Typescript. / Thesis (Ph. D.)--University of Hawaii at Manoa, 1984. / Bibliography: leaves [82]-88. / Photocopy. / Microfilm. / viii, 88 leaves, bound ill. 29 cm

Made available in DSpace on 2014-06-11T19:26:41Z (GMT). No. of bitstreams: 0 Previous issue date: 2001-12Bitstream added on 2014-06-13T20:15:30Z : No. of bitstreams: 1 santos_hs_me_botfca.pdf: 1056814 bytes, checksum: 16624762488626f91755fcda1e8e3cc2 (MD5) / Com o objetivo de avaliar a viabilidade de utilização da enxertia em plantas de pimentão (Capsicum annuum, L.), visando ao controle da murcha de fitóftora, causada por Phytophthora capsici Leonian, instalou-se um experimento na Fazenda de Ensino Pesquisa e Produção de São Manuel da Faculdade de Ciências Agronômicas / UNESP – Campus de Botucatu. As plantas foram conduzidas em ambiente protegido, num módulo de estrutura simples, tipo arco, com 7,0 m de largura, 40,0 m de comprimento e 3,0 m de pé direito, coberto por filme de polietileno de baixa densidade de 100 micras , totalizando uma área de 280 m2. O período de condução foi de setembro de 2000 a julho de 2001. Na Fase 1 do estudo, os tratamentos se constituíram da combinação de dois híbridos, AF-2638 e AF-2640, resistentes a P, capsici utilizados como porta-enxertos, enxertados por garfagem fenda simples em três híbridos comerciais suscetíveis, ‘Magali-R’, ‘Elisa’ e ‘Margarita’ utilizados como enxertos. Estes três híbridos suscetíveis também foram utilizados como pés francos. Esta Fase foi da semeadura até a morte dos pés francos suscetíveis após a infestação do solo com o fungo, 14 dias após o transplante. A Fase 2 constou da condução das plantas enxertadas, que permaneceram vivas devido à resistência dos porta-enxertos, até a obtenção dos frutos provenientes de 9 colheitas. O delineamento experimental foi de blocos casualizados, com 4 repetições e 5 plantas por parcela. Na Fase 1 as características avaliadas foram a compatibilidade inicial de enxertia, expressa pela porcentagem de pegamento; resistência das plantas após a inoculação dos propágulos infectivos do fungo; evolução dos sintomas da doença nos pés francos; tempo gasto em dias da semeadura até a antese da primeira flor... . / With the purpose of verifying the viability of sweet pepper (C. annuum, L.) grafting to control Phytophthora blight, caused by Phytophthora capsici a experiment was carried out at F.C.A/UNESP, São Manuel Experimental Farm, São Paulo, Brazil, under a simple frame arctype vinil house, 7,0m wide, 40,0m long and 3,0m high, covered with a 100mm plastic film. The experimental design was a randomized block with four replication and five plants per plot and the evaluation period was from September 2000 to July 2001. In the first experimental phase three susceptible sweet pepper commercial hybrids (‘Magali-R’, ‘Elisa’ and ‘Margarita’) were cleft grafted on two resistant rootstocks (‘AF-2638’ and ‘AF-2640’) and plants were grown on soil infected with P.capsici, 14 days after transplanting. Ungrafted susceptible hybrids were utilized as a control and grafting compatibility, plant resistance, disease symptom evolution and number of days for flowering were recorded. In the second phase plant height, number weight, length and wall thickness of fruits as well as total and commercial fruit yield of the surviving plants were recorded for nine harvesting dates. Good compatibility between stock and rootstock was observed (93%) and grafted plant did not shower any symptoms of the disease during the evaluation period. The hybrid ‘Elisa’ was the most susceptible one when grown as ungrafted plants, with the faster disease evolution after soil infectation. Ungrafted plants flowered earlier than grafted ones and rootstocks interfered on plant height depending on the studied combinations. The hybrid ‘Magali’grafted on ‘AF-2639’produced the highest number of fruits. Among hybrids ‘Margarita’was intermediate as far as number and fruit weight is concerned. Grafted plants, besides... (Complete abstract, click electronic address below).

