Extraction and analysis of apoplastic phenolic metabolites in carnation roots and stems (Dianthus caryo-phyllus L) / Extracción y análisis de metabolitos fenólicos apoplásticos en raíz y tallo de clavel (Dianthus caryophyllus L) / Extração e análise do meta-bólitos fenólicos apoplásticos na raiz e caule do craveiro (Dianthus caryophyllus L)

Abstract The present study outlines the conditioning of various parameters for the efficient removal of the apoplastic fraction of carnation enriched in polar compounds, mainly phenolics. Several studies can apply the described workflow to different plant species in the particular or global analysis of those metabolites in this peripheral extracellular space. Hence, using carnation (Dianthus caryophyllus L) roots and stems, we evaluated different infiltration solutions for removing apoplastic metabolites. The best outcome was obtained by using the buffer solution NaH2PO4-Na2HPO4 0.1 M pH 6.5/NaCl 50 mM, since the highest amount of apoplastic phenolic metabolites can be obtained with the slightest contamination of intracellular compounds. The metabolites were separated using HPLC-DAD-ESI-MS, affording chromatographic profiles with reasonable quality parameters based on resolution, selectivity, and number of theoretical plates. It was possible to identify eight differential compounds (one flavone and seven flavonols), whose core moieties consisted of (iso)pratol, kaempferide, (dihydro)kaempferol, quercetin, and myricetin-type flavonoids according to the test organ and the cultivar. We deduced that identified flavonoids are related to phytoanticipin-type metabolites in carnation, such as hydroxy-methoxyflavone, di-o-benzoylquercetin, and kaempferide disalicyloylrhamnoside, which are abundantly present in the resistant cultivar. The conditions described in this work are fundamental for delving into the role of apoplastic phenolic metabolites related to the defense mechanisms of this ornamental plant.

Resumen En el presente estudio se describe el acondicionamiento de algunos parámetros con fines de obtención eficiente de extractos apoplásticos enriquecidos en compuestos polares, principalmente fenólicos. Este flujo de trabajo descrito, incluso, puede ser aplicado a diferentes especies vegetales para ser empleado en el análisis particular o global de metabolitos en este espacio extracelular periférico. Para ello, usando raíces y tallos de clavel (Dianthus cariophyllus L), se evaluaron diferentes soluciones de infiltración para la extracción de los metabolitos apoplásticos. El mejor resultado se logró con la disolución amortiguadora NaH2PO4-Na2HPO4 0,1 M pH 6,5/NaCl 50 mM, porque se obtiene la mayor cantidad de metabolitos fenólicos apoplásticos, con la menor contaminación de compuestos intracelulares. Los metabolitos se separaron mediante HPLC-DAD-ESI-MS, obteniendo perfiles cromatográficos con parámetros de calidad razonables basados en resolución, selectividad y número de platos teóricos. Con estas condiciones, fue posible identificar ocho compuestos diferenciales (una flavona y siete flavonoles), cuyas estructuras básicas comprendían flavonoides del tipo (iso)pratol, kaempférido, (dihidro) kaempferol, quercetina y miricetina, según el órgano de prueba y la variedad. Los flavonoides identificados están relacionados con metabolitos de tipo fitoanticipina en el clavel, como hidroxi-metoxiflavona, di-o-benzoilquercetina y kaempférido disaliciloilrhamnósido, abundantemente presentes en la variedad resistente. Las condiciones descritas en este trabajo son fundamentales para profundizar en el papel de los metabolitos fenólicos apoplásticos relacionados con los mecanismos de defensa de esta planta ornamental.

