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Sample records for black rot pathogen

  1. Evidence that the Ceratobasidium-like white-thread blight and black rot fungal pathogens from persimmon and tea crops in the Brazilian Atlantic Forest agroecosystem are two distinct phylospecies

    OpenAIRE

    Ceresini, Paulo C. [UNESP; Costa-Souza, Elaine [UNESP; Zala, Marcello; Furtado, Edson Luiz [UNESP; Souza, Nilton L. [UNESP

    2012-01-01

    The white-thread blight and black rot (WTBR) caused by basidiomycetous fungi of the genus Ceratobasidium is emerging as an important plant disease in Brazil, particularly for crop species in the Ericales such as persimmon (Diospyros kaki) and tea (Camellia sinensis). However, the species identity of the fungal pathogen associated with either of these hosts is still unclear. In this work, we used sequence variation in the internal transcribed spacer regions, including the 5.8S coding region of...

  2. EXTRACELLULAR POLYSACCHARIDES OF POTATO RING ROT PATHOGEN

    Directory of Open Access Journals (Sweden)

    Shafikova Т.N.

    2006-03-01

    Full Text Available Many bacteria, including phytopathogenic ones produce extracellular polysaccharides or exopolysaccharides which are universal molecules. Causal agent of potato ring rot, Clavibacter michiganensis subspecies sepedonicus, secretes exopolysaccharides which role in pathogenesis is poorly investigated. The aim of our research is to ascertain the composition and structure of Clavibacter michiganensis subspecies sepedonicus exopolysaccharides. Exopolysaccharides of Clavibacter michiganensis subspecies sepedonicus are determined to consist of 4-6 anionic and neutral components which have molecular weights from 700 kDa. Glucose is a major monomer of polysaccharides and arabinose, rhamnose and mannose are minor monomers. Glucose is present in α-Dglucopyranose and β-D-glucopyranose configurations. Calcium is determined to be a component of exopolysaccharides. Components of exopolysaccharides of potato ring rot pathogen are probably capableto associate via calcium ions and other ionic interactions that may result in a change of their physiological activity. Further studies of Clavibacter michiganensis subspecies sepedonicus exopolysaccharides composition and structure can serve a base for the synthesis of their chemical analogues with elicitor action.

  3. Antagonistic Effect of Native Bacillus Isolates against Black Root Rot ...

    African Journals Online (AJOL)

    Faba bean (Vicia faba L.) is one of the most important pulse crops grown in eastern Africa. Black root rot (Fusarium solani) is known to cause great yield losses in faba bean, especially in the highlands of Ethiopia. The objective of this study was to evaluate the biological control ability of native Bacillus species on the basis of ...

  4. Distribution and prevalence of crown rot pathogens affecting wheat crops in southern Chile

    OpenAIRE

    Ernesto Moya-Elizondo; Nolberto Arismendi; María Paz Castro; Herman Doussoulin

    2015-01-01

    Crown rot pathogens are associated with higher losses for wheat crop farmers, but information about the distribution and prevalence of these pathogens in Chile is inadequate. Distribution and prevalence of wheat (Triticum aestivum L.) crown rot pathogens were examined in a survey of 48 commercial fields from December 2011 to February 2012 in southern Chile. These fields were located between Collipulli (37°56'00" S; 72°26'39" W) and Purranque (40°50'30" S; 73°22'03" W). Severity of crown rot d...

  5. Thermal control of some post-harvest rot pathogens of Irish potato (solanum tuberosum l.)

    OpenAIRE

    Salami Olusola Abiodun; Popoola Omololu Olumide

    2007-01-01

    Thermal control effect on the incidence of some post-harvest rot pathogens of Solanum tuberosum (potato) was investigated in this study. Three cultivars of potato tuber whose local names are, Patiska, Mai Bawondoya and Nicola were used for the study. Five pathogenic fungi viz: Botryodiplodia theobromae, Fusarium redolens, Fusarium oxysporum, Penicillium sp. and Rhizopus oryzae associated with post harvest storage rot of root-tubers, were isolated from diseased potatoes. Among the three specie...

  6. Distribution and prevalence of crown rot pathogens affecting wheat crops in southern Chile

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    Ernesto Moya-Elizondo

    2015-03-01

    Full Text Available Crown rot pathogens are associated with higher losses for wheat crop farmers, but information about the distribution and prevalence of these pathogens in Chile is inadequate. Distribution and prevalence of wheat (Triticum aestivum L. crown rot pathogens were examined in a survey of 48 commercial fields from December 2011 to February 2012 in southern Chile. These fields were located between Collipulli (37°56'00" S; 72°26'39" W and Purranque (40°50'30" S; 73°22'03" W. Severity of crown rot disease was determined through visual assessment of the first internode of 20 tillers obtained from each field. Incidence of crown rot pathogens per field was determined by plating the 20 tillers on Petri plates with 20% potato dextrose agar amended with lactic acid (aPDA medium. Resulting fungal colonies from monoxenic culture were identified by morphological or molecular-assisted identification. Severity of crown rot varied between 11.3% and 80% for individual fields. Culture plate analysis showed 72.2% of stems were infected with some fungus. Fusarium avenaceum, F. graminearum, and F. culmorum, pathogens associated with Fusarium crown rot disease were isolated from 13.5% of tillers. Gaeumannomyces graminis, causal agent of take-all disease in cereals, was isolated from 11.1% of culms. Phaeosphaeria sp., an endophyte and possibly a non-pathogenic fungus, was isolated from 13.9% of tillers. Pathogenic fungi such as Rhizoctonia spp. and Microdochium nivale, other saprophyte, and several unidentified non-sporulating fungi were isolated at frequencies lower than 3% of the total. Fusarium crown rot and take-all were the most prevalent and distributed crown rot diseases present in wheat crops in southern Chile.

  7. Phytophthora megakarya and P. palmivora, closely related causal agents of cacao black pod rot, underwent increases in genome sizes and gene numbers by different mechanisms

    Science.gov (United States)

    Phytophthora megakarya (Pmeg) and P. palmivora (Ppal) are closely related species causing black pod rot of cacao. While Ppal is a cosmopolitan plant pathogen, cacao is the only known host of importance for Pmeg. Pmeg is more virulent on cacao than Ppal. Therefore, we have sequenced both the Pmeg and...

  8. Comparative Assessment of Pathogenicity of Storage Rot Causing ...

    African Journals Online (AJOL)

    L)Schott) corms were assessed for their potency in causing rot of the corms during storage. The isolates were Sclerotium rolfsii Sacc., Botryodiplodia theobromae Pat., Fusarium solanii (Mart) Sac., Fusarium SP. and Rhizopus stolonifer (Ehren ...

  9. Simultaneous Detection of Brown Rot- and Soft Rot-Causing Bacterial Pathogens from Potato Tubers Through Multiplex PCR.

    Science.gov (United States)

    Ranjan, R K; Singh, Dinesh; Baranwal, V K

    2016-11-01

    Ralstonia solanacearum (Smith) Yabuuchi et al. and Erwinia carotovora subsp. carotovora (Jones) Bergey et al. (Pectobacterium carotovorum subsp. carotovorum) are the two major bacterial pathogens of potato causing brown rot (wilt) and soft rot diseases, respectively, in the field and during storage. Reliable and early detection of these pathogens are keys to avoid occurrence of these diseases in potato crops and reduce yield loss. In the present study, multiplex polymerase chain reaction (PCR) protocol was developed for simultaneous detection of R. solanacearum and E. carotovora subsp. carotovora from potato tubers. A set of oligos targeting the pectatelyase (pel) gene of E. carotovora subsp. carotovora and the universal primers based on 16S r RNA gene of R. solanacearum were used. The standardized multiplex PCR protocol could detect R. solanacearum and E. carotovora subsp. carotovora up to 0.01 and 1.0 ng of genomic DNA, respectively. The protocol was further validated on 96 stored potato tuber samples, collected from different potato-growing states of India, viz. Uttarakhand, Odisha, Meghalaya and Delhi. 53.1 % tuber samples were positive for R. solanacearum, and 15.1 % of samples were positive for E. carotovora subsp. carotovora, and both the pathogens were positive in 26.0 % samples when BIO-PCR was used. This method offers sensitive, specific, reliable and fast detection of two major bacterial pathogens from potato tubers simultaneously, particularly pathogen-free seed certification in large scale.

  10. Genome Sequence of the Banana Pathogen Dickeya zeae Strain MS1, Which Causes Bacterial Soft Rot.

    Science.gov (United States)

    Zhang, Jing-Xin; Lin, Bi-Run; Shen, Hui-Fang; Pu, Xiao-Ming

    2013-06-13

    We report a draft genome sequence of Dickeya zeae strain MS1, which is the causative agent of banana soft rot in China, and we show several of its specific properties compared with those of other D. zeae strains. Genome sequencing provides a tool for understanding the genomic determination of the pathogenicity and phylogeny placement of this pathogen.

  11. Genome Sequence of the Banana Pathogen Dickeya zeae Strain MS1, Which Causes Bacterial Soft Rot

    OpenAIRE

    Zhang, Jing-Xin; Lin, Bi-Run; Shen, Hui-Fang; Pu, Xiao-Ming

    2013-01-01

    We report a draft genome sequence of Dickeya zeae strain MS1, which is the causative agent of banana soft rot in China, and we show several of its specific properties compared with those of other D.?zeae strains. Genome sequencing provides a tool for understanding the genomic determination of the pathogenicity and phylogeny placement of this pathogen.

  12. Effect of Environment and Sugar Beet Genotype on Root Rot Development and Pathogen Profile During Storage.

    Science.gov (United States)

    Liebe, Sebastian; Varrelmann, Mark

    2016-01-01

    Storage rots represent an economically important factor impairing the storability of sugar beet by increasing sucrose losses and invert sugar content. Understanding the development of disease management strategies, knowledge about major storage pathogens, and factors influencing their occurrence is crucial. In comprehensive storage trials conducted under controlled conditions, the effects of environment and genotype on rot development and associated quality changes were investigated. Prevalent species involved in rot development were identified by a newly developed microarray. The strongest effect on rot development was assigned to environment factors followed by genotypic effects. Despite large variation in rot severity (sample range 0 to 84%), the spectrum of microorganisms colonizing sugar beet remained fairly constant across all treatments with dominant species belonging to the fungal genera Botrytis, Fusarium, and Penicillium. The intensity of microbial tissue necrotization was strongly correlated with sucrose losses (R² = 0.79 to 0.91) and invert sugar accumulation (R² = 0.91 to 0.95). A storage rot resistance bioassay was developed that could successfully reproduce the genotype ranking observed in storage trials. Quantification of fungal biomass indicates that genetic resistance is based on a quantitative mechanism. Further work is required to understand the large environmental influence on rot development in sugar beet.

  13. Phytophthora megakarya, a causal agent of black pod rot in Africa

    Science.gov (United States)

    In most parts of the world where Theobroma cacao is grown, Phytophthora palmivora is the major concern for causing black pod rot (BPR). Phytophthora megakarya, on the other hand, occurs only in Africa, but represents a major threat to cacao production, the countries of West Africa being the largest ...

  14. Evaluation of rhizobacterial indicators of tobacco black root rot suppressiveness in farmers' fields

    Czech Academy of Sciences Publication Activity Database

    Kyselková, Martina; Almario, J.; Kopecký, J.; Ságová-Marečková, M.; Haurat, J.; Muller, D.; Grundmann, G.L.; Moënne-Loccoz, Y.

    2014-01-01

    Roč. 6, č. 4 (2014), s. 346-353 ISSN 1758-2229 Institutional support: RVO:60077344 Keywords : rhizobacterial indicators * tobacco black root rot suppressiveness * farmers' fields Subject RIV: EH - Ecology, Behaviour Impact factor: 3.293, year: 2014

  15. Genome Sequence of Pectobacterium carotovorum subsp. carotovorum Strain PCC21, a Pathogen Causing Soft Rot in Chinese Cabbage

    OpenAIRE

    Park, Tae-Ho; Choi, Beom-Soon; Choi, Ah-Young; Choi, Ik-Young; Heu, Sunggi; Park, Beom-Seok

    2012-01-01

    Pectobacterium carotovorum is a plant-pathogenic enterobacterium responsible for soft rot in various commercially important plants. Here we report the complete genome sequence and automatic annotation of strain PCC21.

  16. Genome sequence of Pectobacterium carotovorum subsp. carotovorum strain PCC21, a pathogen causing soft rot in Chinese cabbage.

    Science.gov (United States)

    Park, Tae-Ho; Choi, Beom-Soon; Choi, Ah-Young; Choi, Ik-Young; Heu, Sunggi; Park, Beom-Seok

    2012-11-01

    Pectobacterium carotovorum is a plant-pathogenic enterobacterium responsible for soft rot in various commercially important plants. Here we report the complete genome sequence and automatic annotation of strain PCC21.

  17. Identification and Pathogenicity of Phytopathogenic Bacteria Associated with Soft Rot Disease of Girasole Tuber

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    Mamdoh Ewis ISMAIL

    2012-02-01

    Full Text Available During 2010-2011 growing seasons six bacterial isolates were separated from naturally infected girasole plants tubers (Helianthus tuberosus L. cv. Balady, showing soft rot, collected from experimental Farm of the Faculty of Agriculture, in El-Minia University, Egypt. Pathogenicity tests showed various virulence for the bacteria isolated from girasole tubers, found pathogenic. These organisms were characterized as rod-shaped, Gram negative, ?-methyl-d-glucoside medium, reducing substances from sucrose, phos, phatase activity and deep cavities on pectate medium. Otherwise, diagnostic tests suggested that the pathogen was Erwinia carotovora ssp. carotovora. The isolated bacteria caused soft rot of wounded tubers when inoculated into tissues. The bacterial isolates were compared for their degree of pathogenicity as well as for differences in specific symptoms, induced in different hosts. The tested isolates could infect several host ranges, such as fruits of apricot, apple, olive, lemon, squash, eggplant and potato tubers, bulbs and garlic and onion cloves, roots radish, carrot, sweet potato and rape. On the other hand, no symptoms were exhibited on pods of bean and cowpea, faba bean, fruits of pepper and tomato. The extracts of experimentally diseased girasole tubers were active in pectinase and also in caboxymethyl cellulose at pH 6 compared to enzyme activities in healthy tissues. Also, the isolated bacteria increased the total and reducing sugars in infected tissues.

  18. Identification and Pathogenicity of Phytopathogenic Bacteria Associated with Soft Rot Disease of Girasole Tuber

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    Mamdoh Ewis ISMAIL

    2012-02-01

    Full Text Available During 2010-2011 growing seasons six bacterial isolates were separated from naturally infected girasole plants tubers (Helianthus tuberosus L. cv. �Balady�, showing soft rot, collected from experimental Farm of the Faculty of Agriculture, in El-Minia University, Egypt. Pathogenicity tests showed various virulence for the bacteria isolated from girasole tubers, found pathogenic. These organisms were characterized as rod-shaped, Gram negative, ?-methyl-d-glucoside medium, reducing substances from sucrose, phos, phatase activity and deep cavities on pectate medium. Otherwise, diagnostic tests suggested that the pathogen was Erwinia carotovora ssp. carotovora. The isolated bacteria caused soft rot of wounded tubers when inoculated into tissues. The bacterial isolates were compared for their degree of pathogenicity as well as for differences in specific symptoms, induced in different hosts. The tested isolates could infect several host ranges, such as fruits of apricot, apple, olive, lemon, squash, eggplant and potato tubers, bulbs and garlic and onion cloves, roots radish, carrot, sweet potato and rape. On the other hand, no symptoms were exhibited on pods of bean and cowpea, faba bean, fruits of pepper and tomato. The extracts of experimentally diseased girasole tubers were active in pectinase and also in caboxymethyl cellulose at pH 6 compared to enzyme activities in healthy tissues. Also, the isolated bacteria increased the total and reducing sugars in infected tissues.

  19. Population genomic analyses of the brown root-rot pathogen, Phellinus noxius, examine potential invasive spread among Pacific islands

    Science.gov (United States)

    Jane E. Stewart; Mee-Sook Kim; Louise Shuey; Norio Sahashi; Yuko Ota; Robert L. Schlub; Phil G. Cannon; Ned B. Klopfenstein

    2016-01-01

    Phellinus noxius (Corner) G. H. Cunn is a vastly destructive, fast-growing fungal pathogen that affects a wide range of woody hosts in pan-tropical areas, including Asia, Australia, Africa, and Oceania (Ann et al. 2002; Figure 1) . This pathogen causes brown root-rot disease on cacao, coffee, and rubber, as well as diverse fruit, nut, ornamental, and other...

  20. Phylogenetic, Morphological, and Pathogenic Characterization of Alternaria Species Associated with Fruit Rot of Blueberry in California.

    Science.gov (United States)

    Zhu, X Q; Xiao, C L

    2015-12-01

    Fruit rot caused by Alternaria spp. is one of the most important factors affecting the postharvest quality and shelf life of blueberry fruit. The aims of this study were to characterize Alternaria isolates using morphological and molecular approaches and test their pathogenicity to blueberry fruit. Alternaria spp. isolates were collected from decayed blueberry fruit in the Central Valley of California during 2012 and 2013. In total, 283 isolates were obtained and five species of Alternaria, including Alternaria alternata, A. tenuissima, A. arborescens, A. infectoria, and A. rosae, were identified based on DNA sequences of the plasma membrane ATPase, Alt a1 and Calmodulin gene regions in combination with morphological characters of the culture and sporulation. Of the 283 isolates, 61.5% were identified as A. alternata, 32.9% were A. arborescens, 5.0% were A. tenuissima, and only one isolate of A. infectoria and one isolate of A. rosae were found. These fungi were able to grow at temperatures from 0 to 35°C, and mycelial growth was arrested at 40°C. Optimal radial growth occurred between 20 to 30°C. Pathogenicity tests showed that all five Alternaria spp. were pathogenic on blueberry fruit at 0, 4, and 20°C, with A. alternata, A. arborescens, and A. tenuissima being the most virulent species, followed by A. infectoria and A. rosae. Previously A. tenuissima has been reported to be the primary cause of Alternaria fruit rot of blueberry worldwide. Our results indicated that the species composition of Alternaria responsible for Alternaria fruit rot in blueberry can be dependent on geographical region. A. alternata, A. arborescens, A. infectoria, and A. rosae are reported for the first time on blueberry in California. This is also the first report of A. infectoria and A. rosae infecting blueberry fruit.

  1. Alternaria mycotoxins in black rot lesion of tomato fruit: conditions and regulation of their production.

    Science.gov (United States)

    Hasan, H A

    1996-01-01

    Alternaria represents the most colon decay organism of the post-harvest tomato fruit. The prevalent type of decay, black rot lesion, is caused by Alternaria alternata which may invade tomato tissue damaged by sun scald. The mainly natural mycotoxins produced in rotted tomato are alternariol (AOH), alternariol monomethyl ether (AME), and tenuazonic acid (TA). Whereas, altertoxin-I and -II (AT-I and -II), in addition to AOH, AME and TA were produced by local A. alternata in a synthetic medium. The optimum temperature for toxin production by A. alternata IMI 89344 was 28 degrees C for AOH and AME, 21 degrees C for TA and 14 degrees C for AT-I and -II. The growth and toxin were produced in a noticeable amount at 7 degrees C but drop at 35 degrees C. Significant inhibition in these toxins was attained at 500 ppm cinnamon oil in YES-Czapek's medium and in homogenate of tomato.

  2. Somaclonal variation of sugar beet resistant to pathogenic root rot Fusarium oxysporum var. orthoceras

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    Urazaliev Kairat

    2013-01-01

    Full Text Available Sugar beet (Beta vulgaris L. - one of the most important crop in the world. In Kazakhstan, it is a traditional and major source of domestic sugar. The industry of cultivation and production of sugar beet is one of the priority areas of agricultural development of the country. In this paper, we studied the regeneration ability of different genotypes of sugar beet explants on selective media with the culture filtrate of the pathogen fungus F. oxysporum var. orthoceras. From the roots and shoots of sugar beet the pathogen Fusarium root rot was isolated. Was obtained pure cultures of the isolated pathogen. As a result, of morphological and cultural descriptions, as well as microbiological analysis it was revealed that the isolated pathogen is Fusarium Oxysporum. The results showed the pathogenicity of the fungus. For regeneration in vitro of the sugar beet genotypes resistant to the pathogen the culture media was optimized to the culture filtrate of the fungus F. oxysporum var. orthoceras. The frequency of shoot regeneration, depending on the genotype, was 1,0-12,5 %. On these explants the multiple shoot formations were observed.

  3. Introgression of Black Rot Resistance from Brassica carinata to Cauliflower (Brassica oleracea botrytis Group) through Embryo Rescue

    Science.gov (United States)

    Sharma, Brij B.; Kalia, Pritam; Singh, Dinesh; Sharma, Tilak R.

    2017-01-01

    Black rot caused by Xanthomonas campestris pv. campestris (Xcc) is a very important disease of cauliflower (Brassica oleracea botrytis group) resulting into 10–50% yield losses every year. Since there is a dearth of availability of resistance to black rot disease in B. oleracea (C genome), therefore exploration of A and B genomes was inevitable as they have been reported to be potential reservoirs of gene(s) for resistance to black rot. To utilize these sources, interspecific hybrid and backcross progeny (B1) were generated between cauliflower “Pusa Sharad” and Ethiopian mustard “NPC-9” employing in vitro embryo rescue technique. Direct ovule culture method was better than siliqua culture under different temperature regime periods. Hybridity testing of F1 inter-specific plants was carried out using co-dominant SSR marker and Brassica B and C genome-specific (DB and DC) primers. Meiosis in the di-genomic (BCC) interspecific hybrid of B. oleracea botrytis group (2n = 18, CC) × B. carinata (2n = 4x = 34, BBCC) was higly disorganized and cytological analysis of pollen mother cells revealed chromosomes 2n = 26 at metaphase-I. Fertile giant pollen grain formation was observed frequently in interspecific F1 hybrid and BC1 plants. The F1 inter-specific plants were found to be resistant to Xcc race 1. Segregation distortion was observed in BC1 generation for black rot resistance and different morphological traits. The At1g70610 marker analysis confirmed successful introgression of black rot resistance in interspecific BC1 population. This effort will go a long way in pyramiding gene(s) for resistance against black rot in Cole crops, especially cauliflower and cabbage for developing durable resistance, thus minimize dependency on bactericides. PMID:28769959

  4. Introgression of Black Rot Resistance from Brassica carinata to Cauliflower (Brassica oleracea botrytis Group through Embryo Rescue

    Directory of Open Access Journals (Sweden)

    Brij B. Sharma

    2017-07-01

    Full Text Available Black rot caused by Xanthomonas campestris pv. campestris (Xcc is a very important disease of cauliflower (Brassica oleracea botrytis group resulting into 10–50% yield losses every year. Since there is a dearth of availability of resistance to black rot disease in B. oleracea (C genome, therefore exploration of A and B genomes was inevitable as they have been reported to be potential reservoirs of gene(s for resistance to black rot. To utilize these sources, interspecific hybrid and backcross progeny (B1 were generated between cauliflower “Pusa Sharad” and Ethiopian mustard “NPC-9” employing in vitro embryo rescue technique. Direct ovule culture method was better than siliqua culture under different temperature regime periods. Hybridity testing of F1 inter-specific plants was carried out using co-dominant SSR marker and Brassica B and C genome-specific (DB and DC primers. Meiosis in the di-genomic (BCC interspecific hybrid of B. oleracea botrytis group (2n = 18, CC × B. carinata (2n = 4x = 34, BBCC was higly disorganized and cytological analysis of pollen mother cells revealed chromosomes 2n = 26 at metaphase-I. Fertile giant pollen grain formation was observed frequently in interspecific F1 hybrid and BC1 plants. The F1 inter-specific plants were found to be resistant to Xcc race 1. Segregation distortion was observed in BC1 generation for black rot resistance and different morphological traits. The At1g70610 marker analysis confirmed successful introgression of black rot resistance in interspecific BC1 population. This effort will go a long way in pyramiding gene(s for resistance against black rot in Cole crops, especially cauliflower and cabbage for developing durable resistance, thus minimize dependency on bactericides.

  5. Identification of Pathogenic Fusarium spp. Causing Maize Ear Rot and Potential Mycotoxin Production in China.

    Science.gov (United States)

    Duan, Canxing; Qin, Zihui; Yang, Zhihuan; Li, Weixi; Sun, Suli; Zhu, Zhendong; Wang, Xiaoming

    2016-06-21

    Ear rot is a serious disease that affects maize yield and grain quality worldwide. The mycotoxins are often hazardous to humans and livestock. In samples collected in China between 2009 and 2014, Fusarium verticillioides and F. graminearum species complex were the dominant fungi causing ear rot. According to the TEF-1α gene sequence, F. graminearum species complex in China included three independent species: F. graminearum, F. meridionale, and F. boothii. The key gene FUM1 responsible for the biosynthesis of fumonisin was detected in all 82 F. verticillioides isolates. Among these, 57 isolates mainly produced fumonisin B₁, ranging from 2.52 to 18,416.44 µg/g for each gram of dry hyphal weight, in vitro. Three different toxigenic chemotypes were detected among 78 F. graminearum species complex: 15-ADON, NIV and 15-ADON+NIV. Sixty and 16 isolates represented the 15-ADON and NIV chemotypes, respectively; two isolates carried both 15-ADON and NIV-producing segments. All the isolates carrying NIV-specific segment were F. meridionale. The in vitro production of 15-ADON, 3-ADON, DON, and ZEN varied from 5.43 to 81,539.49; 6.04 to 19,590.61; 13.35 to 19,795.33; and 1.77 to 430.24 µg/g of dry hyphal weight, respectively. Altogether, our present data demonstrate potential main mycotoxin production of dominant pathogenic Fusarium in China.

  6. Pathogenic characterization of lasiodplodia causing stem end rot of mango and its control using botanicals

    International Nuclear Information System (INIS)

    Ullah, S. F.; Hussain, Y.; Iram, S.

    2017-01-01

    Two widely cultivated mango fruit varieties White chounsa and Sindhri were collected from two major mango growing areas of Punjab and Sindh Provinces of Pakistan. This study was focused on pathological characterization of predominant postharvest diseases such as stem end rot of mango (Mangifera indica) caused by Lasiodiplodia theobromae, and evaluation of bio-control activity by different plant extracts. L. theobromae aggressiveness of isolates was tested by artificial inoculations under controlled conditions, all isolates proved pathogenic in varying degree of aggressiveness on (Sindhri and White chounsa) with reference to control. Calculated standard error mean varied in lesion area produced by pathogens 6-63cm/sup 2/ (Sindhri) and 60-170 cm/sup 2/ (White chounsa). Re-isolation of respective fungi verified the Koch's postulates. Plant extract of Datura stramonium, Aloe-vera, Eucalyptus camaldulensis, were used to control the radial growth of L. theobromae. Comparative analysis showed D. Stramonium and E. camaldulensis extracts most efficiently reduced the growth of Lasiodiplodia isolates, in comparison to Aloe-vera extract, restrict the 15-20% growth. All pathological results and treatments were significant at p<0.05 through ANOVA. This study emphasizes the behavior of pathogens which could be helpful in mango breeding to introduce resistance toward Lasiodiplodia and referred plants provide the best alternative of chemical fungicides. (author)

  7. Short Rotations in Forest Plantations Accelerate Virulence Evolution in Root-Rot Pathogenic Fungi

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    Jean-Paul Soularue

    2017-06-01

    Full Text Available As disease outbreaks in forest plantations are causing concern worldwide, a clear understanding of the influence of silvicultural practices on the development of epidemics is still lacking. Importantly, silvicultural practices are likely to simultaneously affect epidemiological and evolutionary dynamics of pathogen populations. We propose a genetically explicit and individual-based model of virulence evolution in a root-rot pathogenic fungus spreading across forest landscapes, taking the Armillaria ostoyae–Pinus pinaster pathosystem as reference. We used the model to study the effects of rotation length on the evolution of virulence and the propagation of the fungus within a forest landscape composed of even-aged stands regularly altered by clear-cutting and thinning operations. The life cycle of the fungus modeled combines asexual and sexual reproduction modes, and also includes parasitic and saprotrophic phases. Moreover, the tree susceptibility to the pathogen is primarily determined by the age of the stand. Our simulations indicated that the shortest rotation length accelerated both the evolution of virulence and the development of the epidemics, whatever the genetic variability in the initial fungal population and the asexuality rate of the fungal species

  8. QTL mapping of fruit rot resistance to the plant pathogen Phytophthora capsici in a recombinant inbred line Capsicum annuum population.

    Science.gov (United States)

    Naegele, R P; Ashrafi, H; Hill, T A; Chin-Wo, S Reyes; Van Deynze, A E; Hausbeck, M K

    2014-05-01

    Phytophthora capsici is an important pepper (Capsicum annuum) pathogen causing fruit and root rot, and foliar blight in field and greenhouse production. Previously, an F6 recombinant inbred line population was evaluated for fruit rot susceptibility. Continuous variation among lines and partial and isolate-specific resistance were found. In this study, Phytophthora fruit rot resistance was mapped in the same F6 population between Criollo del Morelos 334 (CM334), a landrace from Mexico, and 'Early Jalapeno' using a high-density genetic map. Isolate-specific resistance was mapped independently in 63 of the lines evaluated and the two parents. Heritability of the resistance for each isolate at 3 and 5 days postinoculation (dpi) was high (h(2) = 0.63 to 0.68 and 0.74 to 0.83, respectively). Significant additive and epistatic quantitative trait loci (QTL) were identified for resistance to isolates OP97 and 13709 (3 and 5 dpi) and 12889 (3 dpi only). Mapping of fruit traits showed potential linkage with few disease resistance QTL. The partial fruit rot resistance from CM334 suggests that this may not be an ideal source for fruit rot resistance in pepper.

  9. Genetic diversity and pathogenicity of Fusarium species associated with fruit rot disease in banana across Peninsular Malaysia.

    Science.gov (United States)

    Abd Murad, N B; Mohamed Nor, N M I; Shohaimi, S; Mohd Zainudin, N A I

    2017-12-01

    The aims of this study were to identify the Fusarium isolates based on translation elongation factor (tef) 1α sequence, to determine the genetic diversity among isolates and species using selected microsatellite markers and to examine the pathogenicity of Fusarium isolates causing fruit rot disease of banana. One-hundred and thirteen microfungi isolates were obtained from fruit rot infected banana in Peninsular Malaysia. However, this study was focused on the dominant number of the discovered microfungi that belongs to the genus Fusarium; 48 isolates of the microfungi have been identified belonging to 11 species of Fusarium, namely Fusarium incarnatum, Fusarium equiseti, Fusarium camptoceras, Fusarium solani, Fusarium concolor, Fusarium oxysporum, Fusarium proliferatum, Fusarium verticillioides, Fusarium sacchari, Fusarium concentricum and Fusarium fujikuroi. All Fusarium isolates were grouped into their respective clades indicating their similarities and differences in genetic diversity among isolates. Out of 48 Fusarium isolates tested, 42 isolates caused the fruit rot symptom at different levels of severity based on Disease Severity Index (DSI). The most virulent isolate was F. proliferatum B2433B with DSI of 100%. All the isolated Fusarium species were successfully identified and some of them were confirmed as the causal agents of pre- and postharvest fruit rot in banana across Peninsular Malaysia. Our results will provide additional information regarding new report of Fusarium species in causing banana fruit rot and in the search of potential biocontrol agent of the disease. © 2017 The Society for Applied Microbiology.

  10. Effects of glucose on the Reactive Black 5 (RB5 decolorization by two white rot basidiomycetes

    Directory of Open Access Journals (Sweden)

    Tony Hadibarata

    2011-11-01

    Full Text Available The capacities of glucose in the decolorization process of an azo dye, Reactive Black 5 (RB5, by two white rot basidiomycetes, Pleurotus sp. F019 and Trametes sp. F054 were investigated. The results indicated that the dye degradation by the two fungi was extremely correlated with the presence of glucose in the culture and the process of fungi growth. Decolorization of 200 mg dye/l was increased from 62% and 69% to 100% within 20–25 h with the increase of glucose from 5 to 15 g/l, and the activity of manganese dependent peroxidase (MnP increased by 2–9 fold in this case. Hydrogen peroxide of 0.55 mg/l and 0.43 mg/l were detected in 10 h in Pleurotus sp. F019 and Trametes sp. F054 cultures.

  11. [Fusarium species associated with basal rot of garlic in North Central Mexico and its pathogenicity].

    Science.gov (United States)

    Delgado-Ortiz, Juan C; Ochoa-Fuentes, Yisa M; Cerna-Chávez, Ernesto; Beltrán-Beache, Mariana; Rodríguez-Guerra, Raúl; Aguirre-Uribe, Luis A; Vázquez-Martínez, Otilio

    Garlic in Mexico is one of the most profitable vegetable crops, grown in almost 5,451ha; out of which more than 83% are located in Zacatecas, Guanajuato, Sonora, Puebla, Baja California and Aguascalientes. Blossom-end rot caused by Fusarium spp is widely distributed worldwide and has been a limiting factor in onion and garlic production regions, not only in Mexico but also in other countries. The presence of Fusarium oxysporum has been reported in Guanajuato and Aguascalientes. Fusarium culmorum has been reported in onion cultivars of Morelos; and Fusarium proliferatum, Fusarium verticillioides, Fusarium solani and Fusarium acuminatum have been previously reported in Aguascalientes. The goal of this work was identifying the Fusarium species found in Zacatecas, Guanajuato and Aguascalientes, to assess their pathogenicity. Plants with disease symptoms were collected from hereinabove mentioned States. The samples resulted in the identification of: F. oxysporum, F. proliferatum, F. verticillioides, F. solani and F. acuminatum species; out of which Aguascalientes AGS1A (F. oxysporum), AGS1B (F. oxysporum) and AGSY-10 (F. acuminatum) strains showed higher severity under greenhouse conditions. Copyright © 2016 Asociación Argentina de Microbiología. Publicado por Elsevier España, S.L.U. All rights reserved.

