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by Daniel Castrillo Sequeira, Rodrigo Jiménez Robles, Milagro Granados Montero
Accepted: 10/December/2023 – Published: 27/December/2023 – DOI: https://doi.org/10.18781/R.MEX.FIT.2309-3
Abstract Viticulture is one of the oldest agricultural activities, and its exploitation has traditionally been limited to temperate climate zones, where the european grapevine (Vitis vinifera) and wine originate. Given the effects of climate change, more areas lose the capacity to grow this crop, and the tropics are presented as potential regions for this market. In Costa Rica, viticultural activity has been reported since the mid20th century, however, technical information on the crop is scarce. Downy mildew, caused by the oomycete Plasmopara viticola, represents one of the diseases with the greatest economic impact for viticulture worldwide, as well as the most limiting phytosanitary problem in Costa Rica. Under high humidity conditions, the development of the pathogen is accelerated, and the host remains susceptible throughout the crop cycle, which makes proper management of epidemics difficult. Chemical control is the most common management strategy around the world, however, the appearance of P. viticola populations with resistance to fungicides has been observed in most grape vine-growing areas, hence the search for more ecological alternatives is a necessity. Currently, Costa Rica does not have integrated management strategies that allow sustainable production, and there is only one registered product for protection against this pathogen. This situation justifies paying more attention to the investigation of this pathosystem […] View more.
Induction of defense response mediated by inulin from dahlia tubers (Dahlia sp.) in Capsicum annuum
by Julio César López Velázquez, Soledad García Morales, Joaquín Alejandro Qui Zapata, Zaira Yunuen García Carvajal, Diego Eloyr Navarro López, Rebeca García Varela
Accepted: 11/December/2023 – Published: 29/December/2023 – DOI: https://doi.org/10.18781/R.MEX.FIT.2305-2
Abstract Objective / Background. Phytophthora capsici is the causal agent of chili wilt. Among the strategies for its control is the use of resistance inducers. Fructans are molecules with interesting biological properties, including the ability to induce resistance mechanisms in some plants. In this work, the protective effect of four concentrations inulin from dahlia tubers on chili infected with P. capsici was evaluated. Materials and Methods. The concentration that showed the highest protection was chosen to evaluate the induction of defense response through the enzymatic activity of β-1,3 glucanases, peroxidases and the production of total phenolic compounds. Results. Inulin showed a protective effect against infection at concentrations of 100 to 300 μM, as symptoms decreased and seedlings showed improved vegetative development. It was observed that inulin at 200 μM concentration was able to induce an effective defense response associated with increased activity of β-1,3 glucanases and peroxidases through a local and systemic response in seedlings. This response was differentiated between seedlings treated with inulin and seedlings infected with P. capsici. Conclusion. It was concluded that inulin has the ability to protect chili bell pepper from P. capsici by induction of resistance. […] View more.
by María Guadalupe Aguilar Rito, Amaury Martín Arzate Fernández, Hilda Guadalupe García Núñez, Tomas Héctor Norman Mondragón
Accepted: 29/November/2023 – Published: 20/December/2023 – DOI: https://doi.org/10.18781/R.MEX.FIT.2310-1
Abstract Background. Disinfection of Agave seeds is a crucial step in in vitro culture to prevent contamination, which can be caused by microorganisms such as bacteria, fungi and viruses that can affect seedling growth and reduce seed germination rate. Therefore, proper seed disinfection is essential to ensure vigorous and healthy plant growth. Objective. Generate an efficient seed disinfection protocol in seven species of Agave; Agave marmorata, A. karwinskii, A. potatorum, A. angustifolia, A. cupreata, A. horrida and A. salmiana to reduce pollution levels. Materials and methods. A total of 12 disinfection treatments with disinfectants and different combinations were evaluated. The disinfectants used were; 3 % Hydrogen Peroxide for 24 h, Commercial Sodium Hypochlorite 5 % (v/v) for 5 min, Calcium Hypochlorite 8 % (w/v) for 15 min, Copper Sulfate 30 % (v/v) for 10 min, Mercury Chloride II 0.1 % (w/v) for 10 min. Before each treatment was tested, the seeds were pre-washed with liquid soap and subjected to the treatments, Subsequently, they were sown in DM medium and the percentage of germination and contamination for each treatment was evaluated weekly for a period of 30 days. Additionally, the contaminating microorganisms found were identified. Results. The best treatment for seed disinfection was 30 % copper sulfate (v/v) for 10 min, 0.1 % mercuric chloride II for 10 min and 3 % hydrogen peroxide for 24 h, obtaining 100 % disinfection. Four genera of fungi were identified: Monilinia sp., Aspergillus sp., Penicillium sp., and Alternaria alternata, a bacterium; Bacillus sp., and a yeast, Schizosaccharomyces sp. […] View more.