Resumo O presente estudo descreve o condicionamento de alguns parâmetros para a obtenção eficiente de extratos apoplásticos enriquecidos em compostos polares, principalmente fenólicos. Este fluxo de trabalho descrito pode até mesmo ser aplicado a diferentes espécies de plantas para serem usadas na análise particular ou global de metabólitos neste espaço extracelular periférico. Para isso, utilizando raízes e caules de craveiro (Dianthus cariophyllus L), diferentes soluções de infiltração foram avaliadas para a extração de metabólitos apoplásticos. O melhor resultado foi obtido com a solução tampão NaH2PO4-Na2HPO40 0.1 M pH 6.5/NaCl 50 mM, pois a maior quantidade de metabólitos fenólicos apoplásticos é extraída. Os metabólitos foram separados por HPLC-DAD-ESI-MS, obtendo-se perfis cromatográficos com parâmetros de qualidade razoáveis baseados na resolução, seletividade e número de pratos teóricos. Nessas condições, foi possível identificar oito compostos diferenciais (uma flavona e sete flavonóis), cujas estruturas básicas compreendem flavonóides do tipo (iso) pratol, kaempferida, (dihidro)kaempferol, quercetina e miricetina, de acordo com o órgão e a variedade de craveiro utilizado. Os flavonóides identificados estão relacionados a metabólitos do tipo fitoanticipinas no craveiro, como hidroxi-metoxiflavona, di-O-benzoilquercetina e kaempférido disaliciloilramnósido, abundantemente ocorridos na cultivar resistente. As condições descritas neste trabalho são essenciais para se aprofundar no papel dos metabólitos fenólicos apoplásticos relacionados aos mecanismos de defesa dessa planta ornamental.

Fructosan form Paenibacillus kribbensis PS04 enhance disease resistance against Rhizoctonia solani and tobacco mosaic virus

BACKGROUND: Rice sheath blight (caused by Rhizoctonia solani) and tobacco mosaic virus are very important plant diseases, causing a huge loss in global crop production. Paenibacillus kribbensis PS04 is a broad-spectrum biocontrol agent, used for controlling these diseases. Previously, extracellular polysaccharides (EPS) from P. kribbensis PS04 had been purified and their structure was inferred to be fructosan. This study aimed to evaluate the effects of exogenous EPS treatment on plant­pathogen interactions. RESULTS: Plant defense genes such as phenylalanine ammonia-lyase, catalase, chitinase, allene oxide synthase, and PR1a proteins were significantly induced by exogenous EPS treatment. Moreover, subsequent challenge of EPSpretreated plants with the pathogens (R. solani or tobacco mosaic virus) resulted in higher expression of defenseassociated genes. Increased activities of defense-associated enzymes, total phenols, and flavonoids were also observed in EPS pretreated plants. The contents of malondialdehyde in plants, which act as indicator of lipid peroxidation, were reduced by EPS treatment. CONCLUSIONS: This study comprehensively showed that EPS produced from P. kribbensis PS04 enhances disease resistance in plants by the activation of defense-associated genes as well as through the enhancement of activities of defense-related enzymes.

Identification and characterization of antifungal compounds from a Burkholderia strain against plant pathogenic fungi

Aims@#Biocontrol of fungal plant pathogens using beneficial microorganisms is a safer alternative over synthetic fungicides. PHP12 is a bacterial strain isolated from healthy oil palm rhizosphere and is closely related to the recently described Burkholderia stagnalis, a member of the Burkholderia cepacia complex. This study aimed to characterize the antifungal activity spectrum of PHP12 and identify the antifungal compounds produced by the strain.@*Methodology and results@#The antifungal activity of PHP12 was characterized by growing fungal strains in the presence and absence of PHP12 and measuring the radius of the antifungal zone. PHP12 inhibited the growth of fungal pathogens including Ganoderma boninense, Curvularia oryzae, Phellinus noxius and Colletotrichum capsici. However, PHP12 did not inhibit the growth of Trichoderma asperellum, a known fungal biocontrol agent. The antifungal compounds of PHP12 were precipitated using ammonium sulfate and further purified with HPLC followed by identification using Liquid Chromatography Electrospray Ionization Tandem Mass Spectrometric (LC/ESI-MS). The LC/ESI-MS analysis showed the presence of an oligopeptide with a molecular weight of 1210.63 Da. The peptide consists of heavily modified amino acids that are linked by a hexose residue. @*Conclusion, significance and impact of study@#Although characteristics of the antifungal compounds are similar to other antifungal peptides from Burkholderia such as occidiofungin, there have been no reports of antifungal peptides from B. stagnalis with the corresponding molecular weight or fragmentation profile. The novelty of the compound, as well as its antifungal spectrum, makes PHP12 an interesting strain to be investigated further as a biocontrol agent.