  12. Gluconate metabolism is required for virulence of the soft-rot pathogen Pectobacterium carotovorum.

    Science.gov (United States)

    Mole, Beth; Habibi, Sohrab; Dangl, Jeffery L; Grant, Sarah R

    2010-10-01

    Pectobacterium carotovorum is a ubiquitous soft rot pathogen that uses global virulence regulators to coordinate pathogenesis in response to undefined environmental conditions. We characterize an operon in P. carotovorum required for gluconate metabolism and virulence. The operon contains four genes that are highly conserved among proteobacteria (initially annotated ygbJKLM), one of which was misassigned as a type III secreted effector, (ygbK, originally known as hopAN1). A mutant with a deletion-insertion within this operon is unable to metabolize gluconate, a precursor for the pentose phosphate pathway. The mutant exhibits attenuated growth on the leaves of its host of isolation, potato, and those of Arabidopsis thaliana. Notably, the mutant hypermacerates potato tubers and is deficient in motility. Global virulence regulators that are responsive to cell wall pectin breakdown products and other undefined environmental signals, KdgR and FlhD, respectively, are misregulated in the mutant. The alteration of virulence mediated via changes in transcription of known global virulence regulators in our ygbJ-M operon mutant suggests a role for host-derived catabolic intermediates in P. carotovorum pathogenesis. Thus, we rename this operon in P. carotovorum vguABCD for virulence and gluconate metabolism.

  13. Mutation breeding against black pod (Phytophthora pod rot) disease of cacao (Theobroma cacao)

    International Nuclear Information System (INIS)

    Opeke, L.K.

    1977-01-01

    Black pod rot disease, caused by Phytophthora palmivora, is an important disease of cacao (Theobroma cacao L.) in Nigeria and other cacao producing countries of West Africa and Latin America. A naturally occurring source of genetic resistance to the disease has not been found. This paper completes the report, the first part of which was published in Induced Mutations in Vegetatively Propagated Plants, IAEA, Vienna (1973). The survivors of the irradiated seedlings reported on in this publication were transplanted to the field along with their controls. When the Phytophthora pod disease season began in 1973, all experimental plants along with the controls were sprayed with active and freshly prepared dense sporangial suspension of P. palmivora. Observations on Phytophthora infection were recorded at two-weekly intervals for three months. Results were pooled for each set of experimental plants, after having confirmed that no marked difference appeared among individual plants of each group. Contrary to the observations recorded at the nursery stage, all experimental plants that showed no infection indicated disease infection levels normally characteristic of the F 3 Amazon cultivar of Cacao in Nigeria. Although the nursery and the field data are difficult to reconcile and interpret, it is suggested that probably temporary disease tolerance/resistance, which some irradiated plants showed at the nursery (seedling) stage, was lost as the plants matured, thus suggesting different resistance factor systems for juvenile and mature cacao trees. (author)

  14. Phylogenetic and population analyses of the invasive brown root-rot pathogen (Phellinus noxius) highlight the existence of at least two distinct populations

    Science.gov (United States)

    J. E. Stewart; N. Sahashi; T. Hattori; M. Akiba; Y. Ota; L. Shuey; R. L. Schlub; N. Atibalentia; F. Brooks; A. M. C. Tang; R. Y. C. Lam; M. W. K. Leung; L. M. Chu; H. S. Kwan; A. Mohd Farid; S. S. Lee; C. -L. Chung; H. -H. Lee; Y.- C. Huang; R. -F. Liou; J. -N. Tsai; P. G. Cannon; J. W. Hanna; N. B. Klopfenstein; M. -S. Kim

    2017-01-01

    Phellinus noxius (Corner) G. H. Cunn is a vastly destructive, fast-growing pathogen that affects a wide range of woody hosts in pan-tropical areas, including Asia, Australia, Africa, and Oceania (Ann et al. 2002). This invasive pathogen causes brown root-rot disease on cacao, coffee, and rubber, as well as diverse fruit, nut, ornamental, and other native/exotic trees,...

  15. Transgenic sweet potato expressing thionin from barley gives resistance to black rot disease caused by Ceratocystis fimbriata in leaves and storage roots.

    Science.gov (United States)

    Muramoto, Nobuhiko; Tanaka, Tomoko; Shimamura, Takashi; Mitsukawa, Norihiro; Hori, Etsuko; Koda, Katsunori; Otani, Motoyasu; Hirai, Masana; Nakamura, Kenzo; Imaeda, Takao

    2012-06-01

    Black rot of sweet potato caused by pathogenic fungus Ceratocystis fimbriata severely deteriorates both growth of plants and post-harvest storage. Antimicrobial peptides from various organisms have broad range activities of killing bacteria, mycobacteria, and fungi. Plant thionin peptide exhibited anti-fungal activity against C. fimbriata. A gene for barley α-hordothionin (αHT) was placed downstream of a strong constitutive promoter of E12Ω or the promoter of a sweet potato gene for β-amylase of storage roots, and introduced into sweet potato commercial cultivar Kokei No. 14. Transgenic E12Ω:αHT plants showed high-level expression of αHT mRNA in both leaves and storage roots. Transgenic β-Amy:αHT plants showed sucrose-inducible expression of αHT mRNA in leaves, in addition to expression in storage roots. Leaves of E12Ω:αHT plants exhibited reduced yellowing upon infection by C. fimbriata compared to leaves of non-transgenic Kokei No. 14, although the level of resistance was weaker than resistance cultivar Tamayutaka. Storage roots of both E12Ω:αHT and β-Amy:αHT plants exhibited reduced lesion areas around the site inoculated with C. fimbriata spores compared to Kokei No. 14, and some of the transgenic lines showed resistance level similar to Tamayutaka. Growth of plants and production of storage roots of these transgenic plants were not significantly different from non-transgenic plants. These results highlight the usefulness of transgenic sweet potato expressing antimicrobial peptide to reduce damages of sweet potato from the black rot disease and to reduce the use of agricultural chemicals.

  16. Antagonistic activity of endo-β-1,3-glucanase from a novel isolate, Streptomyces sp. 9X166, against black rot in orchids.

    Science.gov (United States)

    Sakdapetsiri, Chatsuda; Fukuta, Yasuhisa; Aramsirirujiwet, Yaovapa; Shirasaka, Norifumi; Kitpreechavanich, Vichien

    2016-05-01

    A total of 123 actinomycetes was isolated from 12 varieties of wild orchids and screened for potential antagonistic activity against Phytophthora, which causes black rot disease in orchids. In vitro and in vivo experimental results revealed that Streptomyces sp. strain 9X166 showed the highest antagonistic activity; its β-1,3-glucanase production ability was a key mechanism for growth inhibition of the pathogen. PCR amplification and DNA sequencing of the 16S ribosomal RNA gene allowed the identification of this strain, with high similarity (99.93%) to the novel species Streptomyces similaensis. The glucanase enzyme, purified to homogeneity by anion exchange and gel filtration chromatography, showed a specific activity of 58 U mg(-1) (a 3.9-fold increase) and yield of 6.4%. The molecular weight, as determined by SDS-PAGE and gel filtration, was approximately 99 and 80 kDa, respectively, suggesting that the enzyme was a monomer. The purified enzyme showed the highest substrate specificity to laminarin, indicating that it was β-1,3-glucanase. The hydrolyzed products of cello-oligosaccharides suggested that this enzyme was endo-type β-1,3-glucanase. Streptomyces sp. 9X166 culture filtrate, possessing β-1,3-glucanase activity, could degrade both freeze-dried and living mycelium. This is the first report on a β-1,3-glucanase-producing Streptomyces sp. that could be an effective biocontrol agent for black rot disease in orchids. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. Root rot peas in the Netherlands : fungal pathogens, inoculum potential and soil receptivity

    NARCIS (Netherlands)

    Oyarzun, P.J.

    1994-01-01

    Fungi associated to pea (Pisum sativum L.) root rot were studied. Fusarium and Oomycetes were most common. Fusarium solani f. sp. pisi, Fsp, was widely distributed and the most frequent

  18. Armillaria root rot of tea in Kenya : characterization of the pathogen and approaches to disease management

    NARCIS (Netherlands)

    Otieno, W.

    2002-01-01

    The rare occurrence of basidiomata and rhizomorphs constrains diagnosis of Armillaria root rot and identification of Armillaria species in Africa. This has had a negative impact on taxonomic research on the genus Armillaria in the continent, where the

  19. Phylogenetic, morphological and pathogenic characterization of Alternaria species associated with fruit rots of blueberry in California

    Science.gov (United States)

    Fruit rot caused by Alternaria spp. is one of the most important factors affecting the postharvest quality and shelf life of blueberry fruits. Alternaria spp. isolates were collected from decayed fruits of blueberry in the Central Valley of California during 2012 and 2013. The aims of this study wer...

  20. Isolation and characterization of mutants of Pseudomonas maltophila PM-4 altered in chitinolytic activity and antagonistic activity against root rot pathogens of clusterbean (Cyamopsis tetragonoloba).

    Science.gov (United States)

    Yadav, E; Pathak, D V; Sharma, S K; Kumar, M; Sharma, P K

    2007-03-01

    Pseudomonas maltophila PM-4, an antagonist of pathogenic fungi including Rhizoctonia bataticola, R. solani, Fusarium oxysporum and Sclerotinia sclerotiorum associated with root rot of clusterbean (Cyamopsis tetragonoloba) was mutagenized with Tn5. Hyperchitinase producing mutants showing large zone of colloidal chitin dissolution were identified on medium containing calcoflor dye as an indicator. A mutant P-48 producing 137% higher chitinase activity than the parent strain PM-4 was identified. Seed bacterization of clusterbean (Cyamopsis tetragonoloba) with P-48 controlled the root rot upto 40.8% in the presence of conglomerate of all the four fungal pathogens Rhizoctonia bataticola, R. solani, F. oxysporum and Sclerotinia sclerotiorum.

  1. A novel, multiplexed, probe-based quantitative PCR assay for the soybean root- and stem-rot pathogen, Phytophthora sojae, utilizes its transposable element

    Science.gov (United States)

    Phytophthora root rot of soybean (Glycine max Merr.) is caused by the oomycete Phytophthora sojae (Kaufm. and Gerd.). P. sojae has a narrow host range, consisting primarily of soybean, and it is a serious pathogen worldwide. It exists in root and stem tissues as mycelium, wherein it can form oospo...

  2. Endophytic bacteria from Piper tuberculatum Jacq.: isolation, molecular characterization, and in vitro screening for the control of Fusarium solani f. sp piperis, the causal agent of root rot disease in black pepper (Piper nigrum L.).

    Science.gov (United States)

    Nascimento, S B; Lima, A M; Borges, B N; de Souza, C R B

    2015-07-06

    Endophytic bacteria have been found to colonize internal tissues in many different plants, where they can have several beneficial effects, including defense against pathogens. In this study, we aimed to identify endophytic bacteria associated with roots of the tropical piperaceae Piper tuberculatum, which is known for its resistance to infection by Fusarium solani f. sp piperis, the causal agent of black pepper (Piper nigrum) root rot disease in the Amazon region. Based on 16S rRNA gene sequence analysis, we isolated endophytes belonging to 13 genera: Bacillus, Paenibacillus, Pseudomonas, Enterobacter, Rhizobium, Sinorhizobium, Agrobacterium, Ralstonia, Serratia, Cupriavidus, Mitsuaria, Pantoea, and Staphylococcus. The results showed that 56.52% of isolates were associated with the phylum Proteobacteria, which comprised α, β, and γ classes. Other bacteria were related to the phylum Firmicutes, including Bacillus, which was the most abundant genus among all isolates. Antagonistic assays revealed that Pt12 and Pt13 isolates, identified as Pseudomonas putida and Pseudomonas sp, respectively, were able to inhibit F. solani f. sp piperis growth in vitro. We describe, for the first time, the molecular identification of 23 endophytic bacteria from P. tuberculatum, among which two Pseudomonas species have the potential to control the pathogen responsible for root rot disease in black pepper in the Amazon region.

  3. Characteristics and complete genome analysis of a novel jumbo phage infecting pathogenic Bacillus pumilus causing ginger rhizome rot disease.

    Science.gov (United States)

    Yuan, Yihui; Gao, Meiying

    2016-12-01

    Tailed phages with genomes larger than 200 kbp are classified as jumbo phage and exhibit extremely high diversity. In this study, a novel jumbo phage, vB_BpuM_BpSp, infecting pathogenic Bacillus pumilus, the cause of ginger rhizome rot disease, was isolated. Notable features of phage vB_BpuM_BpSp are the large phage capsid of 137 nm and baseplate-attached curly tail fibers. The genome of the phage is 255,569 bp in size with G+C content of 25.9 %, and it shows low similarity to known biological entities. The phage genome contains 318 predicted coding sequences. Among these predicted coding sequences, 26 genes responsible for nucleotide metabolism were found, and seven structural genes could be identified. The findings of this study provide new understanding of the genetic diversity of phages.

  4. Simultaneous detection of major blackleg and soft rot bacterial pathogens in potato by multiplex polymerase chain reaction‡

    Science.gov (United States)

    Potrykus, M; Sledz, W; Golanowska, M; Slawiak, M; Binek, A; Motyka, A; Zoledowska, S; Czajkowski, R; Lojkowska, E

    2014-01-01

    A multiplex polymerase chain reaction (PCR) assay for simultaneous, fast and reliable detection of the main soft rot and blackleg potato pathogens in Europe has been developed. It utilises three pairs of primers and enables detection of three groups of pectinolytic bacteria frequently found in potato, namely: Pectobacterium atrosepticum, Pectobacterium carotovorum subsp. carotovorum together with Pectobacterium wasabiae and Dickeya spp. in a multiplex PCR assay. In studies with axenic cultures of bacteria, the multiplex assay was specific as it gave positive results only with strains of the target species and negative results with 18 non-target species of bacteria that can possibly coexist with pectinolytic bacteria in a potato ecosystem. The developed assay could detect as little as 0.01 ng µL–1 of Dickeya sp. genomic DNA, and down to 0.1 ng µL–1 of P. atrosepticum and P. carotovorum subsp. carotovorum genomic DNA in vitro. In the presence of competitor genomic DNA, isolated from Pseudomonas fluorescens cells, the sensitivity of the multiplex PCR decreased tenfold for P. atrosepticum and Dickeya sp., while no change was observed for P. carotovorum subsp. carotovorum and P. wasabiae. In spiked potato haulm and tuber samples, the threshold level for target bacteria was 101 cfu mL–1 plant extract (102 cfu g–1 plant tissue), 102 cfu mL–1 plant extract (103 cfu g–1 plant tissue), 103 cfu mL–1 plant extract (104 cfu g–1 plant tissue), for Dickeya spp., P. atrosepticum and P. carotovorum subsp. carotovorum/P. wasabiae, respectively. Most of all, this assay allowed reliable detection and identification of soft rot and blackleg pathogens in naturally infected symptomatic and asymptomatic potato stem and progeny tuber samples collected from potato fields all over Poland. PMID:25506085

  5. Assessment of the relationship between geologic origin of soil, rhizobacterial community composition and soil receptivity to tobacco black root rot in Savoie region (France)

    Czech Academy of Sciences Publication Activity Database

    Almario, J.; Kyselková, Martina; Kopecký, J.; Ságová-Marečková, M.; Muller, D.; Grundmann, G.L.; Moënne-Loccoz, Y.

    2013-01-01

    Roč. 371, 1/2 (2013), s. 397-408 ISSN 0032-079X Grant - others:MŚMT(CZ) ME09077 Institutional support: RVO:60077344 Keywords : suppressive soils * Thielaviopsis basicola * black root rot Subject RIV: EE - Microbiology, Virology Impact factor: 3.235, year: 2013

  6. Seed rot fungal pathogen of post harvest irvingia gabonensis in the ...

    African Journals Online (AJOL)

    %), Fusarium moniliforme (12.67%), Penicillium notatum (14.48%) and Rhizopus nigricans (24.70%) as the associated pathogens. The distribution, pathogenicity and spore germination kinetics were discussed and control measures proffered.

  7. Morphology, Pathogenicity and Management of Coniella Fruit Rot (Coniella granati on Pomegranate

    Directory of Open Access Journals (Sweden)

    Aysun Uysal

    2018-04-01

    Full Text Available One of the objectives of the study was to identify the fungus involved in fruit rot on pomegranates in the Mediterranean Region of Turkey. The fungus designated as Coniella granati (Saccardo Petrak and Sydow based on morphological characteristics. The fungus colonized the fruit after 5 to 8 days, followed by the appearance of fruit rot symptoms leading to the formation of abundant pycnidia covering the peel. Secondly, the efficacy of fungicides against C. granati was evaluated by mycelial growth and conidial germination assays. Tebuconazole, boscalid+pyraclostrobin and iprodione at 1.0, 25, and 50 μgml-1 concentrations, respectively, completely inhibited mycelial growth. In the azoxystrobin and dodine, relatively higher concentrations required to inhibit mycelial growth. Tebuconazole exhibited the greatest inhibition (82.2% of mycelium growth. The EC50 values in mycelial growth of C. granati ranged from 0.13 to 151.9. The highest EC50 values occurred for tebuconazole (0.13μgml-1. Tebuconazole, boscalid+pyraclostrobin and iprodione at 200, 10 and 5 μgml-1 concentrations, respectively, were the highly effective in inhibiting conidial germination. Azoxystrobin exhibited a low effect (61% on conidial germination. The EC50 values on conidial germination of C. granati ranged from 0.2 to 28.7. Tebuconazole had the lowest EC50 value, while boscalid+pyraclostrobin exhibited the highest EC50 value.

  8. Characterization and pathogenicity of Alternaria spp. strains associated with grape bunch rot during post-harvest withering.

    Science.gov (United States)

    Lorenzini, Marilinda; Zapparoli, Giacomo

    2014-09-01

    Alternaria is a fungal agent of grape bunch rot which occurs during withering, a process which produces passito style wines. Seven isolates of Alternaria spp. were characterized using morphological examination, genotypic analysis and pathogenicity. Six of these isolates produced conidiophores and conidia displaying sporulation patterns typical of the Alternaria alternata species-group. Variability in colony morphology and growth on different media was observed. Phylogenetic analysis of internal transcribed spacer (ITS) sequences clustered all isolates within a monophyletic clade, while intergenic spacer region (IGS)-RFLP profiles were congruent with those of A. alternata and Alternaria arborescens. RAPD-PCR proved helpful in discriminating between strains. To assay strain pathogenicity, grape berries were infected while undergoing withering conditions at different temperatures. Disease capacity was found to be strain dependent and varied consistently between the most and least aggressive strains. This study has provided interesting information on polymorphism within Alternaria spp. populations in withered grapes and on understanding the saprophytic role of this fungus during the post-harvest dehydrating process. Copyright © 2014 Elsevier B.V. All rights reserved.

  9. Phytophthora megakarya and Phytophthora palmivora, Closely Related Causal Agents of Cacao Black Pod Rot, Underwent Increases in Genome Sizes and Gene Numbers by Different Mechanisms

    Science.gov (United States)

    Ali, Shahin S.; Shao, Jonathan; Lary, David J.; Kronmiller, Brent A.; Shen, Danyu; Strem, Mary D.; Amoako-Attah, Ishmael; Akrofi, Andrew Yaw; Begoude, B.A. Didier; ten Hoopen, G. Martijn; Coulibaly, Klotioloma; Kebe, Boubacar Ismaël; Melnick, Rachel L.; Guiltinan, Mark J.; Tyler, Brett M.; Meinhardt, Lyndel W.

    2017-01-01

    Phytophthora megakarya (Pmeg) and Phytophthora palmivora (Ppal) are closely related species causing cacao black pod rot. Although Ppal is a cosmopolitan pathogen, cacao is the only known host of economic importance for Pmeg. Pmeg is more virulent on cacao than Ppal. We sequenced and compared the Pmeg and Ppal genomes and identified virulence-related putative gene models (PGeneM) that may be responsible for their differences in host specificities and virulence. Pmeg and Ppal have estimated genome sizes of 126.88 and 151.23 Mb and PGeneM numbers of 42,036 and 44,327, respectively. The evolutionary histories of Pmeg and Ppal appear quite different. Postspeciation, Ppal underwent whole-genome duplication whereas Pmeg has undergone selective increases in PGeneM numbers, likely through accelerated transposable element-driven duplications. Many PGeneMs in both species failed to match transcripts and may represent pseudogenes or cryptic genetic reservoirs. Pmeg appears to have amplified specific gene families, some of which are virulence-related. Analysis of mycelium, zoospore, and in planta transcriptome expression profiles using neural network self-organizing map analysis generated 24 multivariate and nonlinear self-organizing map classes. Many members of the RxLR, necrosis-inducing phytophthora protein, and pectinase genes families were specifically induced in planta. Pmeg displays a diverse virulence-related gene complement similar in size to and potentially of greater diversity than Ppal but it remains likely that the specific functions of the genes determine each species’ unique characteristics as pathogens. PMID:28186564

  10. Evaluating the Ability of some Medicinal Plants for Controlling Rhizopus (Rhizopu snigricans and Black Spot Rot (Alternaria alternate as Postharvest Diseases in Tomato Produced under Conventional and Organic Cropping Systems

    Directory of Open Access Journals (Sweden)

    S.M Seyyedi

    2016-11-01

    Full Text Available Introduction After crops harvesting, conditions and durations of storage are considered as the most crucial factors formaintaining the nutritional value and quality of agro-horticultural products such as tomato (Lycopersicom esculentum Mill. and its waste reduction. However, the rhizopus rot (Rhizopus stolonifer and black spot rot (Alternaria alternate are the most important postharvest diseases in tomato during storage. In other word, among the factors reducing quality of the postharvest tomato, Rhizopus nigricans Ehrenb. (Rhizopus stolonifer and Alternaria alternate (Fr.:Fr. Keissl. f. sp. lycopersici paly a special role in the contaminated tomato fruits that can affect its taste, firmness and stiffness. In recent years, due to the problems and threats arising from the use of chemical fungicides in agricultural systems, principled management of alternative biological approaches for reducing the postharvest contamination in tomato, especially during storage, is emphasized more than ever. Considering these conditions, the current study was aimed to investigate the effects of some medicinal plants including thyme (Thymus vulgaris L., pennyroyal (Mentha pulegium L., peppermint (Mentha piperita L., eucalyptus (Eucalyptus globules L., caster bean (Ricinus communis L. and tomato in their ability to control the rhizopus (Rhizopus nigricans and black spot rot (Alternaria alternate in tomato production under conventional and organic cropping systems. Materials and methods The experiment was conducted at Faculty of Agriculture, Ferdowsi University of Mashhad, Iran, during theyear of 2010. A completely randomized design was used based on factorial arrangement with three replications and 14 treatments. Two cropping production systems (conventional and organic and seven medicinal plants (thyme, pennyroyal, peppermint, eucalyptus, caster bean, tomato and control were the first and the second experimental factors, respectively. After collecting plant samples

  11. Genetic mechanisms of host-pathogen interactions for charcoal rot in soybean

    Science.gov (United States)

    Soybean is a leading agronomic crop and it is contributing to food and agricultural security with expanding production in diverse regions around the world. Although soybean is attacked by several diseases and pests, and progress has been made in understanding and managing some of these pathogens and...

  12. Use of jasmonic acid and salicylic acid to inhibit growth of sugarbeet storage rot pathogens

    Science.gov (United States)

    Jasmonic acid (JA) and salicylic acid (SA) are endogenous plant hormones that induce native plant defense responses and provide protection against a wide range of diseases. Previously, JA, applied after harvest, was shown to protect sugarbeet roots against the storage pathogens, Botrytis cinerea, P...

  13. Survival of Stenocarpella spp. in maize debris and soil suppressiveness to maize ear rot pathogens

    NARCIS (Netherlands)

    Moretti Ferreira Pinto, Felipe; Novaes Medeiros, H.; Biazzotto Correia Porto, V.; Silva Siqueira, da C.; Cruz Machado, da J.; Köhl, J.; Vasconcelos de Medeiros, Flavio

    2016-01-01

    Stenocarpella species (S. maydis and S. macrospora) overwinter saprophytically in maize stubble but little is known about the factors that contribute to its survival and to the induction of suppressiveness of pathogen colonization. We aimed at determining the role of crop rotation on the survival of

  14. Multiplex detection and identification of bacterial pathogens causing potato blackleg and soft rot in Europe, using padlock probes

    NARCIS (Netherlands)

    Slawiak, M.; Doorn, van R.; Szemes, M.; Speksnijder, A.G.C.L.; Waleron, M.; Wolf, van der J.M.; Lojkowska, E.; Schoen, C.D.

    2013-01-01

    The objective of this study was to develop a multiplex detection and identification protocol for bacterial soft rot coliforms, namely Pectobacterium wasabiae (Pw), Pectobacterium atrosepticum (Pba) and Dickeya spp., responsible for potato blackleg and tuber soft rot. The procedures were derived from

  15. Clarification of the Etiology of Glomerella Leaf Spot and Bitter Rot of Apple Caused by Colletotrichum spp. Based on Morphology and Genetic, Molecular, and Pathogenicity Tests.

    Science.gov (United States)

    González, Eugenia; Sutton, Turner B; Correll, James C

    2006-09-01

    ABSTRACT Morphological characteristics and vegetative compatibility groups (VCGs) of 486 isolates of Glomerella cingulata, Colletotrichum gloeosporioides, and C. acutatum collected from apple leaves with Glomerella leaf spot (GLS) symptoms and fruit with bitter rot symptoms in the United States and Brazil were studied. From this collection, 155 isolates of G. cingulata (93 from fruit, 61 from leaves, and 1 from buds), 42 isolates of C. gloeosporioides from fruit, and 14 isolates of C. acutatum (10 from fruit and 4 from leaves) were studied using mitochondrial (mt)DNA restriction fragment length polymorphism (RFLP) haplotypes. A subset of 24 isolates was studied by examining the sequence of a 200-bp intron of the glyceraldehyde 3-phosphate dehydrogenase (GDPH) nuclear gene. In addition, 98 isolates were tested for pathogenicity on leaves of cvs. Gala and Golden Delicious in the greenhouse, and 24 isolates were tested for pathogenicity on fruit of cv. Gala in growth chambers. In total, 238 and 225 isolates of G. cingulata were separated into four distinct morphological types and six VCGs, respectively. Five morphological types and six VCGs were identified among 74 and 36 isolates of C. gloeosporioides, respectively. Three morphological types and four VCGs were identified among 74 and 23 isolates of C. acutatum, respectively. Seven different mtDNA RFLP haplotypes were observed within isolates of G. cingulata, two within isolates of C. gloeosporioides, and two within isolates of C. acutatum. Phylogenetic trees, inferred based on maximum likelihood and maximum parsimony methods using the intron sequence, produced similar topologies. Each species was separated into distinct groups. All isolates tested were pathogenic on fruit, though only isolates with specific VCGs and haplotypes were pathogenic to leaves. Vegetative compatibility was a better tool than molecular characters for distinguishing isolates of G. cingulata pathogenic on both leaves and fruit from the ones

  16. Root rots

    Science.gov (United States)

    Kathryn Robbins; Philip M. Wargo

    1989-01-01

    Root rots of central hardwoods are diseases caused by fungi that infect and decay woody roots and sometimes also invade the butt portion of the tree. By killing and decaying roots, root rotting fungi reduce growth, decrease tree vigor, and cause windthrow and death. The most common root diseases of central hardwoods are Armillaria root rot, lnonotus root rot, and...

  17. The mitochondrial genome of Moniliophthora roreri, the frosty pod rot pathogen of cacao.

    Science.gov (United States)

    Costa, Gustavo G L; Cabrera, Odalys G; Tiburcio, Ricardo A; Medrano, Francisco J; Carazzolle, Marcelo F; Thomazella, Daniela P T; Schuster, Stephen C; Carlson, John E; Guiltinan, Mark J; Bailey, Bryan A; Mieczkowski, Piotr; Pereira, Gonçalo A G; Meinhardt, Lyndel W

    2012-05-01

    In this study, we report the sequence of the mitochondrial (mt) genome of the Basidiomycete fungus Moniliophthora roreri, which is the etiologic agent of frosty pod rot of cacao (Theobroma cacao L.). We also compare it to the mtDNA from the closely-related species Moniliophthora perniciosa, which causes witches' broom disease of cacao. The 94 Kb mtDNA genome of M. roreri has a circular topology and codes for the typical 14 mt genes involved in oxidative phosphorylation. It also codes for both rRNA genes, a ribosomal protein subunit, 13 intronic open reading frames (ORFs), and a full complement of 27 tRNA genes. The conserved genes of M. roreri mtDNA are completely syntenic with homologous genes of the 109 Kb mtDNA of M. perniciosa. As in M. perniciosa, M. roreri mtDNA contains a high number of hypothetical ORFs (28), a remarkable feature that make Moniliophthoras the largest reservoir of hypothetical ORFs among sequenced fungal mtDNA. Additionally, the mt genome of M. roreri has three free invertron-like linear mt plasmids, one of which is very similar to that previously described as integrated into the main M. perniciosa mtDNA molecule. Moniliophthora roreri mtDNA also has a region of suspected plasmid origin containing 15 hypothetical ORFs distributed in both strands. One of these ORFs is similar to an ORF in the mtDNA gene encoding DNA polymerase in Pleurotus ostreatus. The comparison to M. perniciosa showed that the 15 Kb difference in mtDNA sizes is mainly attributed to a lower abundance of repetitive regions in M. roreri (5.8 Kb vs 20.7 Kb). The most notable differences between M. roreri and M. perniciosa mtDNA are attributed to repeats and regions of plasmid origin. These elements might have contributed to the rapid evolution of mtDNA. Since M. roreri is the second species of the genus Moniliophthora whose mtDNA genome has been sequenced, the data presented here contribute valuable information for understanding the evolution of fungal mt genomes among

  18. Reação de cultivares de alface a Thielaviopsis basicola Lettuce reaction to black root rot caused by Thielaviospsis basicola

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    Fernando C Sala

    2008-09-01

    Full Text Available A alface é a folhosa de maior importância no Brasil. O presente trabalho visou determinar a reação de cultivares de alface à murchadeira provocada pelo fungo Thielaviopsis basicola, na fase juvenil. Um experimento foi conduzido em casa-de-vegetação em delineamento inteiramente casualizado, em esquema fatorial 37 x 2 (cultivares, com e sem inoculação, com três repetições. Mudas com 30 dias foram transplantadas para bandejas de 128 células preenchidas com 1/3 de substrato colonizado com 7,5 x 10(5 conídios/g de substrato. Logo após o transplante, inoculou-se 3 mL de suspensão de esporos de concentração 2 x 10(6 conídios/mL, próximo ao colo de cada planta. A reação do hospedeiro ao patógeno e sua avaliação foi realizada utilizando escala de nota de 1 (ausência de sintomas a 5 (mais de 90% das raízes afetadas, com base na severidade da doença. Cultivares do tipo crespa e batavia foram todas resistentes. Cultivares do tipo americana e lisa apresentaram variação inter-varietal quanto à reação da hospedeira ao patógeno.Lettuce is the most important leafy crop in Brazil. The varietal reaction of four lettuce types to lettuce black root rot (LBRR caused by Thielaviopsis basicola at the juvenile stage were determined. The trial was carried out in controlled greenhouse conditions and arranged in completely randomized design, in a 37 x 2 (cultivars with and without inoculation cheme with three replications. 30-day old seedlings were transplanted to styrofoam tray of 128 cells filled with 1/3 of colonized substrate with 7,5 x 10(5 conidia/g of substrate. After transplant, seedlings were reinoculated with a spore suspension with 2 x 10(6 conidia/mL poured next to the seedling stem. Host reaction to the pathogen and its evaluation were performed according to a severity scale from 1 (absence of symptoms to 5 (more than 90% of rotted roots. Lettuce cultivars belonging to the loose leaf and batavia types were all resistant to

  19. Endophytic fungi harbored inPanax notoginseng: diversity and potential as biological control agents against host plant pathogens of root-rot disease.

    Science.gov (United States)

    Zheng, You-Kun; Miao, Cui-Ping; Chen, Hua-Hong; Huang, Fang-Fang; Xia, Yu-Mei; Chen, You-Wei; Zhao, Li-Xing

    2017-07-01

    Endophytic fungi play an important role in balancing the ecosystem and boosting host growth. In the present study, we investigated the endophytic fungal diversity of healthy Panax notoginseng and evaluated its potential antimicrobial activity against five major phytopathogens causing root-rot of P. notoginseng . A culture-dependent technique, combining morphological and molecular methods, was used to analyze endophytic fungal diversity. A double-layer agar technique was used to challenge the phytopathogens of P. notoginseng . A total of 89 fungi were obtained from the roots, stems, leaves, and seeds of P. notoginseng , and 41 isolates representing different morphotypes were selected for taxonomic characterization. The fungal isolates belonged to Ascomycota (96.6%) and Zygomycota (3.4%). All isolates were classified to 23 genera and an unknown taxon belonging to Sordariomycetes. The number of isolates obtained from different tissues ranged from 12 to 42 for leaves and roots, respectively. The selected endophytic fungal isolates were challenged by the root-rot pathogens Alternaria panax , Fusarium oxysporum , Fusarium solani , Phoma herbarum , and Mycocentrospora acerina. Twenty-six of the 41 isolates (63.4%) exhibited activity against at least one of the pathogens tested. Our results suggested that P. notoginseng harbors diversified endophytic fungi that would provide a basis for the identification of new bioactive compounds, and for effective biocontrol of notoginseng root rot.

  20. When genome-based approach meets the ‘old but good’: revealing genes involved in the antibacterial activity of Pseudomonas sp. P482 against soft rot pathogens.

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    Dorota Magdalena Krzyżanowska

    2016-05-01

    Full Text Available Dickeya solani and Pectobacterium carotovorum subsp. brasili¬ense are recently established species of bacterial plant pathogens causing black leg and soft rot of many vegetables and ornamental plants. Pseudomonas sp. strain P482 inhibits the growth of these pathogens, a desired trait considering the limited measures to combat these diseases. In this study, we determined the genetic background of the antibacterial activity of P482, and established the phylogenetic position of this strain.Pseudomonas sp. P482 was classified as Pseudomonas donghuensis. Genome mining revealed that the P482 genome does not contain genes determining the synthesis of known antimicrobials. However, the ClusterFinder algorithm, designed to detect atypical or novel classes of secondary metabolite gene clusters, predicted 18 such clusters in the genome. Screening of a Tn5 mutant library yielded an antimicrobial negative transposon mutant. The transposon insertion was located in a gene encoding an HpcH/HpaI aldolase/citrate lyase family protein. This gene is located in a hypothetical cluster predicted by the ClusterFinder, together with the downstream homologues of four nfs genes, that confer production of a nonfluorescent siderophore by P. donghuensis HYST. Site-directed inactivation of the HpcH/HpaI aldolase gene, the adjacent short chain dehydrogenase gene, as well as a homologue of an essential nfs cluster gene, all abolished the antimicrobial activity of the P482, suggesting their involvement in a common biosynthesis pathway. However, none of the mutants showed a decreased siderophore yield, neither was the antimicrobial activity of the wild type P482 compromised by high iron bioavailability.A genomic region comprising the nfs cluster and three upstream genes is involved in the antibacterial activity of P. donghuensis P482 against D. solani and P. carotovorum subsp. brasiliense. The genes studied are unique to the two known P. donghuensis strains. This study

  1. Screening of Seed Treatment Agents against Leaf Blight and Black Root Rot for Carrot Organic Cultivation

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    Jae Eun Lee,

    2011-08-01

    Full Text Available This study was conducted to control the seed borne pathogens (Alternaria spp. of carrot and to examine the seed germination rate by using 13 environment friendly agricultural materials instead of conventional chemicals for organic cultivation. The growth inhibiting effects on pathogens showed the different responses according to each agricultural material and effective 7 materials against seed borne pathogens were selected. Among 7 materials, the carrot seeds sterilized with plant extracts, Tanger Stop and Land Saver were not germinated at all. The germination rate of seeds sterilized with other materials showed the similar levels with reference chemical (Benlate-T and non-treated seeds. Infection rates of seeds sterilized with seaweed extract, Bellopper for controlling A. radicina and plant extract, Ssial-100 for A. dauci were similar or low infection rate compared with reference chemical. The germination rate and root length of seeds sterilized with Bellopper and Ssial-100 was similar or superior to those of chemical sterilized seeds. The optimal condition seemed to be a little bit different depending on the concentration of materials. As a result, the sterilization of carrot seeds by using the environment friendly materials could be effectively utilized as a technology to inhibit the infection of seed-borne pathogens

  2. Evaluation of biocontrol potential of epiphytic fluorescent pseudomonas as associated with healthy fruits and vegetables against root rot and root knot pathogens of mungbean

    International Nuclear Information System (INIS)

    Habiba, A.; Noreen, R.; Ali, S. A.; Sultana, V.; Ara, J.