Orientador: Rumy Goto / Resumo: Com o objetivo de avaliar a viabilidade de utilização da enxertia em plantas de pimentão (Capsicum annuum, L.), visando ao controle da murcha de fitóftora, causada por Phytophthora capsici Leonian, instalou-se um experimento na Fazenda de Ensino Pesquisa e Produção de São Manuel da Faculdade de Ciências Agronômicas / UNESP - Campus de Botucatu. As plantas foram conduzidas em ambiente protegido, num módulo de estrutura simples, tipo arco, com 7,0 m de largura, 40,0 m de comprimento e 3,0 m de pé direito, coberto por filme de polietileno de baixa densidade de 100 micras , totalizando uma área de 280 m2. O período de condução foi de setembro de 2000 a julho de 2001. Na Fase 1 do estudo, os tratamentos se constituíram da combinação de dois híbridos, AF-2638 e AF-2640, resistentes a P, capsici utilizados como porta-enxertos, enxertados por garfagem fenda simples em três híbridos comerciais suscetíveis, 'Magali-R', 'Elisa' e 'Margarita' utilizados como enxertos. Estes três híbridos suscetíveis também foram utilizados como pés francos. Esta Fase foi da semeadura até a morte dos pés francos suscetíveis após a infestação do solo com o fungo, 14 dias após o transplante. A Fase 2 constou da condução das plantas enxertadas, que permaneceram vivas devido à resistência dos porta-enxertos, até a obtenção dos frutos provenientes de 9 colheitas. O delineamento experimental foi de blocos casualizados, com 4 repetições e 5 plantas por parcela. Na Fase 1 as características avaliadas foram a compatibilidade inicial de enxertia, expressa pela porcentagem de pegamento; resistência das plantas após a inoculação dos propágulos infectivos do fungo; evolução dos sintomas da doença nos pés francos; tempo gasto em dias da semeadura até a antese da primeira flor... (Resumo completo, clicar acesso eletrônico abaixo). / Abstract: With the purpose of verifying the viability of sweet pepper (C. annuum, L.) grafting to control Phytophthora blight, caused by Phytophthora capsici a experiment was carried out at F.C.A/UNESP, São Manuel Experimental Farm, São Paulo, Brazil, under a simple frame arctype vinil house, 7,0m wide, 40,0m long and 3,0m high, covered with a 100mm plastic film. The experimental design was a randomized block with four replication and five plants per plot and the evaluation period was from September 2000 to July 2001. In the first experimental phase three susceptible sweet pepper commercial hybrids ('Magali-R', 'Elisa' and 'Margarita') were cleft grafted on two resistant rootstocks ('AF-2638' and 'AF-2640') and plants were grown on soil infected with P.capsici, 14 days after transplanting. Ungrafted susceptible hybrids were utilized as a control and grafting compatibility, plant resistance, disease symptom evolution and number of days for flowering were recorded. In the second phase plant height, number weight, length and wall thickness of fruits as well as total and commercial fruit yield of the surviving plants were recorded for nine harvesting dates. Good compatibility between stock and rootstock was observed (93%) and grafted plant did not shower any symptoms of the disease during the evaluation period. The hybrid 'Elisa' was the most susceptible one when grown as ungrafted plants, with the faster disease evolution after soil infectation. Ungrafted plants flowered earlier than grafted ones and rootstocks interfered on plant height depending on the studied combinations. The hybrid 'Magali'grafted on 'AF-2639'produced the highest number of fruits. Among hybrids 'Margarita'was intermediate as far as number and fruit weight is concerned. Grafted plants, besides... (Complete abstract, click electronic address below). / Mestre

Plants are sessile organisms adapted to cope with dynamic changes in their environment. Abiotic stresses, such as heat, drought, or nutrient deficiency must be overcome simultaneously with biotic threats such as pathogens and herbivores. Oomycete pathogens represent a significant threat to global food production and natural ecosystems. Novel modes of oomycete disease control could increase crop yield and reduce pesticide application. Overlaps between the plant response to iron deficiency and pathogens have been documented, but the impact of simultaneous imposition of both stresses on the plant have not been studied. Additionally, nothing is known about the impact of iron deficiency on oomycete infection, or mechanisms of oomycete iron uptake. We adapted a hydroponic system to simultaneously impose iron deficiency and monitor pathogen infection. The oomycete pathogens Hyaloperonospora arabidopsidis, and Phytophthora capsici grew less well on iron-deficient Arabidopsis thaliana, at least in part because of observed activation of immunity due to iron stress. We screened A. thaliana T-DNA insertion mutants defective in iron metabolism and transport and identified potential mechanisms of H. arabidopsidis iron acquisition. We conducted RNA sequencing to understand how A. thaliana responds to iron deficiency and root infection of P. capsici. 