TEDE Communidade:
http://www.tede2.ufrpe.br:8080/tede2/handle/tede2/4311
2023-02-01T06:56:33ZDeterminação do estado de células viáveis e não cultiváveis e caracterização fisiopatológica de isolados de Xanthomonas citri pv. viticola sob estresse térmico
http://www.tede2.ufrpe.br:8080/tede2/handle/tede2/8666
Título: Determinação do estado de células viáveis e não cultiváveis e caracterização fisiopatológica de isolados de Xanthomonas citri pv. viticola sob estresse térmico
Autor: DEL CORONA, Fernanda de Pádua
Primeiro orientador: GAMA, Marco Aurélio Siqueira da
Abstract: The Northeast region stands out as the largest producer of fine table grapes, corresponding to 99% of Brazilian exports of the fruit. In this region, bacterial canker of the grapevine, caused by Xanthomonas citri pv. viticola, is one of the main plant bacteriosis that threatens this crop. To achieve effective disease management, it is essential to understand the pathogenesis mechanisms of the bacterium, the plant-pathogen interaction, and how the environment affects the pathogen and the disease. In this context, understanding the dynamics of bacterial growth and the influence of temperature on the physio-pathological behavior of bacteria becomes essential to prevent the spread of the pathogen and create efficient strategies for managing the disease. Thus, the present work evaluated the ability to form viable but non-culturable cells (VBNC) and the physio-pathological behavior of X. citri pv. viticola under temperature stress. The CCRMXCV17, CCRMXCV80 and CCRMXCV117 strains had their growth curves determined, the logarithmic phase being observed at 96 h for all strains, while the death phase was observed at 480 h for the CCRMXCV17 strain and 288 h for the other two strains. With qPCR analysis, the occurrence of VBNC state was confirmed at 480 h for the strain CCRMXCV17 and 288 h for CCRMXCV80 and CCRMXCV117. The incubation period (IP) and the final severity (FS) of the artificial inoculation of the strains in the logarithmic and VBNC phases, did not obtain a significant interaction (P>0.05) between the phase and isolate factors, however, there was a significant difference in the IP between the means of the strain factor. All strains were resuscitated at the VBNC stage after inoculation in NYD medium. However, only the strain CCRMXCV117 showed a significant difference between the concentrations of the exponential and VBNC phases. The strains were cultivated at temperatures 29, 33, 37, 41, and 45 ºC and inoculated in grapevine seedlings to determine the epidemiological components of bacterial canker and were evaluated for in vitro biofilm formation and influence of swarming motility. The inoculation of strains cultivated under temperature stress showed a significant interaction between the factors, strain and temperature, only for the FS parameter. Weak biofilm matrix formation was observed in all strains, with a significant interaction between the factors, temperature and strain. Swarming motility under temperature stress was not detected in all three stains, since the colony growth was restricted to the center of the plate, however, there was a significant difference between the means of the factors evaluated individually. This is the first report of the occurrence of VBNC condition in strains of X. citri pv. viticola, as well as the pathogenic capacity at this stage. Thus, we emphasize the importance of applying a set of techniques for more accurate detection of this disease, as well as the continuous research of other characteristics, beyond biofilm and motility, that may influence the mechanisms of pathogenicity.
Instituição: Universidade Federal Rural de Pernambuco
Tipo do documento: Dissertação2022-07-29T00:00:00ZSeleção, identificação e aplicação de leveduras no controle da murcha-de-fusário em Vigna unguiculata (L.) Walp
http://www.tede2.ufrpe.br:8080/tede2/handle/tede2/8402
Título: Seleção, identificação e aplicação de leveduras no controle da murcha-de-fusário em Vigna unguiculata (L.) Walp
Autor: TORRES, Tiago Bezerra
Primeiro orientador: LARANJEIRA, Delson
Abstract: Cowpea fusarium wilt caused by Fusarium oxysporum f. sp. tracheiphilum (Fot) is reported in many producing regions causing production and productivity losses in Brazil and worldwide. There is no efficient control measure for this disease, as the pathogen produces chlamydospore-like resistance structures capable of remaining inactive for long periods of time under adverse conditions. The integrated use of host genetic resistance coupled with the application of antagonist yeasts is presented as a control alternative to this disease. In this context, the objective of this work was to investigate the pathogenicity and resistance of different cowpea genotypes to Fot, as well as the application of antagonistic yeast strains as biological control agents of cowpea fusarium wilt. Fot isolates were evaluated by the method of dipping or immersing roots of conidial suspended plants using two genotypes considered susceptible to the pathogen under greenhouse conditions. Isolates CFS-296 and CMM-732 promoted disease with wilting, yellowing and reduced growth in cv. BR-17 Gurguéia and IPA-206. From these isolates, twenty genotypes were characterized for resistance and interference in height, root length, number of leaves, number of branches, stem diameter, green biomass and plant dryness in relation to the disease. The genotypes presented different resistance to disease in relation to pathogen isolates, affecting the morphological characteristics of the plants. All genotypes were highly resistant to CMM-732, except the Casa Amarela-06 genotype, which was susceptible. While for CFS-296, six genotypes were moderately resistant, five susceptible and nine highly susceptible. Thirty strains of yeast isolated from cowpea plant parts were selected and characterized for inhibitory and antibiotic action in vitro on the most aggressive isolate (CMM-732), and compared with the two pathogenic isolates, demonstrating that the strains CFS-644, CFS-652 and CFS-699 were effective in reducing mycelial growth for CFS-296, as well as CFS-738 for CMM-732 isolate. In the bioprotective assay, cowpea seeds and 6-day old twinned plants treated with four yeasts by immersion and spraying at a concentration of 1x106 cells mL-1 respectively, as well as inoculated with the two pathogenic isolates, showed a reduction of 12-46%. of the severity of the disease. In particular, the CFS-652-treated Encruzilhada-04 genotype reduced the disease infection by 46%. Use of yeast biocontrol combined with host resistance has been shown to be an alternative management approach to fusarium wilt.