    2016-01-01

    Endophytic and rhizospheric fluorescent Pseudomonas have widely been used as biological control agents against soilborne plant pathogens. In this study, fifteen epiphytic fluorescent Pseudomonas isolated from the surfaces of citrus (grapefruit, orange and lemon) melon and tomato fruits were characterized for their in vitro activity against root rotting fungi viz., Macrophomina phaseolina, Fusarium solani, F. oxysporum and Rhizoctonia solani and nematicidal activity against the second stage juveniles of Meloidogyne javanica. Out of fifteen Pseudomonas isolates HAB-16, HAB-1 and HAB-25 inhibited the growth of all the test fungi and showed maximum nematicidal activity against second stage juvenile of M. javanica. Based on their effective in vitro activity nine epiphytic fluorescent Pseudomonas were evaluated for their growth promoting ability and biocontrol activity in screen house on mungbean. Pseudomonas isolates (HAB-13, HAB-2, HAB-4, HAB-1, HAB-14, HAB-9, HAB-7 and HAB-25) used as soil drench greatly reduced the root rot-root knot infection and thereby enhanced plant growth, root nodulation and yield in mungbean. Besides, rhizospheric and endophytic, epiphytic fluorescent Pseudomonas associated with healthy fruits may be used as biocontrol agent against root rotting fungi, besides, using for the mangemnet of postharvest diseases. (author)

  3. Etiology of phomopsis root rot in soybean

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    Valéria Cecília Ghissi

    2014-09-01

    Full Text Available In a survey of damages caused by soybean root rot to crops in the south of Brazil for several years, a root rot caused by Phomopsis sp has been found with increasing frequency. The primary symptoms are seen when the main root is cut longitudinally, including the death of the wood which shows white coloration and well-defined black lines that do not have a defined format. Thus, based on similarity, it has been called geographic root rot due to its aspect resembling irregular lines that separate regions on a map. In isolations, colonies and alpha spores of Phomopsis have prevailed. Pathogenicity test was done by means of inoculation in the crown of plants cultivated in a growth chamber. The geographic symptoms were reproduced in plants and the fungus Phomopsis sp. was reisolated. In soybean stems naturally infected with pod and stem blight, geographic symptoms caused by Phomopsis phaseoli are found. To the known symptoms on stems, pods and grains, that of root rot caused by P. phaseoli is now added.

  4. A Leaf-Inhabiting Endophytic Bacterium, Rhodococcus sp. KB6, Enhances Sweet Potato Resistance to Black Rot Disease Caused by Ceratocystis fimbriata.

    Science.gov (United States)

    Hong, Chi Eun; Jeong, Haeyoung; Jo, Sung Hee; Jeong, Jae Cheol; Kwon, Suk Yoon; An, Donghwan; Park, Jeong Mee

    2016-03-01

    Rhodococcus species have become increasingly important owing to their ability to degrade a wide range of toxic chemicals and produce bioactive compounds. Here, we report isolation of the Rhodococcus sp. KB6, which is a new leaf-inhabiting endophytic bacterium that suppresses black rot disease in sweet potato leaves. We determined the 7.0 Mb draft genome sequence of KB6 and have predicted 19 biosynthetic gene clusters for secondary metabolites, including heterobactins, which are a new class of siderophores. Notably, we showed the first internal colonization of host plants with Rhodococcus sp. KB6 and discuss its potential as a biocontrol agent for sustainable agriculture.

  5. Transgenic expression of a maize geranyl geranyl transferase gene sequence in maize callus increases resistance to ear rot pathogens

    Science.gov (United States)

    Determining the genes responsible for pest resistance in maize can allow breeders to develop varieties with lower losses and less contamination with undesirable toxins. A gene sequence coding for a geranyl geranyl transferase-like protein located in a fungal ear rot resistance quantitative trait loc...

  6. CorA, the magnesium/nickel/cobalt transporter, affects virulence and extracellular enzyme production in the soft rot pathogen Pectobacterium carotovorum.

    Science.gov (United States)

    Kersey, Caleb M; Agyemang, Paul A; Dumenyo, C Korsi

    2012-01-01

    Pectobacterium carotovorum (formerly Erwinia carotovora ssp. carotovora) is a phytopathogenic bacterium that causes soft rot disease, characterized by water-soaked soft decay, resulting from the action of cell wall-degrading exoenzymes secreted by the pathogen. Virulence in soft rot bacteria is regulated by environmental factors, host and bacterial chemical signals, and a network of global and gene-specific bacterial regulators. We isolated a mini-Tn5 mutant of P. carotovorum that is reduced in the production of extracellular pectate lyase, protease, polygalacturonase and cellulase. The mutant is also decreased in virulence as it macerates less host tissues than its parent and is severely impaired in multiplication in planta. The inactivated gene responsible for the reduced virulent phenotype was identified as corA. CorA, a magnesium/nickel/cobalt membrane transporter, is the primary magnesium transporter for many bacteria. Compared with the parent, the CorA(-) mutant is cobalt resistant. The mutant phenotype was confirmed in parental strain P. carotovorum by marker exchange inactivation of corA. A functional corA(+) DNA from P. carotovorum restored exoenzyme production and pathogenicity to the mutants. The P. carotovorum corA(+) clone also restored motility and cobalt sensitivity to a CorA(-) mutant of Salmonella enterica. These data indicate that CorA is required for exoenzyme production and virulence in P. carotovorum. © 2011 THE AUTHORS. MOLECULAR PLANT PATHOLOGY © 2011 BSPP AND BLACKWELL PUBLISHING LTD.

  7. Rhizoctonia solani AG-3PT is the major pathogen associated with potato stem canker and black scurf in Colombia

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    Rosa Lilia Ferrucho

    2012-08-01

    Full Text Available Stem canker and black scurf diseases of potatoes are caused by the basidiomycetous fungus Thanatephorus cucumeris (anamorphic species complex Rhizoctonia solani. These diseases have worldwide distribution wherever potato is grown but their etiology varies depending on the predominance of distinct R. solani anastomosis groups (AG s in a particular area. Within the species complex, several AG s have been associated with stem canker or black scurf diseases, including AG -1, AG -2-1, AG -2-2, AG -3, AG -4, AG -5 and AG -9. This article reports on the most comprehensive population-based study, providing evidence on the distribution of R. solani AG s in Colombian potato fields. A total of 433 isolates were sampled from the main potato cropping areas in Colombia from 2005 to 2009. Isolates were assigned to AG s by conventional PCR assays using specific primers for AG -3, sequencing of the ITS -rDNA and hyphal interactions. Most of the isolates evaluated were assigned to AG -3PT (88.45%, and a few to AG -2-1 (2.54%. The remaining isolates were binucleate Rhizoctonia (AG -A, E, and I. Pathogenicity tests on the stems and roots of different plant species, including the potato, showed that AG -3PT affects the stems of solanaceous plants. In other plant species, damage was severe in the roots, but not the stems. AG -2-1 caused stem canker of Solanum tuberosum cv. Capiro and in R. raphanistrumi and B.campestris subsp. Rapa plantlets and root rot in other plants. The results of our study indicated that R. solani AG -3PT was the principal pathogen associated with potato stem canker and black scurf diseases of potatoes in Colombia

  8. The Draft Genome Sequence of Mycosphaerella fijiensis, the Black Sigatoka Pathogen of Banana

    Science.gov (United States)

    Mycosphaerella fijiensis is a fungal pathogen of banana and the causal agent of the devastating Black Sigatoka or black leaf streak disease. Its control requires weekly fungicide applications when bananas are grown under disease-conducive conditions, which mostly represent precarious tropical enviro...

  9. Decolourization potential of white-rot fungus Phanerochaete chrysosporium on synthetic dye bath effluent containing Amido black 10B

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    S. Senthilkumar

    2014-12-01

    Full Text Available Synthetic azo dyes are extensively used in textile industry and are not easily degraded into the environment due to their complex structure. Due to the low degree of fixation of these dyes to fabrics, more than 10–15% of the dye does not bind to fabrics during colour processing and release into water bodies as effluent cause serious environmental pollution. White-rot fungus is found to be capable of degrading lignin which has a complex structure similar to azo dyes. In this study, the decolourization potential of white-rot fungus Phanerochaete chrysosporium, which is capable of decolourizing synthetic dye bath effluent, was investigated. Maximum decolourization of 98% was achieved on the third day under normal conditions. The rate of decolourization carried out at different concentrations revealed that the increase in dye effluent concentration suppresses the percentage decolourization. The optimized amounts of nutrients were found to be 0.5%, 0.1% and 0.5% of glucose, manganese sulphate and ammonium salts, respectively. The addition of inducers such as starch and lignin increased enzyme production and the rate of decolourization.

  10. Whole-Genome Re-Alignment Facilitates Development of Specific Molecular Markers for Races 1 and 4 of Xanthomonas campestris pv. campestris, the Cause of Black Rot Disease in Brassica oleracea

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    Mehede Hassan Rubel

    2017-11-01

    Full Text Available Black rot, caused by Xanthomonas campestris pv. campestris (Xcc, is a seed borne disease of Brassicaceae. Eleven pathogenic races have been identified based on the phenotype interaction pattern of differential brassica cultivars inoculated with different strains. Race 1 and 4 are the two most frequent races found in Brassica oleracea crops. In this study, a PCR molecular diagnostic tool was developed for the identification of Xcc races 1 and 4 of this pathogen. Whole genomic sequences of races 1, 3, 4 and 9 and sequences of three other Xanthomonas pathovars/species (X. campestris pv. incanae (Xci, X. campestris pv. raphani (Xcr and X. euvesicatoria (Xev were aligned to identify variable regions among races. To develop specific markers for races 1 and 4, primers were developed from a region where sequences were dissimilar in other races. Sequence-characterized amplified regions (SCAR and insertion or deletion of bases (InDel were used to develop each specific set of primers. The specificity of the selected primers was confirmed by PCR tests using genomic DNA of seven different Xcc races, two strains of X. campestris pathovars and other species of bacteria. Bacterial samples of the races 1 and 4 isolates were collected from artificially inoculated cabbage leaves to conduct bio-PCR. Bio-PCR successfully detected the two Xcc isolates. By using our race-specific markers, a potential race 1 strain from the existing Korean Xcc collection was identified. The Xcc race 1 and 4-specific markers developed in this study are novel and can potentially be used for rapid detection of Xcc races through PCR.

  11. Molecular Characterization of Resistant Accessions of Cocoa (Theobroma cocoa L.) to Phytophthora Pod Rot Selected on-Farm in Côte-d’Ivoire.

    Science.gov (United States)

    Cocoa is (Theobroma cacao L.) is a significant agricultural commodity in Côted’Ivoire which ranks 1st in the world cocoa export. Phytophthora pod rot (Ppr)also call Black pod is the most widespread disease of cocoa. Lost due to this disease depends on the species of the pathogen and vary globally fr...

  12. Extensive sampling of basidiomycete genomes demonstrates inadequacy of the white-rot/brown-rot paradigm for wood decay fungi

    Science.gov (United States)

    Robert Riley; Asaf A. Salamov; Daren W. Brown; Laszlo G. Nagy; Dimitrios Floudas; Benjamin W. Held; Anthony Levasseur; Vincent Lombard; Emmanuelle Morin; Robert Otillar; Erika A. Lindquist; Hui Sun; Kurt M. LaButti; Jeremy Schmutz; Dina Jabbour; Hong Luo; Scott E. Baker; Antonio G. Pisabarro; Jonathan D. Walton; Robert A. Blanchette; Bernard Henrissat; Francis Martin; Daniel Cullen; David S. Hibbett; Igor V. Grigoriev

    2014-01-01

    Basidiomycota (basidiomycetes) make up 32% of the described fungi and include most wood-decaying species, as well as pathogens and mutualistic symbionts. Wood-decaying basidiomycetes have typically been classified as either white rot or brown rot, based on the ability (in white rot only) to degrade lignin along with cellulose and hemicellulose. Prior genomic...

  13. Extensive sampling of basidiomycete genomes demonstrates inadequacy of the white rot/brown rot paradigm for wood decay fungi

    Science.gov (United States)

    Basidiomycota (basidiomycetes) make up 32% of the described fungi and include most wood decaying species, as well as pathogens and mutualistic symbionts. Wood-decaying basidiomycetes have typically been classified as either white rot or brown rot, based on the ability (in white rot only) to degrade ...

  14. Control of wilt and rot pathogens of tomato by antagonistic pink pigmented facultative methylotrophic Delftia lacustris and Bacillus spp.

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    Veeranan Janahiraman

    2016-11-01

    Full Text Available The studies on the biocontrol potential of pink pigmented facultative methylotrophic (PPFM bacteria other than the genus Methylobacterium are scarce. In the present study, we report three facultative methylotrophic isolates; PPO-1, PPT-1 and PPB-1, respectively identified as Delftia lacustris, Bacillus subtilis and Bacillus cereus by 16S rRNA gene sequence analysis. Hemolytic activity was tested to investigate the potential pathogenicity of isolates to plants and humans, the results indicates that the isolates PPO-1, PPT-1 and PPB-1 are not pathogenic strains. Under in vitro conditions, D. lacustris PPO-1, B. subtilis PPT-1 and B. cereus PPB-1 showed direct antagonistic effect by inhibiting the mycelial growth of fungal pathogens; Fusarium oxysporum f. sp. lycopersici (2.15, 2.05 and 1.95 cm, Sclerotium rolfsii (2.14, 2.04 and1.94 cm, Pythium ultimum (2.12, 2.02 and 1.92cm, and Rhizoctonia solani (2.18, 2.08 and 1.98 cm and also produced volatile inhibitory compounds. Under plant growth chamber condition methylotrophic bacterial isolates; D. lacustris PPO-1, B. subtilis PPT-1 and B. cereus PPB-1 significantly reduced the disease incidence of tomato. Under greenhouse condition, D. lacustris PPO-1, B. subtilis PPT-1 and B. cereus PPB-1 inoculated tomato plants, when challenged with F. oxysporum f. sp. lycopersici, S. rolfsii, P. ultimum and R. solani, increased the pathogenesis related proteins (β-1, 3-glucanase and chitinase and defense enzymes (phenylalanine ammonia lyase, peroxidase, polyphenol oxidase, and catalase on day 5 after inoculation. In the current study, we first report the facultative methylotrophy in pink pigmented Delftia lacustris, B. subtilis, and B. cereus and their antagonistic potential against fungal pathogens. Direct antagonistic and ISR effects of these isolates against fungal pathogens of tomato evidenced their possible use as a biocontrol agent.

  15. Xylem defense wood of Norway spruce compromised by the pathogenic white-rot fungus Heterobasidion parviporum shows a prolonged period of selective decay.

    Science.gov (United States)

    Nagy, Nina Elisabeth; Ballance, Simon; Kvaalen, Harald; Fossdal, Carl Gunnar; Solheim, Halvor; Hietala, Ari M

    2012-10-01

    Heterobasidion parviporum, a common pathogenic white-rot fungus in managed Norway spruce forests in northern and central Europe, causes extensive decay columns within stem heartwood of the host tree. Infected trees combat the lateral spread of decay by bordering the heartwood with a fungistatic reaction zone characterized by elevated pH and phenol content. To examine the mode of fungal feeding in the reaction zone of mature Norway spruce trees naturally infected by H. parviporum, we conducted spatial profiling of pectin and hemicellulose composition, and established transcript levels of candidate fungal genes encoding enzymes involved in degradation of the different cell wall components of wood. Colonized inner heartwood showed pectin and hemicellulose concentrations similar to those of healthy heartwood, whereas the carbohydrate profiles of compromised reaction zone, irrespective of the age of fungal activity in the tissue, indicated selective fungal utilization of galacturonic acid, arabinose, xylose and mannose. These data show that the rate of wood decay in the reaction zone is slow. While the up-regulation of genes encoding pectinases and hemicellulases preceded that of the endoglucanase gene during an early phase of fungal interaction with xylem defense, the manganese peroxidase gene showed similar transcript levels during different phases of wood colonization. It seems plausible that the reaction zone components of Norway spruce interfere with both lignin degradation and the associated co-hydrolysis of hemicelluloses and pectin, resulting in a prolonged phase of selective decay.

  16. Agro-ecological variations of sheath rot disease of rice caused by Sarocladium oryzae and DNA fingerprinting of the pathogen's population structure.

    Science.gov (United States)

    Tajul Islam Chowdhury, M; Salim Mian, M; Taher Mia, M A; Rafii, M Y; Latif, M A

    2015-12-28

    To examine the impact of regional and seasonal variations on the incidence and severity of sheath rot, a major seed-borne disease of rice caused by Sarocladium oryzae, data on incidence and severity were collected from 27 selected fields in the Gazipur, Rangpur, Bogra, Chittagong, Comilla, Gopalgonj, Jessore, Manikgonj, and Bhola districts of Bangladesh in rain-fed and irrigated conditions. Cultural variability of 29 pathogen isolates obtained from 8 different locations was studied on potato dextrose agar (PDA) and genetic variability was determined by DNA fingerprinting using variable number tandem repeat-polymerase chain reaction markers. Overall, disease incidence and severity were higher in irrigated rice. Disease incidence and severity were highest in the Bhola district in rain-fed rice and lowest in irrigated rice. Mycelial growth of 29 representative isolates was found to vary on PDA and the isolates were divided into 6 groups. The range of the overall size of conidia of the selected isolates was 2.40-7.20 x 1.20-2.40 μm. Analysis of the DNA fingerprint types of the 29 isolates of S. oryzae, obtained from the amplification reactions, revealed 10 fingerprinting types (FPTs) that were 80% similar. FPT-1 was the largest group and included 13 isolates (44.8%), while FPT-2 was the third largest group and included 3 isolates. Each of FPT-3, 4, 5, and 6 included only 1 isolate. We observed no relationship between cultural and genetic groupings.

  17. High-density genetic mapping identifies the genetic basis of a natural colony morphology mutant in the root rot pathogen Armillaria ostoyae.

    Science.gov (United States)

    Heinzelmann, Renate; Croll, Daniel; Zoller, Stefan; Sipos, György; Münsterkötter, Martin; Güldener, Ulrich; Rigling, Daniel

    2017-11-01

    Filamentous fungi exhibit a broad spectrum of heritable growth patterns and morphological variations reflecting the adaptation of the different species to distinct ecological niches. But also within species, isolates show considerable variation in growth rates and other morphological characteristics. The genetic basis of this intraspecific variation in mycelial growth and morphology is currently poorly understood. By chance, a growth mutant in the root rot pathogen Armillaria ostoyae was discovered. The mutant phenotype was characterized by extremely compact and slow growth, as well as shorter aerial hyphae and hyphal compartments in comparison to the wildtype phenotype. Genetic analysis revealed that the abnormal phenotype is caused by a recessive mutation, which segregates asa single locus in sexual crosses. In order to identify the genetic basis of the mutant phenotype, we performed a quantitative trait locus (QTL) analysis. A mapping population of 198 haploid progeny was genotyped at 11,700 genome-wide single nucleotide polymorphisms (SNPs) making use of double digest restriction site associated DNA sequencing (ddRADseq). In accordance with the genetic analysis, a single significant QTL was identified for the abnormal growth phenotype. The QTL confidence interval spans a narrow, gene dense region of 87kb in the A. ostoyae genome which contains 37 genes. Overall, our study reports the first high-density genetic map for an Armillaria species and shows its successful application in forward genetics by resolving the genetic basis of a mutant phenotype with a severe defect in hyphal growth. Copyright © 2017 Elsevier Inc. All rights reserved.

  18. A novel, multiplexed, probe-based quantitative PCR assay for the soybean root- and stem-rot pathogen, Phytophthora sojae, utilizes its transposable element.

    Directory of Open Access Journals (Sweden)

    James S Haudenshield

    Full Text Available Phytophthora root rot of soybean [Glycine max (L. Merr.] is caused by the oomycete Phytophthora sojae (Kaufm. & Gerd.. P. sojae has a narrow host range, consisting primarily of soybean, and it is a serious pathogen worldwide. It exists in root and stem tissues as mycelium, wherein it can form oospores which subsequently germinate to release motile, infectious zoospores. Molecular assays detecting DNA of P. sojae are useful in disease diagnostics, and for determining the presence of the organism in host tissues, soils, and runoff or ponded water from potentially infested fields. Such assays as published have utilized ITS sequences from the nuclear ribosomal RNA genes in conventional PCR or dye-binding quantitative PCR (Q-PCR but are not amenable to multiplexing, and some of these assays did not utilize control strategies for type I or type II errors. In this study, we describe primers and a bifunctional probe with specificity to a gypsy-like retroelement in the P. sojae genome to create a fluorogenic 5'-exonuclease linear hydrolysis assay, with a multiplexed internal control reaction detecting an exogenous target to validate negative calls, and with uracil-deglycosylase-mediated protection against carryover contamination. The assay specifically detected 13 different P. sojae isolates, and excluded 17 other Phytophthora species along with 20 non-Phytophthora fungal and oomycete species pathogenic on soybean. A diagnostic limit of detection of 34 fg total P. sojae DNA was observed in serial dilutions, equivalent to 0.3 genome, and a practical detection sensitivity of four zoospores per sample was achieved, despite losses during DNA extraction.

  19. A novel, multiplexed, probe-based quantitative PCR assay for the soybean root- and stem-rot pathogen, Phytophthora sojae, utilizes its transposable element.

    Science.gov (United States)

    Haudenshield, James S; Song, Jeong Y; Hartman, Glen L

    2017-01-01

    Phytophthora root rot of soybean [Glycine max (L.) Merr.] is caused by the oomycete Phytophthora sojae (Kaufm. & Gerd.). P. sojae has a narrow host range, consisting primarily of soybean, and it is a serious pathogen worldwide. It exists in root and stem tissues as mycelium, wherein it can form oospores which subsequently germinate to release motile, infectious zoospores. Molecular assays detecting DNA of P. sojae are useful in disease diagnostics, and for determining the presence of the organism in host tissues, soils, and runoff or ponded water from potentially infested fields. Such assays as published have utilized ITS sequences from the nuclear ribosomal RNA genes in conventional PCR or dye-binding quantitative PCR (Q-PCR) but are not amenable to multiplexing, and some of these assays did not utilize control strategies for type I or type II errors. In this study, we describe primers and a bifunctional probe with specificity to a gypsy-like retroelement in the P. sojae genome to create a fluorogenic 5'-exonuclease linear hydrolysis assay, with a multiplexed internal control reaction detecting an exogenous target to validate negative calls, and with uracil-deglycosylase-mediated protection against carryover contamination. The assay specifically detected 13 different P. sojae isolates, and excluded 17 other Phytophthora species along with 20 non-Phytophthora fungal and oomycete species pathogenic on soybean. A diagnostic limit of detection of 34 fg total P. sojae DNA was observed in serial dilutions, equivalent to 0.3 genome, and a practical detection sensitivity of four zoospores per sample was achieved, despite losses during DNA extraction.

  20. Serosurvey for selected pathogens in free-ranging American black bears (Ursus americanus) in Maryland, USA.

    Science.gov (United States)

    Bronson, Ellen; Spiker, Harry; Driscoll, Cindy P

    2014-10-01

    American black bears (Ursus americanus) in Maryland, USA, live in forested areas in close proximity to humans and their domestic pets. From 1999 to 2011, we collected 84 serum samples from 63 black bears (18 males; 45 females) in five Maryland counties and tested them for exposure to infectious, including zoonotic, pathogens. A large portion of the bears had antibody to canine distemper virus and Toxoplasma gondii, many at high titers. Prevalences of antibodies to zoonotic agents such as rabies virus and to infectious agents of carnivores including canine adenovirus and canine parvovirus were lower. Bears also had antibodies to vector-borne pathogens common to bears and humans such as West Nile virus, Borrelia burgdorferi, Rickettsia rickettsii, and Anaplasma phagocytophilum. Antibodies were detected to Leptospira interrogans serovars Pomona, Icterohaemorrhagiae, Canicola, Grippotyphosa, and Bratislava. We did not detect antibodies to Brucella canis or Ehrlichia canis. Although this population of Maryland black bears demonstrated exposure to multiple pathogens of concern for humans and domesticated animals, the low levels of clinical disease in this and other free-ranging black bear populations indicate the black bear is likely a spillover host for the majority of pathogens studied. Nevertheless, bear populations living at the human-domestic-wildlife interface with increasing human and domestic animal exposure should continue to be monitored because this population likely serves as a useful sentinel of ecosystem health.

  1. Identification of host-microbe interaction factors in the genomes of soft rot-associated pathogens Dickeya dadantii 3937 and Pectobacterium carotovorum WPP14 with supervised machine learning.

    Science.gov (United States)

    Ma, Bing; Charkowski, Amy O; Glasner, Jeremy D; Perna, Nicole T

    2014-06-21

    A wealth of genome sequences has provided thousands of genes of unknown function, but identification of functions for the large numbers of hypothetical genes in phytopathogens remains a challenge that impacts all research on plant-microbe interactions. Decades of research on the molecular basis of pathogenesis focused on a limited number of factors associated with long-known host-microbe interaction systems, providing limited direction into this challenge. Computational approaches to identify virulence genes often rely on two strategies: searching for sequence similarity to known host-microbe interaction factors from other organisms, and identifying islands of genes that discriminate between pathogens of one type and closely related non-pathogens or pathogens of a different type. The former is limited to known genes, excluding vast collections of genes of unknown function found in every genome. The latter lacks specificity, since many genes in genomic islands have little to do with host-interaction. In this study, we developed a supervised machine learning approach that was designed to recognize patterns from large and disparate data types, in order to identify candidate host-microbe interaction factors. The soft rot Enterobacteriaceae strains Dickeya dadantii 3937 and Pectobacterium carotovorum WPP14 were used for development of this tool, because these pathogens are important on multiple high value crops in agriculture worldwide and more genomic and functional data is available for the Enterobacteriaceae than any other microbial family. Our approach achieved greater than 90% precision and a recall rate over 80% in 10-fold cross validation tests. Application of the learning scheme to the complete genome of these two organisms generated a list of roughly 200 candidates, many of which were previously not implicated in plant-microbe interaction and many of which are of completely unknown function. These lists provide new targets for experimental validation and

  2. A survey of zoonotic pathogens carried by house mouse and black rat populations in Yucatan, Mexico.

    Science.gov (United States)

    Panti-May, J A; DE Andrade, R R C; Gurubel-González, Y; Palomo-Arjona, E; Sodá-Tamayo, L; Meza-Sulú, J; Ramírez-Sierra, M; Dumonteil, E; Vidal-Martínez, V M; Machaín-Williams, C; DE Oliveira, D; Reis, M G; Torres-Castro, M A; Robles, M R; Hernández-Betancourt, S F; Costa, F

    2017-08-01

    The house mouse (Mus musculus) and the black rat (Rattus rattus) are reservoir hosts for zoonotic pathogens, several of which cause neglected tropical diseases (NTDs). Studies of the prevalence of these NTD-causing zoonotic pathogens, in house mice and black rats from tropical residential areas are scarce. Three hundred and two house mice and 161 black rats were trapped in 2013 from two urban neighbourhoods and a rural village in Yucatan, Mexico, and subsequently tested for Trypanosoma cruzi, Hymenolepis diminuta and Leptospira interrogans. Using the polymerase chain reaction we detected T. cruzi DNA in the hearts of 4·9% (8/165) and 6·2% (7/113) of house mice and black rats, respectively. We applied the sedimentation technique to detect eggs of H. diminuta in 0·5% (1/182) and 14·2% (15/106) of house mice and black rats, respectively. Through the immunofluorescent imprint method, L. interrogans was identified in 0·9% (1/106) of rat kidney impressions. Our results suggest that the black rat could be an important reservoir for T. cruzi and H. diminuta in the studied sites. Further studies examining seasonal and geographical patterns could increase our knowledge on the epidemiology of these pathogens in Mexico and the risk to public health posed by rodents.

  3. Control of Black Rot Disease in Tomato Fruits by Using Formulated Ginger Essential oil Treated by Gamma Radiation

    International Nuclear Information System (INIS)

    Helal, I.M.; Abdeldaiem, M.H.

    2008-01-01

    Ginger essential oil (Zingiber officinale) treated by gamma radiation at dose of 10 kGy was selected as an active ingredient for formulation of the biocide. Liquid formulations (emulsifiable concentrates) were prepared using different emulsifiers (Emulgator B.L.M. and tween 80 or tween 20) and additive oil (soybean oil). Physicochemical properties of the formulated oil (spontaneous emulsification, emulsion stability; cold stability and heat stability, viscosity, surface tension and ph) were measured. The formulated oil was tested in vivo to investigate its efficiency for controlling the growth of Alternaria alternata inoculated into tomato fruits. The results indicated that soaking inoculated tomato fruits in the formulated oil (ginger essential oil + soybean oil + emulgator B.L.M. + tween 80) treatment at concentration of 300 ppm for a period of 12 minute was the most effective for controlling the growth of the tested fungus. In addition, the formulated oil had efficiency for controlling the rot development on tomato fruits when applied as therapeutic and protective agents

  4. Isolation, identification, and pathogenicity of O142 avian pathogenic Escherichia coli causing black proventriculus and septicemia in broiler breeders.

    Science.gov (United States)

    Wang, Xiaobo; Cao, Chunguang; Huan, Haixia; Zhang, Liuli; Mu, Xiaohui; Gao, Qingqing; Dong, Xianglei; Gao, Song; Liu, Xiufan

    2015-06-01

    Avian colibacillosis, characterized by black proventriculus and caused by avian pathogenic Escherichia coli (APEC) with an uncommon O142 serogroup, was diagnosed in young broiler breeders. Colonization and persistence assays performed in 7-day-old broilers showed that the bacterial load of the APEC 4d/9-1 O142 proventricular isolate in the lung was about 10-fold higher than that of the APEC 4d/9-1 O142 heart blood isolate (P<0.01), and about 100-fold higher in the heart blood, livers, spleens, kidneys, and proventriculi of inoculated broilers (P<0.001). When 32 common virulence genes of APEC were tested, the two isolates had nearly identical profiles, except that only the APEC 4d/9-1 O142 proventricular isolate carried the feoB gene. Furthermore, 100% mortality was observed in both 1-day-old Arbor Acres (AA) broilers and 1-day-old specific-pathogen-free (SPF) chickens inoculated with 10(6) colony-forming units of the APEC 4d/9-1 O142 proventricular isolate. However, black proventriculus was only observed in the dead AA broilers, consistent with the clinical occurrence of the disease. This implies that the black proventriculi seen in the dead birds, caused by the APEC 4d/9-1 O142 proventricular isolate, was breed-specific. Both the APEC 4d/9-1 O142 proventricular and heart blood isolates belong to phylogroup B2. However, the former was assigned to ST131 and the latter to ST2704 with multilocus sequence typing, demonstrating the genetic heterogeneity of these two bacterial isolates, although they were derived from the same dead broiler. These results suggest that the O142 APEC isolate was the main pathogenic agent for black proventriculi in 7-day-old broiler breeders. Copyright © 2015 Elsevier B.V. All rights reserved.

  5. Endophytic fungi harbored in Panax notoginseng: diversity and potential as biological control agents against host plant pathogens of root-rot disease

    Directory of Open Access Journals (Sweden)

    You-Kun Zheng

    2017-07-01

    Conclusion: Our results suggested that P. notoginseng harbors diversified endophytic fungi that would provide a basis for the identification of new bioactive compounds, and for effective biocontrol of notoginseng root rot.

  6. Preliminary Studies on the Development of Monoclonal Antibodies Against Mycelia of Ganoderma boninense, the Causal Pathogen of Basal Stem Rot of Oil Palm

    Directory of Open Access Journals (Sweden)

    Shamala, S.

    2006-01-01

    Full Text Available This study aimed to raise specific MAbs against G. boninense, the causal pathogen of basal stem rot (BSR of oil palm. Crude mycelium extract of G. boninense was used as immunogen to generate MAbs. Mycelium was harvested from liquid culture and freeze-dried followed by re-suspension in phosphate buffer saline (PBS. Two 10-week old BALB-C mice were immunized with the mycelial extract. The mice were boosted once before harvesting their spleens for fusion. The MAbs were fused with myeloma cells from BALB-C mice. Initial screening was carried out using plate-trapped antigen enzyme-linked immunosorbent assay (PTA-ELISA with mycelial immunogen of G. boninense. The MAbs with positive signals were verified via secondary screening and cloned for cross-reactivity test. Cross-reactivity testing was carried out with 2 other fungi namely; Trichoderma and Botrytis along with 2 different species of Ganoderma commonly found in oil palm plantations namely; G. zonatum, and G. miniatocinctum. This study found that the MAbs raised against G. boninense were not specific as the MAbs gave positive signals through the cross-reactivity test with all fungi tested in the cross-reactivity. Future work would be using these MAbs in a co-immunization program whereby the generated Ganoderma sp generic monoclonal antibody will be pre-mixed with the G. boninense mycelium immunogen to allow reduction in the potential cross-reactivity of newly generated antibodies with Ganoderma sp. Our efforts are also currently directed at optimizing the immunogen preparation for the production of MAbs specific to G. boninense.

  7. Distinguishing Galactomyces citri-aurantii from G. geotrichum and characterizing population structure of the two postharvest sour rot pathogens of fruit crops in California.

