BIODIVERSIDADE DE BACTÉRIAS ANTAGÔNICAS A FUNGOS ASSOCIADOS À SINDROME DA MORTE DO CAPIM-MARANDU (Brachiaria brizantha)

A síndrome da morte do capim-marandu (Brachiaria brizantha) é um dos principais problemas na degradação das pastagens no bioma Amazônia. A morte das forrageiras ocorre durante a época chuvosa por suscetibilidade a fitopatógenos. Assim, objetivou-se estudar sistemas de produção e selecionar bactérias antagônicas a Fusarium spp., um dos agentes fitopatogênicos. Os isolados bacterianos foram obtidos de 10 sistemas de produção, mata nativa e pousio, na chuva e na seca. Realizou-se a caracterização molecular de isolados por sequenciamento. Dois isolados de Fusarium foram testados. Para o patógeno 1, na época da chuva, 7,5% dos isolados apresentaram antagonismo enquanto na seca foi 15%. Para o patógeno 2, nem todos os isolados positivos para o patógeno 1 foram eficientes no controle, demonstrando a ocorrência de interações entre isolados bacterianos e Fusarium spp. Na chuva, para o patógeno 1, a mata apresentou maior número de isolados positivos (20%). Na seca, os tratamentos mata, 1-Floresta e 8-integração lavoura floresta para o patógeno 1, foram os que apresentaram maior número de positivos (25%). Na identificação molecular, 8 foram os gêneros bacterianos encontrados: Burkholderia, Bacillus, Brevibacillus, Streptomyces, Pseudomonas, Escherichia, Paenibacillus e Pandoraea, em que a maioria é descrita como capaz de controlar Fusarium spp. in vitro. Palavras-chave: Burkholderia; controle biológico; integração lavoura-pecuária-floresta. Biodiversity of bacteria antagonic to fungi associated with syndrome's death palisadegrass (Brachiaria brizantha) ABSTRACT: The death syndrome of marandu grass (Brachiaria brizantha) is one of the main problems in the degradation of pastures in the Amazon biome. Plant death occurs during the rainy season due to susceptibility to phytopathogens. Thus, the objective was to study production systems and select bacteria antagonistic to Fusarium spp., one of the phytopathogenic agents. Bacterial isolates were obtained from 10 production systems, native forest and fallow, in rain and drought season. Molecular characterization of isolates was carried out by sequencing. Two Fusarium isolates were assessed. For pathogen 1, in the rainy season, 7.5% of the isolates showed antagonism, while in the dry season it was 15%. For pathogen 2, not all isolates positive for pathogen 1 were efficient in the control, showing correlations between bacterial isolates and Fusarium spp. In the rain, for pathogen 1, the forest showed the highest number of positive isolates (20%). In the dry season, the treatments forest, 1-Forest and 8-plant-forest integration for pathogen 1, were ones with the highest number of positives (25%). In the molecular identification, 8 bacterial genera were found: Burkholderia, Bacillus, Brevibacillus, Streptomyces, Pseudomonas, Escherichia, Paenibacillus and Pandoraea, most of which are described as able to controlling Fusarium spp. in vitro. Keywords: Burkholderia; biological control; integrated crop-livestock-forest.

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Density and morphological characterization of bacteria in integrated and exclusive production systems

Scientific Electronic Archives ◽

10.36560/13920201194 ◽

2020 ◽

Vol 13 (11) ◽

pp. 1

Author(s):

A. R. B. Zanco ◽

A. Ferreira ◽

G. C. M. Berber ◽

E. N. Gonzaga ◽

D. C. C. Sabino

Keyword(s):

Bacterial Community ◽

Rainy Season ◽

Production Systems ◽

Cropping System ◽

Morphological Characterization ◽

Native Forest ◽

Exclusive Production ◽

Colony Forming Units

The different integrated production systems can directly interfere with its bacterial community. The present study aimed to assess density, bacterial diversity and the influence of dry and rainy season in different integrated and an exclusive production system. The fallow and a native forest area was assessed to. Samples were collected in 2012 March and September. The isolation were carried out into Petri dishes containing DYGS medium. The number of colony forming units (CFU) was counted after 48 hours and. The bacterial density ranged between 106 and 107 CFU g-1 soil. The crop system affected the dynamics of the bacterial community only in the rainy season. The rainy season showed greater density of total bacteria when compared to the dry period regardless of the cropping system. The dendrograms with 80 % similarity showed thirteen and fourteen groups in the rainy and dry seasons. Isolates with the capacity to solubilize phosphate in vitro were obtained from all areas in the two seasons, but this feature has been prevalent in bacteria isolated during the rainy season