323 genes were differentially upregulated in iron-starved plants over three days, irrespective of pathogen infection, representing a core iron deficiency response. This group of core genes included the primary A. thaliana iron uptake pathway and genes for coumarin biosynthesis. Salicylic acid responsive genes were observed in both treatments consistent with this defense hormone's previously identified role in iron deficiency. Genes related to glucosinolate production – shown to be important in defense against P. capsici – were down regulated during infection, potentially due to the activity of virulence effectors. Our work demonstrates crosstalk between the iron deficiency response and plant immunity, and that iron acquisition remains important to the plant even after pathogen invasion. These new insights provide a first step in developing novel resistance strategies to control oomycetes in agronomically important crops. / Doctor of Philosophy / Oomycetes can cause diseases in plants resulting in loss of crops and requiring application of chemical pesticides. Better understanding of how oomycetes interact with plants will lead to new strategies to control them and more efficient agriculture. In this study, we investigated the role of iron in plant-oomycete interactions, to see what this important metal nutrient might be doing to help or hurt the plants response to infection. We developed a growth system to limit iron to the plant and simultaneously observe oomycete infection. We studied the leaf pathogen Hyaloperonospora arabidopsidis or downy mildew, and Phytophthora capsici, a root pathogen that infects many types of vegetable crops. In rice, iron restriction hurt the plant's ability to fight off disease, but we observed the opposite: iron limitation caused the plant to be more resistant to both oomycete pathogens. Microscopic observation revealed that the plants ability to fight off downy mildew was not compromised by iron deficiency. Our results suggest that iron limitation triggers an immune response in the plant, which limits pathogen growth. We performed RNA sequencing on iron-deficient roots also infected with the root pathogen. This allowed us to observe how the plant responded to both stresses. The plant balances the response to iron deficiency and infection. Again, we found that iron deficiency triggers immune activation, and observed that iron-deficient plants are more resistant to infection.

Made available in DSpace on 2014-06-11T19:32:26Z (GMT). No. of bitstreams: 0 Previous issue date: 2005-08-22Bitstream added on 2014-06-13T20:04:00Z : No. of bitstreams: 1 santos_hs_dr_botfca.pdf: 1546408 bytes, checksum: d25b46b4f52200f204737b84f9ba16ae (MD5) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / Avaliou-se a produtividade, o acúmulo e a exportação de nutrientes por plantas de pimentão (Capsicum annuum L.) enxertadas e não enxertadas, cultivadas sob ambiente protegido. O experimento foi conduzido de agosto de 2003 a maio de 2004 na Escola Técnica Estadual Augusto Tortolero Araújo pertencente ao Centro Estadual de Educação Tecnológica Paula Souza, em Paraguaçu Paulista, SP. Os porta-enxertos utilizados, AF 2638 e AF 2640, possuem resistência à Phytophthora capsici Leonian e Meloidogyne incognita raça 2. Os tratamentos constaram dos híbridos 'Rúbia R' e 'Margarita' sem enxertar, enxertados sobre os dois porta-enxertos e enxertados neles mesmos. O delineamento experimental foi em blocos ao acaso com oito tratamentos, quatro repetições e 15 plantas por parcela. As plantas foram avaliadas quanto a altura da maior haste, altura da primeira bifurcação, precocidade de florescimento, comprimento e número médio de internódios, produção e características dos frutos produzidos em 12 colheitas, massa de matéria verde e seca de folhas, caules e frutos. As análises químicas foram realizadas em uma planta por parcela aos 35, 83, 135, 178 e 213 dias após o transplante, para determinar a marcha de absorção e exportação de nutrientes. Verificou-se que os híbridos enxertados e não enxertados apresentaram produtividades médias de 132 e 153 t ha-1 para as combinações enxertadas de 'Rúbia R' e 'Rúbia R' pé-franco respectivamente e de 144 e 132 t