    Science.gov (United States)

    McKay, A H; Förster, H; Adaskaveg, J E

    2012-05-01

    A growth assay in lemon juice and polymerase chain reaction amplifications using newly designed species-specific primers from endopolygalacturonase and β-tubulin genes rapidly differentiated isolates of the morphologically similar fruit sour rot pathogens Galactomyces citriaurantii and G. geotrichum. Isolates of both species were collected from agricultural soils and decaying fruit at locations within and outside California, including worldwide locations, and were used in population genetic studies based on amplified fragment length polymorphic (AFLP) DNA markers. For all four geographically defined subpopulations (three counties of California and locations outside California) among 97 isolates of G. citri-aurantii and for the two subpopulations (origin within or outside California) among 35 isolates of G. geotrichum, the proportion of polymorphic loci and haplotypic diversity was high. In total, 82 unique haplotypes were identified for G. citri-aurantii for the four subpopulations and, of these, 80 haplotypes were unique among subpopulations. For G. geotrichum, 25 unique haplotypes were identified among the two subpopulations and no haplotype was shared. Indices of genetic differences (F(ST)) between subpopulations within each species were all low (e.g., 0.038 for G. geotrichum and 0.085 to 0.226 for G. citriaurantii), indicating a low level of genetic differentiation. Following clone correction, mating type segregation ratios for G. citri-aurantii did not significantly (P > 0.1) deviate from a 1:1 ratio for all four subpopulations or the entire population. Tests of the index of association (I(A)) and parsimony tree-length permutation tests (PTLPT) supported a random mating structure for clone-corrected data for the Kern, Tulare, and Ventura County subpopulations and the null hypothesis of random mating could not be rejected. Additionally, PTLPT also supported random mating for the "outside of California" population. For G. geotrichum, random mating was only

  8. Genome and secretome analysis of the hemibiotrophic fungal pathogen, Moniliophthora roreri, which causes frosty pod rot disease of cacao: mechanisms of the biotrophic and necrotrophic phases.

    Science.gov (United States)

    Meinhardt, Lyndel W; Costa, Gustavo Gilson Lacerda; Thomazella, Daniela P T; Teixeira, Paulo José P L; Carazzolle, Marcelo Falsarella; Schuster, Stephan C; Carlson, John E; Guiltinan, Mark J; Mieczkowski, Piotr; Farmer, Andrew; Ramaraj, Thiruvarangan; Crozier, Jayne; Davis, Robert E; Shao, Jonathan; Melnick, Rachel L; Pereira, Gonçalo A G; Bailey, Bryan A

    2014-02-27

    The basidiomycete Moniliophthora roreri is the causal agent of Frosty pod rot (FPR) disease of cacao (Theobroma cacao), the source of chocolate, and FPR is one of the most destructive diseases of this important perennial crop in the Americas. This hemibiotroph infects only cacao pods and has an extended biotrophic phase lasting up to sixty days, culminating in plant necrosis and sporulation of the fungus without the formation of a basidiocarp. We sequenced and assembled 52.3 Mb into 3,298 contigs that represent the M. roreri genome. Of the 17,920 predicted open reading frames (OFRs), 13,760 were validated by RNA-Seq. Using read count data from RNA sequencing of cacao pods at 30 and 60 days post infection, differential gene expression was estimated for the biotrophic and necrotrophic phases of this plant-pathogen interaction. The sequencing data were used to develop a genome based secretome for the infected pods. Of the 1,535 genes encoding putative secreted proteins, 1,355 were expressed in the biotrophic and necrotrophic phases. Analysis of the data revealed secretome gene expression that correlated with infection and intercellular growth in the biotrophic phase and invasive growth and plant cellular death in the necrotrophic phase. Genome sequencing and RNA-Seq was used to determine and validate the Moniliophthora roreri genome and secretome. High sequence identity between Moniliophthora roreri genes and Moniliophthora perniciosa genes supports the taxonomic relationship with Moniliophthora perniciosa and the relatedness of this fungus to other basidiomycetes. Analysis of RNA-Seq data from infected plant tissues revealed differentially expressed genes in the biotrophic and necrotrophic phases. The secreted protein genes that were upregulated in the biotrophic phase are primarily associated with breakdown of the intercellular matrix and modification of the fungal mycelia, possibly to mask the fungus from plant defenses. Based on the transcriptome data, the

  9. Sclerotinia Rot on Basil Caused by Sclerotinia sclerotiorum in Korea

    Directory of Open Access Journals (Sweden)

    Soo Sang Hahm

    2017-03-01

    Full Text Available During growing season of 2011 to 2013, Sclerotinia rot symptoms consistently have been observed on basil in Yesan-gun, Chungcheongnam-do in Korea. The typical symptom formed initially brownish spot on leaf and stem, and then advancing margins, wilting the whole plant and blighting, eventually died. On the surface of diseased lesions was observed cottony, white, dense mat of mycelial growth, and sclerotia (30–100 µm diameter formed on stem and leaf. Morphological and cultural characteristic on potato dextrose agar, color of colony was white and colorless chocolate, sclerotium of irregular shape of the oval was black and 5–50 µm diameter in size. In pathogenicity test, necrosis and wilt of the inoculated stem were observed in all plants and the pathogen was reisolated from stems. On the basis of mycological characteristics, pathogenicity, and internal transcribed spacer rDNA sequence analysis, this fungus was identified as Sclerotinia sclerotiorum. This is the first report of Sclerotinia rot on basil caused by S. sclerotiorum in Korea.

  10. Genome and secretome analysis of the hemibiotrophic fungal pathogen, Moniliophthora roreri, which causes frosty pod rot disease of cacao: mechanisms of the biotrophic and necrotrophic phases

    Science.gov (United States)

    Background: Moniliophthora roreri is the causal agent of Frosty pod rot (FPR) disease of Theobroma cacao, the source of chocolate and is one of the most destructive diseases of cacao in the Americas. This Basidiomycete only infects cacao pods and has an extended biotrophic phase lasting up to sixty ...

  11. Development and application of qPCR and RPA genus and species-specific detection of Phytophthora sojae and Phytophthora sansomeana root rot pathogens of soybean

    Science.gov (United States)

    Phytophthora root rot of soybean, caused by Phytophthora sojae is one of the most important diseases in the Midwest US, causing losses of up to 44 million bushels per year. Disease may also be caused by P. sansomeana, however the prevalence and damage caused by this species is not well known, partl...

  12. Studies on storage rot of cocoyam

    African Journals Online (AJOL)

    uc network

    Department of Botany, University of Nigeria, Nsukka, Nigeria, were employed for this study. These were fungal organisms which had earlier been established as the major rot pathogens of cocoyam corms during storage. Pathogenicity assessment studies of fungal organisms: To assess the potency of the fungal organisms.

  13. Phytophthora megakarya and P. palmivora, Causal Agents of Black Pod Rot, Induce Similar Plant Defense Responses Late during Infection of Susceptible Cacao Pods

    Science.gov (United States)

    Ali, Shahin S.; Shao, Jonathan; Lary, David J.; Strem, Mary D.; Meinhardt, Lyndel W.; Bailey, Bryan A.

    2017-01-01

    Phytophthora megakarya (Pmeg) and Phytophthora palmivora (Ppal) cause black pod rot of Theobroma cacao L. (cacao). Of these two clade 4 species, Pmeg is more virulent and is displacing Ppal in many cacao production areas in Africa. Symptoms and species specific sporangia production were compared when the two species were co-inoculated onto pod pieces in staggered 24 h time intervals. Pmeg sporangia were predominantly recovered from pod pieces with unwounded surfaces even when inoculated 24 h after Ppal. On wounded surfaces, sporangia of Ppal were predominantly recovered if the two species were simultaneously applied or Ppal was applied first but not if Pmeg was applied first. Pmeg demonstrated an advantage over Ppal when infecting un-wounded surfaces while Ppal had the advantage when infecting wounded surfaces. RNA-Seq was carried out on RNA isolated from control and Pmeg and Ppal infected pod pieces 3 days post inoculation to assess their abilities to alter/suppress cacao defense. Expression of 4,482 and 5,264 cacao genes was altered after Pmeg and Ppal infection, respectively, with most genes responding to both species. Neural network self-organizing map analyses separated the cacao RNA-Seq gene expression profiles into 24 classes, 6 of which were largely induced in response to infection. Using KEGG analysis, subsets of genes composing interrelated pathways leading to phenylpropanoid biosynthesis, ethylene and jasmonic acid biosynthesis and action, plant defense signal transduction, and endocytosis showed induction in response to infection. A large subset of genes encoding putative Pr-proteins also showed differential expression in response to infection. A subset of 36 cacao genes was used to validate the RNA-Seq expression data and compare infection induced gene expression patterns in leaves and wounded and unwounded pod husks. Expression patterns between RNA-Seq and RT-qPCR were generally reproducible. The level and timing of altered gene expression was

  14. Population Structure of the Sour Rot Pathogens Galactomyces citri-aurantii and G. geotrichum and Evaluation of Sterol Demethylation Inhibitors for Postharvest Management of Citrus Decays

    OpenAIRE

    McKay, Alistair Hartley

    2011-01-01

    Sour rot of citrus caused by Galactomyces citri-aurantii (anamorph: Geotrichum citri-aurantii (Ferraris) Butler) is an important postharvest disease that affects all varieties of citrus fruit grown in California and is particularly prevalent in the lemon industry since the fruit is stored at approximately 12°C and 95% relative humidity. The postharvest fungicides currently registered to manage green mold caused by Penicillium digitatum including imazalil, thiabendazole, as well as azoxystrobi...

  15. Detection of human bacterial pathogens in ticks collected from Louisiana black bears (Ursus americanus luteolus).

    Science.gov (United States)

    Leydet, Brian F; Liang, Fang-Ting

    2013-04-01

    There are 4 major human-biting tick species in the northeastern United States, which include: Amblyomma americanum, Amblyomma maculatum, Dermacentor variabilis, and Ixodes scapularis. The black bear is a large mammal that has been shown to be parasitized by all the aforementioned ticks. We investigated the bacterial infections in ticks collected from Louisiana black bears (Ursus americanus subspecies luteolus). Eighty-six ticks were collected from 17 black bears in Louisiana from June 2010 to March 2011. All 4 common human-biting tick species were represented. Each tick was subjected to polymerase chain reaction (PCR) targeting select bacterial pathogens and symbionts. Bacterial DNA was detected in 62% of ticks (n=53). Rickettsia parkeri, the causative agent of an emerging spotted fever group rickettsiosis, was identified in 66% of A. maculatum, 28% of D. variabilis, and 11% of I. scapularis. The Lyme disease bacterium, Borrelia burgdorferi, was detected in 2 I. scapularis, while one A. americanum was positive for Borrelia bissettii, a putative human pathogen. The rickettsial endosymbionts Candidatus Rickettsia andeanae, rickettsial endosymbiont of I. scapularis, and Rickettsia amblyommii were detected in their common tick hosts at 21%, 39%, and 60%, respectively. All ticks were PCR-negative for Anaplasma phagocytophilum, Ehrlichia spp., and Babesia microti. This is the first reported detection of R. parkeri in vector ticks in Louisiana; we also report the novel association of R. parkeri with I. scapularis. Detection of both R. parkeri and B. burgdorferi in their respective vectors in Louisiana demands further investigation to determine potential for human exposure to these pathogens. Copyright © 2013 Elsevier GmbH. All rights reserved.

  16. Resistance to charcoal rot identified in ancestral soybean germplasm

    Science.gov (United States)

    Charcoal rot, caused by the fungal pathogen Macrophomina phaseolina, is an economically important disease on soybean and other crops including maize, sorghum, and sunflowers. Without effective cultural or chemical options to control charcoal rot in soybean, finding sources of genetic resistance is o...

  17. Persistence of Gliocephalotrichum spp. causing fruit rot of rambutan (Nephelium lappaceum L.) in Puerto Rico

    Science.gov (United States)

    Worldwide, fruit rot of rambutan is an important problem that limits the storage, marketing and long-distance transportation of the fruit. A complex of pathogens has been reported to cause fruit rot of rambutan and significant post-harvest economic losses. During 2009 and 2011 rambutan fruit rot was...

  18. Genetic variation between Phytophthora cactorum isolates differing in their ability to cause crown rot in strawberry.

    Science.gov (United States)

    Eikemo, Håvard; Klemsdal, Sonja S; Riisberg, Ingvild; Bonants, Peter; Stensvand, Arne; Tronsmo, Anne M

    2004-03-01

    Analysis of 44 isolates of Phytophthora cactorum, isolated from strawberry and other hosts, by AFLP showed that the crown rot pathotype is different from leather rot isolates and from P. cactorum isolated from other hosts. 16 of 23 crown rot isolates, including isolates from Europe, Japan, Australia, and New Zealand, were identical in an analysis based on 96 polymorphic bands from seven primer combinations. Leather rot isolates of strawberry could not be distinguished from isolates from other hosts. The pathogenicity test of all 44 isolates on strawberry plants mostly gave unambiguous results, except for three American isolates, which seemed to have reduced aggressiveness compared to the crown rot isolates. These isolates also differed in the AFLP analysis. Comparing information on the origin of the isolates with results from the pathogenicity test, showed that isolates from strawberry fruits or petioles could be either leather rot or crown rot pathotypes. None of the isolates from hosts other than strawberry caused crown rot symptoms in strawberry.

  19. Sulfate reducing bacteria as secondary and necessary pathogens in black band disease of corals

    Directory of Open Access Journals (Sweden)

    Abigael C. Brownell

    2014-09-01

    Full Text Available Black band disease (BBD is a complex, polymicrobial disease that consists of cyanobacteria, sulfide-oxidizing and sulfate-reducing bacteria (SRB, and heterotrophic bacteria. The cyanobacterium Roseofilum reptotaenium has been implicated as the primary pathogen of BBD, but other consortium members may be secondary pathogens that are necessary to the development of the disease. It is known that populations of the sulfate-reducing bacterium Desulfovibrio are present in BBD and that these populations generate sulfide within the band as a byproduct of dissimilatory sulfate reduction. It is also known that exposure of healthy corals to sulfide leads to cell lysis and coral tissue death. Previous work showed that when freshly collected BBD, which easily infects healthy corals, is exposed to sodium molybdate, a specific inhibitor of sulfate reduction, infection does not occur. In this study we examined the effect of sodium molybdate on infection of corals by a unialgal culture of R. reptotaenium. Coral fragments of Montastraea cavernosa and Siderastrea siderea were transferred into two experimental aquaria, one a control with only artificial seawater (ASW and the second containing ASW and 2mM sodium molybdate. Small mats of cultured R. reptotaenium were inoculated onto the surface of experimental coral fragments. Both M. cavernosa (n = 6 and S. siderea (n=4 became infected and developed BBD-like infections in the control tank, while there were temporary attachments to, but no successful infection of M. cavernosa (n=3 or S. siderea (n=2 in the experimental tank containing sodium molybdate. The results of this study reveal that a secondary pathogen is essential to the infection process and development of BBD in scleractinian corals. Specifically, SRB such as Desulfovibrio are required for the development of BBD on the coral host. This is the first step in understanding the roles of secondary pathogens in a complex, polymicrobial coral disease.

  20. Laminated Root Rot of Western Conifers

    Science.gov (United States)

    E.E. Nelson; N.E. Martin; R.E. Williams

    1981-01-01

    Laminated root rot is caused by the native fungus Phellinus weirii (Murr.) Gilb. It occurs throughout the Northwestern United States and in southern British Columbia, Canada. The disease has also been reported in Japan and Manchuria. In the United States, the pathogen is most destructive in pure Douglas-fir stands west of the crest of the Cascade Range in Washington...

  1. Efficacy of Heat Treatment for the Thousand Cankers Disease Vector and Pathogen in Small Black Walnut Logs

    Science.gov (United States)

    A. E. Mayfield; S. W. Fraedrich; A. Taylor; P. Merten; S. W. Myers

    2014-01-01

    Thousand cankers disease, caused by the walnut twig beetle (Pityophthorus juglandis Blackman) and an associated fungal pathogen (Geosmithia morbida M. Kolarõ´k, E. Freeland, C. Utley, and N. Tisserat), threatens the health and commercial use of eastern black walnut (Juglans nigra L.), one of the most economically...

  2. Extensive sampling of basidiomycete genomes demonstrates inadequacy of the white rot/ brown rot paradigm for wood decay fungi

    Energy Technology Data Exchange (ETDEWEB)

    Riley, Robert; Salamov, Asaf; Brown, Daren W.; Nagy, Laszlo G.; Floudas, Dimitris; Held, Benjamin; Levasseur, Anthony; Lombard, Vincent; Morin, Emmanuelle; Otillar, Robert; Lindquist, Erika; Sun, Hui; LaButti, Kurt; Schmutz, Jeremy; Jabbour, Dina; Luo, Hong; Baker, Scott E.; Pisabarro, Antonio; Walton, Jonathan D.; Blanchette, Robert; Henrissat, Bernard; Martin, Francis; Cullen, Dan; Hibbett, David; Grigoriev, Igor V.

    2014-03-14

    Basidiomycota (basidiomycetes) make up 32percent of the described fungi and include most wood decaying species, as well as pathogens and mutualistic symbionts. Wood-decaying basidiomycetes have typically been classified as either white rot or brown rot, based on the ability (in white rot only) to degrade lignin along with cellulose and hemicellulose. Prior genomic comparisons suggested that the two decay modes can be distinguished based on the presence or absence of ligninolytic class II peroxidases (PODs), as well as the abundance of enzymes acting directly on crystalline cellulose (reduced in brown rot). To assess the generality of the white rot/brown rot classification paradigm we compared the genomes of 33 basidiomycetes, including four newly sequenced wood decayers, and performed phylogenetically-informed Principal Components Analysis (PCA) of a broad range of gene families encoding plant biomass-degrading enzymes. The newly sequenced Botryobasidium botryosum and Jaapia argillacea genomes lack PODs, but possess diverse enzymes acting on crystalline cellulose, and they group close to the model white rot species Phanerochaete chrysosporium in the PCA. Furthermore, laboratory assays showed that both B. botryosum and J. argillacea can degrade all polymeric components of woody plant cell walls, a characteristic of white rot. We also found expansions in reducing polyketide synthase genes specific to the brown rot fungi. Our results suggest a continuum rather than a dichotomy between the white rot and brown rot modes of wood decay. A more nuanced categorization of rot types is needed, based on an improved understanding of the genomics and biochemistry of wood decay.

  3. Detection of the sour-rot pathogen Geotrichum candidum in tomato fruit and juice by using a highly specific monoclonal antibody-based ELISA.

    Science.gov (United States)

    Thornton, Christopher R; Slaughter, David C; Davis, R Michael

    2010-10-15

    Geotrichum candidum is a common soil-borne fungus that causes sour-rot of tomatoes, citrus fruits and vegetables, and is a major contaminant on tomato processing equipment. The aim of this work was to produce a monoclonal antibody and diagnostic assay for its detection in tomato fruit and juice. Using hybridoma technology, a cell line (FE10) was generated that produced a monoclonal antibody belonging to the immunoglobulin class M (IgM) that was specific to G. candidum and the closely related teleomorphic species Galactomyces geotrichum and anamorphic species Geotrichum europaeum and Geotrichum pseudocandidum in the G. geotrichum/G. candidum complex. The MAb did not cross-react with a wide range of unrelated fungi, including some likely to be encountered during crop production and processing. The MAb binds to an immunodominant high molecular mass (> 200 kDa) extracellular polysaccharide antigen that is present on the surface of arthroconidia and hyphae of G. candidum. The MAb was used in a highly specific enzyme-linked immunosorbent assay (ELISA) to accurately detect the fungus in infected tomato fruit and juice. Specificity of the ELISA was confirmed by sequencing of the internally transcribed spacer (ITS) 1-5.8S-ITS2 rRNA-encoding regions of fungi isolated from naturally-infected tomatoes. Copyright © 2010 Elsevier B.V. All rights reserved.

  4. Brain transcriptomes of honey bees (Apis mellifera experimentally infected by two pathogens: Black queen cell virus and Nosema ceranae

    Directory of Open Access Journals (Sweden)

    Vincent Doublet

    2016-12-01

    Full Text Available Regulation of gene expression in the brain plays an important role in behavioral plasticity and decision making in response to external stimuli. However, both can be severely affected by environmental factors, such as parasites and pathogens. In honey bees, the emergence and re-emergence of pathogens and potential for pathogen co-infection and interaction have been suggested as major components that significantly impaired social behavior and survival. To understand how the honey bee is affected and responds to interacting pathogens, we co-infected workers with two prevalent pathogens of different nature, the positive single strand RNA virus Black queen cell virus (BQCV, and the Microsporidia Nosema ceranae, and explored gene expression changes in brains upon single infections and co-infections. Our data provide an important resource for research on honey bee diseases, and more generally on insect host-pathogen and pathogen-pathogen interactions. Raw and processed data are publicly available in the NCBI/GEO database: (http://www.ncbi.nlm.nih.gov/geo/ under accession number GSE81664.

  5. Diversity and activity of biosurfactant-producing Pseudomonas in the rhizosphere of black pepper in Vietnam.

    Science.gov (United States)

    Tran, H; Kruijt, M; Raaijmakers, J M

    2008-03-01

    Phytophthora capsici is a major pathogen of black pepper and zoospores play an important role in the infection process. Fluorescent pseudomonads that produce biosurfactants with zoosporicidal activities were isolated from the black pepper rhizosphere in Vietnam, and their genotypic diversity and potential to control Phy. capsici root rot was determined. Biosurfactant-producing pseudomonads were genotypically and biochemically characterized by BOX-polymerase chain reaction (PCR), 16S-rDNA sequencing, reverse-phase-high-performance liquid chromatography and liquid chromatography-mass spectrometry analyses. Biosurfactant-producing fluorescent pseudomonads make up c. 1.3% of the culturable Pseudomonas population in the rhizosphere of black pepper. Although BOX-PCR revealed substantial genotypic diversity, the isolates were shown to produce the same biosurfactants and were all identified as Pseudomonas putida. When applied to black pepper stem cuttings, several of the biosurfactant-producing strains provided significant disease control. In absence of the disease, several of the bacterial strains promoted shoot and root growth of black pepper stem cuttings. Biosurfactant-producing pseudomonads indigenous to the rhizosphere of black pepper plants are genotypically diverse and provide a novel resource for the control of Phy. capsici root rot and growth promotion of black pepper stem cuttings. The results of this study provide a strong basis for further development of supplementary strategies with antagonistic bacteria to control foot and root rot of black pepper and to promote plant growth.

  6. Rhizopus Soft Rot on Lily Caused by Rhizopus oryzae in Korea

    Directory of Open Access Journals (Sweden)

    Soo-Sang Hahm

    2014-03-01

    Full Text Available Rhizopus soft rot of lily (Lilium longiflorum caused by Rhizopus oryzae was observed in the experimental field in Taean Lily Experiment Station in Korea, 2012. The typical symptoms were water-soaked lesions on bottom stem and leaf rot. The lesion rapidly expanded and the plant was softened totally. The fungus grew vigorously at an optimum temperature (25oC and brownish colony and black sporangia were formed on potato dextrose agar medium. Sporangiophores formed on end of sporangia were sub-globose, brownish and 6-10 μm in size. Sporangia were globose, blackish and 87-116 μm in size. Sporangiospores were irregularly oval and sub-globose, brownish 4-8 μm in size. On the basis of mycological characteristics, analyzing sequences of internal transcribed spacer region of ribosomal DNA, and pathogenicity test on host plants, the causal fungus was identified as R. oryzae. This is the first report of Rhizopus soft rot on lily caused by R. oryzae in Korea.

  7. Fungi associated with storage rots of cocoyams (Colocasia spp.) in Nsukka, Nigeria.

    Science.gov (United States)

    Ugwuanyi, J O; Obeta, J A

    1996-04-01

    Cocoyam (Colocasia spp.) corms and cormels showing spoilage symptoms were collected from many stores in Nsukka locality and examined for rot and associated fungal pathogens. Aspergillus niger, Botryodiplodia theobromae, Corticium rolfsii, Geotrichum candidum, Fusarium oxysporum, and F. solani were recovered from rotten cocoyams. The representative isolates of these species caused cocoyam rot in pathogenicity tests. The rot due to A. niger, B. theobromae and C. rolfsii was extensive resulting in complete maceration of cocoyam tissue. Potassium sorbate (0.1 mg/ml) protected cocoyams from fungal rot with the exception of C. rolfsii.

  8. Association of Pectolytic Fluorescent PSeudomonas with Postharvest Rots of Onion

    OpenAIRE

    H.H. El-Hendawy

    2004-01-01

    Five isolates of pectolytic fluorescent pseudomonads were obtained from a rotted onion bulb and identified as Pseudomonas marginalis. At both 4 and 25oC, all isolates caused soft rot to detached plant parts of onion and to carrot, celery, cucumber, pepper, spinach, tomato and turnip (but not garlic). They did not however cause any symptoms in living plants of these same species. These results suggest that the onion isolates are a postharvest pathogen which is not destructive in th...

  9. Experimental infection of highly pathogenic avian influenza virus H5N1 in black-headed gulls (Chroicocephalus ridibundus)

    OpenAIRE

    Ramis , Antonio; van Amerongen , Geert; van de Bildt , Marco; Leijten , Loneke; Vanderstichel , Raphael; Osterhaus , Albert; Kuiken , Thijs

    2014-01-01

    Historically, highly pathogenic avian influenza viruses (HPAIV) rarely resulted in infection or clinical disease in wild birds. However, since 2002, disease and mortality from natural HPAIV H5N1 infection have been observed in wild birds including gulls. We performed an experimental HPAIV H5N1 infection of black-headed gulls (Chroicocephalus ridibundus) to determine their susceptibility to infection and disease from this virus, pattern of viral shedding, clinical signs, pathological changes a...

  10. A gaseous acetic acid treatment to disinfect fenugreek seeds and black pepper inoculated with pathogenic and spoilage bacteria.

    Science.gov (United States)

    Nei, Daisuke; Enomoto, Katsuyoshi; Nakamura, Nobutaka

    2015-08-01

    Contamination of spices by pathogenic and/or spoilage bacteria can be deleterious to consumer's health and cause deterioration of foods, and inactivation of such bacteria is necessary for the food industry. The present study examined the effect of gaseous acetic acid treatment in reducing Escherichia coli O157:H7, Salmonella Enteritidis and Bacillus subtilis populations inoculated on fenugreek seeds and black pepper. Treatment with gaseous acetic acid at 0.3 mmol/L, 0.6 mmol/L and 4.7 mmol/L for 1-3 h significantly reduced the populations of E. coli O157:H7 and Salmonella Enteritidis on black pepper and fenugreek seeds at 55 °C (p pathogens than the treatment at 0.3 mmol/L. An approximately 5.0 log reduction was obtained after 3 h of treatment with 4.7 mmol/L acetic acid. No significant reductions in the population of B. subtilis spores inoculated on fenugreek seeds and black pepper were obtained after the gas treatments at 0.3 mmol/L or 0.6 mmol/L (p > 0.05). However, the gas treatment at 4.7 mmol/L significantly reduced B. subtilis spores (p < 0.05), and 4.0 log CFU/g and 3.5 log CFU/g reductions on fenugreek seeds and black pepper, respectively, were obtained after 3 h of treatment. Copyright © 2015 Elsevier Ltd. All rights reserved.

  11. QTLs for Resistance to Major Rice Diseases Exacerbated by Global Warming: Brown Spot, Bacterial Seedling Rot, and Bacterial Grain Rot

    OpenAIRE

    Mizobuchi, Ritsuko; Fukuoka, Shuichi; Tsushima, Seiya; Yano, Masahiro; Sato, Hiroyuki

    2016-01-01

    In rice (Oryza sativa L.), damage from diseases such as brown spot, caused by Bipolaris oryzae, and bacterial seedling rot and bacterial grain rot, caused by Burkholderia glumae, has increased under global warming because the optimal temperature ranges for growth of these pathogens are relatively high (around 30??C). Therefore, the need for cultivars carrying genes for resistance to these diseases is increasing to ensure sustainable rice production. In contrast to the situation for other impo...

  12. Huanglongbing increases Diplodia Stem End Rot in Citrus sinensis

    Science.gov (United States)

    Huanglongbing (HLB), one of the most devastating diseases of citrus is caused by the a-Proteobacteria Candidatus Liberibacter. Diplodia natalensis Pole-Evans is a fungal pathogen which has been known to cause a postharvest stem-end rot of citrus, the pathogen infects citrus fruit under the calyx, an...

  13. Root rots of common and tepary beans in Puerto Rico

    Science.gov (United States)

    Root rots are a disease complex affecting common bean and can be severe in bean growing areas in the tropics and subtropics. The presence of several pathogens makes it difficult to breed for resistance because of the synergistic effect of the pathogens in the host and the interaction of soil factors...

  14. Evaluating host resistance to Macrophomina crown rot in strawberry

    Science.gov (United States)

    Macrophomina crown rot, caused by the soilborne fungus Macrophomina phaseolina, is an emerging pathogen in California strawberry production. When established, the pathogen can cause extensive plant decline and mortality. Host resistance will be a critical tool for managing this disease and guiding ...

  15. Mycosphaerella fijiensis, the black leaf streak pathogen of banana: progress towards understanding pathogen biology and detection, disease development, and the challenges of control.

    Science.gov (United States)

    Churchill, Alice C L

    2011-05-01

    Banana (Musa spp.) is grown throughout the tropical and subtropical regions of the world. The fruits are a key staple food in many developing countries and a source of income for subsistence farmers. Bananas are also a major, multibillion-dollar export commodity for consumption primarily in developed countries, where few banana cultivars are grown. The fungal pathogen Mycosphaerella fijiensis causes black leaf streak disease (BLSD; aka black Sigatoka leaf spot) on the majority of edible banana cultivars grown worldwide. The fact that most of these cultivars are sterile and unsuitable for the breeding of resistant lines necessitates the extensive use of fungicides as the primary means of disease control. BLSD is a significant threat to the food security of resource-poor populations who cannot afford fungicides, and increases the environmental and health hazards where large-acreage monocultures of banana (Cavendish subgroup, AAA genome) are grown for export. Mycosphaerella fijiensis M. Morelet is a sexual, heterothallic fungus having Pseudocercospora fijiensis (M. Morelet) Deighton as the anamorph stage. It is a haploid, hemibiotrophic ascomycete within the class Dothideomycetes, order Capnodiales and family Mycosphaerellaceae. Its taxonomic placement is based on DNA phylogeny, morphological analyses and cultural characteristics. Mycosphaerella fijiensis is a leaf pathogen that causes reddish-brown streaks running parallel to the leaf veins, which aggregate to form larger, dark-brown to black compound streaks. These streaks eventually form fusiform or elliptical lesions that coalesce, form a water-soaked border with a yellow halo and, eventually, merge to cause extensive leaf necrosis. The disease does not kill the plants immediately, but weakens them by decreasing the photosynthetic capacity of leaves, causing a reduction in the quantity and quality of fruit, and inducing the premature ripening of fruit harvested from infected plants. Although Musa spp. are the

  16. The post-harvest fruit rots of tomato (Lycopersicum esculentum) in Nigeria.

    Science.gov (United States)

    Fajola, A O

    1979-01-01

    A survey of the post-harvest fruit rot diseases of tomato was conducted in five states of Nigeria. During severe infections, the diseases could cause 25% loss at harvest and 34% loss of the remaining product in transit, storage and market stalls; thus giving an overall loss of about 50% of the product. Two types of rots, soft and dry were recognised. The soft rot was found to account for about 85% and the dry rot about 15% of the overall loss. Erwinia carotovora, Rhizopus oryzae, R. stolonifer, Fusarium equiseti, F. nivale and F. oxysporum were established as the soft rot pathogens; while Aspergillus aculeatus, A. flavus, Cladosporium tenuissimum, Corynespora cassiicola, Curvularia lunata, Penicillium expansum P. multicolor and Rhizoctonia solani were established as the dry rot pathogens of tomato fruits in Nigeria.

  17. First Report of Postharvest Gray Mold Rot on Carrot Caused by Botrytis cinerea in Korea

    OpenAIRE

    Md. Aktaruzzaman; Joon-Young Kim; Sheng-Jun Xu; Byung-Sup Kim

    2014-01-01

    In February 2014, gray mold rotting symptoms were observed in carrots in cold storage at Gangneung, Gangwon province, Korea. The typical symptom of gray mold rot showed abundant blackish gray mycelia and conidia was observed on the infected root. The pathogen was isolated from infected root and cultured on PDA for further fungal morphological observation and confirming its pathogenicity according to Koch’s postulates. Results of morphological data, pathogenicity test and rDNA internal transcr...

  18. Pathogenicity of Nectriaceous Fungi on Avocado in Australia.

    Science.gov (United States)

    Parkinson, Louisamarie E; Shivas, Roger G; Dann, Elizabeth K

    2017-12-01

    Black root rot is a severe disease of young avocado trees in Australia causing black necrotic roots, tree stunting, and leaf drop prior to tree death. Nectriaceous fungi (Nectriaceae, Hypocreales), are commonly isolated from symptomatic roots. This research tested the pathogenicity of 19 isolates from Calonectria, Cylindrocladiella, Dactylonectria, Gliocladiopsis, and Ilyonectria, spp. collected from young avocado trees and other hosts. Glasshouse pathogenicity tests with 'Reed' avocado (Persea americana) seedlings confirmed that Calonectria ilicicola is a severe pathogen of avocado, causing stunting, wilting, and seedling death within 5 weeks of inoculation. Isolates of C. ilicicola from peanut, papaya, and custard apple were also shown to be aggressive pathogens of avocado, demonstrating a broad host range. An isolate of a Calonectria sp. from blueberry and avocado isolates of Dactylonectria macrodidyma, D. novozelandica, D. pauciseptata, and D. anthuriicola caused significant root rot but not stunting within 5 to 9 weeks of inoculation. An isolate of an Ilyonectria sp. from grapevine closely related to Ilyonectria liriodendri, and avocado isolates of Cylindrocladiella pseudoinfestans, Gliocladiopsis peggii, and an Ilyonectria sp. were not pathogenic to avocado.