Bacillus sp. A8a reduces leaf wilting by Phytophthora and modifies tannin accumulation in avocado
by Edgar Guevara Avendaño, Itzel Anayansi Solís García, Alfonso Méndez Bravo, Fernando Pineda García, Guillermo Angeles Alvarez, Carolina Madero Vega, Sylvia P. Fernández Pavía, Alejandra Mondragón Flores, Frédérique Reverchon
Accepted: 06/November/2023 – Published: 08/December/2023 – DOI: https://doi.org/10.18781/R.MEX.FIT.2309-2
Abstract Objective / Background. The objective was to assess the biocontrol capacity of Bacillus sp. A8a in avocado (Persea americana) plants infected by Phytophthora cinnamomi. Materials and Methods. A greenhouse experiment was implemented with four treatments: 1) control plants; 2) plants infected with P. cinnamomi; 3) plants inoculated with Bacillus sp. A8a; 4) plants infected with P. cinnamomi and inoculated with Bacillus sp. A8a. We evaluated several morpho physiological variables during the experiment, which lasted 25 days after infection (dai). Moreover, we analyzed tannin density in stems at 25 dai to determine the plant defense response against the disease. Results. Inoculation with strain A8a reduced wilting symptoms by 49 % at 25 dai, compared with non-inoculated plants. No differences were detected in morpho physiological variables between treatments. However, a greater tannin accumulation was registered in the xylem of infected plants, whilst plants inoculated with strain A8a displayed a larger tannin density in the cortex. Conclusion. Our results confirm the biocontrol activity of Bacillus sp. A8a in avocado plants and suggest that tannin differential accumulation in the cortex of plants inoculated with the bacteria may contribute to the enhanced tolerance of avocado plants against Phytophthora root rot. […] View more.
Characterization of endophytic bacteria growth-promoting in potato plants (Solanum tuberosum)
by Rosa María Longoria Espinoza, Cristal Leyva Ruiz, Gloria Margarita Zamudio Aguilasocho, Rubén Félix Gastélum
Accepted: 10/January/2024 – Published: 23/January/2024 – DOI: https://doi.org/10.18781/R.MEX.FIT.2310-4
Abstract Objective/Background. The purpose of this research was to evaluate the in vitro plant growth-promoting activity of endophytic bacteria isolated in tissue from Atlantic variety potato plants from the municipality of Guasave, Sinaloa, Mexico. Materials and Methods. The bacterial population was isolated in Lb agar culture medium; two bacterial isolates were obtained from the root and two from the stem, all four Gram positive. The bacterial population of the tissue samples was expressed as (CFU/g-1). The phosphate solubilization capacity, production of chitinases and siderophores were qualitatively evaluated. Results. Partial sequencing of the 16S rDNA gene was performed, allowing the identification of associated bacterial species within the Firmicutes. 100% of the strains were identified as Bacillus sp. with identities greater than 97%: B. cereus, B. tropicus, B. thuringiensis, B. fungorum. The B. thuringiensis and B. cereus strains showed positive activity in promoting plant growth in vitro through phosphate solubilization, production of chitinases and siderophores. B. cereus and B. tropicus presented inhibitory capacity greater than 50% for Sclerothium rolfsii. Conclusion. It is relevant to continue research carried out in the laboratory, in order to determine its potential in the field, improving the production of potato crops. […] View more.
