomic studies have demonstrated that endophyte genes associated to specific metabolites are involved in plant growth promotion (PGP) by stimulating plant hormones production such as auxins and gibberellins or as plant protective agents against microbial pathogens, cancer, and insect pests, but eco-friendly and eco-safe. A number of metabolites of Gram-positive endophytes isolated from agriculture, forest, mangrove, and medicinal plants, mainly related to the Firmicutes phyla, possess distinctive biocontrol and plant growth-promoting activities. In general, Actinobacteria and Bacillus endophytes produce aromatic compounds, lipopeptides, plant hormones, polysaccharides, and several enzymes linked to phenylpropanoid metabolism, thus representing high potential for PGP and crop management strategies. Furthermore, Actinobacteria have been shown to produce metabolites with antimicrobial and antitumor activities, useful in agriculture, medicine, and veterinary areas. The great endophytes diversity, their metabolites production, and their adaptation to stress conditions make them a suitable and unlimited source of novel metabolites, whose application could reduce agrochemicals usage in food and drugs production.

6 January 2022 in World Journal of Microbiology and Biotechnology
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ITIrán Tapia-Vázquez
Irán Tapia-Vázquez
AMAmelia C. Montoya-Martinez
Amelia C. Montoya-Martinez
SVSergio de los Santos Villalobos
Sergio de los Santos Villalobos
Maria Julissa Ek-RamosMaria Julissa Ek-Ramos
Maria Julissa Ek-Ramos
RMRoberto Montesinos-Matías
Roberto Montesinos-Matías
CMClaudia Martínez-Anaya
Claudia Martínez-Anaya

1 June 2021 in Biotechnology Reports
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Journal Article
Open access
JMJendri Mamangkey
Jendri Mamangkey
DSDwi Suryanto
Dwi Suryanto
EMErman Munir
Erman Munir
AMApon Zaenal Mustopa
Apon Zaenal Mustopa
MSMada Triandala Sibero
Mada Triandala Sibero
LRLa Ode Adi Parman Rudia
La Ode Adi Parman Rudia
• Bruguiera cylindrica is a mangrove plant in North Sumatra with limited information on its microbial endophytes. • An enzyme bioprospection study was conducted revealing Vibrio alginolyticus as a prominent proteolytic strain. • Vibrio alginolyticus Jme3-20 produced a multitude of extracellular enzymes such as amylase, cellulase, chitinase, phosphatase, and urease. • This is the first report on finding Vibrio alginolyticus from mangrove area of North Sumatra.

11 June 2013 in PLOS ONE
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Maria Julissa Ek-RamosMaria Julissa Ek-Ramos
Maria Julissa Ek-Ramos
WZWenqing Zhou
Wenqing Zhou
CVCésar U. Valencia
César U. Valencia
JAJosephine B. Antwi
Josephine B. Antwi
LKLauren L. Kalns
Lauren L. Kalns
GSGregory A. Sword
Gregory A. Sword
Studies of fungi in upland cotton ( Gossypium hirsutum ) cultivated in the United States have largely focused on monitoring and controlling plant pathogens. Given increasing interest in asymptomatic fungal endophytes as potential biological control agents, surveys are needed to better characterize their diversity, distribution patterns and possible applications in integrated pest management. We sampled multiple varieties of cotton in Texas, USA and tested for temporal and spatial variation in fungal endophyte diversity and community composition, as well as for differences associated with organic and conventional farming practices. Fungal isolates were identified by morphological and DNA identification methods. We found members of the genera Alternaria , Colletotrichum and Phomopsis , previously isolated as endophytes from other plant species. Other recovered species such as Drechslerella dactyloides (formerly Arthrobotrys dactyloides ) and Exserohilum rostratum have not, to our knowledge, been previously reported as endophytes in cotton. We also isolated many latent pathogens, but some species such as Alternaria tennuissima , Epicoccum nigrum , Acremonium alternatum , Cladosporium cladosporioides , Chaetomium globosum and Paecilomyces sp., are known to be antagonists against plant pathogens, insects and nematode pests. We found no differences in endophyte species richness or diversity among different cotton varieties, but did detect differences over time and in different plant tissues. No consistent patterns of community similarity associated with variety, region, farming practice, time of the season or tissue type were observed regardless of the ecological community similarity measurements used. Results indicated that local fungal endophyte communities may be affected by both time of the year and plant tissue, but the specific community composition varies across sites. In addition to providing insights into fungal endophyte community structure, our survey provides candidates for further evaluation as potential management tools against a variety of pests and diseases when present as endophytes in cotton and other plants.

2 April 2010 in Plant Physiology
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SPSunchung Park
Sunchung Park
SOSookyung Oh
Sookyung Oh
Maria Julissa Ek-RamosMaria Julissa Ek-Ramos
Maria Julissa Ek-Ramos
SNSteven van Nocker
Steven van Nocker
The human Paf1 complex (Paf1C) subunit Parafibromin assists in mediating output from the Wingless/Int signaling pathway, and dysfunction of the encoding gene HRPT2 conditions specific cancer-related disease phenotypes. Here, we characterize the organismal and molecular roles of PLANT HOMOLOGOUS TO PARAFIBROMIN (PHP), the Arabidopsis (Arabidopsis thaliana) homolog of Parafibromin. PHP resides in an approximately 670-kD protein complex in nuclear extracts, and physically interacts with other known Paf1C-related proteins in vivo. In striking contrast to the developmental pleiotropy conferred by mutation in other plant Paf1C component genes in Arabidopsis, loss of PHP specifically conditioned accelerated phase transition from vegetative growth to flowering and resulted in misregulation of a very limited subset of genes that included the flowering repressor FLOWERING LOCUS C. Those genes targeted by PHP were distinguished from the bulk of Arabidopsis genes and other plant Paf1C targets by strong enrichment for trimethylation of lysine-27 on histone H3 (H3K27me3) within chromatin. These findings suggest that PHP is a component of a plant Paf1C protein in Arabidopsis, but has a more specialized role in modulating expression of a subset of Paf1C targets.