REVISÃO: MICRORGANISMOS PROMOTORES DE CRESCIMENTO APLICADOS NA PRODUÇÃO DE MORANGOS

Introdução: Os microrganismos desempenham funções fundamentais no desenvolvimento vegetal. Eles atuam como catalizadores na obtenção de nutrientes indispensáveis para o seu crescimento e indutores de respostas contra patógenos e estresses abióticos. É de comum acordo que a sustentabilidade se tornou uma obrigatoriedade para o desenvolvimento e integralização da sociedade, principalmente na agricultura que é uma atividade indispensável e que pode acarretar danos severos ao meio ambiente quando praticada inconsequentemente. A cultura do morango é um exemplo, o estado de Minas Gerais lidera a produção nacional com 2,8 mil ha cultivados e que essencialmente necessitam de alternativas ecologicamente viáveis para sua manutenção. Objetivo: Sendo assim, o presente trabalho foi elaborado com o objetivo de revisar a literatura e proporcionar um breve estudo de caso sobre as pesquisas acerca de microrganismos promotores de crescimento aplicados à cultura do morango, apontando quais vem sendo estudados e como podem contribuir para o desenvolvimento e produção. Material e Métodos: Foram realizadas buscas em diversas plataformas de pesquisa, o critério adotado foi o termo “strawberry inoculation” como palavra chave assim recorrendo a trabalhos relevantes que contemplassem o caráter descritivo e científico da aplicação de inóculos bacterianos e fúngicos em cultivares de morango. Resultados: Os trabalhos revisados evidenciaram o benefício que os microrganismos acarretam na obtenção de nutrientes como P, K, Ca e Fe, seja com sua acumulação no solo ou nos tecidos foliares (Bacillus sp.e Aspergillus sp.), também possibilitando na redução da adubação nitrogenada e incremento do tamanho e matéria seca da raiz (Azospirillum brasiliense). Respostas na indução de tolerância a seca são promovidas (Glomus mosseae), como também o biocontrole do fungo necrotrófico Botrytis cinerea (várias espécies de Bacillus sp.). Melhoras na qualidade dos frutos também são proporcionados como aumento de compostos flavonóides e fenólicos (Glomus intraradices) e o aumento dos açúcares, antocianinas, modulação do pH, ácido málico e compostos voláteis (Pseudomonas sp.+ Funneliformis mosseae, Septoglomus viscosum, Rhizophagus irregulares. Conclusão: Visto o atual advento na produção de inoculantes de natureza biológica este estudo expõe diversos trabalhos que podem contribuir como inspiração tecno científica para a elaboração de novas pesquisas e produtos, além de contribuir na disseminação de conhecimentos sobre microbiologia e sustentabilidade agrícola.

Germinación y vigor de semillas de especies hortícolas inoculadas con biofertilizantes y soluciones salinas

El presente trabajo de investigación se realizó en Tepatitlán de Morelos, Jalisco, en las instalaciones del Campo Experimental Centro Altos de Jalisco. Se utilizaron semillas de especies hortícolas (chile chilaca, melón y pepino) inoculadas con biofertilizantes (Azospirillum brasilenses y Glomus intraradices) y sometidas a diferentes concentraciones de cloruro de potasio (KCl). El objetivo fue evaluar el efecto de los biofertilizantes y KCl, en la germinación y vigor en semillas de especies hortícolas. Los tratamientos evaluados bajo condiciones de laboratorio fueron mediante la inoculación de biofertilizantes, combinación de biofertilizantes más solución salina en diferentes concentraciones, tratamiento químico y testigo absoluto, lo anterior para observar el efecto fisiológico en las semillas mediante las variables evaluadas: germinación estándar, longitud media de plúmula, vigor y peso seco. La información obtenida de cada una de las variables se analizó mediante un diseño completamente al azar con arreglo factorial y con cuatro repeticiones, siendo la unidad experimental los tacos (sustrato entre papel). Se detectaron diferencias significativas entre tratamientos y variables, esto debido a los resultados por inoculación de biofertilizantes en combinación con las concentraciones salinas, promovieron fisiológicamente las especies hortícolas en estudio siendo tratamientos T7 y T8, con mejor respuesta con respecto al testigo absoluto; es decir, tienen un efecto positivo en germinación y vigor en las especies estudiadas.