The potential of compounds isolated from Xylaria spp. as antifungal agents against anthracnose

ABSTRACT Anthracnose is a crop disease usually caused by fungi in the genus Colletotrichum or Gloeosporium. These are considered one of the main pathogens, causing significant economic losses, such as in peppers and guarana. The current forms of control include the use of resistant cultivars, sanitary pruning and fungicides. However, even with the use of some methods of controlling these cultures, the crops are not free of anthracnose. Additionally, excessive application of fungicides increases the resistance of pathogens to agrochemicals and cause harm to human health and the environment. In order to find natural antifungal agents against guarana anthracnose, endophytic fungi were isolated from Amazon guarana. The compounds piliformic acid and cytochalasin D were isolated by chromatographic techniques from two Xylaria spp., guided by assays with Colletotrichum gloeosporioides. The isolated compounds were identified by spectrometric techniques, as NMR and mass spectrometry. This is the first report that piliformic acid and cytochalasin D have antifungal activity against C. gloeosporioides with MIC 2.92 and 2.46 µmol mL-1 respectively. Captan and difenoconazole were included as positive controls (MIC 16.63 and 0.02 µmol mL-1, respectively). Thus, Xylaria species presented a biotechnological potential and production of different active compounds which might be promising against anthracnose disease.

Condiciones para el análisis electrofóretico de proteínas apoplásticas de tallos y raíces de clavel (Dianthus caryophyllus L.) para estudios proteómicos / Electrophoretic conditions for analysis of apoplastic proteins in stems and roots of carnation (Dianthus caryophyllus L.) for proteomic studies / Condições para a análise eletroforética de proteínas apoplásticas de caules e raízes de cravo (Dianthus caryophyllus L.) para estudos proteômicos

Resumen En el presente estudio se describe un flujo de trabajo que puede ser aplicado a diferentes especies vegetales, con el fin de obtener extractos apoplásticos que puedan ser usados para análisis proteómicos. Para ello, usando tallos y raíces de clavel, se evaluaron parámetros claves para la extracción de estas proteínas. Se determinó que para esta especie (Dianthus caryophyllus L.) se debe usar la solución amortiguadora fosfato de sodio 0,1 M pH 6,5, cloruro de sodio 50 mM y 0,1% β-mercaptoetanol para la infiltración; con tres tiempos de vacío de 20 s a 70 kPa y centrifugación a 1000 x g durante 20 min a 4 °C, seguido de precipitación y concentración de proteínas con el método Ácido tricloroacético/acetona. Bajo estas condiciones, se obtienen extractos que permiten análisis electroforéticos en 2D de proteínas de apoplasto, usando para el isolectroenfoque tiras con gradientes de pH 5-8 para raíz y pH 3-10 para tallo. Las condiciones descritas permitirán profundizar sobre el papel de las proteínas apoplásticas en diversidad de fenómenos biológicos que involucren esta especie vegetal.

Abstract In the present study a workflow, that can be applied to different plant species, to obtain a high quality apoplastic extract and for proteomic analysis is described. For that, using carnation roots and stems, some important parameters for the extraction of these proteins were evaluated. The best conditions for the infiltration were provided by using a 0.1 M sodium phosphate buffer pH 6.5, 50 mM sodium chloride and β -mercaptoethanol 0.1%, with 3 vacuum times at 70 kPa for 20 s and centrifuged at 4°C at 1,000 g for 20 min, and then a subsequent protein precipitation and concentration with the Trichloroacetic acid/acetone protocol. These conditions can be used to obtain a good quality extract for 2D electrophoretic analysis of apoplastic proteins. Strips with pH gradients between 5-8 and 3-10 were used to run isoelectric analysis for extracts obtained from apoplast in roots and stems, respectively. The conditions described can be used to perform studies focused on apoplastic proteins and its role in biological phenomena involving this plant species.