  19. Soft rot erwiniae: from genes to genomes.

    Science.gov (United States)

    Toth, Ian K; Bell, Kenneth S; Holeva, Maria C; Birch, Paul R J

    2003-01-01

    SUMMARY The soft rot erwiniae, Erwinia carotovora ssp. atroseptica (Eca), E. carotovora ssp. carotovora (Ecc) and E. chrysanthemi (Ech) are major bacterial pathogens of potato and other crops world-wide. We currently understand much about how these bacteria attack plants and protect themselves against plant defences. However, the processes underlying the establishment of infection, differences in host range and their ability to survive when not causing disease, largely remain a mystery. This review will focus on our current knowledge of pathogenesis in these organisms and discuss how modern genomic approaches, including complete genome sequencing of Eca and Ech, may open the door to a new understanding of the potential subtlety and complexity of soft rot erwiniae and their interactions with plants. The soft rot erwiniae are members of the Enterobacteriaceae, along with other plant pathogens such as Erwinia amylovora and human pathogens such as Escherichia coli, Salmonella spp. and Yersinia spp. Although the genus name Erwinia is most often used to describe the group, an alternative genus name Pectobacterium was recently proposed for the soft rot species. Ech mainly affects crops and other plants in tropical and subtropical regions and has a wide host range that includes potato and the important model host African violet (Saintpaulia ionantha). Ecc affects crops and other plants in subtropical and temperate regions and has probably the widest host range, which also includes potato. Eca, on the other hand, has a host range limited almost exclusively to potato in temperate regions only. Disease symptoms: Soft rot erwiniae cause general tissue maceration, termed soft rot disease, through the production of plant cell wall degrading enzymes. Environmental factors such as temperature, low oxygen concentration and free water play an essential role in disease development. On potato, and possibly other plants, disease symptoms may differ, e.g. blackleg disease is associated

  20. The persistence of Gliocephalotrichum bulbilium and G. simplex causing fruit rot of rambutan in Puerto Rico

    Science.gov (United States)

    Fruit rot of rambutan (Nephelium lappaceum L.) is a pre and post-harvest disease problem that affects fruit quality. Significant post-harvest losses have occurred worldwide and several pathogens have been identified in Malaysia, Costa Rica, Hawaii, Thailand, and Puerto Rico. In 2011, fruit rot was o...

  1. Antifungal Effects Of Botanical Leaf Extracts On Tuber Rots Of Yam ...

    African Journals Online (AJOL)

    The fungicidal effects of dry and fresh leaf extracts of Axardirachta indica (L) and Ocimum grattissimum on the rot of yam tubers were investigated. Fusaruim oxysporium, Rhjzopus stolonifer, Botryodiplodia theobromae and Aspergillus Niger (root pathogens) were isolated from the rotted yam. Both dry and fresh leaf extracts ...

  2. Armillaria root rot

    Science.gov (United States)

    First described on grapevines in California in the 1880s, Armillaria root rot occurs in all major grape-growing regions of the state. The causal fungus, Armillaria mellea, infects woody grapevine roots and the base of the trunk (the root collar), resulting in a slow decline and eventual death of the...

  3. Ticks and tick-borne pathogens and putative symbionts of black bears (Ursus americanus floridanus) from Georgia and Florida.

    Science.gov (United States)

    Yabsley, Michael J; Nims, Todd N; Savage, Mason Y; Durden, Lance A

    2009-10-01

    Ticks were collected from 38 black bears (Ursus americanus floridanus) from northwestern Florida (n = 18) from 2003 to 2005 and southern Georgia (n = 20) in 2006. Five species (Amblyomma americanum, A. maculatum, Dermacentor variabilis, Ixodes scapularis, and I. affinis) were collected from Florida bears, and 4 species (A. americanum, A. maculatum, D. variabilis, I. scapularis) were collected from bears in Georgia. Ixodes scapularis was the most frequently collected tick, followed by D. variabilis, A. americanum, A. maculatum, and I. affinis. The collection of I. affinis from a Florida bear represents a new host record. A subset of ticks was screened for pathogens and putative symbionts by polymerase chain reaction (PCR). The zoonotic tick-borne pathogens Ehrlichia chaffeensis and Rickettsia parkeri were detected in 1 of 23 (4.3%) A. americanum and 1 of 12 (8.3%) A. maculatum, respectively. The putative zoonotic pathogen "Rickettsia amblyommii" was detected in 4 (17.4%) A. americanum and 1 (8.3%) A. maculatum. Other putative symbiotic rickettsiae detected included R. bellii and R. montanensis in D. variabilis, a Rickettsia cooleyi-like sp. and Rickettsia sp. Is-1 in I. scapularis, and Rickettsia TR39-like sp. in I. scapularis and A. americanum. All ticks were PCR-negative for Anaplasma phagocytophilum, Panola Mountain Ehrlichia sp., E. ewingii, Francisella tularensis, and Borrelia spp.

  4. Endophytic and pathogenic Phyllosticta species, with reference to those associated with Citrus Black Spot

    NARCIS (Netherlands)

    Glienke, C.; Pereira, O.L.; Stringari, D.; Fabris, J.; Kava-Cordeiro, V.; Galli-Terasawa, L.; Cunnington, J.; Shivas, R.G.; Groenewald, J.Z.; Crous, P.W.

    2011-01-01

    We investigated the identity and genetic diversity of more than 100 isolates belonging to Phyllosticta (teleomorph Guignardia), with particular emphasis on Phyllosticta citricarpa and Guignardia mangiferae s.l. occurring on Citrus. Phyllosticta citricarpa is the causal agent of Citrus Black Spot and

  5. QTLs for Resistance to Major Rice Diseases Exacerbated by Global Warming: Brown Spot, Bacterial Seedling Rot, and Bacterial Grain Rot.

    Science.gov (United States)

    Mizobuchi, Ritsuko; Fukuoka, Shuichi; Tsushima, Seiya; Yano, Masahiro; Sato, Hiroyuki

    2016-12-01

    In rice (Oryza sativa L.), damage from diseases such as brown spot, caused by Bipolaris oryzae, and bacterial seedling rot and bacterial grain rot, caused by Burkholderia glumae, has increased under global warming because the optimal temperature ranges for growth of these pathogens are relatively high (around 30 °C). Therefore, the need for cultivars carrying genes for resistance to these diseases is increasing to ensure sustainable rice production. In contrast to the situation for other important rice diseases such as blast and bacterial blight, no genes for complete resistance to brown spot, bacterial seedling rot or bacterial grain rot have yet been discovered. Thus, rice breeders have to use partial resistance, which is largely influenced by environmental conditions. Recent progress in molecular genetics and improvement of evaluation methods for disease resistance have facilitated detection of quantitative trait loci (QTLs) associated with resistance. In this review, we summarize the results of worldwide screening for cultivars with resistance to brown spot, bacterial seedling rot and bacterial grain rot and we discuss the identification of QTLs conferring resistance to these diseases in order to provide useful information for rice breeding programs.

  6. Butt Rot of Southern Hardwoods

    Science.gov (United States)

    F. I. McCracken

    1977-01-01

    Butt rot is the most serious cause of cull throughout the South, and affects all hardwood species. Defined as any decay at the base of a living tree, butt rot accounts for the loss of millions of board feet of southern hardwood timber annually. In one study of loess and alluvial hardwood sites in the Midsouth, butt rot was found in 40 percent of the trees being...

  7. Pathogenic and molecular characterisation of Pythium spp. inducing ...

    African Journals Online (AJOL)

    Pathogenic and molecular characterisation of Pythium spp. inducing root rot symptoms in other crops intercropped with beans in Southwestern Uganda. Virginia Gichuru, Robin Buruchara, Patrick Okori ...

  8. Root rot diseases of sugar beet

    Directory of Open Access Journals (Sweden)

    Jacobsen Barry J.

    2006-01-01

    Full Text Available Root rot diseases of sugar beet caused by Rhizoctonia solani (AG 2-2 IIIB and AG 2-2 IV, R. crocorum, Aphanomyces cochlioides, Phoma betae, Macrophomina phaeseolina, Fusarium oxysporum f.sp. radicis-betae, Pythium aphanidermatum Phytophthora drechsleri, Rhizopus stolonifer, R. arrhizus and Sclerotium rolfsii cause significant losses wherever sugar beets are grown. However, not all these soil-borne pathogens have been reported in all sugar beet production areas. Losses include reduced harvestable tonnage and reduced white sugar recovery. Many of these pathogens also cause post harvest losses in storage piles. Control for diseases caused by these pathogens include disease resistant cultivars, avoidance of stresses, cultural practices such as water management and the use of fungicides.

  9. Integrated management of foot rot of lentil using biocontrol agents under field condition.

    Science.gov (United States)

    Hannan, M A; Hasan, M M; Hossain, I; Rahman, S M E; Ismail, Alhazmi Mohammed; Oh, Deog-Hwan

    2012-07-01

    The efficacy of cowdung, Bangladesh Institute of Nuclear Agriculture (BINA)-biofertilizer, and Bangladesh Agricultural University (BAU)-biofungicide, alone or in combination, was evaluated for controlling foot rot disease of lentil. The results exhibited that BINA-biofertilizer and BAUbiofungicide (peat soil-based Rhizobium leguminosarum and black gram bran-based Trichoderma harzianum) are compatible and have combined effects in controlling the pathogenic fungi Fusarium oxysporum and Sclerotium rolfsii, which cause the root rot of lentil. Cowdung mixing with soil (at 5 t/ha) during final land preparation and seed coating with BINA-biofertilizer and BAU-biofungicide (at 2.5% of seed weight) before sowing recorded 81.50% field emergence of lentil, which showed up to 19.85% higher field emergence over the control. Post-emergence deaths of plants due to foot rot disease were significantly reduced after combined seed treatment with BINA-biofertilizer and BAU-biofungicide. Among the treatments used, only BAU-biofungicide as the seed treating agent resulted in higher plant stand (84.82%). Use of BINA-biofertilizer and BAU-biofungicide as seed treating biocontrol agents and application of cowdung in the soil as an organic source of nutrient resulted in higher shoot and root lengths, and dry shoot and root weights of lentil. BINA-biofertilizer significantly increased the number of nodules per plant and nodules weight of lentil. Seeds treating with BAUbiofungicide and BINA-biofertilizer and soil amendment with cowdung increased the biomass production of lentil up to 75.56% over the control.

  10. Sheath rot of rice in Iran.

    Science.gov (United States)

    Naeimi, S; Okhovvat, S M; Hedjaroude, G A; Khosravi, V

    2003-01-01

    Sheath rot of rice occurs in most rice-growing regions of the world. It usually causes yield losses from 20 to 85%. Sheath rot was reported from Iran in 1993. Year after year, the number of diseased plants increased in the Northern Iran. In summer of 2001, these symptoms were observed in most fields: lesions occur on the upper leaf sheaths, especially the flag leaf sheath. As the disease progresses, lesions enlarge and coalesce and may cover most of the leaf sheath. Panicle may fail to completely or at all. Brown or partially brown not filled or partially filled grain is also associated with infection of the panicle. A whitish powdery growth may be found inside affected sheaths. Infected plants were collected and trasferred to laboratory. Small pieces of diseased tissues were washed under tap water for one hour. Then tissues were placed on WA and incubated at 25 degrees C. These isolates were purified and identified as: Sarocladium oryzae, Fusarium udum, F. semitectum, F. avenaceum, F. flocciferum, F. graminearum, Bipolaris oryzae, Alternaria padwickii, Rhizoctonia solani, Paecilomyces sp., Nigrospora sp. and Trichoderma sp. This is the first report of F. udum in Iran. Also this is the first report that rice is the host for F. semitectum, F. avenaceum and F. flocciferum in Iran. Pathogenicity tests were conducted in glass house. Following species were found to be associated with sheath rot of rice: S. oryzae, F. graminearum, F. udum, F. avenaceum, B. oryzae, A. padwickii. This is the first report in the world that F. udum and A. padwickii are the causal agents of the sheath rot on rice plants.

  11. Antimicrobial properties of black grape (Vitis vinifera L.) peel extracts against antibiotic-resistant pathogenic bacteria and toxin producing molds.

    Science.gov (United States)

    Yadav, Devbrat; Kumar, Arvind; Kumar, Pramod; Mishra, Diwaker

    2015-01-01

    Black grape peel possesses a substantial amount of polyphenolic antimicrobial compounds that can be used for controlling the growth of pathogenic microorganisms. The purpose of this study was to assess antibacterial and antifungal activity of black grape peel extracts against antibiotic-resistant pathogenic bacteria and toxin producing molds, respectively. Peel of grape was subjected to polyphenolic extraction using different solvents viz., water, ethanol, acetone, and methanol. Antibiotic-resistant strains of Staphylococcus aureus, Enterococcus faecalis, Enterobacter aerogenes, Salmonella typhimurium, and Escherichia coli were screened for the antibacterial activity of different grape extracts. Antibacterial activity was analyzed using agar well diffusion method. Penicillium chrysogenum, Penicillium expansum, Aspergillus niger and Aspergillus versicolor were screened for the antifungal activity. Antifungal activity was determined by counting nongerminated spores in the presence of peel extracts. As compared to other solvent extracts, methanol extracts possessed high antibacterial and antifungal activity. S. typhimurium and E. coli showed complete resistance against antibacterial action at screened concentrations of grape peel extracts. Maximum zone of inhibition was found in case of S. aureus, i.e., 22 mm followed by E. faecalis and E. aerogenes, i.e., 18 and 21 mm, respectively, at 1080 mg tannic acid equivalent (TAE)/ml. The maximum and minimum percent of growth inhibition was shown by P. expansum and A. niger as 73% and 15% at 1080 TAE/ml concentration of grape peel extract, respectively. Except S. typhimurium and E. coli, growth of all bacterial and mold species were found to be significantly (P < 0.05) inhibited by all the solvent extracts.

  12. The Black Yeast Exophiala dermatitidis and Other Selected Opportunistic Human Fungal Pathogens Spread from Dishwashers to Kitchens.

    Directory of Open Access Journals (Sweden)

    Jerneja Zupančič

    Full Text Available We investigated the diversity and distribution of fungi in nine different sites inside 30 residential dishwashers. In total, 503 fungal strains were isolated, which belong to 10 genera and 84 species. Irrespective of the sampled site, 83% of the dishwashers were positive for fungi. The most frequent opportunistic pathogenic species were Exophiala dermatitidis, Candida parapsilosis sensu stricto, Exophiala phaeomuriformis, Fusarium dimerum, and the Saprochaete/Magnusiomyces clade. The black yeast E. dermatitidis was detected in 47% of the dishwashers, primarily at the dishwasher rubber seals, at up to 106 CFU/cm2; the other fungi detected were in the range of 102 to 105 CFU/cm2. The other most heavily contaminated dishwasher sites were side nozzles, doors and drains. Only F. dimerum was isolated from washed dishes, while dishwasher waste water contained E. dermatitidis, Exophiala oligosperma and Sarocladium killiense. Plumbing systems supplying water to household appliances represent the most probable route for contamination of dishwashers, as the fungi that represented the core dishwasher mycobiota were also detected in the tap water. Hot aerosols from dishwashers contained the human opportunistic yeast C. parapsilosis, Rhodotorula mucilaginosa and E. dermatitidis (as well as common air-borne genera such as Aspergillus, Penicillium, Trichoderma and Cladosporium. Comparison of fungal contamination of kitchens without and with dishwashers revealed that virtually all were contaminated with fungi. In both cases, the most contaminated sites were the kitchen drain and the dish drying rack. The most important difference was higher prevalence of black yeasts (E. dermatitidis in particular in kitchens with dishwashers. In kitchens without dishwashers, C. parapsilosis strongly prevailed with negligible occurrence of E. dermatitidis. F. dimerum was isolated only from kitchens with dishwashers, while Saprochaete/Magnusiomyces isolates were only found within

  13. First Report of Postharvest Gray Mold Rot on Carrot Caused by Botrytis cinerea in Korea

    Directory of Open Access Journals (Sweden)

    Md. Aktaruzzaman

    2014-06-01

    Full Text Available In February 2014, gray mold rotting symptoms were observed in carrots in cold storage at Gangneung, Gangwon province, Korea. The typical symptom of gray mold rot showed abundant blackish gray mycelia and conidia was observed on the infected root. The pathogen was isolated from infected root and cultured on PDA for further fungal morphological observation and confirming its pathogenicity according to Koch’s postulates. Results of morphological data, pathogenicity test and rDNA internal transcribed spacer (ITS 1 and 4 sequence showed that the postharvest gray mold rot of carrot was caused by Botyrtis cinerea. This is the first report of postharvest gray mold rot on carrot in Korea.

  14. Experimental infection of highly pathogenic avian influenza virus H5N1 in black-headed gulls (Chroicocephalus ridibundus).

    Science.gov (United States)

    Ramis, Antonio; van Amerongen, Geert; van de Bildt, Marco; Leijten, Loneke; Vanderstichel, Raphael; Osterhaus, Albert; Kuiken, Thijs

    2014-08-19

    Historically, highly pathogenic avian influenza viruses (HPAIV) rarely resulted in infection or clinical disease in wild birds. However, since 2002, disease and mortality from natural HPAIV H5N1 infection have been observed in wild birds including gulls. We performed an experimental HPAIV H5N1 infection of black-headed gulls (Chroicocephalus ridibundus) to determine their susceptibility to infection and disease from this virus, pattern of viral shedding, clinical signs, pathological changes and viral tissue distribution. We inoculated sixteen black-headed gulls with 1 × 10(4) median tissue culture infectious dose HPAIV H5N1 (A/turkey/Turkey/1/2005) intratracheally and intraesophageally. Birds were monitored daily until 12 days post inoculation (dpi). Oropharyngeal and cloacal swabs were collected daily to detect viral shedding. Necropsies from birds were performed at 2, 4, 5, 6, 7, and 12 dpi. Sampling from selected tissues was done for histopathology, immunohistochemical detection of viral antigen, PCR, and viral isolation. Our study shows that all inoculated birds were productively infected, developed systemic disease, and had a high morbidity and mortality rate. Virus was detected mainly in the respiratory tract on the first days after inoculation, and then concentrated more in pancreas and central nervous system from 4 dpi onwards. Birds shed infectious virus until 7 dpi from the pharynx and 6 dpi from the cloaca. We conclude that black-headed gulls are highly susceptible to disease with a high mortality rate and are thus more likely to act as sentinel species for the presence of the virus than as long-distance carriers of the virus to new geographical areas.

  15. Disease notes - Bacterial root rot

    Science.gov (United States)

    Bacterial root rot initiated by lactic acid bacteria, particularly Leuconostoc, occurs every year in Idaho sugarbeet fields. Hot fall weather seems to make the problem worse. Although Leuconostoc initiates the rot, other bacteria and yeast frequently invade the tissue as well. The acetic acid bac...

  16. Corm Rot and Yellows of Gladiolus and Its Biomanagement

    Directory of Open Access Journals (Sweden)

    M. Khan

    2005-08-01

    Full Text Available A corm dressing containing Trichoderma harzianum (T014 and Pseudomonas fluorescens (PS07 cultured on a bagasse-soil-molasses mixture was tested for its efficacy against corm rot and yellows caused by Fusarium oxysporum f. sp. gladioli on the gladiolus (Gladiolus psittacinus L. cv. White Prosperity (WP, King Lear (KL, Friendship (FR, Her Majesty (HM and American Beauty (AB in a pot culture experiment. The effectiveness of the biocontrol agents was compared with that of the fungicide carbendazim (200 ppm. All cultivars were susceptible to the pathogenic fungus and developed the characteristic symptoms of corm rot and yellows. Cultivars HM and AB were highly susceptible, scoring 2.9–3.2 on a corm rot and yellows scale (0–5 scale; compared with 1.5–2.9 for the other cultivars. Fungal infection reduced plant growth and flowering significantly, with a 15–28% decrease in the number of florets/spike. Application of carbendazim, T. harzianum (P=0.001 and P. fluorescens (P=0.05 decreased the corm rot and yellows scores and the soil population of the pathogen, and increased plant growth and flowering. The greatest improvement in the flower variables of infected plants was recorded with P. fluorescens (+18–31% over control. The soil population of the bioagents increased significantly over time, both in the presence and in the absence of the pathogenic fungus, but more in its absence.

  17. Combating a global threat to a clonal crop: banana black sigatoka pathogen pseudocercospora fijiensis (synonym mycosphaerella fijiensis) genomes reveal clues for disease control

    Science.gov (United States)

    Mycosphaerella fijiensis is the fungal pathogen that causes black Sigatoka or leaf streak disease of banana. Control of this disease requires weekly applications of fungicides in most cultivation areas. Major problems for disease management are fungicide resistance and the lack of effective genes fo...

  18. Occurrence of Root Rot and Vascular Wilt Diseases in Roselle (Hibiscus sabdariffa L.) in Upper Egypt

    Science.gov (United States)

    Hassan, Naglaa; Shimizu, Masafumi

    2014-01-01

    Roselle (Hibiscus sabdariffa L.) family Malvaceae is an important crop used in food, cosmetics and pharmaceutics industries. Roselle is cultivated mainly in Upper Egypt (Qena and Aswan governorates) producing 94% of total production. Root rot disease of roselle is one of the most important diseases that attack both seedlings and adult plants causing serious losses in crop productivity and quality. The main objective of the present study is to identify and characterize pathogens associated with root rot and wilt symptoms of roselle in Qena, Upper Egypt and evaluate their pathogenicity under greenhouse and field condition. Fusarium oxysporum, Macrophomina phaseolina, Fusarium solani, Fusarium equiseti and Fusarium semitectum were isolated from the natural root rot diseases in roselle. All isolated fungi were morphologically characterized and varied in their pathogenic potentialities. They could attack roselle plants causing damping-off and root rot/wilt diseases in different pathogenicity tests. The highest pathogenicity was caused by F. oxysporum and M. phaseolina followed by F. solani. The least pathogenic fungi were F. equiseti followed by F. semitectum. It obviously noted that Baladi roselle cultivar was more susceptible to infection with all tested fungi than Sobhia 17 under greenhouse and field conditions. This is the first report of fungal pathogens causing root rot and vascular wilt in roselle in Upper Egypt. PMID:24808737

  19. Suppression of crown and root rot of wheat by the rhizobacterium Paenibacillus polymyxa

    Directory of Open Access Journals (Sweden)

    Lamia LOUNACI

    2017-01-01

    Full Text Available A seedling bioassay was developed for screening a wheat root-associated rhizobacterial strain of Paenibacillus polymyxa for ability to suppress crown and root rot pathogens of wheat. The primary aim was to evaluate the ability of P. polymyxa to suppress Fusarium graminearum, F. culmorum, F. verticillioides and Microdochium nivale, the fungal pathogens responsible for Fusarium crown and root rot and head blight of wheat in Algeria. Bioassays conducted under controlled conditions indicated that seed treatments with P. polymyxa strain SGK2 significantly reduced disease symptoms caused by all four fungal pathogens. Plant growth promotion (increased shoot and root dry weights, however, depended on the pathogen tested. Our results indicate that seed treatments with a biocontrol agent could be an additional strategy for management of wheat crown and root rot pathogens.

  20. Fusarium rot of onion and possible use of bioproduct

    Directory of Open Access Journals (Sweden)

    Klokočar-Šmit Zlata

    2008-01-01

    Full Text Available Several species of Fusarium are causal agents of onion rot in field and storage. Most prevalent are F. oxysporum f. sp. cepae and F. solani, and recently F. proliferatum, a toxigenic species. Most frequently isolated fungi in our field experiments were F. solani and F. proliferatum with different pathogenicity. Certain differences in antagonistic activity of Trichoderma asperellum on different isolates of F. proliferatum and F. solani have been found in in vitro study in dual culture, expressed as a slower inhibition of growth of the former, and faster of the latter pathogen. Antagonistic abilities of species from genus Trichoderma (T. asperellum are important, and have already been exploited in formulated biocontrol products in organic and conventional production, in order to prevent soil borne pathogens inducing fusarium wilt and rot. The importance of preventing onion infection by Fusarium spp., possible mycotoxin producers, has been underlined.

  1. Control of lettuce bottom rot by isolates of Trichoderma spp

    Directory of Open Access Journals (Sweden)

    Zayame Vegette Pinto

    2014-06-01

    Full Text Available Bottom rot, caused by Rhizoctonia solani AG 1-IB, is an important disease affecting lettuce in Brazil, where its biological control with Trichoderma was not developed yet. The present study was carried out with the aim of selecting Trichoderma isolates to be used in the control of lettuce bottom rot. Forty-six Trichoderma isolates, obtained with baits containing mycelia of the pathogen, were evaluated in experiments carried out in vitro and in vivo in a greenhouse in two steps. In the laboratory, the isolates were evaluated for their capabilities of parasitizing and producing toxic metabolic substances that could inhibit the pathogen mycelial growth. In the first step of the in vivo experiments, the number and the dry weight of lettuce seedlings of the cultivar White Boston were evaluated. In the second step, 12 isolates that were efficient in the first step and showed rapid growth and abundant sporulation in the laboratory were tested for their capability of controlling bottom rot in two repeated experiments, and had their species identified. The majority of the isolates of Trichoderma spp. (76% showed high capacity for parasitism and 50% of them produced toxic metabolites capable of inhibiting 60-100% of R. solani AG1-IB mycelial growth. Twenty-four isolates increased the number and 23 isolates increased the dry weight of lettuce seedlings inoculated with the pathogen in the first step of the in vivo experiments.In both experiments of the second step, two isolates of T. virens, IBLF 04 and IBLF 50, reduced the severity of bottom rot and increased the number and the dry weight of lettuce seedlings inoculated with R. solani AG1-IB. These isolates had shown a high capacity for parasitism and production of toxic metabolic substances, indicating that the in vitro and in vivo steps employed in the present study were efficient in selecting antagonists to be used for the control of lettuce bottom rot.

  2. Armillaria root rot -- rev. revised edition. Information leaflet No. LFC 14E

    Energy Technology Data Exchange (ETDEWEB)

    Lachance, D.

    1996-11-01

    Armillaria root rot is a disease of the roots of plants and is caused by a fungus belonging to the genus `Armillaria spp.`. Most tree species in both the temperate and tropical zones can be affected by this disease; however, the damage is most notable and probably greatest in plantations. Armillaria root rot can be controlled, albeit with difficulty. This document looks at armillaria root rot and looks at the following points: Hosts and extent of the disease; the pathogens; symptoms and signs; infection and development; control; prevention; compromise solution; and, bibliography.

  3. Neofusicoccum luteum associated with leaf necrosis and fruit rot of olives in New South Wales, Australia

    Directory of Open Access Journals (Sweden)

    V. Sergeeva

    2009-09-01

    Full Text Available Neofusicoccum luteum is reported for the first time from olives (Olea europaea, causing fruit rot and leaf necrosis. Affected fruits initially became brown with pycnidia developing on the surface, later drying out and becoming mummified. The fungus was shown to be pathogenic on both fruits and leaves. The association of Botryosphaeriaceae with rotting olive fruits in Mediterranean regions and in New South Wales, Australia indicates that these fungi play a significant role in fruit rots of olives and deserve greater attention.

  4. High-throughput sequencing of black pepper root transcriptome

    Science.gov (United States)

    2012-01-01

    Background Black pepper (Piper nigrum L.) is one of the most popular spices in the world. It is used in cooking and the preservation of food and even has medicinal properties. Losses in production from disease are a major limitation in the culture of this crop. The major diseases are root rot and foot rot, which are results of root infection by Fusarium solani and Phytophtora capsici, respectively. Understanding the molecular interaction between the pathogens and the host’s root region is important for obtaining resistant cultivars by biotechnological breeding. Genetic and molecular data for this species, though, are limited. In this paper, RNA-Seq technology has been employed, for the first time, to describe the root transcriptome of black pepper. Results The root transcriptome of black pepper was sequenced by the NGS SOLiD platform and assembled using the multiple-k method. Blast2Go and orthoMCL methods were used to annotate 10338 unigenes. The 4472 predicted proteins showed about 52% homology with the Arabidopsis proteome. Two root proteomes identified 615 proteins, which seem to define the plant’s root pattern. Simple-sequence repeats were identified that may be useful in studies of genetic diversity and may have applications in biotechnology and ecology. Conclusions This dataset of 10338 unigenes is crucially important for the biotechnological breeding of black pepper and the ecogenomics of the Magnoliids, a major group of basal angiosperms. PMID:22984782

  5. High-throughput sequencing of black pepper root transcriptome

    Directory of Open Access Journals (Sweden)

    Gordo Sheila MC

    2012-09-01

    Full Text Available Abstract Background Black pepper (Piper nigrum L. is one of the most popular spices in the world. It is used in cooking and the preservation of food and even has medicinal properties. Losses in production from disease are a major limitation in the culture of this crop. The major diseases are root rot and foot rot, which are results of root infection by Fusarium solani and Phytophtora capsici, respectively. Understanding the molecular interaction between the pathogens and the host’s root region is important for obtaining resistant cultivars by biotechnological breeding. Genetic and molecular data for this species, though, are limited. In this paper, RNA-Seq technology has been employed, for the first time, to describe the root transcriptome of black pepper. Results The root transcriptome of black pepper was sequenced by the NGS SOLiD platform and assembled using the multiple-k method. Blast2Go and orthoMCL methods were used to annotate 10338 unigenes. The 4472 predicted proteins showed about 52% homology with the Arabidopsis proteome. Two root proteomes identified 615 proteins, which seem to define the plant’s root pattern. Simple-sequence repeats were identified that may be useful in studies of genetic diversity and may have applications in biotechnology and ecology. Conclusions This dataset of 10338 unigenes is crucially important for the biotechnological breeding of black pepper and the ecogenomics of the Magnoliids, a major group of basal angiosperms.

  6. High-throughput sequencing of black pepper root transcriptome.

    Science.gov (United States)

    Gordo, Sheila M C; Pinheiro, Daniel G; Moreira, Edith C O; Rodrigues, Simone M; Poltronieri, Marli C; de Lemos, Oriel F; da Silva, Israel Tojal; Ramos, Rommel T J; Silva, Artur; Schneider, Horacio; Silva, Wilson A; Sampaio, Iracilda; Darnet, Sylvain

    2012-09-17

    Black pepper (Piper nigrum L.) is one of the most popular spices in the world. It is used in cooking and the preservation of food and even has medicinal properties. Losses in production from disease are a major limitation in the culture of this crop. The major diseases are root rot and foot rot, which are results of root infection by Fusarium solani and Phytophtora capsici, respectively. Understanding the molecular interaction between the pathogens and the host's root region is important for obtaining resistant cultivars by biotechnological breeding. Genetic and molecular data for this species, though, are limited. In this paper, RNA-Seq technology has been employed, for the first time, to describe the root transcriptome of black pepper. The root transcriptome of black pepper was sequenced by the NGS SOLiD platform and assembled using the multiple-k method. Blast2Go and orthoMCL methods were used to annotate 10338 unigenes. The 4472 predicted proteins showed about 52% homology with the Arabidopsis proteome. Two root proteomes identified 615 proteins, which seem to define the plant's root pattern. Simple-sequence repeats were identified that may be useful in studies of genetic diversity and may have applications in biotechnology and ecology. This dataset of 10338 unigenes is crucially important for the biotechnological breeding of black pepper and the ecogenomics of the Magnoliids, a major group of basal angiosperms.

  7. First Report of Sclerotium Rot on Cymbidium Orchids Caused by Sclerotium rolfsii in Korea

    Science.gov (United States)

    Lee, Seong-Chan; Lee, Jung-Sup; Soh, Jae-Woo; Kim, Su

    2012-01-01

    Sclerotium rot was found on Cymbidium orchids at Seosan-si, Chungcheongnam-do, Korea, in July, 2010. Symptoms occurred on low leaves, which turned yellowish, after which the entire plant wilted. Severely infected plants were blighted and eventually died. White mycelial mats and sclerotia appeared on pseudobulbs. Based on the mycological characteristics and pathogenicity, the causal fungus was identified as Sclerotium rolfsii. This is the first report of new Sclerotium rot on Cymbidium spp. caused by S. rolfsii in Korea. PMID:23323053

  8. No Reported Species, Botrytis aclada Causing Gray Mold Neck Rot Disease on Onion Bulbs in Korea

    OpenAIRE

    Hwang, Sun–Kyoung; Lee, Seung–Yeol; Back, Chang–Gi; Kang, In–Kyu; Lee, Hyang–Burm; Jung, Hee-Young; Ohga, Shoji; Oga, Shoji

    2016-01-01

    Gray mold neck rot was observed on onion bulbs (Allium cepa L.) in low–temperature warehouses in Changnyeong–gun, Korea. The causative pathogen was isolated from rotted onion bulb lesions and identified as Botrytis aclada based on morphological and culture characteristics, the sequences of three nuclear genes (G3PDH, HSP60, and RPB2), and polymerase chain reaction–restriction fragment length polymorphism (PCR–RFLP) for Botrytis spp. identification. Although onion gray mold disease caused by B...

  9. Conifer root and butt rot caused by Heterobasidion annosum (Fr.) Bref. s.l.

    Science.gov (United States)

    Asiegbu, Fred O; Adomas, Aleksandra; Stenlid, Jan

    2005-07-01

    ). Disease symptoms: symptoms (e.g. exhudation of resin, crown deterioration) due to Heterobasidion root rot in living trees are not particularly characteristic and in most cases cannot be distinguished from those caused by other root pathogens. Heterobasidion annosum s.l. is a white rot fungus. Initial growth in wood causes a stain that varies in colour depending on host tree species. Incipient decay is normally pale yellow and it develops into a light brown decay to become a white pocket rot with black flecks in its advanced stage. silvicultural methods (e.g. stump removal), chemicals (urea, borates) and biological control agent (Phlebiopsis gigantea, marketed as PG Suspension(R) in the UK, PG IBL(R) in Poland and Rotstop(R) in Fennoscandia) are commonly used approaches for minimizing the disease spread.

  10. Root Rot Disease of Five Fruit Tree Seedlings in the Nursery ...

    African Journals Online (AJOL)

    The incidence of root rot disease in the nursery of Chrysophyllum albidun Dacryodes edulis, persea Americana, Irvingia gabonensis and Annona muricala was assessed. Ten fungal pathogen were isolated using serial dilution and pathogenicity tests were carried out on the 5 fruit trees with the 10 isolated fungi. The 5 fruit ...