Microbial Inoculants Modulate Physiological Behaviour Of Troyer Citrange Under Drought Stress

A study was undertaken with Troyer citrange (Citrus sinensis × Poncirus trifoliata), the rootstock of citrus, to elucidate the interaction effects of arbuscular mycorrhizal fungi and plant-growth-promoting bacteria on plant physiology under both ample watered and water stress conditions. The result exhibited significant influence of Glomus intraradices and phosphorus solubilising bacteria (PSB) (mixture of Bacillus subtilis and B. megatherium) on plant growth due to root-fungus-bacteria interaction leading to reduced accumulation of reactive oxygen species, production of antioxidant metabolites, higher anti-scavenging enzymes and higher acquisition of plant nutrients, besides enhancing rhizosphere microbial activity. Thus, Troyer citrange could be co-inoculated with G. intraradices and PSB during propagation for healthy growth of the seedlings thereby pre-ponding the budding and subsequent establishment of composite plants under field conditions. Bangladesh J. Bot. 50(3): 467-474, 2021 (September)

Application of biological products at cultivation of garden pea Pisum sativum l.

The possibilities of using the biological products “Trichodermine” (Trichoderma viride Pers ex Fr.), “Gliocladine” (Gliocladium virens Miller et al.) and the mycorrhizal activator “Rhizo VAM Basic” (Glomus intraradices Schenck&Smith) for control of fungal diseases in garden pea and and their impact on the biometric indicators of young plants were studied. Biological preparations based on antagonistic fungi Trichoderma viride and Gliocladium virens improve the phytosanitary condition of the plants, the mycorrhizal fungus Glomus intraradices stimulates the formation of the root system and tuber formation, but has a weak fungicidal effect against Fusarium wilt in this culture. The experiment was performed on an artificial infectious background by Fusarium oxysporum Schlecht. f. sp. pisi (Hal.) Raillo, isolated from diseased plants. The effect of application of the biological products“Trichodermine” and “Gliocladine” is 34-68%, from “Rhizo VAM Basic” - 8% compared to the infected control. The combined application of biological preparations with fungicidal and mycorrhizal action significantly protects the crop from infection with the causative agent of Fusarium wilt of garden pea.

Glomus intraradices and Funneliformis mosseae am Strains Influence on Soil Physical, Biological and Chemical Characteristics in Tea Plantations in Kenya

Arbuscular mycorrhizal (AM) fungi occur over a wide range of agro climatic conditions and are geographically ubiquitous. Arbuscular mycorrhizal fungi are the medium of soil structure, they determine the flow of water, nutrients, and air, directs the pathways of root growth, and opens channels for the movement of soil animals. As the moderator of the microbial community, they also determine the metabolic processes of the soil. In other words, the mycorrhizal network is practically synonymous with ecosystem function. The tremendous advances in research on mycorrhizal physiology and ecology over the past 40 years have led to a greater understanding of the multiple roles of AMF in the ecosystem. The current study was informed due to the depletion of nutrients and poor soil microbiology in tea production whose production has declined in the recent years. The trial was conducted in the research and development greenhouse at the James Finlays Farm in Kericho County, Kenya. The experiment was laid out in a Randomized Complete Block Design (RCBD) with factorial arrangements of tea clones and mycorrhizae levels. The phosphorus treatments consisted of a standard rate of 107.66kg ha -1, two clones of the tea (S15/10 and SC 12/28) and two mycorrhizal strains (Funneliformis mosseae and Glomus intraradices) at two rates (50 kg ha-1 and 70 kg ha-1) and an untreated control without mycorrhizae. The soil pH was positively influenced by reducing the acidity content significantly where mycorrhizae strains were introduced with the highest unit change (1.3) was recorded on clone SC 12/28 at the 50 kg Mycorrhizae ha-1 rate. The same treatment also significantly increased the soil total phosphorus level (2.3 g/kg) compared to all other treatments with the least change observed on the control. Application of AMF strains Glomus intraradices and Funneliformis mosseae is recommended in tea production at the rate of 50 kg ha-1 which improves and enhances the general positive characteristics of soil health.