by Ana María López López, Juan Manuel Tovar Pedraza, Josefina León Félix, Raúl Allende Molar, Nelson Bernardi Lima, Isidro Márquez Zequera, Raymundo Saúl García Estrada
Accepted: 28/January/2024 – Published: 13/February/2024 – DOI: https://doi.org/10.18781/R.MEX.FIT.2309-5
Abstract Objective / Background. Tomato (Solanum lycopersicum) is one of Mexico’s main crops. In the years 2017 and 2018, symptoms of corky and pink roots were observed with an incidence of 10 to 20% in Culiacan, Sinaloa, Mexico. In the foliage, plants presented a generalized chlorosis, with stunted growth and senescence in the leaves. In the roots, brown and pink lesions were formed, as well as a corky texture. The objective of this study was to morphologically and molecularly characterize fungal isolates associated to corky and pink root in tomato orchards in Culiacan, Sinaloa, as well as to evaluate their pathogenicity. Materials and methods. Monoconidial isolates were obtained and they were identified as Setophoma terrestris, based on their morphological characteristics. To confirm the identity, the area of the internal transcribed spacers (ITS) of the rDNA was amplified and sequenced, along with a fragment of the gene 28S of the rRNA (LSU). Results. Using the sequences obtained, a phylogenetic tree was created using the Bayesian Inference and it was found that the sequences were grouped with the ex–type sequences of Setophoma terrestris. The pathogenicity of the isolates was verified by inoculating mycelial discs into the root of 10 one-month-old tomato seedlings. The roots of the seedlings inoculated with PDA discs without mycelium served as a control. Thirty days after inoculation, corky and pink root symptoms appeared, whereas the roots of control plants remained healthy Conclusion. According to the morphological characterization, the molecular identification and the pathogenicity tests, Setophoma terrestris was confirmed to be the causal agent of corky and pink root in agricultural tomato orchards in Culiacan, Sinaloa. […] View more.
Genus Orthotospovirus in Costa Rica: A Central American case
by Mauricio Montero Astúa, Natasha Dejuk Protti, David Bermúdez Gómez, Elena Vásquez Céspedes, Laura Garita Salazar, Federico J. Albertazzi, Scott Adkins , Lisela Moreira Carmona
Accepted: 10/December/2023 – Published: 28/December/2023 – DOI: https://doi.org/10.18781/R.MEX.FIT.2023-6
Abstract Objective/Background. The Orthotospovirus genus encompasses a range of economically significant and emerging plant viruses that affect a variety of crops globally. While the prevalence and characteristics of these phytopathogenic viruses are extensively documented in North and South America, their presence in Central America remains comparatively underexplored. This study focuses on Costa Rica, strategically positioned at the nexus of North and South America, to enhance our understanding of Orthotospovirus in this region. Materials and Methods. We analyzed 295 plant samples using enzyme-linked immunosorbent assay (ELISA) to test for the presence of INSV, IYSV, TSWV, and the GRSV/TCSV serogroup. Additionally, a subset (20 samples) underwent further scrutiny through reverse transcription-polymerase chain reaction (RT-PCR) employing both universal and species-specific primers. Results. Our ELISA results indicated the absence of TSWV and the GRSV/TCSV serogroup. However, the presence of INSV in Costa Rica was substantiated through ELISA, RT-PCR, and partial sequencing, revealing its prevalence in both open- field and greenhouse environments. Despite previous diagnostic reports suggesting the presence of TSWV in Costa Rica, our study did not detect this virus. RT-PCR analysis with degenerate primers also found no evidence of other Orthotospovirus species in our samples. The identification of a dominant INSV haplotype, along with three additional variants, suggests the likelihood of at least two independent virus introductions into the region. Conclusion. These findings underscore the necessity for more comprehensive surveys and research on Orthotospoviruses in Central America to better understand their epidemiology and impact on agriculture. […] View more.