  11. Avaliação da atividade de indutores de resistência abiótica, fungicida químico e extratos vegetais no controle da podridão-negra em Abacaxi 'Pérola' Activity evaluation of abiotic resistance inducers, chemical fungicide and natural plant extracts on black rot of pineapple, cv. pérola

    Directory of Open Access Journals (Sweden)

    Mônica Danielly de Mello Oliveira

    2009-03-01

    probabilidade. O tratamento que apresentou melhor resultado foi o indutor de resistência Ecolife®, aumentando o período de vida útil dos frutos e diminuindo a severidade dos sintomas da doença.Black rot of pineapple, caused by Chalara paradoxa (De Seyn. Sacc., is a postharvest disease responsible by high losses on fruits destined to the fresh market and to the processing industry. Penetration of fungus inside cells occurs through wounds and stem cutting, causing infection. The objective of this work was to evaluate the effect of abiotic resistance inducers, chemical fungicide and natural plant extracts on black rot of pineapple control. 32 fruits of pineapple cv pérola were used. They were disinfested with sodium hypochlorite (commercial product at 4% for 5 minutes. After drying at room temperature, fruits were treated, by spraying, with: 1 Distilled water (control, 2 Derosal 3 Bion® (Acibenzolar-S-methyl; 4 Ecolife®; 5 Agro-Mos®; 6 Allium sativum extract at 20%; 7 A. cepa at 20% and 8 Azadirachta indica at 20%. Treated fruits were incubated on humid chamber with polyethylene bags during 24 hours before inoculation procedure using a mycelia disk added to a wound at the epidermic area of the fruit. Evaluation of disease progress was done by a disease index: 1- no symptoms, 2- black rot on epidermis reaching 1-5 simple fruits, 3- black rot on epidermis reaching 6-10 simple fruits, 4- internal brown yellow rot, 5- black rot and disintegration of internal area in more than 50%. The experimental design was a completely randomized with eight treatments and five replicates, using general linear models with multinomial distribution and the averages were compared by Scott-Knott test at 5%. The best results were found in the Ecolife treatment with longer fruit life span and less severity in the symptoms of the disease.

  12. Management of Potato Soft Rot by Gamma Irradiation

    International Nuclear Information System (INIS)

    Abd El-Ghany, H.; Moussa, Z.; Abd El-Rahman, A.F.; Salem, E.A.

    2017-01-01

    This investigation aims to apply a safe practice to minimize potato losses due to soft rot disease of tubers kept under ambient temperature. In this regard, gamma irradiation was used to extend keeping quality through its effect on soft rot bacteria. Eight bacterial isolates were recovered on Logan’s medium from kitchen kept tubers with symptoms of soft rot disease. Five isolates were found pathogenic and tentatively identified as Pectobacterium atrosepticum and Pectobacterium carotovorum sub sp. brasiliense on the basis of the usual bacteriological methods. A molecular method using 16SrDNA sequence analysis for verification of the identity of two isolates was made. The two bacterial isolates, Pectobacterium atrosepticum and Pectobacterium carotovorum sub sp. brasiliense, were irradiated by different doses of gamma rays. Complete inhibition occurred at doses 2.5 and 2.0 KGy for high densities (Approximately 4.0x10 9 CFU/ml) of P. atrosepticum and P. carotovorum sub sp. brasiliense, respectively. The D10 value of gamma irradiation was 0.24 KGy for P. atrosepticum and 0.20 KGy for P. carotovorum subsp. brasiliense. Irradiation of artificially infected tubers with soft rot bacteria using the two mentioned D10 doses for the two bacterial species increased the shelf life of tubers kept under ambient temperature. The internal chemical quality of tubers was shown to be improved by keeping the tubers under ambient temperature after irradiation by the two D10 doses 0.24 and 0.20 KGy

  13. Characterization of calla Lily sot rot caused by Pectobacterium Carotovorum subsp. Carotovorum ZT0505 bacterial growth and pectate lyase activity under different conditions.

    NARCIS (Netherlands)

    Ni, L.; Guo, L.; Custers, J.B.M.; Zhang, L.

    2010-01-01

    Soft rot is a major disease of calla lily (Zantedeschia spp.) and other important crops worldwide. In this report, the bacterial isolate ZT0505 proved to be a soft rot pathogen of calla lily growing around Kunming (subtropical China) and was identified as Pectobacterium carotovorum subsp.

  14. Using the Resistograph®to distinguish different types of wood rot on living silver fir in Molise (Italy

    Directory of Open Access Journals (Sweden)

    Lasserre B

    2010-10-01

    Full Text Available he study was performed in two silver-fir forests (Abies alba Mill. located in Alto Molise, Province of Isernia: Collemeluccio, near Pescolanciano and Abeti Soprani near Capracotta. The aim of this work was to distinguish different types of wood rot on living silver fir individuals by using the Resistograph® (IML-RESI E400, a device that allows to estimate the variation of wood density by measuring the resistance to micro-perforation. The occurrence of different types of wood rot (white rot and brown rot in living trees was pointed out and discriminated by the device. In the detected deteriorated zones, fungal pathogens and decomposers were isolated and identified, causing either white (Phellinus hartigii, Ganoderma adspersum, Heterobasidion abietinum and Armillaria ostoyae or brown rot (Fomitopsis pinicola.

  15. Targeted enrichment of ancient pathogens yielding the pPCP1 plasmid of Yersinia pestis from victims of the Black Death.

    Science.gov (United States)

    Schuenemann, Verena J; Bos, Kirsten; DeWitte, Sharon; Schmedes, Sarah; Jamieson, Joslyn; Mittnik, Alissa; Forrest, Stephen; Coombes, Brian K; Wood, James W; Earn, David J D; White, William; Krause, Johannes; Poinar, Hendrik N

    2011-09-20

    Although investigations of medieval plague victims have identified Yersinia pestis as the putative etiologic agent of the pandemic, methodological limitations have prevented large-scale genomic investigations to evaluate changes in the pathogen's virulence over time. We screened over 100 skeletal remains from Black Death victims of the East Smithfield mass burial site (1348-1350, London, England). Recent methods of DNA enrichment coupled with high-throughput DNA sequencing subsequently permitted reconstruction of ten full human mitochondrial genomes (16 kb each) and the full pPCP1 (9.6 kb) virulence-associated plasmid at high coverage. Comparisons of molecular damage profiles between endogenous human and Y. pestis DNA confirmed its authenticity as an ancient pathogen, thus representing the longest contiguous genomic sequence for an ancient pathogen to date. Comparison of our reconstructed plasmid against modern Y. pestis shows identity with several isolates matching the Medievalis biovar; however, our chromosomal sequences indicate the victims were infected with a Y. pestis variant that has not been previously reported. Our data reveal that the Black Death in medieval Europe was caused by a variant of Y. pestis that may no longer exist, and genetic data carried on its pPCP1 plasmid were not responsible for the purported epidemiological differences between ancient and modern forms of Y. pestis infections.

  16. Black Zira essential oil: Chemical compositions and antimicrobial activity against the growth of some pathogenic strain causing infection.

    Science.gov (United States)

    Noshad, Mohammad; Hojjati, Mohammad; Alizadeh Behbahani, Behrooz

    2018-03-01

    The aim of this study was to perform chemical compositions and phytochemical analysis of Black Zira essential oil and other goal of this research was to investigate the antimicrobial effects of Black Zira essential oil against Enterobacter aerogenes, Pseudomonas aeruginosa, Escherichia coli, Shigella flexneri, Staphylococcus epidermidis, Streptococcus pyogenes and Candida albicans. Black Zira essential oil was extracted by hydrodistillation method using clevenger apparatus. Black Zira essential oil chemical composition was identified through gas chromatography/mass spectrometry. γ-terpinene with a percentage of 24.8% was the major compound of Black Zira essential oil. The antimicrobial effect Black Zira essential oil was evaluated by several qualitative and quantitative methods (disk diffusion, well diffusion, microdilution broth, agar dilution and minimum bactericidal/fungicidal concentration). Phytochemical analysis Black Zira essential oil were appraised based on qualitative methods. Antioxidant activity (2,2-diphenyl-1-picrylhydrazyl and β-carotene/linoleic acid inhibition) and total phenolic content (Folin-Ciocalteu) were examined. The results of phytochemical analysis of Black Zira essential oil showed the existence of phenolic, flavonoids, saponins, alkaloids and tannins. The total phenolic content and antioxidant activity (reported as IC 50 ) of Black Zira essential oil were equal to 120.50 ± 0.50 mg GAE/g and 11.55 ± 0.25 μg/ml, respectively. The MIC of the Black Zira essential oil ranged from 1 mg/ml to 8 mg/ml, while its MBC and MFC ranged from 1 mg/ml to 16 mg/ml. The results presented that the longest and the shortest inhibition zone diameter at the concentration of 8 mg/ml pertained to C. albicans and E. aerogenes, respectively. Copyright © 2018. Published by Elsevier Ltd.

  17. Interactions of Salmonella enterica Serovar Typhimurium and Pectobacterium carotovorum within a Tomato Soft Rot.

    Science.gov (United States)

    George, Andrée S; Cox, Clayton E; Desai, Prerak; Porwolik, Steffen; Chu, Weiping; de Moraes, Marcos H; McClelland, Michael; Brandl, Maria T; Teplitski, Max

    2018-03-01

    Salmonella spp. are remarkably adaptable pathogens, and this adaptability allows these bacteria to thrive in a variety of environments and hosts. The mechanisms with which these pathogens establish within a niche amid the native microbiota remain poorly understood. Here, we aimed to uncover the mechanisms that enable Salmonella enterica serovar Typhimurium strain ATCC 14028 to benefit from the degradation of plant tissue by a soft rot plant pathogen, Pectobacterium carotovorum The hypothesis that in the soft rot, the liberation of starch (not utilized by P. carotovorum ) makes this polymer available to Salmonella spp., thus allowing it to colonize soft rots, was tested first and proven null. To identify the functions involved in Salmonella soft rot colonization, we carried out transposon insertion sequencing coupled with the phenotypic characterization of the mutants. The data indicate that Salmonella spp. experience a metabolic shift in response to the changes in the environment brought on by Pectobacterium spp. and likely coordinated by the csrBC small regulatory RNA. While csrBC and flhD appear to be of importance in the soft rot, the global two-component system encoded by barA sirA (which controls csrBC and flhDC under laboratory conditions) does not appear to be necessary for the observed phenotype. Motility and the synthesis of nucleotides and amino acids play critical roles in the growth of Salmonella spp. in the soft rot. IMPORTANCE Outbreaks of produce-associated illness continue to be a food safety concern. Earlier studies demonstrated that the presence of phytopathogens on produce was a significant risk factor associated with increased Salmonella carriage on fruits and vegetables. Here, we genetically characterize some of the requirements for interactions between Salmonella and phytobacteria that allow Salmonella spp. to establish a niche within an alternate host (tomato). Pathways necessary for nucleotide synthesis, amino acid synthesis, and motility

  18. Association of Pectolytic Fluorescent PSeudomonas with Postharvest Rots of Onion

    Directory of Open Access Journals (Sweden)

    H.H. El-Hendawy

    2004-12-01

    Full Text Available Five isolates of pectolytic fluorescent pseudomonads were obtained from a rotted onion bulb and identified as Pseudomonas marginalis. At both 4 and 25oC, all isolates caused soft rot to detached plant parts of onion and to carrot, celery, cucumber, pepper, spinach, tomato and turnip (but not garlic. They did not however cause any symptoms in living plants of these same species. These results suggest that the onion isolates are a postharvest pathogen which is not destructive in the field but becomes a threat to fresh vegetables stored at low-temperature. Analysis of cellulosolytic and pectic enzymes revealed that pectic lyases, but not polygalacturonases, pectin methyl esterases and cellulases were produced in culture by each isolate.

  19. Control of potato soft rot caused by Pectobacterium carotovorum and Pectobacterium atrosepticum by Moroccan actinobacteria isolates.

    Science.gov (United States)

    Baz, M; Lahbabi, D; Samri, S; Val, F; Hamelin, G; Madore, I; Bouarab, K; Beaulieu, C; Ennaji, M M; Barakate, Mustapha

    2012-01-01

    Pectobacterium carotovorum and Pectobacterium atrosepticum are dreadful causal agents of potato soft rot. Actually, there are no efficient bactericides used to protect potato against Pectobacterium spp. Biological control using actinobacteria could be an interesting approach to manage this disease. Thus, two hundred actinobacteria isolated from Moroccan habitats were tested for their ability to inhibit in vitro 4 environmental Pectobacterium strains and the two reference strains (P. carotovorum CFBP 5890 and P. atrosepticum CFBP 5889). Eight percent of these isolates were active against at least one of the tested pathogens and only 2% exhibited an antimicrobial activity against all tested Pectobacterium strains. Four bioactive isolates having the greatest pathogen inhibitory capabilities and classified as belonging to the genus Streptomyces species through 16S rDNA analysis were subsequently tested for their ability to reduce in vivo soft rot symptoms on potato slices of Bintje, Yukon Gold, Russet and Norland cultivars caused by the two pathogens P. carotovorum and P. atrosepticum. This test was carried out by using biomass inoculums and culture filtrate of the isolates as treatment. Among these, strain Streptomyces sp. OE7, reduced by 65-94% symptom severity caused by the two pathogens on potato slices. Streptomyces OE7 showed a potential for controlling soft rot on potato slices and could be useful in an integrated control program against potato soft rot pathogens in the objective to reduce treatments with chemical compounds.

  20. Decolorization of textile dyes and their effluents using white rot fungi ...

    African Journals Online (AJOL)

    Reactive dyes are important chemical pollutants from textile industries .The two species of white rot fungi were evaluated for their ability to decolorize Blue CA, Black B133, Corazol Violet SR. Trametes hirsuta and Pleurotus florida displayed the greatest extent of decolorization. Laccase is the ligneolytic enzyme from these ...

  1. A new mechanism for reduced sensitivity to demethylation-inhibitor fungicides in the fungal banana black Sigatoka pathogen Pseudocercospora fijiensis

    NARCIS (Netherlands)

    Díaz-Trujillo, C.; Chong, P.; Stergiopoulos, I.; Meijer, H.J.G.; Wit, de P.J.G.M.; Kema, G.H.J.

    2017-01-01

    The Dothideomycete Pseudocercospora fijiensis, previously Mycosphaerella fijiensis, is the causal agent of black Sigatoka, one of the most destructive diseases of bananas and plantains. Disease management depends on fungicide applications with a major share for sterol demethylation-inhibitors

  2. Survey of root rot diseases of sugar bett in Central Greece

    Directory of Open Access Journals (Sweden)

    Karadimos Dimitros A.

    2006-01-01

    Full Text Available An extensive survey was conducted during the summer and autumn of 2004 in sugar beet fields in the area of Larissa, Thessaly region, with plants showing symptoms of root rot diseases. The aim of the monitoring was to identify the causal agents of root rot diseases. In total, 76 sugar beet fields were surveyed and 5-10 diseased roots were examined from each field. Isolations, carried out on PDA, showed that two main fungal pathogens causing root rot were Rhizoctonia solani and Phytophthora cryptogea. The former was isolated in 46% of the fields and the latter in 38% of the fields. In addition, Rhizopus stolonifer, Fusarium spp., Scerotium rolfsii and Rhizoctonia violacea were isolated in 14%, 7%, 4% and 1% of the fields respectively. In most of the surveyed fields only one pathogen species was isolated and only in a few of them more than one fungal species was identified.

  3. Root rot diseases of sugarbeet (Beta vulgaris L as affected by defloliation intensity

    Directory of Open Access Journals (Sweden)

    Karadimos Dimitros A.

    2006-01-01

    Full Text Available The aim of this work was to study the effect of sugar beet re-growth after water stress defoliation on root rots of three cultivars (Europa, Rival Corsica, which were spring sown in Thessaly, central Greece, for two growing seasons (2003-04. At the beginning of July, sugar beets were subjected to water deficit with irrigation withholding. A month later, three defoliation levels (control - C, moderate - MD, severe - SD and irrigation were applied. Thus, sugar beets were forced to re-grow and three harvests (15, 30 and 40 days after defoliation - DAD were conducted. Rotted roots per hectare were counted and pathogens were identified. Data were analyzed as a four-factor randomized complete block design with years, defoliation levels, sampling times and cultivars as main factors. The number of rotted roots was increased with the defoliation level and was significantly higher for SD sugar beets (3748 roots ha–1. No significant differences were found between C and MD treatments (1543 and 2116 roots ha–1, respectively. Rival was the most susceptible cultivar to root rots. Sugar beets were more susceptible to rotting 15 and 40 DAD (2778 and 2998 roots ha–1. The causal agents of root rots were the fungi, Fusarium spp., Rhizopus stolonifer, Macrophomina phaseolina and Rhizoctonia solani.

  4. Phytophthora cinnamon causing stem canker and root rot of nursery-grown Platanus × acerifolia: first report in the Northern emisphere

    Directory of Open Access Journals (Sweden)

    Massimo PILOTTI

    2014-05-01

    Full Text Available Lethal stem and root cankers were observed in nursery-grown Platanus × acerifolia trees in Rome. Externally, canker lesions appeared as bluish or blackish areas starting from the stem base and extending upward. Inner bark was necrotised. In some cases an irregularly-shaped callus reaction attempted to heal the bark lesions. Black-stained necrosis affected the primary roots and the small branch roots to different degrees. The presence of Ceratocystis platani was excluded in the diseased trees. Phytophthora-like organisms were isolated from the altered tissue. Morphological and ITS-region-based analyses identified the isolates as Phytophthora cinnamomi. A pathogenicity test confirmed P. cinnamomi as the causal agent of the disease here defined as: stem canker and root rot of plane tree. This is the first report of P. cinnamomi in Platanus spp. in the Northern emisphere.

  5. Canker Rots in Southern Hardwoods

    Science.gov (United States)

    F.I. McCracken

    1978-01-01

    Canker-rot fungi cause serious degrade and cull in southern hardwoods, especially the red oaks. Heartwood decay is the most serious form of damage, but the fungi also kill the cambium and decay the sapwood for as much as 3 feet (.91 m) above and below the entrance point into the tree. The ability of these fungi to kill the cambium and cause cankers distinguishes them...

  6. First report of Gliocephalotrichum bulbilium and G. simplex causing fruit rot of rambutan in Puerto Rico

    Science.gov (United States)

    Worldwide, significant post-harvest disease losses of rambutan (Nephelium lappaceum L.) have been reported and several pathogens have been associated with fruit rot. Even though rambutan was introduced to Puerto Rico in 1927, it was not until 1998 that commercial farms were established in the wester...

  7. Distribution of Rhizoctonia Bare Patch and Root Rot in Eastern Washington and Relation to Climatic Variables

    Science.gov (United States)

    Rhizoctonia is a fungus that attacks the roots of wheat and barley, causing a root rot and bare patch in the dryland wheat cropping area of the inland Pacific Northwest. Over the last 7 years, we have been investigating the distribution of this pathogen, using molecular methods based on extracting a...

  8. Post Harvest Control of Tomato Fruit Rot Caused by Fusarium solani ...

    African Journals Online (AJOL)

    Fusarium Solani is an important rot-causing organism of tomato fruit in storage. Alcohol and water extracts of bark, rootand leaves of the neem plant (Azadirachta indica) were tested against the pathogen both in vitro and in vivo. The alcoholextract of different parts, especially the bark of the plant, gave the highest growth ...

  9. Plectosphaerella species associated with root and collar rots of horticultural crops in southern Italy

    NARCIS (Netherlands)

    Carlucci, A.; Raimondo, M.L.; Santos, J.; Phillips, A.J.L.

    2012-01-01

    Plectosphaerella cucumerina, most frequently encountered in its Plectosporium state, is well known as a pathogen of several plant species causing fruit, root and collar rot, and collapse. It is considered to pose a serious threat to melon (Cucumis melo) production in Italy. In the present study, an

  10. Mechanisms of qualitative and quantitative resistance to Aphanomyces root rot in alfalfa

    Science.gov (United States)

    Aphanomyces root rot (ARR), caused by Aphanomyces euteiches, is one of the most important diseases of alfalfa (Medicago sativa) in the United States. Two races of the pathogen are currently recognized. Most modern alfalfa cultivars have high levels of resistance to race 1 but few cultivars have resi...

  11. Identification of markers associated with race-specific resistance to Aphanomyces root rot in alfalfa

    Science.gov (United States)

    Aphanomyces root rot, caused by Aphanomyces euteiches, is one of the most important diseases of alfalfa in the United States. Two races of the pathogen are recognized and although most cultivars are resistant to race 1, fewer have resistance to race 2, the predominant race in North America. Molecula...

  12. Involvement of phenolic compounds in the susceptibility of bananas to crown rot. A review

    Directory of Open Access Journals (Sweden)

    Lassois, L.

    2012-01-01

    Full Text Available Crown rot of bananas, caused by a fungal parasitic complex, is one of the main quality defects of exported bananas. Major variations in the susceptibility of bananas to crown rot have been observed in different production zones. The physiological state of the banana fruit at harvest is said to influence its response to pathogenic attack and thus to modulate its susceptibility to crown rot. The susceptibility of bananas to this disease, however, appears to be influenced by many pre-harvest factors, although the underlying defense mechanisms have not been clearly identified. A recent report based on molecular analyses suggests that phenolic compounds might be involved in the different variations in the susceptibility of bananas to crown rot. Results of other earlier studies point to an involvement of phenolic compounds in the defensive reactions of banana plants against various pathogens. The present paper reviews the current state of knowledge on the variations in the susceptibility of bananas to crown rot and takes stock of what is known about phenolic compounds in relation to their potential involvement in the defense mechanisms of the banana plant.

  13. Studies on black stain root disease in ponderosa pine. pp. 236-240. M. Garbelotto & P. Gonthier (Editors). Proceedings 12th International Conference on Root and Butt Rots of Forest Trees.

    Science.gov (United States)

    W. J. Otrosina; J. T. Kliejunas; S. S. Sung; S. Smith; D. R. Cluck

    2008-01-01

    Black stain root disease of ponderosa pine, caused by Lepfographium wageneri var. ponderosum (Harrington & Cobb) Harrington & Cobb, is increasing on many eastside pine stands in northeastern California. The disease is spread from tree to tree via root contacts and grafts but new infections are likely vectored by root...

  14. EndophyticTrichoderma gamsiiYIM PH30019: a promising biocontrol agent with hyperosmolar, mycoparasitism, and antagonistic activities of induced volatile organic compounds on root-rot pathogenic fungi ofPanax notoginseng.

    Science.gov (United States)

    Chen, Jin-Lian; Sun, Shi-Zhong; Miao, Cui-Ping; Wu, Kai; Chen, You-Wei; Xu, Li-Hua; Guan, Hui-Lin; Zhao, Li-Xing

    2016-10-01

    Biocontrol agents are regarded as promising and environmental friendly approaches as agrochemicals for phytodiseases that cause serious environmental and health problems. Trichoderma species have been widely used in suppression of soil-borne pathogens. In this study, an endophytic fungus, Trichoderma gamsii YIM PH30019, from healthy Panax notoginseng root was investigated for its biocontrol potential. In vitro detached healthy roots, and pot and field experiments were used to investigate the pathogenicity and biocontrol efficacy of T. gamsii YIM PH30019 to the host plant. The antagonistic mechanisms against test phytopathogens were analyzed using dual culture, scanning electron microscopy, and volatile organic compounds (VOCs). Tolerance to chemical fertilizers was also tested in a series of concentrations. The results indicated that T. gamsii YIM PH30019 was nonpathogenic to the host, presented appreciable biocontrol efficacy, and could tolerate chemical fertilizer concentrations of up to 20%. T. gamsii YIM PH30019 displayed antagonistic activities against the pathogenic fungi of P . notoginseng via production of VOCs. On the basis of gas chromatography-mass spectrometry, VOCs were identified as dimethyl disulfide, dibenzofuran, methanethiol, ketones, etc., which are effective ingredients for antagonistic activity. T. gamsii YIM PH30019 was able to improve the seedlings' emergence and protect P. notoginseng plants from soil-borne disease in the continuous cropping field tests. The results suggest that the endophytic fungus T. gamsii YIM PH30019 may have a good potential as a biological control agent against notoginseng phytodiseases and can provide a clue to further illuminate the interactions between Trichoderma and phytopathogens.

  15. The origin, versatility and distribution of azole fungicide resistance in the banana black Sigatoka pathogen Pseudocercospora fijiensis

    NARCIS (Netherlands)

    Chong Aguirre, Pablo A.

    2016-01-01

    Pseudocercospora fijiensis causes black Sigatoka disease of banana. It is one of the most damaging threats of the crop requiring excessive fungicide applications for disease control as the major export “Cavendish” clones are highly susceptible. The consequence of this practice is the

  16. The origin, versatility and distribution of azole fungicide resistance in the banana black Sigatoka pathogen Pseudocercospora fijiensis

    NARCIS (Netherlands)

    Chong Aguirre, Pablo A.

    2016-01-01

    Pseudocercospora fijiensis causes black Sigatoka disease of banana. It is one of the most damaging threats of the crop requiring excessive fungicide applications for disease control as the major export “Cavendish” clones are highly susceptible. The consequence of this practice is the

  17. Bacteriophages of Soft Rot Enterobacteriaceae-a minireview.

    Science.gov (United States)

    Czajkowski, Robert

    2016-01-01

    Soft rot Enterobacteriaceae (Pectobacterium spp. and Dickeya spp., formerly pectinolytic Erwinia spp.) are ubiquitous necrotrophic bacterial pathogens that infect a large number of different plant species worldwide, including economically important crops. Despite the fact that these bacteria have been studied for more than 50 years, little is known of their corresponding predators: bacteriophages, both lytic and lysogenic. The aim of this minireview is to critically summarize recent ecological, biological and molecular research on bacteriophages infecting Pectobacterium spp. and Dickeya spp. with the main focus on current and future perspectives in that field. © FEMS 2015. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  18. Characterisation of Alternaria species-groups associated with core rot of apples in South Africa

    DEFF Research Database (Denmark)

    Serdani, M.; Kang, J.C.; Andersen, Birgitte

    2002-01-01

    Alternaria core rot of red apple cultivars is a serious post-harvest disease in South Africa. Thirty isolates of Alternaria spp. previously isolated from apple, together with reference isolates of A. alternata and A. infectoria, were characterised and grouped according to their sporulation patterns...... the other species-groups, as all isolates had a distinction of 35 base pair insertions and 6 base pair deletions in the ITS regions. The results obtained in the present study showed that the major pathogens associated with core rot disease of Top Red apples in South Africa belong to the A. tenuissima...

  19. Control of Root-rot Diseases of Phaseolus vulgaris Using Gliotoxin

    Directory of Open Access Journals (Sweden)

    Aliaa, R. E.

    2008-01-01

    Full Text Available Effect of the antifungal antibiotic gliotoxin on root-rot diseases caused by Fusarium solani and its influence on population of fungal flora in soil were investigated. Bean seeds were treated with different concentrations of gliotoxin before sowing. The results obtained from the green house application of bioagent indicated that soaking seeds in different concentrations of gliotoxin from 1µg/mL to 15µg/mL (for 60 minutes significantly reduced the percentage of damping off and root rot as compared with control (pathogen only. Also 10µg/mL of gliotoxin was significantly decreased the population of fungal flora as compared with control.

  20. Experimental infection of highly pathogenic avian influenza virus H5N1 in black-headed gulls (Chroicocephalus ridibundus)

    NARCIS (Netherlands)

    A. Ramis (Antonio); G. van Amerongen (Geert); M.W.G. van de Bildt (Marco); L.M.E. Leijten (Lonneke); R. Vanderstichel (R.); A.D.M.E. Osterhaus (Albert); T. Kuiken (Thijs)

    2014-01-01

    textabstractHistorically, highly pathogenic avian influenza viruses (HPAIV) rarely resulted in infection or clinical disease in wild birds. However, since 2002, disease and mortality from natural HPAIV H5N1 infection have been observed in wild birds including gulls. We performed an experimental

  1. Growth Inhibition of Cocoa Pod Rot Fungus Phytophthora palmivora byPseudomonas fluorescence and Bacillus subtilis bacteria

    Directory of Open Access Journals (Sweden)

    Sakti Widyanta Pratama

    2013-08-01

    Full Text Available Black pod disease caused by Phytophthora palmivorafungus is one of the important diseases on cocoa crop. Pod rot is the most important disease because it may cause loss of cocoa pod. Until now, the fungal pathogen of cocoa black pod disease is still a crucial problem and there is no fungicide that is really effective against the disease. One alternative to control the cocoa black pod disease is by using biological agents as biofungicide, including utilizing Pseudomonas fluorescenceand Bacillus subtilis bacteria. The research was done by isolation of P. palmivora from infected pods of Kaliwining Experimental Station to obtain pure cultures of fungus and by multiplication of P. fluorescence and B. subtilis. Antagonist test was performed by inoculating P. palmivora into a petri dish in a distance of 3 cm from the edge. P. fluorescenceand B. Subtilis were inoculated into petridishes in three days after the fungal treatment. Control was inoculated with isolate of P. palmivora only. Fungal growth was measured everyday by measuring radius of fungal colonies first time 24 hours after inoculation. Growth of Phytophthora palmivora in the two treatmens were used to calculate the percentage of inhibition. The results of this study indicated that P. fluorescence and B. subtiliswere able to inhibit fungal growth of P. palmivora. Both bacterial antagonists had the same effectiveness in inhibiting the growth of P. palmivora fungus based on the percentage of inhibition and effectiveness criteria. Based on the results of translucent zones indicated that B. subtiliswas more powerfull in inhibiting growth of P. Palmivora compared to P. fluorescence. Key words: Black pod disease of cocoa, biological control, Phytophthora palmivora, Pseudomonas fluorescence, Bacillus subtilis

  2. Pathogenicity of fungal species in aroid ( Colocasia and Xanthosoma ) rhizomes

    OpenAIRE

    Amaurys Dávila Martínez; Lidcay Herrera Isla; Maryluz Folgueras Montiel; Ernesto Espinosa Cuellar

    2016-01-01

    Among the diseases affecting aroids is rhizome rot caused by various pathogen fungi. These rots usually appear in poorly drained heavy soils with high organic matter content. These diseases appear more during the rainy season because it is a fungus complex living in the soil and is favored by high humidity. In order to know the virulence of different pathogens involved in this syndrome, cross-species inoculations were performed. Species of Rhizoctonia solani Kühn and Sclerotiun rolfsii Sacc w...

  3. Fusarium basal rot in the Netherlands

    NARCIS (Netherlands)

    Visser, de C.L.M.; Broek, van den R.C.F.M.; Brink, van den L.

    2006-01-01

    Fusarium basal rot of onion, caused by Fusarium oxysporum f.sp. cepae, is a steadily increasing problem in The Netherlands. Financial losses for Dutch farmers confronted with Fusarium basal rot is substantial, due to yield reduction and high storage costs. This paper describes the development and

  4. The Black Aspergillus Species of Maize and Peanuts and Their Potential for Mycotoxin Production

    Science.gov (United States)

    Palencia, Edwin R.; Hinton, Dorothy M.; Bacon, Charles W.

    2010-01-01

    The black spored fungi of the subgenera Circumdata, the section Nigri (=Aspergillus niger group) is reviewed relative to their production of mycotoxins and their effects on plants as pathogens. Molecular methods have revealed more than 18 cryptic species, of which several have been characterized as potential mycotoxin producers. Others are defined as benign relative to their ability to produce mycotoxins. However, these characterizations are based on in vitro culture and toxins production. Several can produce the ochratoxins that are toxic to livestock, poultry, and humans. The black aspergilli produce rots of grapes, maize, and numerous other fruits and grain and they are generally viewed as post-harvest pathogens. Data are review to suggest that black aspergilli, as so many others, are symptomless endophytes. These fungi and their mycotoxins contaminate several major grains, foodstuffs, and products made from them such as wine, and coffee. Evidence is presented that the black aspergilli are producers of other classes of mycotoxins such as the fumonisins, which are known carcinogenic and known prior investigations as being produced by the Fusarium species. Three species are identified in U.S. maize and peanuts as symptomless endophytes, which suggests the potential for concern as pathogens and as food safety hazards. PMID:22069592

  5. Hot water treatment to reduce incidence of black foot pathogens in young grapevines grown in cool climates

    Directory of Open Access Journals (Sweden)

    Carolyn BLEACH

    2013-09-01

    Full Text Available Black foot disease causes death of infected grapevines but management of this soil-borne disease by preventative measures such as pre-planting fungicide dips has not been totally effective. Hot water treatment (HWT; 50°C for 30 min of young dormant grapevine plants has been shown to significantly reduce infection. However, it has been reported to cause unacceptable damage to young vines in cooler climate countries like New Zealand, so this study examined the effects of different HWT protocols on the New Zealand black foot isolates. In vitro testing of different HWT protocols was conducted on conidia, mycelium and detached, inoculated grapevine canes using three isolates each of the species I. liriodendri (“C”. liriodendri and the complexes, I. radicicola (“C”. destructans and I. macrodidyma (“C”. macrodidymum. Heat treatments greater than 40°C for 5 min killed all conidia (P<0.001, and treatments greater than 47°C for 30 min inhibited (P≤0.003 further growth of treated mycelium plugs for all but one isolate. Within cane pieces, infection by Ilyonectria (“Cylindrocarpon” isolates was significantly reduced (P<0.001 by 30 min at 48.5 and 50°C. Additionally, these studies showed different responses to the different treatments for the three isolates of each species complex and differences between species. In field trials, HWT of 48.5 and 50°C for 30 min significantly reduced disease incidence in dormant plants to 0% (P≤0.001. This study confirmed that HWT of 48.5°C for 30 min could be used to eliminate black foot disease in dormant nursery grapevines grown in New Zealand prior to their use for establishing new vineyards.

  6. PHOTOSYNTHETIC RESPONSES OF Eucalyptus nitens Maiden AT INITIAL STAGES OF ROOT-ROT INFECTION

    Directory of Open Access Journals (Sweden)

    Luciasih Agustini

    2015-04-01

    Full Text Available Root-rots are known to be latent diseases that may be present in plants for an extended period without any noticeable expression of symptoms above ground. Photosynthetic responses of Eucalyptus nitens saplings artificially inoculated with the root-rot pathogen, Armillaria luteobubalina were examined to characterize the initial stages of root-rot infection. This paper studies three photosynthetic parameters, i.e. photosystem II yield (Fv/Fm, chlorophyll content and photosynthetic capacity (Amax for two strains of A. luteobubalina over a seven-month period. Root systems were either wounded or left intact before inoculation. A significant difference was observed in the Fv/Fm ratio between the uninoculated control and inoculated saplings. Photosystem II yield was considered the most sensitive parameter for the early detection of root-rot disease. Chlorophyll content and Amax decreased for all trees, including controls, during the period of the experiment, and most likely reflected host responses to seasonal change rather than treatment effects. Fungal re-isolations from symptomatic roots of inoculated trees confirmed the presence of A. luteobubalina. Findings from this preliminary trial indicated that there were detectable physiological changes associated with early infection of root-rot. However, to detect more widespread physiological changes an experiment of longer duration is needed.