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Density and morphological characterization of bacteria in integrated and exclusive production systems

Scientific Electronic Archives ◽

10.36560/131120201240 ◽

2020 ◽

Vol 13 (11) ◽

pp. 1

Author(s):

A. R. B. Zanco ◽

A. Ferreira ◽

G. C. M. Berber ◽

E. N. Gonzaga ◽

D. C. C. Sabino

Keyword(s):

Bacterial Community ◽

Rainy Season ◽

Production Systems ◽

Cropping System ◽

Morphological Characterization ◽

Native Forest ◽

Exclusive Production ◽

Colony Forming Units

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Virulence and Genetic Characterization of Six Baculovirus Strains Isolated From Different Populations of Spodoptera Frugiperda (Lepidoptera: Noctuidae)

10.21203/rs.3.rs-988050/v1 ◽

2021 ◽

Author(s):

Ingrid Zanella-Saenz ◽

Elisabeth A. Herniou ◽

Jorge E. Ibarra ◽

Ma.Cristina Del Rincón-Castro ◽

Ilse Alejandra Huerta-Arredondo

Keyword(s):

Biological Control ◽

Cell Cultures ◽

Spodoptera Frugiperda ◽

Fall Armyworm ◽

The United States ◽

Infection Mechanisms ◽

Different Populations

Abstract Fall armyworm (FAW), Spodoptera frugiperda (Smith, 1797), is a polyphagous, voracious, and economically important agricultural pest. Biological control of FAW is a strategy that must be further explored. This study evaluated six baculovirus strains isolated from infected FAW larvae from Mexico, Argentina, Honduras, and the United States. Five alphabaculoviruses (SfNPV-An2, SfNPV-Arg, SfNPV-Fx, SfNPV-Ho and SfNPV-Sin) and one betabaculovirus (SfGV-RV), were tested against FAW larvae, showing a wide diversity of virulence levels among strains when their estimated LC50s were compared, being SfNPVArg, SfNPV-Ho and SfNPV-Fx more virulent than SfNPV-An 2 , SfNPV-Sin and SfGV-RV. To determine any virulence difference in vitro studies of these isolates, Sf9 cell cultures were used. Interestingly, only ODVs from four of the test SfNPV strains showed infectivity on Sf9 cell cultures, and some differences in virulence were observed. Genomic restriction analyses and partial sequences of lef-8, lef-9 , and polh/granulin genes showed little variability among alphabaculoviruses, both, among them and with previously reported sequences. However, sequences from SfGV-RV were closer to previously reported sequences from the SfGVVG008 strain than the SfGV-Arg and SfGV-VG014 strains. The great difference in the in vivo virulence was not correlated with great similarity among the isolates. The characterization of these six baculoviruses isolates offers the basis for exploring their potential as biological control agents against S. frugiperda, as well the initial studies on their specific infection mechanisms, evolution, and ecology.

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Biocontrol of the Potato Blackleg and Soft Rot Diseases Caused by Dickeya dianthicola

Applied and Environmental Microbiology ◽

10.1128/aem.02525-15 ◽

2015 ◽

Vol 82 (1) ◽

pp. 268-278 ◽

Cited By ~ 27

Author(s):

Yannick Raoul des Essarts ◽

Jérémy Cigna ◽

Angélique Quêtu-Laurent ◽

Aline Caron ◽

Euphrasie Munier ◽

...