ha-1 para as combinações enxertadas de 'Margarita' e 'Margarita' pé-franco respectivamente. O acúmulo de nutrientes não foi significativamente diferente entre plantas enxertadas e pés-francos, e a ordem decrescente dos nutrientes acumulados foi: K>N>Ca>Mg>P>S. A partir do que foi observado, concluiu-se que, nessas condições, a enxertia em plantas de pimentão não alterou seu desempenho agronômico, nem teve influência sobre a marcha de absorção de nutrientes. / It was evaluated the yield, accumulation and exportation of nutrients by sweet pepper plants grafted and non grafted, under protected cultivation. The research was carried out from August 2003 to May 2004, at the Technical School Augusto Tortolero Araújo, part of Paula Souza State Center of Technological Education, in Paraguaçu Paulista, SP, in Brazil. The rootstocks used - AF 2638 and AF 2640, are resistant to Phytophthora capsici Leonian and Meloidogyne incognita race 2. The treatments were constituted of non grafted hybrids 'Rúbia R' and 'Margarita'; grafted on two evaluated rootstocks and grafted on themselves. The experimental design was of completely randomized blocks with eight treatments, four replications and fifteen plants per plot. Five plants were sent for chemical analysis. Evaluations of the total plants height, first fork height, early blossom, length and average number of internodes, total yield and fruits characteristics of 12 harvests, fresh and dry matter of leaves, stems and fruits, were carried out. The samples for the chemical analysis were taken at the 35th, 83th, 135th, 173th and 213th days after transplantation, with the objective of determining the accumulation and exportation of the nutrients. The results proved that the grafted and non grafted plants had average yield, with the average of 132 and 153 t ha-1 for the grafted combinations of 'Rúbia R' and non grafted plants of 'Rúbia R' respectively and 144 and 132 t ha-1 for the grafted combinations of 'Margarita' and non grafted plants of 'Margarita' respectively. The accumulation of the nutrients was equivalent for grafted combinations and non grafted plants, and nutrients in decreasing order of accumulation were: K>N>Ca>Mg>P>S. It was evidenced that grafting sweet pepper plants neither its agronomic performance, nor interfered on the uptake of nutrients' absorption.

Orientador: Rumy Goto / Banca: Roberto Lyra Villas Bôas / Banca: Dirceu Maximino Fernandes / Banca: Sebastião Wilson Tivelli / Banca: Arlete Marchi Tavares de Melo / Resumo: Avaliou-se a produtividade, o acúmulo e a exportação de nutrientes por plantas de pimentão (Capsicum annuum L.) enxertadas e não enxertadas, cultivadas sob ambiente protegido. O experimento foi conduzido de agosto de 2003 a maio de 2004 na Escola Técnica Estadual Augusto Tortolero Araújo pertencente ao Centro Estadual de Educação Tecnológica Paula Souza, em Paraguaçu Paulista, SP. Os porta-enxertos utilizados, AF 2638 e AF 2640, possuem resistência à Phytophthora capsici Leonian e Meloidogyne incognita raça 2. Os tratamentos constaram dos híbridos 'Rúbia R' e 'Margarita' sem enxertar, enxertados sobre os dois porta-enxertos e enxertados neles mesmos. O delineamento experimental foi em blocos ao acaso com oito tratamentos, quatro repetições e 15 plantas por parcela. As plantas foram avaliadas quanto a altura da maior haste, altura da primeira bifurcação, precocidade de florescimento, comprimento e número médio de internódios, produção e características dos frutos produzidos em 12 colheitas, massa de matéria verde e seca de folhas, caules e frutos. As análises químicas foram realizadas em uma planta por parcela aos 35, 83, 135, 178 e 213 dias após o transplante, para determinar a marcha de absorção e exportação de nutrientes. Verificou-se que os híbridos enxertados e não enxertados apresentaram produtividades médias de 132 e 153 t ha-1 para as combinações enxertadas de 'Rúbia R' e 'Rúbia R' pé-franco respectivamente e de 144 e 132 t ha-1 para as combinações enxertadas de 'Margarita' e 'Margarita' pé-franco respectivamente. O acúmulo de nutrientes não foi significativamente diferente entre plantas enxertadas e pés-francos, e a ordem decrescente dos nutrientes acumulados foi: K>N>Ca>Mg>P>S. A partir do que foi observado, concluiu-se que, nessas condições, a enxertia em plantas de pimentão não alterou seu desempenho agronômico, nem teve influência sobre a marcha de absorção de nutrientes. / Abstract: It was evaluated the yield, accumulation and exportation of nutrients by sweet pepper plants grafted and non grafted, under protected cultivation. The research was carried out from August 2003 to