  7. Caracterização de isolados de Xanthomonas campestris pv campestris de sistemas de produção orgânico e reação de brássicas à podridão-negra Characterization of strains of Xanthomonas campestris pv campestris from organic farming systems and reaction of brassicas to black rot

    Directory of Open Access Journals (Sweden)

    Liliana Andréa dos Santos

    2008-12-01

    .3%, resistance to amoxicilin (70%, gentamicin (40.0% and norfloxacin (45.5% and medium sensitivity (44.4% or resistance (44.4% to neomycin. Fifty-five strains of Xcc were resistant to copper sulfate at 50 mg mL-1 and all of them to 200 mg mL-1; 92.22% of the strains showed esterase activity. Strains were grouped in seven similarity groups by the Euclidean analysis-single linkage. The reaction of 14 genotypes of brassicas to strain "B21" of Xcc was also studied. The genotypes significantly differed among them in relation to incubation period, incidence and disease severity. The highest disease severity was recorded on broccoli "Ramoso", cauliflower "Bola de Neve" and "Piracicaba de Verão", and cabbage "Chato de Quintal", classified as highly susceptible to black rot. The Chinese cabbage hybrids "AF 70", "AF 72", "AF 69" and "AF 66" were highly resistant to black-rot, while broccolis "Ramoso" and "Piracicaba Precoce", cauliflower "Piracicaba de Verão" and "Híbrido Cindy" and cabbage "60 Dias" showed intermediate resistance.

  8. Water relations in untreated and modified wood under brown-rot and white-rot decay

    DEFF Research Database (Denmark)

    Thybring, Emil Engelund

    2017-01-01

    from several literature sources, the water relations of untreated and modified wood decayed by brown-rot and white-rot fungi are examined. The aim is to investigate to what extent observations and assumptions regarding brown-rot and white-rot decay can explain changes in water relations observed during...... and after decay. Although the available experimental data for modified wood is scarce, it indicates that brown-rot and white-rot decay of non-resistant modified wood occurs by similar degradation mechanisms with similar effects on water relations as for untreated wood. From simplistic, mathematical...... modelling, it is shown that changes in water relations during decay can be partly explained by accompanying changes in chemical composition and void volume....

  9. A new mechanism for reduced sensitivity to demethylation-inhibitor fungicides in the fungal banana black Sigatoka pathogen Pseudocercospora fijiensis.

    Science.gov (United States)

    Diaz-Trujillo, Caucasella; Chong, Pablo; Stergiopoulos, Ioannis; Cordovez, Viviane; Guzman, Mauricio; De Wit, Pierre J G M; Meijer, Harold J G; Scalliet, Gabriel; Sierotzki, Helge; Lilia Peralta, Esther; Arango Isaza, Rafael E; Kema, Gerrit H J

    2017-11-04

    The Dothideomycete Pseudocercospora fijiensis, previously Mycosphaerella fijiensis, is the causal agent of black Sigatoka, one of the most destructive diseases of bananas and plantains. Disease management depends on fungicide applications, with a major contribution from sterol demethylation-inhibitors (DMIs). The continued use of DMIs places considerable selection pressure on natural P. fijiensis populations, enabling the selection of novel genotypes with reduced sensitivity. The hitherto explanatory mechanism for this reduced sensitivity was the presence of non-synonymous point mutations in the target gene Pfcyp51, encoding the sterol 14α-demethylase enzyme. Here, we demonstrate a second mechanism involved in DMI sensitivity of P. fijiensis. We identified a 19-bp element in the wild-type (wt) Pfcyp51 promoter that concatenates in strains with reduced DMI sensitivity. A polymerase chain reaction (PCR) assay identified up to six Pfcyp51 promoter repeats in four field populations of P. fijiensis in Costa Rica. We used transformation experiments to swap the wt promoter of a sensitive field isolate with a promoter from a strain with reduced DMI sensitivity that comprised multiple insertions. Comparative in vivo phenotyping showed a functional and proportional up-regulation of Pfcyp51, which consequently decreased DMI sensitivity. Our data demonstrate that point mutations in the Pfcyp51 coding domain, as well as promoter inserts, contribute to the reduced DMI sensitivity of P. fijiensis. These results provide new insights into the importance of the appropriate use of DMIs and the need for the discovery of new molecules for black Sigatoka management. © 2017 The Authors. Molecular Plant Pathology published by British Society for Plant Pathology and John Wiley & Sons Ltd.

  10. Occurrence, characterization and management of fruit rot of immature cucumber fruits under arid greenhouse conditions

    Directory of Open Access Journals (Sweden)

    ABDULLAH M AL-SADI

    2012-01-01

    Full Text Available A study was undertaken to characterize and manage pathogens associated with fruit rot of immature cucumber fruits in greenhouses in Oman. A survey over 5 growing seasons from 2008 to 2010 in 99 different greenhouses in Oman showed that the disease is prevalent in 91 (92% greenhouses and results in losses of 10 to 60% (avg. 33% of immature fruits per plant. Incidence of the disease was not found to be affected by growing seasons, which could be attributed to the limited fluctuations in ambient temperatures in greenhouses. Isolations from diseased cucumber fruits yielded Alternaria alternata (isolation frequency = 52%, Fusarium equiseti (40%, Cladosporium tenuissium (27%, Botrytis cinerea (6%, Fusarium solani (6%, Corynespora cassiicola (3%, Aspergillus spp. (2%, Curvularia sp. (1% and Bipolaris sp. (1%. With the exception of Curvularia and Bipolaris species, all other fungi were pathogenic on cucumber fruits, with Fusarium equiseti being the most aggressive, followed by Corynespora cassiicola, Botrytis cinerea and Alternaria alternata. Cladosporium and Aspergillus spp. were found to be weakly pathogenic. Comparing the efficacy of foliar and soil applications of carbendazim fungicide on fruit rot of cucumber showed that foliar applications significantly reduced fruit rot and increased cucumber yield when compared to soil application or to control (P < 0.01. This appears to be the first report of the association of Corynespora cassiicola and Fusarium equiseti with fruit rot of immature greenhouse cucumbers. This is also the first report in Oman for the association of Cladosporium tenuissimum with fruit rot of immature cucumbers. Findings are discussed in terms of factors affecting disease control in greenhouses using carbendazim.

  11. Establishment of Orchards with Black Polyethylene Film Mulching: Effect on Nematode and Fungal Pathogens, Water Conservation, and Tree Growth

    Science.gov (United States)

    Duncan, R. A.; Stapleton, J. J.; McKenry, M. V.

    1992-01-01

    Placement of a 3-m-wide, black, polyethylene film mulch down rows of peach (Prunus persica 'Red Haven' on 'Lovell' rootstock) and almond (Prunus dulcis 'Nonpareil' on 'Lovell') trees in the San Joaquin Valley of California resulted in irrigation water conservation of 75%, higher soil temperature in the surface 30 cm, a tendency toward greater root mass, elimination of weeds, and a greater abundance of Meloidogyne incognita second-stage juveniles in soil but reduced root galling when compared to the nonmulched control. Population levels of Pratylenchus hexincisus, a nematode found within tree roots, were reduced by mulching, as were those of Tylenchulus semipenetrans, which survived on old grape roots remaining from a previously planted vineyard, and Paratrichodorus minor, which probably fed on roots of various weed species growing in the nonmulched soil. Populations of Pythium ultimum were not significantly changed, probably also due to the biological refuge of the old grape roots and moderate soil heating level. Trunk diameters of peach trees were increased by mulching, but those of almond trees were reduced by the treatment. Leaf petiole analysis indicated that concentrations of mineral nutrients were inconsistent, except for a significant increase in Ca in both tree species. PMID:19283045

  12. Combating a Global Threat to a Clonal Crop: Banana Black Sigatoka Pathogen Pseudocercospora fijiensis (Synonym Mycosphaerella fijiensis Genomes Reveal Clues for Disease Control.

    Directory of Open Access Journals (Sweden)

    Rafael E Arango Isaza

    2016-08-01

    Full Text Available Black Sigatoka or black leaf streak disease, caused by the Dothideomycete fungus Pseudocercospora fijiensis (previously: Mycosphaerella fijiensis, is the most significant foliar disease of banana worldwide. Due to the lack of effective host resistance, management of this disease requires frequent fungicide applications, which greatly increase the economic and environmental costs to produce banana. Weekly applications in most banana plantations lead to rapid evolution of fungicide-resistant strains within populations causing disease-control failures throughout the world. Given its extremely high economic importance, two strains of P. fijiensis were sequenced and assembled with the aid of a new genetic linkage map. The 74-Mb genome of P. fijiensis is massively expanded by LTR retrotransposons, making it the largest genome within the Dothideomycetes. Melting-curve assays suggest that the genomes of two closely related members of the Sigatoka disease complex, P. eumusae and P. musae, also are expanded. Electrophoretic karyotyping and analyses of molecular markers in P. fijiensis field populations showed chromosome-length polymorphisms and high genetic diversity. Genetic differentiation was also detected using neutral markers, suggesting strong selection with limited gene flow at the studied geographic scale. Frequencies of fungicide resistance in fungicide-treated plantations were much higher than those in untreated wild-type P. fijiensis populations. A homologue of the Cladosporium fulvum Avr4 effector, PfAvr4, was identified in the P. fijiensis genome. Infiltration of the purified PfAVR4 protein into leaves of the resistant banana variety Calcutta 4 resulted in a hypersensitive-like response. This result suggests that Calcutta 4 could carry an unknown resistance gene recognizing PfAVR4. Besides adding to our understanding of the overall Dothideomycete genome structures, the P. fijiensis genome will aid in developing fungicide treatment schedules

  13. Combating a Global Threat to a Clonal Crop: Banana Black Sigatoka Pathogen Pseudocercospora fijiensis (Synonym Mycosphaerella fijiensis) Genomes Reveal Clues for Disease Control.

    Science.gov (United States)

    Arango Isaza, Rafael E; Diaz-Trujillo, Caucasella; Dhillon, Braham; Aerts, Andrea; Carlier, Jean; Crane, Charles F; V de Jong, Tristan; de Vries, Ineke; Dietrich, Robert; Farmer, Andrew D; Fortes Fereira, Claudia; Garcia, Suzana; Guzman, Mauricio; Hamelin, Richard C; Lindquist, Erika A; Mehrabi, Rahim; Quiros, Olman; Schmutz, Jeremy; Shapiro, Harris; Reynolds, Elizabeth; Scalliet, Gabriel; Souza, Manoel; Stergiopoulos, Ioannis; Van der Lee, Theo A J; De Wit, Pierre J G M; Zapater, Marie-Françoise; Zwiers, Lute-Harm; Grigoriev, Igor V; Goodwin, Stephen B; Kema, Gert H J

    2016-08-01

    Black Sigatoka or black leaf streak disease, caused by the Dothideomycete fungus Pseudocercospora fijiensis (previously: Mycosphaerella fijiensis), is the most significant foliar disease of banana worldwide. Due to the lack of effective host resistance, management of this disease requires frequent fungicide applications, which greatly increase the economic and environmental costs to produce banana. Weekly applications in most banana plantations lead to rapid evolution of fungicide-resistant strains within populations causing disease-control failures throughout the world. Given its extremely high economic importance, two strains of P. fijiensis were sequenced and assembled with the aid of a new genetic linkage map. The 74-Mb genome of P. fijiensis is massively expanded by LTR retrotransposons, making it the largest genome within the Dothideomycetes. Melting-curve assays suggest that the genomes of two closely related members of the Sigatoka disease complex, P. eumusae and P. musae, also are expanded. Electrophoretic karyotyping and analyses of molecular markers in P. fijiensis field populations showed chromosome-length polymorphisms and high genetic diversity. Genetic differentiation was also detected using neutral markers, suggesting strong selection with limited gene flow at the studied geographic scale. Frequencies of fungicide resistance in fungicide-treated plantations were much higher than those in untreated wild-type P. fijiensis populations. A homologue of the Cladosporium fulvum Avr4 effector, PfAvr4, was identified in the P. fijiensis genome. Infiltration of the purified PfAVR4 protein into leaves of the resistant banana variety Calcutta 4 resulted in a hypersensitive-like response. This result suggests that Calcutta 4 could carry an unknown resistance gene recognizing PfAVR4. Besides adding to our understanding of the overall Dothideomycete genome structures, the P. fijiensis genome will aid in developing fungicide treatment schedules to combat this

  14. Interactions between cranberries and fungi: the proposed function of organic acids in virulence suppression of fruit rot fungi

    Directory of Open Access Journals (Sweden)

    Mariusz eTadych

    2015-08-01

    Full Text Available Cranberry fruit are a rich source of bioactive compounds that may function as constitutive or inducible barriers against rot-inducing fungi. The content and composition of these compounds change as the season progresses. Several necrotrophic fungi cause cranberry fruit rot disease complex. These fungi remain mostly asymptomatic until the fruit begins to mature in late August. Temporal fluctuations and quantitative differences in selected organic acid profiles between fruit of six cranberry genotypes during the growing season were observed. The concentration of benzoic acid in fruit increased while quinic acid decreased throughout fruit development. In general, more rot-resistant genotypes showed higher levels of benzoic acid early in fruit development and more gradual decline in quinic acid levels than that observed in the more rot-susceptible genotypes. We evaluated antifungal activities of selected cranberry constituents and found that most bioactive compounds either had no effects or stimulated growth or reactive oxygen species (ROS secretion of four tested cranberry fruit rot fungi, while benzoic acid and quinic acid reduced growth and suppressed secretion of ROS by these fungi. We propose that variation in the levels of ROS suppressive compounds, such as benzoic and quinic acids, may influence virulence by the fruit rot fungi. Selection for crops that maintain high levels of virulence suppressive compounds could yield new disease resistant varieties. This could represent a new strategy for control of disease caused by necrotrophic pathogens that exhibit a latent or endophytic phase.

  15. Survey of Basal Stem Rot Disease on Oil Palms (Elaeis guineensis Jacq.) in Kebun Bukit Kijang,North Sumatera, Indonesia

    Science.gov (United States)

    Lisnawita; Hanum, H.; Tantawi, A. R.

    2016-08-01

    Basal stem rot disease caused by Ganoderma sp. is a significant disease on oil palm plantations in Indonesia, especially in North Sumatera. Currently, the pathogen does not only attack the plants that have produced (old plants) but also attacks the plants that have not produced in the first generation yet. A survey of the distribution of the basal stem rot disease in the plantation of the community has been completed in order to illustrate the distribution and the incidence of the basal stem rot disease in 5 locations of the oil palm plantation of the community in Desa Bukit Kijang, Region of Asahan, North Sumatera, Indonesia. From the research, it is revealed that the basal stem rot disease has spread to all of the observed locations with the level of disease incidence between 0.71% in Kebun Bukit Kijang 3 to 50% in the 17 years old oil palm in Kebun Bukit Kijang 4 and Bukit Kijang 5. The observable symptoms of the basal stem rot disease are chlorotic leaves, the appearance of fruiting body, collapsed plants, and the existence of holes on the basal stem. The incidence of basal stem rot disease is higher on land due to a high sand content (>50%).

  16. Pseudomonads associated with midrib rot and soft rot of butterhead lettuce and endive.

    Science.gov (United States)

    Cottyn, B; Vanhouteghem, K; Heyrman, J; Bleyaert, P; Van Vaerenbergh, J; De Vos, P; Höfte, M; Maes, M

    2005-01-01

    During the past ten years, bacterial soft rot and midrib rot of glasshouse-grown butterhead lettuce (Lactuca sativa L. var. capitata) and field-grown endive (Cichorium endivia L.) has become increasingly common in the region of Flanders, Belgium. Severe losses and reduced market quality caused by bacterial rot represent an important economical threat for the production sector. Symptoms of midrib rot are a brownish rot along the midrib of one or more inner leaves, often accompanied by soft rot of the leaf blade. Twenty-five symptomatic lettuce and endive samples were collected from commercial growers at different locations in Flanders. Isolations of dominant bacterial colony types on dilution plates from macerated diseased tissue extracts yielded 282 isolates. All isolates were characterized by colony morphology and fluorescence on pseudomonas agar F medium, oxidase reaction, and soft rot ability on detached chicory leaves. Whole-cell fatty acid methyl esters profile analyses identified the majority of isolates (85%) as belonging to the Gammaproteobacteria, which included members of the family Enterobacteriaceae (14%) and of the genera Pseudomonas (73%), Stenotrophomonas (9%), and Acinetobacter (3%). Predominant bacteria were a diverse group of fluorescent Pseudomonas species. They were further differentiated based on the non-host hypersensitive reaction on tobacco and the ability to rot potato slices into 4 phenotypic groups: HR-/P- (57 isolates), HR-/P+ (54 isolates), HR+/P (16 isolates) and HR+/P+ (35 isolates). Artificial inoculation of suspensions of HR-, pectolytic fluorescent pseudomonads in the leaf midrib of lettuce plants produced various symptoms of soft rot, but they did not readily cause symptoms upon spray inoculation. Fluorescent pseudomonads with phenotype HR+ were consistently isolated from typical dark midrib rot symptoms, and selected isolates reproduced the typical midrib rot symptoms when spray-inoculated onto healthy lettuce plants.

  17. Moniliophthora roreri, causal agent of cacao frosty pod rot.

    Science.gov (United States)

    Bailey, Bryan A; Evans, Harry C; Phillips-Mora, Wilbert; Ali, Shahin S; Meinhardt, Lyndel W

    2017-12-01

    Taxonomy: Moniliophthora roreri (Cif.) H.C. Evans et al. ; Phylum Basidiomycota; Class Agaricomycetes; Order Agaricales; Family Marasmiaceae; Genus Moniliophthora. Biology: Moniliophthora roreri attacks Theobroma and Herrania species causing frosty pod rot. Theobroma cacao (cacao) is the host of major economic concern. Moniliophthora roreri is a hemibiotroph with a long biotrophic phase (45-90 days). Spore masses, of apparent asexual origin, are produced on the pod surface after initiation of the necrotrophic phase. Spores are spread by wind, rain and human activity. Symptoms of the biotrophic phase can include necrotic flecks and, in some cases, pod malformation, but pods otherwise remain asymptomatic. Relationship to Moniliophthora perniciosa: Moniliophthora roreri and Moniliophthora perniciosa, causal agent of witches' broom disease of cacao, are closely related. Their genomes are similar, including many of the genes they carry which are considered to be important in the disease process. Moniliophthora perniciosa, also a hemibiotroph, has a typical basidiomycete lifestyle and morphology, forming clamp connections and producing mushrooms. Basidiospores infect meristematic tissues including flower cushions, stem tips and pods. Moniliophthora roreri does not form clamp connections or mushrooms and infects pods only. Both pathogens are limited to the Western Hemisphere and are a threat to cacao production around the world. Agronomic importance: Disease losses caused by frosty pod rot can reach 90% and result in field abandonment. Moniliophthora roreri remains in the invasive phase in the Western Hemisphere, not having reached Brazil, some islands within the Caribbean and a few specific regions within otherwise invaded countries. The disease can be managed by a combination of cultural (for example, maintenance of tree height and removal of infected pods) and chemical methods. These methods benefit from regional application, but can be cost prohibitive. Breeding for

  18. Singlet molecular oxygen generation by light-activated DHN-melanin of the fungal pathogen Mycosphaerella fijiensis in black Sigatoka disease of bananas.

    Directory of Open Access Journals (Sweden)

    Miguel J Beltrán-García

    Full Text Available In pathogenic fungi, melanin contributes to virulence, allowing tissue invasion and inactivation of the plant defence system, but has never been implicated as a factor for host cell death, or as a light-activated phytotoxin. Our research shows that melanin synthesized by the fungal banana pathogen Mycosphaerella fijiensis acts as a virulence factor through the photogeneration of singlet molecular oxygen O2 (1Δg. Using analytical tools, including elemental analysis, ultraviolet/infrared absorption spectrophometry and MALDI-TOF mass spectrometry analysis, we characterized both pigment content in mycelia and secreted to the culture media as 1,8-dihydroxynaphthalene (DHN-melanin type compound. This is sole melanin-type in M. fijiensis. Isolated melanins irradiated with a Nd:YAG laser at 532 nm produced monomol light emission at 1270 nm, confirming generation of O2 (1Δg, a highly reactive oxygen specie (ROS that causes cellular death by reacting with all cellular macromolecules. Intermediary polyketides accumulated in culture media by using tricyclazole and pyroquilon (two inhibitors of DHN-melanin synthesis were identified by ESI-HPLC-MS/MS. Additionally, irradiation at 532 nm of that mixture of compounds and whole melanized mycelium also generated O2 (1Δg. A pigmented-strain generated more O2 (1Δg than a strain with low melanin content. Banana leaves of cultivar Cavendish, naturally infected with different stages of black Sigatoka disease, were collected from field. Direct staining of the naturally infected leaf tissues showed the presence of melanin that was positively correlated to the disease stage. We also found hydrogen peroxide (H2O2 but we cannot distinguish the source. Our results suggest that O2 (1Δg photogenerated by DHN-melanin may be involved in the destructive effects of Mycosphaerella fijiensis on banana leaf tissues. Further studies are needed to fully evaluate contributions of melanin-mediated ROS to microbial pathogenesis.

  19. Singlet molecular oxygen generation by light-activated DHN-melanin of the fungal pathogen Mycosphaerella fijiensis in black Sigatoka disease of bananas.

    Science.gov (United States)

    Beltrán-García, Miguel J; Prado, Fernanda M; Oliveira, Marilene S; Ortiz-Mendoza, David; Scalfo, Alexsandra C; Pessoa, Adalberto; Medeiros, Marisa H G; White, James F; Di Mascio, Paolo

    2014-01-01

    In pathogenic fungi, melanin contributes to virulence, allowing tissue invasion and inactivation of the plant defence system, but has never been implicated as a factor for host cell death, or as a light-activated phytotoxin. Our research shows that melanin synthesized by the fungal banana pathogen Mycosphaerella fijiensis acts as a virulence factor through the photogeneration of singlet molecular oxygen O2 (1Δg). Using analytical tools, including elemental analysis, ultraviolet/infrared absorption spectrophometry and MALDI-TOF mass spectrometry analysis, we characterized both pigment content in mycelia and secreted to the culture media as 1,8-dihydroxynaphthalene (DHN)-melanin type compound. This is sole melanin-type in M. fijiensis. Isolated melanins irradiated with a Nd:YAG laser at 532 nm produced monomol light emission at 1270 nm, confirming generation of O2 (1Δg), a highly reactive oxygen specie (ROS) that causes cellular death by reacting with all cellular macromolecules. Intermediary polyketides accumulated in culture media by using tricyclazole and pyroquilon (two inhibitors of DHN-melanin synthesis) were identified by ESI-HPLC-MS/MS. Additionally, irradiation at 532 nm of that mixture of compounds and whole melanized mycelium also generated O2 (1Δg). A pigmented-strain generated more O2 (1Δg) than a strain with low melanin content. Banana leaves of cultivar Cavendish, naturally infected with different stages of black Sigatoka disease, were collected from field. Direct staining of the naturally infected leaf tissues showed the presence of melanin that was positively correlated to the disease stage. We also found hydrogen peroxide (H2O2) but we cannot distinguish the source. Our results suggest that O2 (1Δg) photogenerated by DHN-melanin may be involved in the destructive effects of Mycosphaerella fijiensis on banana leaf tissues. Further studies are needed to fully evaluate contributions of melanin-mediated ROS to microbial pathogenesis.

  20. Association of Enterobacter cloacae and other bacteria with onion bulb rot in the Columbia Basin of Washington and Oregon, USA

    Science.gov (United States)

    Approximately 1.6 million metric tons of onion bulbs are produced annually in the Pacific Northwest USA. Bulb decay can be a major problem and is caused by a variety of plant pathogens. Onion bulbs exhibiting symptoms of bacterial rot were sampled to determine the causal agents. Enterobacter cloacae...

  1. Fungicide rotation schemes for managing Phytophthora fruit rot of watermelon across Southeastern United States (NC, SC, and GA)

    Science.gov (United States)

    Phytophthora capsici has been documented as a pathogen on a wide variety of vegetable crops in the family Solanaceae, Cucurbitaceae, Fabaceae, and plants belonging to 23 other families. Phytophthora fruit rot of watermelons caused by P. capsici is particularly severe in southeastern U.S where optima...

  2. Effects of compost amendment and the biocontrol agent Clonostachys rosea on the development of charcoal rot (Macrophomina phaseolina) on cowpea

    NARCIS (Netherlands)

    Ndiaye, M.; Termorshuizen, A.J.; Bruggen, van A.H.C.

    2010-01-01

    Macrophomina phaseolina is a destructive pathogen causing charcoal rot of cowpea and other crops in the semi- arid areas of the Sahel (north-west Africa). Chemical management is not feasible in conditions of subsistence farming, and the plurivorous nature of the fungus limits the effectiveness of

  3. Temporal occurrence and niche preferences of Phytophthora species causing brown rot of citrus in the Central Valley of California

    Science.gov (United States)

    Brown rot of citrus fruits is caused by several species of Phytophthora and is currently of serious concern for the California citrus industry. Two species, P. syringae and P. hibernalis, are quarantine pathogens in China, a major export market for California citrus. To maintain trade and estimate t...

  4. Pectobacterium carotovorum subsp. carotovorum – the Causal Agent of Calla Soft Rot in Serbia and Montenegro

    Directory of Open Access Journals (Sweden)

    Milan Ivanović

    2009-01-01

    Full Text Available Bacterial strains were isolated from above- and underground parts of diseased calla plants originating from different localities in Serbia and one locality in Montenegro. They were characterized by studying their pathogenic, cultural, biochemical and physiologicalcharacteristics. All investigated strains caused soft rot of calla leaf stalks, potato slices and aloe leaves, and induced hypersensitive reaction on tobacco. Bacteriological properties of the strains indicated that symptoms on calla plants were caused by Gram-negative, nonfluorescent, oxidase negative, catalase positive and facultatively anaerobic bacterium belonging to the genus Pectobacterium. The investigated strains grew at 37ºC and in 5% NaCl, utilised lactose and trechalose, and produced neither indol nor lecitinase. These results, as well as the characteristic growth on Logan’s differential medium indicated that soft rot of tuber and stem base of calla plants was caused by Pectobacterium carotovorum subsp. carotovorum. This is the first report of this pathogen affecting calla plants in Serbia.

  5. Changes in cation concentrations in red spruce wood decayed by brown rot and white rot fungi

    Science.gov (United States)

    A. Ostrofsky; J. Jellison; K.T. Smith; W.C. Shortle

    1997-01-01

    Red spruce (Picea rubens Sarg.) wood blocks were incubated in modified soil block jars and inoculated with one of nine white rot or brown rot basidiomycetes. Concentrations of calcium, magnesium, potassium, iron, and aluminum were determined using inductively coupled plasma emission spectroscopy in wood incubated 0, 1.5, 4, and 8 months after...

  6. Comparative and population genomic landscape of Phellinus noxius: A hypervariable fungus causing root rot in trees.

    Science.gov (United States)

    Chung, Chia-Lin; Lee, Tracy J; Akiba, Mitsuteru; Lee, Hsin-Han; Kuo, Tzu-Hao; Liu, Dang; Ke, Huei-Mien; Yokoi, Toshiro; Roa, Marylette B; Lu, Mei-Yeh J; Chang, Ya-Yun; Ann, Pao-Jen; Tsai, Jyh-Nong; Chen, Chien-Yu; Tzean, Shean-Shong; Ota, Yuko; Hattori, Tsutomu; Sahashi, Norio; Liou, Ruey-Fen; Kikuchi, Taisei; Tsai, Isheng J

    2017-11-01

    The order Hymenochaetales of white rot fungi contain some of the most aggressive wood decayers causing tree deaths around the world. Despite their ecological importance and the impact of diseases they cause, little is known about the evolution and transmission patterns of these pathogens. Here, we sequenced and undertook comparative genomic analyses of Hymenochaetales genomes using brown root rot fungus Phellinus noxius, wood-decomposing fungus Phellinus lamaensis, laminated root rot fungus Phellinus sulphurascens and trunk pathogen Porodaedalea pini. Many gene families of lignin-degrading enzymes were identified from these fungi, reflecting their ability as white rot fungi. Comparing against distant fungi highlighted the expansion of 1,3-beta-glucan synthases in P. noxius, which may account for its fast-growing attribute. We identified 13 linkage groups conserved within Agaricomycetes, suggesting the evolution of stable karyotypes. We determined that P. noxius has a bipolar heterothallic mating system, with unusual highly expanded ~60 kb A locus as a result of accumulating gene transposition. We investigated the population genomics of 60 P. noxius isolates across multiple islands of the Asia Pacific region. Whole-genome sequencing showed this multinucleate species contains abundant poly-allelic single nucleotide polymorphisms with atypical allele frequencies. Different patterns of intra-isolate polymorphism reflect mono-/heterokaryotic states which are both prevalent in nature. We have shown two genetically separated lineages with one spanning across many islands despite the geographical barriers. Both populations possess extraordinary genetic diversity and show contrasting evolutionary scenarios. These results provide a framework to further investigate the genetic basis underlying the fitness and virulence of white rot fungi. © 2017 John Wiley & Sons Ltd.

  7. Combating a Global Threat to a Clonal Crop : Banana Black Sigatoka Pathogen Pseudocercospora fijiensis (Synonym Mycosphaerella fijiensis) Genomes Reveal Clues for Disease Control

    NARCIS (Netherlands)

    Arango Isaza, Rafael E.; Diaz-Trujillo, Caucasella; Dhillon, Braham; Aerts, Andrea; Carlier, Jean; Crane, Charles F.; de Jong, Tristan V.; de Vries, Ineke; Dietrich, Robert; Farmer, Andrew D.; Fereira, Claudia Fortes; Garcia, Suzana; Guzman, Mauricio; Hamelin, Richard C.; Lindquist, Erika A.; Mehrabi, Rahim; Quiros, Olman; Schmutz, Jeremy; Shapiro, Harris; Reynolds, Elizabeth; Scalliet, Gabriel; Souza, Manoel; Stergiopoulos, Ioannis; Van der Lee, Theo A. J.; De Wit, Pierre J. G. M.; Zapater, Marie-Francoise; Zwiers, Lute-Harm; Grigoriev, Igor V.; Goodwin, Stephen B.; Kema, Gert H. J.

    2016-01-01

    Black Sigatoka or black leaf streak disease, caused by the Dothideomycete fungus Pseudocercospora fijiensis (previously: Mycosphaerella fijiensis), is the most significant foliar disease of banana worldwide. Due to the lack of effective host resistance, management of this disease requires frequent

  8. Foot Rot of Ulluco Caused by Pythium aphanidermatum

    OpenAIRE

    Keisuke, TOMIOKA; Toyozo, SATO; Tateo, NAKANISHI; National Agricultural Research Center for Western Region; National Institute of Agrobiological Sciences; National Agricultural Research Center for Western Region

    2002-01-01

    Severe rot of stem bases caused by Pythium aphanidermatum was found on ulluco (Ullucus tuberosus) grown in Kagawa Prefecture, Japan, in September 1999. The name "foot rot of ulluco" is proposed for this new disease.

  9. From the investigations on Armillaria root rot occurrence in young Scots pine stands in Zielonka Forest District

    Directory of Open Access Journals (Sweden)

    Wojciech Szewczyk

    2013-12-01

    Full Text Available Armillaria root rot, one of the most dangerous diseases in our forests, is caused in Poland mainly by Armillaria ostoyae, especially severe in young Scots pine stands, established after broadleaved stands or with participation of broadleaved species. In Forest District Zielonka young stands are severly affected by Armillaria root rot. Only one species, A.ostoyae, was found in the young (8-14 yrs Scots pine stands, despite the presence of other Armillaria species in the district. The pathogen's frequent occurrence may be due, inter alia, to favouring environmental factors.

  10. From Glacier to Sauna: RNA-Seq of the Human Pathogen Black Fungus Exophiala dermatitidis under Varying Temperature Conditions Exhibits Common and Novel Fungal Response.

    Directory of Open Access Journals (Sweden)

    Barbara Blasi

    Full Text Available Exophiala dermatitidis (Wangiella dermatitidis belongs to the group of the so-called black yeasts. Thanks in part to its thick and strongly melanized cell walls, E. dermatitidis is extremely tolerant to various kinds of stress, including extreme pH, temperature and desiccation. E. dermatitidis is also the agent responsible for various severe illnesses in humans, such as pneumonia and keratitis, and might lead to fatal brain infections. Due to its association with the human environment, its poly-extremophilic lifestyle and its pathogenicity in humans, E. dermatitidis has become an important model organism. In this study we present the functional analysis of the transcriptional response of the fungus at 1°C and 45°C, in comparison with that at 37°C, for two different exposition times, i.e. 1 hour and 1 week. At 1°C, E. dermatitidis uses a large repertoire of tools to acclimatize, such as lipid membrane fluidization, trehalose production or cytoskeleton rearrangement, which allows the fungus to remain metabolically active. At 45°C, the fungus drifts into a replicative state and increases the activity of the Golgi apparatus. As a novel finding, our study provides evidence that, apart from the protein coding genes, non-coding RNAs, circular RNAs as well as fusion-transcripts are differentially regulated and that the function of the fusion-transcripts can be related to the corresponding temperature condition. This work establishes that E. dermatitidis adapts to its environment by modulating coding and non-coding gene transcription levels and through the regulation of chimeric and circular RNAs.

  11. The Use of Antioxidants to Control Root Rot and Wilt Diseases of Pepper

    Directory of Open Access Journals (Sweden)

    Montaser Fawzy ABDEL-MONAIM

    2010-06-01

    Full Text Available Ten isolates of Fusarium spp were isolated from pepper plants collected from different locations in New Valley Governorate, Egypt. Fusarium solani isolate FP2 and F. oxysporum isolate FP4 were highly pathogenic isolates but the other isolates moderate or less pathogenic to pepper plants (cv. Anaheim-M. The four antioxidant compounds (coumaric acid, citric acid, propylgalate and salicylic acid each at 100 and 200 ppm were evaluated for their in vitro and in vivo agonist to Fusarium pathogenic isolates caused root rot and wilt diseases in pepper plants. All tested antioxidant compounds reduced damping-off, root rot/wilt and area under root rot/wilt progress curve when used as seed soaking, seedling soaking, and soil drench especially at 200 ppm under greenhouse and field conditions compared with untreated plants. All chemicals increased fresh and dry weight of seedling grown in soil drenching or seed treatment with any antioxidants. At the same time, all tested chemicals significantly increase plant growth parameters i.e plant length, plant branching, and total yield per plant in case of seedling soaking or soil drench. In general, propylgalate at 200 ppm was more efficient in reducing infection with damping-off, root rot and wilt diseases as well as increasing the seedling fresh weight, dry weight, plant length, plant branching, number of pod plant-1 and pod yield plant-1. On the other hand, all tested antioxidants had less or no effect on mycelial dry weight and mycelial leaner growth. On the contrary, all chemicals much reduced spore formation in both Fusarium species at 100 or 200 ppm and the inhibitory effect of antioxidants increased with increasing their concentrations.