Resumo No presente estudo, é descrito um fluxo de trabalho que pode ser aplicado a espécies vegetais diferentes, para obter extratos apoplásticos que podem ser utilizados para análise proteômico. Para isto, utilizando os caules e as raízes do cravo, foram avaliados parâmetros considerados chave para a extração destas proteínas. Foi determinado que para esta espécie, deve ser utilizada uma solução tampão de fosfato de sódio 0,1 M pH 6,5 com cloreto de sódio 50 mM e 0,1% β-mercaptoetanol para a infiltração; com três aplicações de vácuo de 20 s a 70 kPa e centrifugação a 1000 x g por 20 minutos a 4°C, e subsequente precipitação e concentração de proteínas usando Ácido ricloroacético/acetona. Nestas condições se podem obter extratos que permitem a análise eletroforética 2D de proteínas do apoplasto utilizando para a focalização isoeléctrica tiras com gradientes de pH 5-8 para a raiz e de pH 3-10 para o caule. As condições descritas permitirão aprofundar sobre o papel das proteínas apoplásticas numa diversidade de fenômenos biológicos que envolvem esta espécie de planta.

Mycoherbicidal Potential of Phaeoacremonium italicum, A New Pathogen of Eichhornia crassipes Infesting Harike Wetland, India

Mycoherbicides are exclusive biotechnology products which offer a non-chemical solution to control noxious weeds on the land as well as aquatic in systems, viz a viz saving environment from hazardous impact of synthetic chemicals. The present paper highlights the mycobiota associated with Eichhornia crassipes infesting Harike wetland area of Punjab and evaluation of their pathogenic potential for futuristic application as a mycoherbicide. Of the 20 isolates tested by leaf detached assay and whole plant bioassays, only one isolate (#8 BJSSL) caused 100% damage to E. crassipes. Further, the culture filtrate of this isolate also exhibited a similar damage to the leaves in an in vitro detached leaf assay. The potential isolate was identified as Phaeoacremonium italicum using classical and modern molecular methods. This is the first report of P. italicum as a pathogen of E. crassipes and of its potential use as a biological control agent for the management of water hyacinth.

Biocontrol Activity of Bacillus amyloliquefaciens CNU114001 against Fungal Plant Diseases

A total of 62 bacterial isolates were obtained from Gomsohang mud flat, Mohang mud flat, and Jeju Island, Republic of Korea. Among them, the isolate CNU114001 showed significant antagonistic activity against pathogenic fungi by dual culture method. The isolate CNU114001 was identified as Bacillus amyloliquefaciens by morphological observation and molecular data analysis, including 16SrDNA and gyraseA (gyrA) gene sequences. Antifungal substances of the isolate were extracted and purified by silica gel column chromatography, thin layer chromatography, and high performance liquid chromatography. The heat and UV ray stable compound was identified as iturin, a lipopeptide (LP). The isolate CNU114001 showed broad spectrum activity against 12 phytopathogenic fungi by dual culture method. The semi purified compound significantly inhibits the mycelial growth of pathogenic fungi (Alternaria panax, Botrytis cinera, Colletotrichum orbiculare, Penicillium digitatum, Pyricularia grisea and Sclerotinia sclerotiorum) at 200 ppm concentration. Spore germ tube elongation of Botrytis cinerea was inhibited by culture filtrate of the isolate. Crude antifungal substance showed antagonistic activity against cucumber scleotiorum rot in laboratory, and showed antagonistic activity against tomato gray mold, cucumber, and pumpkin powdery mildew in greenhouse condition.

Antagonistic and plant growth activity of Trichoderma isolates of Western Himalayas.