Keyword(s):

Soft Rot ◽

Potato Production ◽

Biocontrol Agents ◽

Bacterial Isolates ◽

Potato Blackleg ◽

Content Type ◽

Potato Plants ◽

Potential Strategy

ABSTRACTDevelopment of protection tools targetingDickeyaspecies is an important issue in the potato production. Here, we present the identification and the characterization of novel biocontrol agents. Successive screenings of 10,000 bacterial isolates led us to retain 58 strains that exhibited growth inhibition properties against severalDickeyasp. and/orPectobacteriumsp. pathogens. Most of them belonged to thePseudomonasandBacillusgenera.In vitroassays revealed a fitness decrease of the testedDickeyasp. andPectobacteriumsp. pathogens in the presence of the biocontrol agents. In addition, four independent greenhouse assays performed to evaluate the biocontrol bacteria effect on potato plants artificially contaminated withDickeya dianthicolarevealed that a mix of three biocontrol agents, namely,Pseudomonas putidaPA14H7 andPseudomonas fluorescensPA3G8 and PA4C2, repeatedly decreased the severity of blackleg symptoms as well as the transmission ofD. dianthicolato the tuber progeny. This work highlights the use of a combination of biocontrol strains as a potential strategy to limit the soft rot and blackleg diseases caused byD. dianthicolaon potato plants and tubers.

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Diversity of the edaphic macrofauna in areas managed under no-tillage for different periods

Semina Ciências Agrárias ◽

10.5433/1679-0359.2019v40n2p599 ◽

2019 ◽

Vol 40 (2) ◽

pp. 599

Author(s):

Cláudia dos Reis Ferreira ◽

Jair do Nascimento Guedes ◽

Jean Sérgio Rosset ◽

Lúcia Helena Cunha dos Anjos ◽

Marcos Gervasio Pereira

Keyword(s):

Rainy Season ◽

Production Systems ◽

Dry Season ◽

Soil Biology ◽

No Tillage ◽

Biological Functions ◽

Parametric Statistics ◽

Faunal Diversity ◽

Level Of Significance ◽

Crop Succession

Agriculture can considerably change the composition and richness of the edaphic macrofauna, affecting the ecological and biological functions exerted by the fauna. This study was carried out in commercial production systems in the municipality of Guaíra, state of Paraná, Brazil. The objective of this study was to evaluate the effect of no-tillage systems (NTS) and seasonality on the diversity, richness, and composition of the edaphic macrofauna. Three areas managed under NTS for different periods 7 years (NTS-7), 14 years (NTS-14), and 23 years (NTS-23) under crop succession with soybean (summer) (aNTS7) and maize/wheat (winter) (NTS14 and NTS23) were evaluated, in addition to a native Atlantic Forest segment, which was used as a reference. Faunal samples were collected in the dry season (September 2013) and rainy season (February 2014). The edaphic macrofauna was evaluated using the method proposed by the Tropical Soil Biology and Fertility Program. Parametric statistics were applied, and the results were compared using Tukey’s test at a level of significance of 5%. Species density and total richness were usually higher in the NTS14 and NTS23 in the dry season. However, higher indexes of equability were not detected because of the dominance of groups Formicidae and Isoptera. The areas with the highest equability were the reference area in the dry season and NTS23 in the rainy season, corresponding to 0.87 and 0.61, respectively. These results indicate the higher faunal diversity in these areas, which reflects the greater stability of the ecosystem.

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Characterization of Vietnamese Lacquer Collected in Different Seasons

International Journal of Polymer Science ◽

10.1155/2015/719328 ◽

2015 ◽

Vol 2015 ◽

pp. 1-6 ◽

Cited By ~ 1

Author(s):

Rong Lu ◽

Kenichiro Anzai ◽

Bach Trong Phuc ◽

Tetsuo Miyakoshi

Keyword(s):

Rainy Season ◽

Laccase Activity ◽

Water Concentration ◽

Dry Season ◽

Composition Analysis ◽

Drying Time ◽

Lipid Component ◽

Different Seasons

Vietnamese lacquers collected every month from June to March of next year were characterized. Composition analysis showed that lacquer collected in rainy season contained much water, while those collected in dry season contained more lipid component. Although hardness of lacquer films is not very hard, lacquers tapped in all seasons can reach hard dry (HD) within 48 hours. Refining lacquer can accelerate drying time but the water concentration should be maintained around 10 wt% for laccase activity.

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Morphological and molecular characterization of Fusarium spp. associated to the regional occurrence of wilt and dry bud rot in Agave tequilana

Revista Mexicana de Fitopatología Mexican Journal of Phytopathology ◽

10.18781/r.mex.fit.1911-4 ◽

2019 ◽

Vol 38 (1) ◽

Author(s):

Viridiana López-Bautista ◽

Gustavo Mora-Aguilera ◽

María Alejandra Gutiérrez-Espinosa ◽

Coral Mendoza-Ramos ◽

Verónica Inés Martínez-Bustamante ◽

...