May 2004, at the Technical School Augusto Tortolero Araújo, part of Paula Souza State Center of Technological Education, in Paraguaçu Paulista, SP, in Brazil. The rootstocks used - AF 2638 and AF 2640, are resistant to Phytophthora capsici Leonian and Meloidogyne incognita race 2. The treatments were constituted of non grafted hybrids 'Rúbia R' and 'Margarita'; grafted on two evaluated rootstocks and grafted on themselves. The experimental design was of completely randomized blocks with eight treatments, four replications and fifteen plants per plot. Five plants were sent for chemical analysis. Evaluations of the total plants height, first fork height, early blossom, length and average number of internodes, total yield and fruits characteristics of 12 harvests, fresh and dry matter of leaves, stems and fruits, were carried out. The samples for the chemical analysis were taken at the 35th, 83th, 135th, 173th and 213th days after transplantation, with the objective of determining the accumulation and exportation of the nutrients. The results proved that the grafted and non grafted plants had average yield, with the average of 132 and 153 t ha-1 for the grafted combinations of 'Rúbia R' and non grafted plants of 'Rúbia R' respectively and 144 and 132 t ha-1 for the grafted combinations of 'Margarita' and non grafted plants of 'Margarita' respectively. The accumulation of the nutrients was equivalent for grafted combinations and non grafted plants, and nutrients in decreasing order of accumulation were: K>N>Ca>Mg>P>S. It was evidenced that grafting sweet pepper plants neither its agronomic performance, nor interfered on the uptake of nutrients' absorption. / Doutor

In this thesis, I set out to investigate the nature of nonhost resistance responses of Nicotianae sylvestris against Phytophthora capsici and P. infestans. Schulze-Lefert and Panstruga (2011) proposed that the inability of a pathogen to establish infection in nonhost plants could be a feature of the phylogenetic distance between host and nonhost plants. In distantly related plants PAMP triggered immunity is thought to be the major contribution to resistance as effectors are inappropriately attuned to perturb their orthologous plant targets. In contrast, effector triggered immunity (ETI) could be the major contributor to resistance in nonhost plants that are more closely related to the host plants. P. capsici and P. infestans can both infect Solanaceae plants including Solanum lycopersicum and N. benthamiana but both fail to cause disease or complete their life-cycle in N. sylvestris. Based on the hypothesis of Schulze-Lefert and Panstruga (2011), ETI should be contributing towards effective nonhost resistance responses in N. sylvestris against both pathogens. In addition, it is tempting to speculate that N. sylvestris, with a limited availability of functional resistance genes including Nucleotid binding-Leucine rich repeats (NB-LRRs), could be setup to recognise and responds to sequence-related effectors from P. infestans and P. capsici, rather than to have resistance genes that are specifically attuned to either pathogen. I conducted three research strands to test this theory. In Chapter 3 I used MCL clustering to classify 563 P. infestans and 515 P. capsici RXLR effector genes and defined families on the basis of sequence similarity. I found that the P. infestans and P. capsici RXLR complements are mostly species-specific. To investigate the role of ETI in nonhost resistance, 48 P. capsici and 82 P. infestans RXLR were screened for recognition by the nonhost plant N. sylvestris. Using this approach I identified 4 P. infestans and 8 P. capsici effectors that are consistently recognised in N. sylvestris (Chapter 4). Surprisingly, most of the recognised effectors are part of species-specific clusters. In Chapter 5 I established and implemented PathSeq, an enrichment and sequencing tool that facilitates the massively parallel study of naturally occurring diversity of pathogen effectors, including those that are recognised in N. sylvestris. In the same chapter I also used PathSeq and de novo prediction to expand the P. infestans RXLR complement from 563 to 1220 putative effectors. In this thesis I have shown that P. infestans and P. capsici effector set are diversifying at the sequence level. My data also suggests that ETI might play a part in nonhost resistance of N. sylvestris to P. capsici and P. infestans. Finally I have presented PathSeq, a tool that allows the study of the effectors set in multiple isolates at the time, and this, for a fraction of the cost of a full genome sequencing experiment.