Instituição: Universidade Federal Rural de Pernambuco
Tipo do documento: Dissertação2019-07-30T00:00:00ZDispersão temporal de conídios de Botryosphaeriaceae em parreirais no Vale do Siriji (Pernambuco) e sensibilidade de isolados do Nordeste brasileiro a fungicidas
http://www.tede2.ufrpe.br:8080/tede2/handle/tede2/8401
Título: Dispersão temporal de conídios de Botryosphaeriaceae em parreirais no Vale do Siriji (Pernambuco) e sensibilidade de isolados do Nordeste brasileiro a fungicidas
Autor: SILVA, Fábio Júnior Araújo
Primeiro orientador: MICHEREFF, Sami Jorge
Abstract: The Botryosphaeriaceae dieback is an important disease that occurs in vineyards around the world. Pathogens infect the trunk of the vine by moving toward the central regions such as xylem and wood, promoting slow plant death. In Brazil, studies related to the
Botryosphaeriaceae dieback in grapevine are scarce, the first reports of Botryosphaeriaceae dieback occurring in grapevine, dates back to 1992. Recent studies based on phylogenetic analyzes have demonstrated a wide variation of species associated with symptoms characteristic of this disease in different regions in the Northeast Region. For the proper management of phytopathogens, it is important to know a series of factors including the pathogen dispersal in the area of crop and the availability of methods for the management of the disease. In this sense, this thesis had as objectives: (a) To analyze the conidia dispersal of Botryosphaeriaceae species in vineyards in the Northeast region of Brazil; (b) To evaluate the sensitivity of isolates of Lasiodiplodia theobromae obtained in different grape producing areas in the Northeast of Brazil to different groups of fungicides. The dispersal study was conducted in four table grape producing areas, located in tropical region (Sirijí Valley) in the state of Pernambuco (Brazil). The conidia dispersal in symptomatic plants and pruning debris
throughout the year was evaluated. The conidia dispersal data had a Goodness-of-fit to the logistic mathematical model, indicating that it could be used for future disease prediction studies. In the sensitivity study of L. theobromae the in vitro susceptibility and adaptability components of 62 symptomatic grapevine isolates originating in the Northeast of Brazil were evaluated for tebuconazole, thiophanate-methyl, azoxystrobin and iprodione. In vitro susceptibility to azoxystrobin revealed that the populations of L. theobromae in the Northeast of Brazil show different degrees of sensitivity to the fungicides tested with different values for sensitivity to tebuconazole, thiophanatomethyl, iprodione and azoxystrobin, with EC50 ranging from 0.044 to 3 μg.ml-1 for most isolates. The understanding of the dispersal of Botryosphaeriaceae conidia in the vineyards as well as the current state of the sensitivity of L. theobromae populations to different fungicides can provide parameters to establish the best management strategies for Botryosphaeriaceae dieback.
Instituição: Universidade Federal Rural de Pernambuco
Tipo do documento: Tese2019-02-19T00:00:00ZEstrutura populacional e obtenção de primers específicos para a identificação de Burkholderia cenocepacia
http://www.tede2.ufrpe.br:8080/tede2/handle/tede2/8400
Título: Estrutura populacional e obtenção de primers específicos para a identificação de Burkholderia cenocepacia
Autor: OLIVEIRA, Willams José de
Primeiro orientador: GAMA, Marco Aurélio Siqueira da
Abstract: Brazilian production of onion (Allium cepa) in 2017 was 1.72 million tons. In the northeast of Brazil, the agropolo of the San Francisco Valley was responsible for the production of 99.16% of the Northeast region in this same harvest. Losses caused by scale rot can reach 50%. However, some losses may occur during the cultivation and postharvest phase of this vegetable. This work aimed to study the structure of a population of B. cenocepacia isolates from the São Francisco Valley and to design specific primers to identify B. cenocepacia strains IIIA and IIIB.For this, genomic profiles of 63 isolates were analyzed based on REP and BOX-PCR data in the subpopulations of Petrolândia, Belém de São Francisco, Orocó e Casa Nova. Population variability and genetic structure study revealed significant variation between and inside of the subpopulations. The mantel test showed that 26% of population variability is explained by spatial distance. The genetic diversity index reflected the moderate variability of B. cenocepacia populations. The occurrence of gene flow between subpopulations was verified by the number of migrants (Nm) and shared haplotypes, demonstrated gene flow between all subpopulations. For the identification of B. cenocepacia from lineage IIIB and IIIA, were designed primers based on sequences obtained from pangenomic analysis of the complete genome of 17 isolates available from NCBI. Five pairs of primers were obtained, and two pairs were efficient in identifying and separating the lineage. With the understanding of the population structure of B. cenocepacia in the São Francisco Valley and the dynamics through which it evolves and the correct identification of the pathogen, control measures will be adopted more accurately.
Instituição: Universidade Federal Rural de Pernambuco
Tipo do documento: Tese2019-08-13T00:00:00Z