Keyword(s):

Fusarium Oxysporum ◽

Molecular Characterization ◽

Fusarium Solani ◽

Fusarium Fujikuroi ◽

Agave Tequilana ◽

Fusarium Spp ◽

Impacto Económico ◽

Morphological And Molecular Characterization

La marchitez y pudrición seca del cogollo del agave (Agave tequilana var. azul) son enfermedades de alto impacto económico para este cultivo. En este trabajo se planteó determinar la implicación de Fusarium spp. en ambas enfermedades bajo un enfoque regional. Se colectaron muestras de raíz y suelo en 40 plantaciones comerciales ubicadas en 13 municipios de Los Altos Jalisco, importante región de cultivo de agave azul en México. De cada plantación de colecta se estimó carga de inóculo mediante un índice de Fusarium obtenido de unidades formadoras de colonias (Fusarium vs hongos totales) y se analizó su relación con pH y materia orgánica. Se obtuvieron 109 aislados caracterizados morfológicamente como Fusarium spp. de los cuales se seleccionaron 25 para identificación molecular con ITS y EF-1a. La selección consideró sintomatología, caracteres macro y microscópicos y prevalencia de tipologías de colonia observadas in vitro en medios Komada, Sabouraud, SNA y CLA. Los caracteres culturales y morfológicos evaluados fueron: coloración micelial, tamaño, forma y septación de macro y microconidios, y longitud y número de fiálides. Se asociaron cinco especies con marchitez y/o pudrición seca ubicadas en tres complejos filogenéticos: F. oxysporum del complejo de especies Fusarium oxysporum (FOSC) con 56% (46.2% suelo y 66.7% raíz) de representatividad regional; F. solani, F. falciforme y Fusarium sp. del complejo Fusarium solani (FSSC) (40%); y Fusarium sp. del complejo Fusarium fujikuroi (FFSC) (4%). MO y pH tuvieron correlación inversamente proporcional con Índice de Fusarium (r2 = 0.68-0.70). Se postula que la marchitez y pudrición seca del cogollo de agave azul constituyen un síndrome en el cual se asocian y especializan parasíticamente diversas especies de Fusarium. Se encontró un aislado de los tres complejos de Fusarium asociados específicamente a cada tipo de síntoma y la combinación de ellos. La mayoría se asociaron a marchitez con predominancia de F. oxysporum.

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Partial Characterization of Bacteriophages from Indonesia and its Potency as Biocontrol of Xanthomonas oryzae pv. oryzae

International Journal of Agriculture and Biology ◽

10.17957/ijab/15.1640 ◽

2021 ◽

Vol 25 (01) ◽

pp. 75-80

Author(s):

Desi Rejeki

Keyword(s):

Biological Control ◽

Genome Size ◽

Crop Production ◽

Xanthomonas Oryzae ◽

Biological Control Agents ◽

Vitro Assay ◽

Resistant Varieties ◽

A Genome

Bacterial leaf blight (BLB) is a disease caused by Xanthomonas oryzae pv. oryzae (Xoo) of rice in rice-producing countries including Indonesia and attack rice in all stages of growth. In the advanced, crop production will be decreased by up to 50–70%. Recently, the practical efforts to overcome the problem by using resistant varieties, antibiotics, and sanitation; however, the ability of the pathogen to forms the new virulent pathotypes is noteworthy. Alternatively, the pathogen could be environmental-friendly controlled by utilizing bacteriophages as biological control agents because of their specific characteristics to their bacterial hosts. This research aimed to obtain information about the characteristic of the first isolated bacteriophages from Indonesia. The result showed that two bacteriophages had been isolated from soil in Arjasa Jember and soil in Gadingan Situbondo, namely phage XooX1IDN and phage XooX2IDN, respectively. The two phages were inactivated at 80ºC and stable at pH within the range of 6 to 8. The phage XooX1IDN has a genome size of approximately 39 kb, while phage XooX2IDN had a genome size 38 kb. Morphologically, both phages possessed the family of Myoviridae. Phage biocontrol in vitro assay showed that both phages significantly reduced the growth of BLB pathogen, indicating that both phages potentially, as biological control agents for BLB disease in rice. © 2021 Friends Science Publishers