Este estudo descreve a diversidade de actinobactérias isoladas da esponja marinha Aplysina fulva e o potencial destes microorganismos como produtores de metabólitos bioativos com propriedades fungicidas e herbicidas. Actinobactérias são prolíficas produtoras de compostos farmacologicamente importantes, pois cerca de 70% dos antibióticos naturalmente derivados que estão atualmente em uso clínico são produzidos por estes microorganismos. Entretanto este valor é ainda inexpressivo na indústria agrícola. Agroquímicos sintéticos ainda são dominantes no mercado apesar de estarem menos efetivos contra plantas daninhas e patógenos cada vez mais resistentes. Neste trabalho, um total de 21 actinobactérias foram isoladas com a utilização de meios seletivos. Análises filogenéticas baseadas no sequenciamento parcial do gene que codifica para o rRNA 16S mostrou que estes microorganismos pertencem a oito gêneros do filo Actinobacteria: Kocuria; Citricoccus; Terrabacter; Gordonia; Agrococcus; Tsukamurella; Brevibacterium e Streptomyces. Os extratos de todos os isolados foram testados para verificar a produção de metabólitos secundários com propriedades fungicidas contra os fungos fitopagênicos de importância agrícola: Pythium aphanidermatum; Phytophthora capsici e Magnaporthe grisea. O extrato bruto de 43% dos isolados mostrou atividade fungicida para ao menos um dos patógenos. O perfil químico do extrato dos isolados com bioatividade positiva foram similares mesmo entre gêneros diferentes. Os metabólitos do Streptomyces ASPSP 103 foram mais eficientes devido à forte inibição contra todos os patógenos testados. Portanto este isolado foi selecionado e testado para atividade herbicida por meio de screening que teve início com testes de atividade algicida contra a microalga Selenastrum capricornutum. Acreditamos que actinobactérias associadas a esponjas marinhas desempenham um papel de defesa química contra microalgas que possam obstruir os porócitos asfixiando o animal, e que estes compostos algicidas possivelmente tenham ação herbicida. Foi verificada atividade do extrato bruto do Streptomyces ASPSP 103 contra S. capricornutum, e a atividade herbicida pré-emergência com um efeito fraco em Lactuca sativa (dicotiledônea) e uma forte inibição em Agrostis stolonifera (monocotiledônea). A purificação do extrato bruto para isolamento do composto bioativo foi guiado por bioensaio contra Pythium aphanidermatum, um oomiceto de rápido crescimento e sensível aos metabólitos de ASPSP 103 previamente testados. Foi identificado o composto da classe butenolida com atividade herbicida préemergência contra Agrostis stolonifera (IC50 33.43 μg/mL). Este é o primeiro relato da atividade de butenolida para atividade herbicida. Estudos aprofundados em taxonomia mostraram que as características filogenéticas, morfológicas e químicas do isolado ASPSP 103 são consistentes com o gênero Streptomyces. Portanto devido algumas diferenças em parâmetros taxonômicos, ASPSP 103T foi proposto como linhagem tipo para uma nova espécie de Streptomyces, para qual o nome Streptomyces atlanticus sp. nov. foi sugerido. Estes resultados enfatizam o potencial de Streptomyces marinhos para produzir compostos bioativos com potencial de aplicação em agrobiotecnologia. / Actinobacteria are producers of important pharmacological compounds. About 70% of natural antibiotics are derived from these microorganisms. However, the use of natural compounds are still limited in the agricultural industry, even considering that synthetic pesticides are less effective against pathogens and weed plants. This study describes the diversity of actinobacteria associated with the marine sponge Aplysina fulva and their potential as producers of bioactive compounds with fungicidal and herbicidal properties. In this study, a total of 21 actinomycetes were isolated with the use of selective media. Phylogenetic analyzes based on partial sequencing of the gene encoding for 16S rRNA showed that these microorganisms belong to eight Actinobacteria genera, including Kocuria, Citricoccus, Terrabacter, Gordonia, Agrococcus, Tsukamurella, Brevibacterium and Streptomyces. The extracts of all isolates were tested