![Figure 4. Haplotype Network Graph of Impatiens Necrotic Spot Virus. This graph is a haplotype network inferred using the TCS method, based on a 261 bp sequence alignment of the nucleocapsid protein ORF (S[N] segment) of Impatiens necrotic spot virus. The network includes data from 81 isolates, visually representing the genetic relationships and diversity among the different haplotypes of the virus.](img/RMF/Volumenes/NumEspeciales/VE4142023/RMF2023-6/Figure4.jpg)
![Figure 5. Comprehensive phylogenetic analysis of impatiens necrotic spot virus isolates. This figure illustrates a phylogenetic tree constructed from an alignment of concatenated sequences (2945 positions) encompassing regions of the nucleocapsid [S(N)], glycoprotein precursor [M(G)], movement protein [M(NSM)], and viral polymerase [L(L)] ORFs. The tree includes isolates from various countries, identified by ISO 3166-1 three- letter codes: CHN (China), ITA (Italy), KOR (South Korea), and USA (United States of America). For Costa Rican isolates, additional distinct letter codes in parenthesis signify separate geographic locations. The analysis, executed in MEGA X, utilized the Maximum Likelihood method with a Tamura-3-parameter model and a gamma-distributed rate of variation in nucleotides (+G), involving 2000 permutations. The scale bar indicates the number of nucleotide substitutions per site.](img/RMF/Volumenes/NumEspeciales/VE4142023/RMF2023-6/Figure5.jpg)
Virome of the vegetable prickly pear cactus in the central zone of Mexico
by Candelario Ortega Acosta, Daniel L. Ochoa Martínez, Reyna I. Rojas Martínez, Cristian Nava Díaz, Rodrigo A. Valverde
Accepted: 15/December/2023 – Published: 27/December/2023 – DOI: https://doi.org/10.18781/R.MEX.FIT.2023-2
Abstract Objective / Background. In this study, the ability of high-throughput sequencing (HTS) to detect viruses in vegetable prickly pear cactus was exploited. Materials and Methods. Samples from State of Mexico (EDMX), Hidalgo, and Morelos, as well as Mexico City (CDMX), were analyzed. Results. In the sample from EDMX, the genomes of Opuntia virus 2 (OV2, genus Tobamovirus) and Cactus carlavirus 1 (CCV-1, genus Carlavirus) were detected and recovered. In the sample from CDMX, in addition to OV2 and CCV-1, a new viroid and potexvirus were detected. The former has a circular RNA genome with a length of 412 nt for which the name “Opuntia viroid I” (OVd-I) is proposed. The primary structure of this viroid showed a nucleotide sequence identity of less than 80% with any of the currently known viroids and a phylogenetic relationship with the genus Apscaviroid (Family Pospiviroidae) with which it shares conserved structural motifs. Conclusion. The new potexvirus was named Opuntia potexvirus A (OPV-A), whose viral replicase sequence has a 77.7 % amino acid identity with Schlumbergera virus X. Finally, CCV-1 was detected in 93 (72 %) of 129 vegetable prickly pear cactus samples collected in the four entities. […] View more.
Aspergillus oryzae: An opportunity for agriculture
by Karen Berenice García Conde, Ernesto Cerna Chávez, Yisa María Ochoa Fuentes, Jazmín Janet Velázquez Guerrero
Accepted: 10/October/2023 – Published: 14/November/2023 – DOI: https://doi.org/10.18781/R.MEX.FIT.2302-2
Abstract Aspergillus oryzae is a filamentous fungus capable of degrading various substances employing enzymes, which is why it is widely used in the biotechnological industry, pharmaceutical products, enzymes for industrial use, bleaching agents, anti- pollution textile treatments. However, few works focus on these microorganism’s field applications. This manuscript reviews the potentially beneficial applications of A. oryzae and some by-products in agriculture as biological control, growth inducer, and bioremediation for soils contaminated with heavy metals. […] View more.
Etiology of rhizome rot of asparagus (Asparagus officinalis) in Atenco, Mexico State
by Juan Agustin Gonzalez Cruces, José Sergio Sandoval Islas, Cristian Nava Díaz, Maricarmen Sandoval Sánchez
Accepted: 20/October/2023 – Published: 16/November/2023 – DOI: https://doi.org/10.18781/R.MEX.FIT.2211-1
Abstract Objective/Background. The objective of this research was to identify the causal agent of asparagus rhizome rot, as well as evaluate different inoculation methods and the severity of the isolates. Materials and methods. Sampling was carried out in five producing plots Atenco, Edo. from Mexico. Five isolates of Fusarium spp. were selected. (one per plot) to perform pathogenicity tests. Three isolates were selected for their colonization characteristics for severity tests with different inoculation methods: Immersion for 12 h, immersion for 30 min and inoculation by contact with absorbent paper soaked in 1 mL of inoculum. Concentrations of 1x106 conidia mL-1 were used. 10 rhizomes were used per treatment and 10 rhizomes without inoculation. To determine the severity, photographs (in GIMP®) of the rhizome were analyzed seven days after inoculation. The isolates were molecularly identified with ITS4/ ITS5, EF688/EF1521 and TUBT1/BT2B. Results. Fusarium prolifetatum was morphologically and molecularly identified in the three isolates. The P3DR isolate was the most severe (14.6%), followed by P5DR (13.9%) and P1SIR (11.6%). Conclusion. The most effective inoculation method was immersion for 30 min. They were registered in the NCBI Gene Bank with accessions ON738484 (P3DR), ON973801 (P5DR) and ON738483 (P1SIR). This is the first report of F. prolifetatum in the Edo. from Mexico. […] View more.