Influence of Arbuscular Mycorrhizae on Callusing and root colonization of Tea (Camellia sinensis) Clones in Kenya

Mycorrhizal fungi are a major component of the soil micro flora in many ecosystems, but usually have limited saprophytic abilities. Arbuscular mycorrhizal fungi (AMF) are an important component of soil life and soil chemistry. In soil, phosphorus may be present in relatively large amounts, but much of it is poorly available because of the very low solubility of phosphates by formation of complexes with iron, aluminum, and calcium, leading to soil solution concentrations of 10μm or less and very low mobility. Tea is a major income earner in the country, but yields are declining since high yielding tea varieties have a major problem with rooting and take so long in the nursery. The current study was initiated to investigate the role between Mycorrhizae and plants to explain rooting and growth rates during early stages of tea establishment. It was conducted at James Finlay in Kericho County, Kenya. The experiment was laid out in a Randomized Complete Block Design (RCBD) with factorial arrangements. Phosphorus treatments consisted of a standard rate of 107.66kg ha -1, two clones of the tea (S15/10 and SC 12/28) and two mycorrhizal strains (Glomus mosseae and Glomus intraradices) plus one control without mycorrhizae. Data was collected on rate of callusing, chlorophyll content and rate of root infection by mycorrhizal fungus. Application of 50kg Mycorrhizae ha-1 exhibited the highest callusing rate on clone SC 15/10 with significant differences (P≤0.05) observed on the chlorophyll content from week 1 to week 30 where the standard application of phosphorus plus 50kg Mycorrhizae ha-1 on clone S 15/10 had the highest content consistently throughout the trial. The highest frequency of mycorrhizae colonization in the rhizosphere was observed when 70kg ha-1 was added under clone SC 12/28. AMF strains are recommended for use on tea propagation in improving callusing rate and the chlorophyll content at a rate of 50kg Mycorrhizae ha-1.

INFLUENCE OF ARBUSCULAR MYCORRHIZAL FUNGAL BIOSTIMULANTS AND CONVENTIONAL FERTILIZERS ON SOME SOLANACEOUS CROPS FOR GROWTH, PRODUCTIVITY AND NUTRIENT STOICHIOMETRY UNDER FIELD CONDITIONS IN SEMI- ARID REGION OF MAHARASHTRA, INDIA

The main objective of the study was to evaluate the outcome of inoculation with biological consortium culture of arbuscular mycorrhizal fungal species (Aculospora logula, Glomus fasciculatum, Glomus intraradices, Gigaspora margarita, and Scutellospora heterogama) and chemical fertilizers on Solanaceous crops (Solanum tuberosum L. cultivars, Lycopersicum esculentum L. and Solanum melongena L.) under field conditions during Rabi cropping season. The experimental plot was a randomized block design with four replications. The result revealed that gross yield, plant height, number of branches/plant, leaf moisture, leaf area, root length, and dry biomass were positively affected by the inoculation of consortium culture of arbuscular mycorrhizal fungi with 75% recommended dose of fertilizers (RDF). Overall, our study shows that inoculation of consortium mycorrhizae with 75% RDF gave better growth, dry biomass, nutrient uptake, and yield of solanaceous crops and reduces the dose of chemical fertilizers to improve sustainable crop production and creates a healthy environment.