for the production of secondary metabolites with fungicidal properties against the following phytopathogenic fungi: of Pythium aphanidermatum, Phytophthora capsici and Magnaporthe grisea. The crude extract of 43% of the isolates showed fungicidal activity for at least one of the pathogens. The chemical profiles of the actinobacteria extracts with positive bioactivity were similar even among different genus. The metabolites of Streptomyces ASPSP 103 were more efficient because of the strong inhibition against all tested pathogens. So, the isolate ASPSP 103 was selected and tested for herbicide activity through screening for algaecide activity towards microalgae Selenastrum capricornutum. We believe that actinobacteria associated with marine sponges play a role in chemical defense against algae that can obstruct the pores, choking the animal. These algaecides compounds possibly have herbicide action. Activity of the Streptomyces ASPSP 103 crude extract against S. capricornutum was observed. In addition, it was observed a weak pre-emergence herbicide activity on Lactuca sativa (dicot) and a strong inhibition in Agrostis stolonifera (monocot). The purification of the crude extract to isolate the bioactive compound was guided by bioassay against Pythium aphanidermatum, a fast growing oomycete and sensitive to metabolites from ASPSP 103 previously tested. The butenolide compound was identified with pre-emergence herbicidal activity against Agrostis stolonifera (IC50 33.43 μg/mL). This is the first report of butenolide activity with herbicide activity. Taxonomy studies showed that the phylogenetic, morphological and chemical characteristics of the isolated ASPSP 103 are consistent with the Streptomyces genus. Then, considering some differences in taxonomic parameters, ASPSP 103T was proposed as line type for a new species of Streptomyces, for which the name Streptomyces atlanticus sp. nov. was suggested. These results emphasize the potential of marine Streptomyces to produce bioactive compounds with potential biotechnological application in agricultural industry.

Este estudo descreve a diversidade de actinobactérias isoladas da esponja marinha Aplysina fulva e o potencial destes microorganismos como produtores de metabólitos bioativos com propriedades fungicidas e herbicidas. Actinobactérias são prolíficas produtoras de compostos farmacologicamente importantes, pois cerca de 70% dos antibióticos naturalmente derivados que estão atualmente em uso clínico são produzidos por estes microorganismos. Entretanto este valor é ainda inexpressivo na indústria agrícola. Agroquímicos sintéticos ainda são dominantes no mercado apesar de estarem menos efetivos contra plantas daninhas e patógenos cada vez mais resistentes. Neste trabalho, um total de 21 actinobactérias foram isoladas com a utilização de meios seletivos. Análises filogenéticas baseadas no sequenciamento parcial do gene que codifica para o rRNA 16S mostrou que estes microorganismos pertencem a oito gêneros do filo Actinobacteria: Kocuria; Citricoccus; Terrabacter; Gordonia; Agrococcus; Tsukamurella; Brevibacterium e Streptomyces. Os extratos de todos os isolados foram testados para verificar a produção de metabólitos secundários com propriedades fungicidas contra os fungos fitopagênicos de importância agrícola: Pythium aphanidermatum; Phytophthora capsici e Magnaporthe grisea. O extrato bruto de 43% dos isolados mostrou atividade fungicida para ao menos um dos patógenos. O perfil químico do extrato dos isolados com bioatividade positiva foram similares mesmo entre gêneros diferentes. Os metabólitos do Streptomyces ASPSP 103 foram mais eficientes devido à forte inibição contra todos os patógenos testados. Portanto este isolado foi selecionado e testado para atividade herbicida por meio de screening que teve início com testes de atividade algicida contra a microalga Selenastrum capricornutum. Acreditamos que actinobactérias associadas a esponjas marinhas desempenham um papel de defesa química contra microalgas que possam obstruir os porócitos asfixiando o animal, e que estes compostos algicidas possivelmente tenham ação herbicida. Foi verificada atividade do extrato