The genus Trichoderma is rapidly growing colonies bearing tufted or postulate, repeatedly branched conidiophores with lageniform phialides and hyaline or green conidia born in slimy heads. 62 isolates of Trichoderma species were isolated from different rhizospheric soil samples collected from different places located in Western Himalayas region. Out of these only two species were found i.e. Trichoderma hazianum and Trichoderma viride. Their efficacy against soil borne plant pathogens like Sclerotium rolfsii, Rhizoctonia solani and Sclerotinia sclerotiorum revealed that only three isolates amounting to 5% of the total collected isolates of this region were found highly antagonist. Among them 5% isolates were found against S. rolfsii, 13% isolates against R. solani, 10% against sclerotium caused above 80% inhibition of mycelial growth respectively. 6% isolates out of twenty seven utilized chitin by more than 80 and 16% isolates consumed cellulose by above 80% and therefore are producers of chitinase and cellulases. 58% isolates produced colonies having cottony texture and 41% produced dark green colonies. Pigmentation as observed from reverse side of the colony revealed that 70% of them did not produced pigment in the medium. Plant growth promotion measured as root and shoot lengths were significantly higher than in control. The maximum root length and shoot length were recorded when seeds were treated with isolates were recorded at Srinagar Garhwal was 4.70 and 4.75 cm out of all the isolates in which isolate recorded from Srinagar no 3 caused maximum percent seed germination which was significantly higher 79.49%.

Boty-II, a novel LTR retrotransposon in Botrytis cinerea B05.10 revealed by genomic sequence

Botrytis cinerea is a necrotrophic pathogen causing pre- and post-harvest diseases in at least 235 plant species. It manifests extraordinary genotype and phenotype variation. One of the causes of this variation is transposable elements. Two transposable elements have been discovered in this fungus, the retrotransposon (Boty), and the transposon (Flipper). In this work, two complete (Boty-II-76 and Boty-II-103) and two partial (Boty-II-95 and Boty-II-141) long terminal repeat (LTR) retrotransposons were identified by an in silico genomic sequence analysis. Boty-II-76 and Boty-II-103 contain 6439 bp nucleotides with a pair of LTRs at both ends, and an internal deduced pol gene encoding a polyprotein with reverse transcriptase and DDE integrase domains. They are flanked by 5 bp direct repeats (ACCAT, CTTTC). In Boty-II-141, two LTRs at both ends, and a partial internal pol gene encoding a protein with a DDE integrase domain were identified. In Boty-II-95, a right LTR and a partial internal pol gene encoding a protein with no conserved domains were identified. Boty-II uses a self-priming mechanism to initiate synthesis of reverse transcripts. The sequence of the presumed primer binding site for first-strand reverse transcription is 5’-TTGTACCAT-3’. The polypurine-rich sequence for plus-strand DNA synthesis is 5’-GCCTTGAGCGGGGGGTAC-3’. Fourteen Boty-II LTRs that contain 125-158 bp nucleotides and share 69.1 ~ 100 percent identities with the short inverted terminal repeats of 5 bp (TGTCA…TGACA) were discovered. Analysis of structural features and phylogeny revealed that Boty-II is a novel LTR retrotransposon. It could potentially be used as a novel molecular marker for the investigation of genetic variation in B. cinerea.

Genes associated with hypersensitive response (HR) in the citrus EST database (CitEST)

Plants are continuously exposed to pathogen attack, but successful infection is rare because they protect themselves against pathogens using a wide range of response mechanisms. One of them is the hypersensitive response (HR), which is a form of cell death often associated with plant resistance to pathogen infection to prevent the spreadsebpg@cnpq.br sebpg@cnpq.br of the potential pathogen from infected to uninfected tissues. Cell death is activated by recognition of pathogen-derived molecules by the resistance (R) gene products, and is associated with the massive accumulation of reactive oxygen species (ROS), salicylic acid (SA), and other pro-death signals such as nitric oxide (NO). The analysis of the citrus EST (CitEST) database revealed the presence of putative genes likely to be involved in HR through their products, like metacaspases, lipoxygenases, phospholipases, pathogenesis-related proteins, glutathione transferases/peroxidases, enzymes involved in the phenylpropanoid pathway and in the formation and detoxification of ROS, as well as those involved in the formation and regulation of ion channels, SA and NO. By analysis of the EST database of Citrus, it was possible to identify several putative genes that code for key enzymes involved in HR triggering and also in plant defense against biotic and abiotic stress.

