Examinando por Materia "Bacillus"

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Biocontrol and Plant Growth-Promoting Potential of Bacillus and Actinomycetes Isolated from the Rhizosphere and Phyllosphere of Potato (Solanum tuberosum L.) from Different Agroecological Zones of Peru
(MDPI, 2025-12-23) Mamani Rojas, Lizbeth Margarita; Rengifo Sánchez, Raihil Rabindranath; Velarde Apaza, Leslie Diana; Ramírez Rojas, Max; Cántaro Segura, Hector
Potato (Solanum tuberosum L.) is a key staple crop in the Peruvian Andes, but its productivity is threatened by fungal pathogens such as Rhizoctonia solani and Alternaria alternata. In this study, 71 native bacterial strains (39 from phyllosphere and 32 from rhizosphere) were isolated from potato plants across five agroecological zones of Peru and characterized for their plant growth-promoting (PGPR) and antagonistic traits. Actinomycetes demonstrated broader enzymatic profiles, with 2ACPP4 and 2ACPP8 showing high proteolytic (68.4%, 63.4%), lipolytic (59.5%, 60.6%), chitinolytic (32.7%, 35.5%) and amylolytic activity (76.3%, 71.5%). Strain 5ACPP5 (Streptomyces decoyicus) produced 42.8% chitinase and solubilized both dicalcium (120.6%) and tricalcium phosphate (122.3%). The highest IAA production was recorded in Bacillus strain 2BPP8 (95.4 µg/mL), while 5ACPP6 was the highest among Actinomycetes (83.4 µg/mL). Siderophore production was highest in 5ACPP5 (412.4%) and 2ACPP4 (406.8%). In vitro antagonism assays showed that 5ACPP5 inhibited R. solani and A. alternata by 86.4% and 68.9%, respectively, while Bacillus strain BPP4 reached 51.0% inhibition against A. alternata. In greenhouse trials, strain 4BPP8 significantly increased fresh tuber weight (11.91 g), while 5ACPP5 enhanced root biomass and reduced stem canker severity. Molecular identification confirmed BPP4 as Bacillus halotolerans and 5ACPP5 as Streptomyces decoyicus. These strains represent promising candidates for the development of bioinoculants for sustainable potato cultivation in Andean systems.
Effect of co-inoculation with growth-promoting bacteria and arbuscular Mycorrhizae on growth of Persea americana seedlings infected with Phytophthora cinnamomi
(MDPI, 2024-04-02) Solórzano Acosta, Richard Andi; Toro García, Marcia; Zúñiga Dávila, Doris Elizabeth
Avocado is one of the most in-demand fruits worldwide and the trend towards its sustainable production, regulated by international standards, is increasing. One of the most economically important diseases is root rot, caused by Phythopthora cinnamomi. Regarding this problem, antagonistic microorganism use is an interesting alternative due to their phytopathogen control efficiency. Therefore, the interaction of arbuscular mycorrhizal fungi of the phylum Glomeromycota, native to the Peruvian coast (GWI) and jungle (GFI), and avocado rhizospheric bacteria, Bacillus subtilis and Pseudomonas putida, was evaluated in terms of their biocontrol capacity against P. cinnamomi in the “Zutano” variety of avocado plants. The results showed that the GWI and Bacillus subtilis combination increased the root exploration surface by 466.36%. P. putida increased aerial biomass by 360.44% and B. subtilis increased root biomass by 433.85%. Likewise, P. putida rhizobacteria showed the highest nitrogen (24.60 mg ∙ g−1 DM) and sulfur (2.60 mg ∙ g−1 DM) concentrations at a foliar level. The combination of GWI and Bacillus subtilis was the treatment that presented the highest calcium (16.00 mg ∙ g−1 DM) and magnesium (8.80 mg ∙ g−1 DM) concentrations. The microorganisms’ multifunctionality reduced disease severity by 85 to 90% due to the interaction between mycorrhizae and rhizobacteria. In conclusion, the use of growth promoting microorganisms that are antagonistic to P. cinnamomi represents a potential strategy for sustainable management of avocado cultivation.
Efficiency of entomopathogenic bacteria and fungi on Oligonychus yothersi in vitro and on Persea americana Mill. plants
(Facultad de Agronomía de la Universidad del Zulia,, 2023-11-03) Parco Quinchori, Jhimy Andy; Valverde Rodriguez, Agustina; Cornejo, Antonio; Briceño, Henry; Barrionuevo, Laura; Romero, Javier
In the germplasm bank of 22 varieties of avocado (Persea Americana Mill.) belonging to the Fruit Horticultural Institute Investigation, HermilioValdizan National University (UNHEVAL)-Peru, it is common to observe a high population of the species Oligonychusyothersi, a phytophagous mite harmful to the crop. Controls with commercial acaricides are restricted in place, due to the presence of beehives installed in adjacent plots. The objective of this study was to evaluate the effect of four commercial formulations containing strains of Metarhiziumanisopliae and Beauveria bassiana and the toxins of Bacillussubtilis, Bacillus thuringiensis var.kurstaki (Btk) for the control of O. yothersi. The entomopathogenic products were evaluated in the field applying a randomized complete block design with five treatments and three replicates. In the laboratory, 500 adult mites were selected, placing 100 mites per Petri dish with three repetitions per treatment. It was found that the formulation Bacillus thuringiensis var.kurstaki under field conditions reduced the population incidence of mites by up to 98.07% in 49 days. In the laboratory, the B. subtilis and M. anisopliae formulations caused 100% mortality six days after application proving to be efficient control alternatives.
Synergy Between Microbial Inoculants and Mineral Fertilization to Enhance the Yield and Nutritional Quality of Maize on the Peruvian Coast
(MDPI, 2024-12-21) López Montañez, Ruth; Calero Rios, Emilee Nahomi; Quispe Matos , Kenyi Rolando; Huasasquiche Sarmiento, Lucero; Lastra Paucar, Sphyros Roomel; La Torre , Braulio; Solórzano Acosta, Richard Andi
Hard yellow maize is a crucial crop in Peruvian agriculture that plays a significant role in food security and livestock production. However, intensive fertilization practices in agronomic management have negatively impacted soil health. To explore more sustainable agricultural technologies, researchers investigated solutions using microorganisms to enhance plant growth. This study assessed the synergistic effects of microbial inoculants and mineral fertilization on INIA 619 and Dekal B-7088 maize varieties' yield and nutritional quality. A split-plot design was employed, incorporating four inoculation treatments—no inoculant, Bacillus subtilis, Trichoderma viride, and Pseudomonas putida—combined with fertilization levels of 0%, 50%, 75%, and 100%. The findings revealed that Bacillus subtilis boosted yields by 13.1% in INIA 619 and 55.5% in Dekal B-7088. Additionally, combined with 100% fertilization, microbial inoculation increased protein content by 47% and carbohydrates by 6% in INIA 619 while maintaining nutritional quality with 75% fertilization. Similarly, in Dekal B-7088, inoculation with total fertilization enhanced protein content by 54% and fiber by 27%. These results demonstrated that microbial inoculation could reduce mineral fertilization by up to 25% while sustaining high yields and improving the nutritional quality of maize.