bruto do Streptomyces ASPSP 103 contra S. capricornutum, e a atividade herbicida pré-emergência com um efeito fraco em Lactuca sativa (dicotiledônea) e uma forte inibição em Agrostis stolonifera (monocotiledônea). A purificação do extrato bruto para isolamento do composto bioativo foi guiado por bioensaio contra Pythium aphanidermatum, um oomiceto de rápido crescimento e sensível aos metabólitos de ASPSP 103 previamente testados. Foi identificado o composto da classe butenolida com atividade herbicida préemergência contra Agrostis stolonifera (IC50 33.43 μg/mL). Este é o primeiro relato da atividade de butenolida para atividade herbicida. Estudos aprofundados em taxonomia mostraram que as características filogenéticas, morfológicas e químicas do isolado ASPSP 103 são consistentes com o gênero Streptomyces. Portanto devido algumas diferenças em parâmetros taxonômicos, ASPSP 103T foi proposto como linhagem tipo para uma nova espécie de Streptomyces, para qual o nome Streptomyces atlanticus sp. nov. foi sugerido. Estes resultados enfatizam o potencial de Streptomyces marinhos para produzir compostos bioativos com potencial de aplicação em agrobiotecnologia. / Actinobacteria are producers of important pharmacological compounds. About 70% of natural antibiotics are derived from these microorganisms. However, the use of natural compounds are still limited in the agricultural industry, even considering that synthetic pesticides are less effective against pathogens and weed plants. This study describes the diversity of actinobacteria associated with the marine sponge Aplysina fulva and their potential as producers of bioactive compounds with fungicidal and herbicidal properties. In this study, a total of 21 actinomycetes were isolated with the use of selective media. Phylogenetic analyzes based on partial sequencing of the gene encoding for 16S rRNA showed that these microorganisms belong to eight Actinobacteria genera, including Kocuria, Citricoccus, Terrabacter, Gordonia, Agrococcus, Tsukamurella, Brevibacterium and Streptomyces. The extracts of all isolates were tested for the production of secondary metabolites with fungicidal properties against the following phytopathogenic fungi: of Pythium aphanidermatum, Phytophthora capsici and Magnaporthe grisea. The crude extract of 43% of the isolates showed fungicidal activity for at least one of the pathogens. The chemical profiles of the actinobacteria extracts with positive bioactivity were similar even among different genus. The metabolites of Streptomyces ASPSP 103 were more efficient because of the strong inhibition against all tested pathogens. So, the isolate ASPSP 103 was selected and tested for herbicide activity through screening for algaecide activity towards microalgae Selenastrum capricornutum. We believe that actinobacteria associated with marine sponges play a role in chemical defense against algae that can obstruct the pores, choking the animal. These algaecides compounds possibly have herbicide action. Activity of the Streptomyces ASPSP 103 crude extract against S. capricornutum was observed. In addition, it was observed a weak pre-emergence herbicide activity on Lactuca sativa (dicot) and a strong inhibition in Agrostis stolonifera (monocot). The purification of the crude extract to isolate the bioactive compound was guided by bioassay against Pythium aphanidermatum, a fast growing oomycete and sensitive to metabolites from ASPSP 103 previously tested. The butenolide compound was identified with pre-emergence herbicidal activity against Agrostis stolonifera (IC50 33.43 μg/mL). This is the first report of butenolide activity with herbicide activity. Taxonomy studies showed that the phylogenetic, morphological and chemical characteristics of the isolated ASPSP 103 are consistent with the Streptomyces genus. Then, considering some differences in taxonomic parameters, ASPSP 103T was proposed as line type for a new species of Streptomyces, for which the name Streptomyces atlanticus sp. nov. was suggested. These results emphasize the potential of marine Streptomyces to produce bioactive compounds with potential biotechnological application in agricultural industry.