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Photosynthetic performance and anatomical adaptations in Byrsonima sericea DC. under contrasting light conditions in a remnant of the Atlantic forest

Brazilian Journal of Plant Physiology ◽

10.1590/s1677-04202010000400004 ◽

2010 ◽

Vol 22 (4) ◽

pp. 245-254 ◽

Cited By ~ 12

Author(s):

Anandra S. Silva ◽

Jurandi G. Oliveira ◽

Maura da Cunha ◽

Angela P. Vitória

Keyword(s):

Net Photosynthetic Rate ◽

Photosynthetic Rate ◽

Rainy Season ◽

Photosynthetic Pigment ◽

Photosynthetic Performance ◽

Dry Season ◽

Limiting Factor ◽

Native Forest ◽

The Sun ◽

Adaxial Epidermis

The photosynthetic dynamics of the tropical pioneer species, Byrsonima sericea DC., were studied during the regeneration process of a native forest by evaluating ecophysiological (gas exchange, chlorophyll a fluorescence and photosynthetic pigment contents) and anatomical parameters of plants in sunny and shady environments. Ecophysiological evaluations were carried out monthly for one year, encompassing both a dry and a rainy season. Byrsonima sericea DC. presents anatomical plasticity that enables it to establish in environments with contrasting light regimes. In sunny conditions, it produced a thicker leaf (about 420 mm) and flat adaxial epidermis, whilst in the shade, leaves had a thinner convex adaxial epidermis (about 395 mm). No differences were found in the compositions of the pigments in the different environments, however, during the dry season, the plants presented a significantly higher concentration of photosynthetic pigments. In the sun, plants showed decreases in Fv/F0 ratio (in the rainy season) and NPQ (in the dry season), but no difference was observed between plants that were in the sun or in the shade. A significantly higher net photosynthetic rate was found only in the rainy season in the plants in the sun, compared to shaded plants (9.9±0.8 and 7.4±0.3 µmol m-2s-1, respectively). Significant increase in transpiration was observed in plants in the shade during the dry season, but no alterations were observed in the water use efficiency. Ecophysiological data suggest that mainly plants overexposed to the sun underwent water limitations during the dry season and that, in the rainy season, these plants increased their net photosynthetic rate, possibly due to the greater drainage force resulting from increased growth during this period. Data suggest that anatomic alterations, namely the convex adaxial epidermis, could aid in the supply of light to shaded plants during both seasons, precluding changes in the pigments, such as the increase in chlorophyll b usually observed in shaded plants, but not detected in the present study. Another consequence of the greater quantity of light captured by these shade plants is that during the dry season their net photosynthetic rate was not different from that of plants in a sunny environment. However, when water was not a limiting factor, a better photosynthetic performance was observed in this pioneer specie in open spaces.

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Short Communication: Soil carbon pools in different pasture systems

Spanish Journal of Agricultural Research ◽

10.5424/sjar/2016141-7939 ◽

2016 ◽

Vol 14 (1) ◽

pp. e11SC01

Author(s):

Francisco M. Jr. Cardozo ◽

Romero F. V. Carneiro ◽

Luiz F. C. Leite ◽

Ademir S. F. Araujo

Keyword(s):

Short Communication ◽

Production Systems ◽

Agroforestry System ◽

Dry Season ◽

Carbon Pools ◽

Native Forest ◽

Forage Grasses ◽

Pasture Production ◽

Soil Carbon Pools ◽

Dry And Rainy Seasons

The aim of this study was to assess the carbon pools of a tropical soil where the native forest was replaced with different pasture systems. We studied five pasture production systems, including four monoculture systems with forage grasses such as Andropogon, Brachiaria, Panicum, and Cynodon, and an agroforestry system as well as a native vegetation plot. Greater availability of fulvic acid was detected in the agroforestry system as compared with that in the other systems. Higher lability of C was detected in the Andropogon system during the dry and rainy seasons and during the dry season in Cynodon. During the dry season, all pastures systems showed deficits in the net removal of atmospheric CO2. The structure and practices of the agroforestry system enables more carbon to be sequestered in the soil as compared with the monoculture pasture, suggesting that it is an important practice to mitigate climatic change and to improve soil quality.

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