Phytophthora parasitica transcriptome, a new concept in the understanding of the citrus gummosis

Due to the economic importance of gummosis disease for the citriculture, studies on P. parasitica-Citrus interaction comprise a significant part in the Brazilian Citrus genome data bank (CitEST). Among them, two cDNA libraries constructed from two different growth conditions of the P. parasitica pathogen are included which has generated the PP/CitEST database (CitEST - Center APTA Citros Sylvio Moreira/IAC- Millennium Institute). Through this genomic approach and clustering analyses the following has been observed: out of a total of 13,285 available in the Phytophthora parasitica database, a group of 4,567 clusters was formed, comprising 2,649 singlets and 1,918 contigs. Out of a total of 4,567 possible genes, only 2,651 clusters were categorized; among them, only 4.3 percent shared sequence similarities with pathogenicity factors and defense. Some of these possible genes (103) corresponding to 421 ESTs, were characterized by phylogenetic analysis and discussed. A comparison made with the COGEME database has shown homology which may be part of an evolutionary pathogenicity pathway present in Phytophthora and also in other fungi. Many of the genes which were identified here, which may encode proteins associated to mechanisms of citrus gummosis pathogenicity, represent only one facet of the pathogen-host Phytophthora - Citrus interaction.

Screening for Antifungal Endophytic Fungi Against Six Plant Pathogenic Fungi

A total of 187 endophytic fungi were isolated from 11 plant species, which were collected from 11 locations in Korea. Their antifungal activities were screened in vivo by antifungal bioassays after they were cultured in potato dextrose broth and rice solid media. Antifungal activity against plant pathogenic fungi such as Magnaporthe grisea (rice blast), Corticium sasaki (rice sheath blight), Botrytis cinerea (tomato gray mold), Phytophthora infestans (tomato late blight), Puccinia recondita (wheat leaf rust), and Blumeria graminis f. sp. hordei (barley powdery mildew) was determined in vivo by observing the inhibition of plant disease development. Twenty (11.7%) endophytic fungi fermentation broths were able to control, by more than 90%, at least one of the six plant diseases tested. Among 187 liquid broths, the F0010 strain isolated from Abies holophylla had the most potent disease control activity; it showed control values of more than 90% against five plant diseases, except for tomato late blight. On the other hand, fourteen (7.5%) solid culture extracts exhibited potent disease control values of more than 90% against one of six plant diseases. The screening results of this study strongly suggested that metabolites of plant endophytic fungi could be good potential sources for screening programs of bioactive natural products.

Screening for In Vitro Antifungal Activity of Soil Bacteria Against Plant Pathogens

Antifungal bacteria for biological control of plant diseases or production of novel antibiotics to plant pathogens were isolated in 1997 from various soils of Ansung, Chunan, Koyang, and Paju in Korea. Sixty-four bacterial strains pre-screened from approximately 1,400 strains were tested on V-8 juice agar against eight plant pathogenic fungi using in vitro bioassay technique for inhibition of mycelial growth. Test pathogens were Alternaria mali, Colletotrichum gloeosporioides, C. orbiculare, Fusarium oxysporum f. sp. cucumerinum, F. oxysporum f. sp. lycopersici, Magnaporthe grisea, Phytophthora capsici, and Rhizoctonia solani. A wide range of antifungal activity of bacterial strains was found against the pathogenic fungi, and strain RC-B77 showed the best antifungal activity. Correlation analysis between inhibition of each fungus and mean inhibition of all eight fungi by 64 bacterial strains revealed that C. gloeosporioides would be best appropriate for detecting bacterial strains producing antibiotics with potential as biocontrol agents for plant pathogens.