Anchoring the species Rhizophagus intraradices (formerly Glomus intraradices)

The nomenclatural type material of Rhizophagus intraradices (basionym Glomus intraradices) was originally described from a trap pot culture established with root fragments, subcultures of which later became registered in the INVAM culture collection as FL 208. Subcultures of FL 208 (designated as strain ATT 4) and a new strain, independently isolated from the type location (ATT 1102), were established as both pot cultures with soil-like substrate and in vitro root organ culture. Long-term sampling of these cultures shows spores of the species to have considerable morphological plasticity, not described in the original description. Size, shape and other features of the spores were much more variable than indicated in the protologue. Phylogenetic analyses confirmed earlier published evidence that sequences from all R. intraradices cultures formed a monophyletic clade, well separated from, and not representing a sister clade to, R. irregularis. Moreover, new phylogenetic analyses show that Rhizoglomus venetianum and R. irregularis are synonymous. The morphological characters used to separate these species exemplify the difficulties in species recognition due to the high phenotypic plasticity in the genus Rhizophagus. Rhizophagus intraradices is morphologically re-described, an epitype is designated from a single-spore isolate derived from ATT 4, and R. venetianum is synonymised with R. irregularis.

Nondestructive Evaluation of Inoculation Effects of AMF and Bradyrhizobium japonicum on Soybean under Drought Stress From Reflectance Spectroscopy

Precise estimation of leaf chlorophyll content (LCC) and leaf water content (LWC) of soybean, using remote sensing technology, provides a new avenue for the nondestructive evaluation of inoculation effects of arbuscular mycorrhizal fungi (AMF) and Bradyrhizobium japonicum (BJ) on soybean growth condition. In this study, a series of pot experiments were conducted in the greenhouse, soybean inoculated with Glomus intraradices (G.i, one of AMF species), G.i and BJ, and non-inoculation were planted under drought stress (DS) and normal irrigation (NI) conditions. Leaf spectra and LCC and LWC were measured on the 28th and 56th days after inoculation. Two new simple ratio (SR) indices, derived from the first derivative spectral reflectance at λ1 nm (Dλ1) and the raw spectral reflectance at λ2 nm (Rλ2), were developed to estimate LCC and LWC. The results indicate that under DS, plants inoculated with G.i had higher LCC and LWC than the non-inoculated plants, followed by the counterparts co-inoculated with G.i and BJ. Linear estimation models, established by the D650/Rred edge and D1680/R680, achieved great improved accuracy for quantifying LCC and LWC of soybean under inoculation and drought stress treatments, with determination of coefficient of 0.63 and 0.76, respectively.

Use of microbial inoculants for production of potato tuber seed in greenhouse conditions

Objectives: To determine the effect of Glomus intraradices and Bacillus subtilis on the agronomic performance from in vitro potato seedlings in greenhouse conditions. Methodology: The research was developed in pots under greenhouse conditions at Universidad Nacional José Faustino Sánchez Carrión, Huacho, Lima, from October 2017 to March 2018. The substrate for pots was 45% sand, 45% vermicompost, and 10% rice straw, with an average content of 3% organic matter. The average environmental temperature was 25°C. In vitro seedlings of five potato genotypes were transplanted into 4-liter pots, and inoculated with commercial inoculants of Glomus intraradices, a mixture of G. intraradices + Bacillus subtilis, a fertilization treatment with NPK (220-180-120) and control without inoculation. Completely randomized design with four replications on a factorial arrangement was used, with four inoculant treatments and five potato genotypes. The data of ten agronomic characters, that included the weight of the tubers and biomass per plant, were subjected to analysis of variance and then to tests of mean comparison of Scott-Knott and processed with Infostat software. Results: Inoculation treatments with mycorrhizae or mycorrhizae with rhizobacteria, statistically surpassed (P < 0.05) the controls in the case of weight of tubers per plant, the average weight of tubers, number of tubers per plant and diameter of the tuber, in addition to the height of the plant at 15 and days after the transplant; in the case of fresh foliage weight per plant and the degree of senescence of the foliage, the control treatments statistically surpassed (P < 0.05) to the inoculation treatments. For other characters, number of sprouts per plant, the number of leaves and number of flowers per plant, no significant differences (P > 0.05) was found. Conclusions: The use of microbial inoculants based on mycorrhizae and rhizobacteria, improves the productivity of potato seed tubers under greenhouse conditions.Keywords: Glomus intraradices, agronomic performance, in vitro seedlings, potato varieties, greenhouse