  12. Transcriptome of an Armillaria root disease pathogen reveals candidate genes involved in host substrate utilization at the host­-pathogen interface

    Science.gov (United States)

    A. L. Ross-Davis; J. E. Stewart; J. W. Hanna; M.-S. Kim; B. J. Knaus; R. Cronn; H. Rai; B. A. Richardson; G. I. McDonald; N. B. Klopfenstein

    2013-01-01

    Armillaria species display diverse ecological roles ranging from beneficial saprobe to virulent pathogen. Armillaria solidipes (formerly A. ostoyae), a causal agent of Armillaria root disease, is a virulent primary pathogen with a broad host range of woody plants across the Northern Hemisphere. This white-rot pathogen grows between trees as rhizomorphs and attacks...

  13. Salmonella enterica suppresses Pectobacterium carotovorum subsp. carotovorum population and soft rot progression by acidifying the microaerophilic environment.

    Science.gov (United States)

    Kwan, Grace; Charkowski, Amy O; Barak, Jeri D

    2013-02-12

    Although enteric human pathogens are usually studied in the context of their animal hosts, a significant portion of their life cycle occurs on plants. Plant disease alters the phyllosphere, leading to enhanced growth of human pathogens; however, the impact of human pathogens on phytopathogen biology and plant health is largely unknown. To characterize the interaction between human pathogens and phytobacterial pathogens in the phyllosphere, we examined the interactions between Pectobacterium carotovorum subsp. carotovorum and Salmonella enterica or Escherichia coli O157:H7 with regard to bacterial populations, soft rot progression, and changes in local pH. The presence of P. carotovorum subsp. carotovorum enhanced the growth of both S. enterica and E. coli O157:H7 on leaves. However, in a microaerophilic environment, S. enterica reduced P. carotovorum subsp. carotovorum populations and soft rot progression by moderating local environmental pH. Reduced soft rot was not due to S. enterica proteolytic activity. Limitations on P. carotovorum subsp. carotovorum growth, disease progression, and pH elevation were not observed on leaves coinoculated with E. coli O157:H7 or when leaves were coinoculated with S. enterica in an aerobic environment. S. enterica also severely undermined the relationship between the phytobacterial population and disease progression of a P. carotovorum subsp. carotovorum budB mutant defective in the 2,3-butanediol pathway for acid neutralization. Our results show that S. enterica and E. coli O157:H7 interact differently with the enteric phytobacterial pathogen P. carotovorum subsp. carotovorum. S. enterica inhibition of soft rot progression may conceal a rapidly growing human pathogen population. Whereas soft rotted produce can alert consumers to the possibility of food-borne pathogens, healthy-looking produce may entice consumption of contaminated vegetables. Salmonella enterica and Escherichia coli O157:H7 may use plants to move between animal

  14. Response of the Andean diversity panel to root rot in a root rot nursery in Puerto Rico

    Science.gov (United States)

    The Andean Diversity Panel (ADP) was evaluated under low-fertility and root rot conditions in two trials conducted in 2013 and 2015 in Isabela, Puerto Rico. About 246 ADP lines were evaluated in the root rot nursery with root rot and stem diseases caused predominantly by Fusarium solani, which cause...

  15. Assessment of Injuries Caused by Anastrepha fraterculus (Wied.) (Diptera: Tephritidae) on the Incidence of Bunch Rot Diseases in Table Grape.

    Science.gov (United States)

    Machota, R; Bortoli, L C; Cavalcanti, F R; Botton, M; Grützmacher, A D

    2016-08-01

    Anastrepha fraterculus (Wied.) is the main insect pest of table grapes (Vitis vinifera) in the Southern Region of Brazil. In this study, we aimed to investigate the effect of fruit puncturing by adult females and larval infestation by A. fraterculus on the occurrence of bunch rot disease in the grape (cultivar "Itália") by evaluating grapes (a) punctured for oviposition by females of A. fraterculus, sterilized in laboratory with novaluron (40 mg L(-1)) and further spray-inoculated separately with Botrytis cinerea (1 × 10(6) conidia mL(-1)), Glomerella cingulata (1 × 10(6) conidia mL(-1)), and bacteria and yeast that cause sour rot (1 × 10(5) cells mL(-1)), (b) grapes punctured for oviposition by non-sterilized females with pathogen spraying, (c) grapes with mechanical wounds and pathogen spraying, (d) grapes with no wounds and with pathogen spraying, (e) grapes punctured for oviposition by A. fraterculus chemically sterilized in laboratory with novaluron, (f) grapes punctured for oviposition by A. fraterculus non-sterilized in laboratory with novaluron, (g) grapes with mechanical wounds, and (h) grapes with no sterilization or pathogen spraying. Our data indicated that the mechanical and oviposition wounds caused by A. fraterculus increased the percentage of grapes infected by B. cinerea, G. cingulata, and microorganisms of acid rot. The grape puncturing by A. fraterculus and the mechanical wound allows the penetration of B. cinerea and microorganisms leading to acid rot. We conclude that the fruit fly A. fraterculus may facilitate phytopathogens penetration leading to bunch rots in the table grape Itália.

  16. response of cabbage cultivars to black rot infection

    African Journals Online (AJOL)

    using 10 selected commercial cabbage cultivar(s). Stability was assessed via joint regression analysis and superiority analysis. The result indicated that cultivars Tenacity, Gideon and Gloria expressed average stability with high yield and adequate resistance Cultivar Tenacity was selected for its greater mean yield and ...

  17. antagonistic effect of native bacillus isolates against black root rot

    African Journals Online (AJOL)

    ACSS

    Postharvest biological control of anthracnose. (Colletotrichum gloeosporioides) on mango. (Mangifera indica). Postharvest Biology and. Technology 50: 8-11. Young, F.E., Tupper, J. and Strominger, J.L. 1974. Autolysis of cell walls of Bacillus subtilis mechanism and possible relationship to competence. Journal of Biology ...

  18. Management of chili pepper root rot and wilt (caused by Phytophthora nicotianae by grafting onto resistant rootstock

    Directory of Open Access Journals (Sweden)

    Mourad SAADOUN

    2013-05-01

    Full Text Available Root rot and plant wilting caused by Phytophthora nicotianae is a severe disease of chili pepper (Capsicum annuum L. in open fields and under greenhouse production in Tunisia. Chili pepper grafting for disease manage- ment is attracting increased interest in recent years. Using the tube grafting technique, different compatible scion/rootstock combinations were obtained with the wild-type pepper SCM334 and the local chili pepper cultivars ‘Beldi’ and ‘Baker’. SCM334 was resistant to P. nicotianae, while the cultivars Beldi and Baker were susceptible. Plant inoculations were performed with P. nicotianae zoospores, and severity of root rot was rated 30 days post- inoculation using a 0 (healthy plant to 5 (dead plant severity score. On SCM334 rootstock and with ‘Beldi’ or ‘Baker’ scions, the intensity of root rot was very low (mean score 0.1–0.2 and plants were healthy. However, with Baker or Beldi rootstocks and SCM334 scions, root rot was severe (mean score 3.1–4.6, leading to high numbers of wilting and dead plants. This severe root rot was similar to that observed on non-grafted plants of ‘Baker’ and ‘Beldi’ inoculated with the pathogen. Under greenhouse conditions, measurements of agronomic characters indicated non-consistent improvement of these features on the scion cultivar when SCM334 was the rootstock. Since plant foliage is not attacked by this pathogen, these results show that susceptible chili pepper scions grafted onto SCM334 rootstocks could be used for root rot management and improvement of pepper yields in P. nicotianae infested soils.

  19. Selection of maize inbred lines and gene expression for resistance to ear rot.

    Science.gov (United States)

    Pereira, G S; Pinho, R G V; Pinho, E V R V; Pires, L P M; Bernardo Junior, L A Y; Pereira, J L A; Melo, M P

    2017-07-06

    In recent years, there has been a large incidence of fungi causing "ear rot" in maize in Brazil, the main fungus being Fusarium verticillioides. The most efficient and competitive alternative for control of this disease consists of using maize hybrids resistant to this pathogen. Thus, the aims of this study were to analyze the genetic variability of maize inbred lines in regard to resistance to ear rot to observe if there is a maternal effect to resistance to ear rot, to study genetic control of the traits evaluated in hybrids originating from inbred lines of the maize breeding program at the Agriculture Department of Universidade Federal de Lavras (Lavras, MG, Brazil), and characterize the gene expression pattern related to the plant defense mechanism against F. verticillioides. High genetic availability was observed for resistance to this disease among the inbred lines evaluated. Considering combined diallel analysis, it was observed that the mean square of general combining ability (GCA) was not significant for the characteristic under study. However, specific combining ability (SCA) was significant, which indicates the predominance of non-additive effects involved in control of the characteristic for the population evaluated. A maternal effect was not observed for the characteristic of ear rot resistance in this study. Inbred lines 22, 58, and 91 showed potential for use in breeding programs aiming at resistance to F. verticillioides. Only two genes, LOX8 and Hsp82, had a satisfactory result that was able to be related to a plant defense mechanism when there is ear rot infection, though expression of these genes was observed in only one susceptible genotype. Thus, the genes LOX8 and Hsp82 are potential molecular markers for selection of maize inbred lines resistant to F. verticillioides.

  20. Changes in Molecular Size Distribution of Cellulose during Attack by White Rot and Brown Rot Fungi

    OpenAIRE

    Kleman-Leyer, Karen; Agosin, Eduardo; Conner, Anthony H.; Kirk, T. Kent

    1992-01-01

    The kinetics of cotton cellulose depolymerization by the brown rot fungus Postia placenta and the white rot fungus Phanerochaete chrysosporium were investigated with solid-state cultures. The degree of polymerization (DP; the average number of glucosyl residues per cellulose molecule) of cellulose removed from soil-block cultures during degradation by P. placenta was first determined viscosimetrically. Changes in molecular size distribution of cellulose attacked by either fungus were then det...

  1. Potential worldwide distribution of Fusarium dry root rot in common beans based on the optimal environment for disease occurrence.

    Directory of Open Access Journals (Sweden)

    Renan Macedo

    Full Text Available Root rots are a constraint for staple food crops and a long-lasting food security problem worldwide. In common beans, yield losses originating from root damage are frequently attributed to dry root rot, a disease caused by the Fusarium solani species complex. The aim of this study was to model the current potential distribution of common bean dry root rot on a global scale and to project changes based on future expectations of climate change. Our approach used a spatial proxy of the field disease occurrence, instead of solely the pathogen distribution. We modeled the pathogen environmental requirements in locations where in-situ inoculum density seems ideal for disease manifestation. A dataset of 2,311 soil samples from commercial farms assessed from 2002 to 2015 allowed us to evaluate the environmental conditions associated with the pathogen's optimum inoculum density for disease occurrence, using a lower threshold as a spatial proxy. We encompassed not only the optimal conditions for disease occurrence but also the optimal pathogen's density required for host infection. An intermediate inoculum density of the pathogen was the best disease proxy, suggesting density-dependent mechanisms on host infection. We found a strong convergence on the environmental requirements of both the host and the disease development in tropical areas, mostly in Brazil, Central America, and African countries. Precipitation and temperature variables were important for explaining the disease occurrence (from 17.63% to 43.84%. Climate change will probably move the disease toward cooler regions, which in Brazil are more representative of small-scale farming, although an overall shrink in total area (from 48% to 49% in 2050 and 26% to 41% in 2070 was also predicted. Understanding pathogen distribution and disease risks in an evolutionary context will therefore support breeding for resistance programs and strategies for dry root rot management in common beans.

  2. Potential worldwide distribution of Fusarium dry root rot in common beans based on the optimal environment for disease occurrence.

    Science.gov (United States)

    Macedo, Renan; Sales, Lilian Patrícia; Yoshida, Fernanda; Silva-Abud, Lidianne Lemes; Lobo, Murillo

    2017-01-01

    Root rots are a constraint for staple food crops and a long-lasting food security problem worldwide. In common beans, yield losses originating from root damage are frequently attributed to dry root rot, a disease caused by the Fusarium solani species complex. The aim of this study was to model the current potential distribution of common bean dry root rot on a global scale and to project changes based on future expectations of climate change. Our approach used a spatial proxy of the field disease occurrence, instead of solely the pathogen distribution. We modeled the pathogen environmental requirements in locations where in-situ inoculum density seems ideal for disease manifestation. A dataset of 2,311 soil samples from commercial farms assessed from 2002 to 2015 allowed us to evaluate the environmental conditions associated with the pathogen's optimum inoculum density for disease occurrence, using a lower threshold as a spatial proxy. We encompassed not only the optimal conditions for disease occurrence but also the optimal pathogen's density required for host infection. An intermediate inoculum density of the pathogen was the best disease proxy, suggesting density-dependent mechanisms on host infection. We found a strong convergence on the environmental requirements of both the host and the disease development in tropical areas, mostly in Brazil, Central America, and African countries. Precipitation and temperature variables were important for explaining the disease occurrence (from 17.63% to 43.84%). Climate change will probably move the disease toward cooler regions, which in Brazil are more representative of small-scale farming, although an overall shrink in total area (from 48% to 49% in 2050 and 26% to 41% in 2070) was also predicted. Understanding pathogen distribution and disease risks in an evolutionary context will therefore support breeding for resistance programs and strategies for dry root rot management in common beans.

  3. Postharvest Rhizopus rot on sugar beet

    Science.gov (United States)

    Rhizopus species have been reported as a minor post-harvest rot on sugar beet, particularly under temperatures above 5 deg C. In 2010, Rhizopus was isolated from beets collected from Michigan storage piles in February at a low frequency. However, recent evidence from Michigan has found a high incide...

  4. Fungi associated with fruit crown rot in organic banana (Musa spp. L. in Piura, Peru

    Directory of Open Access Journals (Sweden)

    René Aguilar Anccota

    2013-05-01

    Full Text Available The department of Piura is the principal banana-producing zone in Peru, sharing 87% of exportations. In this zone, one of the most important postharvest diseases is crown rot. The economic loses attributed to this disease are estimated to be between 25 and 30% of organic bananas exported. The objective of this study was to identify the causal agents associated with this disease. Samples taken refrigerated fruit from the areas of Querecotillo, Salitral and Mallares were taken and selected after the fact. Thielaviopsis paradoxa, Lasiodiplodia theobromae, Colletotrichum musae and Fusarium verticilloides. In order to demonstrate the pathogenicity of the isolated species, inoculations were given in the area of the crown of the fruit on healthy bananas. These fungi caused symptoms of infection in different proportions, concluding that crown rot is a disease with a complex etiology.

  5. Gnomoniopsis castanea is the main agent of chestnut nut rot in Switzerland

    Directory of Open Access Journals (Sweden)

    Francesca G. DENNERT

    2015-09-01

    Full Text Available Nuts of sweet chestnut have been an important food source for the alpine population in Switzerland since the Middle Ages and are still valued today for the preparation of traditional food commodities. Nut quality is reduced by insect damage and by various pathogenic fungi. In the last few years, producers and consumers perceived an increase of brown nut rot; while the nut rot agent Gnomoniopsis castanea was reported locally in southern Switzerland, its presence has not been investigated over large areas until now. This study assessed the incidence of brown nut rot and identified the causal agent present in Switzerland. Fully ripened nuts were collected from the main sweet chestnut growing areas of Switzerland. A filamentous fungus morphologically identified as G. castanea was isolated from 10 to 91% of the sampled nuts, despite only 3 to 21% of the sampled nuts showing brown rot symptoms. This fungus was isolated from symptomatic chestnuts as well as from apparently healthy chestnuts. Our results suggest a possible endophytic lifestyle in ripened nuts as well as in branches, leaves and unripe nuts as previously found. Species identity of 45 isolates was confirmed by EF-1alpha, beta-tubulin and ITS sequencing. Concatenation of β-tubulin and calmodulin sequences showed that several haplotypes were present at each sampling locality. No other nut rot pathogens could be isolated in this study, suggesting that G. castanea is the main causal agent of nut rot in Switzerland. The presence of this species is reported for the first time in a site in northern Switzerland. Further studies are needed to assess the influence of meteorological conditions and chestnut varieties on the incidence of G. castanea in order to provide prevention strategies for chestnut growers. Normal 0 21 false false false FR-CH X-NONE X-NONE /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso

  6. Combating a Global Threat to a Clonal Crop: Banana Black Sigatoka Pathogen Pseudocercospora fijiensis (Synonym Mycosphaerella fijiensis) Genomes Reveal Clues for Disease Control

    NARCIS (Netherlands)

    Arango Isaza, Rafael E.; Diaz-Trujillo, Caucasella; Dhillon, Braham; Aerts, Andrea; Carlier, Jean; Crane, Charles F.; V. de Jong, Tristan; de Vries, Ineke; Dietrich, Robert; Farmer, Andrew D.; Fortes Fereira, Claudia; Garcia, Suzana; Guzman, Mauricio; Hamelin, Richard C.; Lindquist, Erika A.; Mehrabi, Rahim; Quiros, Olman; Schmutz, Jeremy; Shapiro, Harris; Reynolds, Elizabeth; Scalliet, Gabriel; Souza Manoel, Jr.; Stergiopoulos, Ioannis; Van der Lee, Theo A. J.; De Wit, Pierre J. G. M.; Zapater, Marie-Françoise; Zwiers, Lute-Harm; Grigoriev, Igor V.; Goodwin, Stephen B.; Kema, Gert H. J.

    2016-01-01

    Black Sigatoka or black leaf streak disease, caused by the ascomycete fungus Pseudocercospora fijiensis, inflicts huge costs on banana producers, due to crop losses and expenses for disease control. The global banana export trade relies on Cavendish clones that are highly susceptible to P.

  7. Dispersion of the soybean root rot by Cycloneda sanguinea (Coleoptera: Coccinellidae).

    Science.gov (United States)

    Salgado-Neto, Geraldo; Vaz, Marcos André Braz; Guedes, Jerson Vanderlei Carús; Muniz, Marlove Fátima Brião; Blume, Elena; Wilcken, Carlos Frederico; Castro, Bárbara Monteiro de Castro E; Plata-Rueda, Angelica; Zanuncio, José Cola

    2018-02-05

    The dispersion of pathogenic microorganisms consists of the transport of pathogens from their source to inoculate a new host. Agricultural and economic importance of the Soybean root rot justifies studying this disease, especially the role of insects as dispersers. The aim of this study was to evaluate the role of the ladybird beetle, Cycloneda sanguinea Linnaeus (Coleoptera: Coccinellidae) in the dispersion of pathogens that cause Soybean root rot. Three pathogen species, Macrophomina phaseolina (Tassi) (Sphaeropsidales: Botryosphaeriaceae), Fusarium incarnatum-equiseti species complex (FIESC), and F. commune (Skovgaard) O'Donnell & Nirenberg were isolated from the midgut of ladybird beetles and cultured. Macrophomina phaseolina was identified by morphology while for the other two species, DNA was sequenced. The DNA extracted was amplified in the Internal Transcriber Spacer (ITS) region, sequenced and compared to voucher sequences deposited in the GenBank. Sequences of nucleotide ITS1-5.8 S were identified in the regions of rDNA-ITS4 ribosomal DNA. This is the first report of Macrophomina phaseolina (Tassi) (Sphaeropsidales: Botryosphaeriaceae), Fusarium incarnatum-equiseti species complex (FIESC), and F. commune (Skovgaard) O'Donnell & Nirenberg, being dispersed by C. sanguinea in Brazilian soybean fields.

  8. Association mapping in sunflower for sclerotinia head rot resistance

    Directory of Open Access Journals (Sweden)

    Fusari Corina M

    2012-06-01

    Full Text Available Abstract Background Sclerotinia Head Rot (SHR is one of the most damaging diseases of sunflower in Europe, Argentina, and USA, causing average yield reductions of 10 to 20 %, but leading to total production loss under favorable environmental conditions for the pathogen. Association Mapping (AM is a promising choice for Quantitative Trait Locus (QTL mapping, as it detects relationships between phenotypic variation and gene polymorphisms in existing germplasm without development of mapping populations. This article reports the identification of QTL for resistance to SHR based on candidate gene AM. Results A collection of 94 sunflower inbred lines were tested for SHR under field conditions using assisted inoculation with the fungal pathogen Sclerotinia sclerotiorum. Given that no biological mechanisms or biochemical pathways have been clearly identified for SHR, 43 candidate genes were selected based on previous transcript profiling studies in sunflower and Brassica napus infected with S. sclerotiorum. Associations among SHR incidence and haplotype polymorphisms in 16 candidate genes were tested using Mixed Linear Models (MLM that account for population structure and kinship relationships. This approach allowed detection of a significant association between the candidate gene HaRIC_B and SHR incidence (P  Conclusions These results suggest that AM will be useful in dissecting other complex traits in sunflower, thus providing a valuable tool to assist in crop breeding.

  9. Identification of some saffron corm rot fungi and their control

    Directory of Open Access Journals (Sweden)

    Ayatollah Saeedizadeh

    2014-10-01

    Full Text Available In order to isolation and identification of causal agents of corm rot and their control, the sampling was done from corms in farms of Bushroueye, southern Khorasan province. After culturing of sections of infected corms, the fungi, Penicillium digitatum, Aspergillus niger, and Rhizopus stolonifer were isolated and identified. For their control test, four concentrations of Pseudomonas fluorescens CHAO, Trichoderma harzianum Bi, and four concentrations of fungicides, cupper oxichlorore and benomil,were used with four replications. The control effect of antagonists and fungicides were determined by measurement of diameter of pathogens colony on medium. The results showed that the maximum of control of antagonistic fungus were obtained in concentrations of 1×107 and 1×108, and in the case of antagonistic bacterium wereshown in concentrations of 1×109 and 1×1010. The fungicides had maximum control in concentrations of 3×10-3 and 4×10-3. In general, among of the treatments, T. harzianumwas most effective to reducing the growth of pathogenic fungi.

  10. Rice-Infecting Pseudomonas Genomes Are Highly Accessorized and Harbor Multiple Putative Virulence Mechanisms to Cause Sheath Brown Rot

    Science.gov (United States)

    Quibod, Ian Lorenzo; Grande, Genelou; Oreiro, Eula Gems; Borja, Frances Nikki; Dossa, Gerbert Sylvestre; Mauleon, Ramil; Cruz, Casiana Vera; Oliva, Ricardo

    2015-01-01

    Sheath rot complex and seed discoloration in rice involve a number of pathogenic bacteria that cannot be associated with distinctive symptoms. These pathogens can easily travel on asymptomatic seeds and therefore represent a threat to rice cropping systems. Among the rice-infecting Pseudomonas, P. fuscovaginae has been associated with sheath brown rot disease in several rice growing areas around the world. The appearance of a similar Pseudomonas population, which here we named P. fuscovaginae-like, represents a perfect opportunity to understand common genomic features that can explain the infection mechanism in rice. We showed that the novel population is indeed closely related to P. fuscovaginae. A comparative genomics approach on eight rice-infecting Pseudomonas revealed heterogeneous genomes and a high number of strain-specific genes. The genomes of P. fuscovaginae-like harbor four secretion systems (Type I, II, III, and VI) and other important pathogenicity machinery that could probably facilitate rice colonization. We identified 123 core secreted proteins, most of which have strong signatures of positive selection suggesting functional adaptation. Transcript accumulation of putative pathogenicity-related genes during rice colonization revealed a concerted virulence mechanism. The study suggests that rice-infecting Pseudomonas causing sheath brown rot are intrinsically diverse and maintain a variable set of metabolic capabilities as a potential strategy to occupy a range of environments. PMID:26422147

  11. Rice-Infecting Pseudomonas Genomes Are Highly Accessorized and Harbor Multiple Putative Virulence Mechanisms to Cause Sheath Brown Rot.

    Directory of Open Access Journals (Sweden)

    Ian Lorenzo Quibod

    Full Text Available Sheath rot complex and seed discoloration in rice involve a number of pathogenic bacteria that cannot be associated with distinctive symptoms. These pathogens can easily travel on asymptomatic seeds and therefore represent a threat to rice cropping systems. Among the rice-infecting Pseudomonas, P. fuscovaginae has been associated with sheath brown rot disease in several rice growing areas around the world. The appearance of a similar Pseudomonas population, which here we named P. fuscovaginae-like, represents a perfect opportunity to understand common genomic features that can explain the infection mechanism in rice. We showed that the novel population is indeed closely related to P. fuscovaginae. A comparative genomics approach on eight rice-infecting Pseudomonas revealed heterogeneous genomes and a high number of strain-specific genes. The genomes of P. fuscovaginae-like harbor four secretion systems (Type I, II, III, and VI and other important pathogenicity machinery that could probably facilitate rice colonization. We identified 123 core secreted proteins, most of which have strong signatures of positive selection suggesting functional adaptation. Transcript accumulation of putative pathogenicity-related genes during rice colonization revealed a concerted virulence mechanism. The study suggests that rice-infecting Pseudomonas causing sheath brown rot are intrinsically diverse and maintain a variable set of metabolic capabilities as a potential strategy to occupy a range of environments.

  12. White-rot fungi capable of decolourising textile dyes under alkaline conditions.

    Science.gov (United States)

    Ottoni, Cristiane A; Santos, Cledir; Kozakiewicz, Zofia; Lima, Nelson

    2013-05-01

    Twelve white-rot fungal strains belonging to seven different species were screened on plates under alkaline condition to study the decolourisation of the textile dyes Reactive Black 5 and Poly R-478. Three strains of Trametes versicolor (Micoteca da Universidade do Minho (MUM) 94.04, 04.100 and 04.101) and one strain of Phanerochaete chrysosporium (MUM 94.15) showed better decolourisation results. These four strains were used for decolourisation studies in liquid culture medium. All four selected strains presented more efficient decolourisation rates on Reactive Black 5 than on Poly R-478. For both dyes on solid and liquid culture media, the decolourisation capability exhibited by these strains depended on dye concentration and pH values of the media. Finally, the decolourisation of Reactive Black 5 by T. versicolor strains MUM 94.04 and 04.100 reached 100 %. In addition, the highest white-rot fungi ligninolytic enzyme activities were found for these two strains.

  13. Biosynthesis and structural characterization of Ag nanoparticles from white rot fungi

    Energy Technology Data Exchange (ETDEWEB)

    Chan, Yen San; Mat Don, Mashitah, E-mail: chmashitah@eng.usm.my

    2013-01-01

    Five species of white rot fungi were screened for their capability to synthesize Ag nanoparticles (AgNPs). Three modes of AgNP bioreduction were developed. Pycnoporus sanguineus is found as a potential candidate for the synthesis of AgNPs with a yield at 98.9%. The synthesized AgNPs were characterized using UV-vis spectroscopy, DLS, FTIR, TEM, and SEM. Results showed that AgNP absorption band was located at a peak of 420 nm. Both the SEM and TEM confirmed that the formation of AgNPs were mainly spherical with average diameters of 52.8-103.3 nm. The signals of silver atoms' presence in the mycelium were observed by SEM-EDS spectrum. - Highlights: Black-Right-Pointing-Pointer Pycnoporus sanguineus was found to be most capable for AgNP production compared to other screened white rot fungi. Black-Right-Pointing-Pointer 98.9% yield of AgNP production was identified in the extracellular synthesis by Pycnoporus sanguineus. Black-Right-Pointing-Pointer FTIR spectra confirmed that proteins from the mycelial surface are responsible for the bioreduction of AgNPs.

  14. Isolation of laccase gene-specific sequences from white rot and brown rot fungi by PCR

    Energy Technology Data Exchange (ETDEWEB)

    D`Souza, T.M.; Boominathan, K.; Reddy, C.A. [Michigan State Univ., East Lansing, MI (United States)

    1996-10-01

    Degenerate primers corresponding to the consensus sequences of the copper-binding regions in the N-terminal domains of known basidiomycete laccases were used to isolate laccase gene-specific sequences from strains representing nine genera of wood rot fungi. All except three gave the expected PCR product of about 200 bp. Computer searches of the databases identified the sequences of each of the PCR product of about 200 bp. Computer searches of the databases identified the sequence of each of the PCR products analyzed as a laccase gene sequence, suggesting the specificity of the primers. PCR products of the white rot fungi Ganoderma lucidum, Phlebia brevispora, and Trametes versicolor showed 65 to 74% nucleotide sequence similarity to each other; the similarity in deduced amino acid sequences was 83 to 91%. The PCR products of Lentinula edodes and Lentinus tigrinus, on the other hand, showed relatively low nucleotide and amino acid similarities (58 to 64 and 62 to 81%, respectively); however, these similarities were still much higher than when compared with the corresponding regions in the laccases of the ascomycete fungi Aspergillus nidulans and Neurospora crassa. A few of the white rot fungi, as well as Gloeophyllum trabeum, a brown rot fungus, gave a 144-bp PCR fragment which had a nucleotide sequence similarity of 60 to 71%. Demonstration of laccase activity in G. trabeum and several other brown rot fungi was of particular interest because these organisms were not previously shown to produce laccases. 36 refs., 6 figs., 2 tabs.

  15. MANAGEMENT OF ROOT ROT IN AVOCADO TREES

    Directory of Open Access Journals (Sweden)

    SIMONE RODRIGUES DA SILVA

    Full Text Available ABSTRACT Root rot (Phytophthora cinnamomi Rands is one of the most restrictive factors to avocado growing in main producing regions worldwide. In Brazil, scientific reports on the effectiveness of control methods are scarce. The objective of this study was to evaluate the efficiency of gypsum applications and dolomitic limestone to the soil and potassium phosphite sprays in controlling this disease in ‘Hass’ avocado, grown without irrigation. The application of dolomitic limestone or gypsum alone is not effective to recover plants affected by root rot. The application of potassium phosphite, combined or not with dolomitic lime or gypsum enables the partial recovery ‘Hass’ avocado plants affected by the disease.

  16. MANAGEMENT OF ROOT ROT IN AVOCADO TREES

    OpenAIRE

    SILVA, SIMONE RODRIGUES DA; CANTUARIAS-AVILÉS, TATIANA; BREMER NETO, HORST; MOURÃO FILHO, FRANCISCO DE ASSIS ALVES; MEDINA, RICARDO BORDIGNON

    2016-01-01

    ABSTRACT Root rot (Phytophthora cinnamomi Rands) is one of the most restrictive factors to avocado growing in main producing regions worldwide. In Brazil, scientific reports on the effectiveness of control methods are scarce. The objective of this study was to evaluate the efficiency of gypsum applications and dolomitic limestone to the soil and potassium phosphite sprays in controlling this disease in ‘Hass’ avocado, grown without irrigation. The application of dolomitic limestone or gypsum...

  17. Stand tending and root rot in Norway spruce stands - economical effects caused by root rot at different thinning regimes

    International Nuclear Information System (INIS)

    Johansson, Mats

    1997-01-01

    This report is divided into three parts: 1) a literature study describing the most common fungi causing rot in wood and descriptions of various strategies to reduce economic loss from root rot, 2) a check of a model describing the development of butt rot in pure Norway spruce plantations in southern Sweden, and 3) simulated economic effects of root rot in stands with various stand tending. The rot model was used to estimate future rot frequencies in the economic calculations. In order to avoid overestimations of rot frequencies, the calculations were also executed when assuming slower growth of rot than shown in the model. When analysing the economical effects of rot, the following three thinning programmes were used: Program 1: thinning at the ages of 30- and 45 years. Final felling at the ages 50-, 55-, 60-, 65-, and 70 years. Program 2: thinning at the ages of 40- and 60- years. Final felling at the ages 65 and 75 years. Program 3: thinning at the ages of 30-, 40-, 55-, and 70 years. Final felling at the ages 80 and 90 years. With an interest rate of 3%, programme 2 (final felling at the age of 65 years) had the highest value at present. This result was valid when presuming butt rot in the stand as well as when presuming no butt rot in the stand. There was a small difference between the value at present in programme 1 (final felling at the age of 60 years) and in programme 3 (final felling at the age of 80 years). When presuming butt rot in the stand, the value at present in programme 3 decreased somewhat more in comparison to the value at present in programme 1. Compared to no butt rot in the stand, the optimal final felling time appeared five to ten years earlier when assuming butt rot in the stand. Stand tending programme 1 and an interest rate of 3% were used. Interest rates 2 and 4% did not indicate shorter rotation. The calculated optimal time of final felling appeared at the same stand age whether assuming rot preset or not. The results in this study

  18. Potential of bulb-associated bacteria for biocontrol of hyacinth soft rot caused by Dickeya zeae.

    Science.gov (United States)

    Jafra, S; Przysowa, J; Gwizdek-Wiśniewska, A; van der Wolf, J M

    2009-01-01

    Dickeya zeae is a pectinolytic bacterium responsible for soft rot disease in flower bulb crops. In this study, the possibility of controlling soft rot disease in hyacinth by using antagonistic bacteria isolated from hyacinth bulbs was explored. Bacterial isolates with potential for biocontrol were selected on the basis of antibiosis against D. zeae, siderophore production, and the N-acyl homoserine lactones (AHLs)-inactivation. In in vitro assays, 35 out of 565 hyacinth-associated bacterial isolates produced antimicrobial substances against D. zeae, whereas 20 degraded AHLs, and 35 produced siderophores. Isolates of interest were identified by 16S rDNA sequence analysis and reaction in BIOLOG tests. Twenty-six isolates that differed in characteristics were selected for pathogenicity testing on hyacinth cultivars, Pink Pearl and Carnegie. Two strains identified as Rahnella aquatilis and one as Erwinia persicinus significantly reduced tissue maceration caused by D. zeae 2019 on hyacinth bulbs, but not on leaves. Hyacinth bulbs harbour bacteria belonging to different taxonomic groups that are antagonistic to D. zeae, and some can attenuate decay of bulb tissue. Selected hyacinth-associated bacterial isolates have potential for control of soft rot disease caused by D. zeae in hyacinth bulb production.

  19. Biological Control of Apple Ring Rot on Fruit by Bacillus amyloliquefaciens 9001

    Directory of Open Access Journals (Sweden)

    Yan Li

    2013-06-01

    Full Text Available Apple ring rot disease, caused by Botryosphaeria dothidea (Moug. ex. Fr Ces. et de Not., is one of the most important diseases on apple fruits. In this study, strain 9001 isolated from healthy apple fruits from an infested orchard was evaluated for its biocontrol activity against apple ring rot in vitro and in vivo. Strain 9001 showed obvious antagonistic activity to B. dothidea YL-1 when plated on potato dextrose agar. Soaking healthy apples in the bacterial suspensions of strain 9001 prior to artificial inoculation of fungal pathogen resulted in a dramatic decrease in disease incidence when compared to the control. Moreover, either field application in the growth season or postharvest treatment of apples from infected orchards with bacterial suspensions of strain 9001 resulted in significantly reduced disease incidence within the storage period for 4 months at room temperature. Based on the phylogenetic analysis of 16S rRNA and the gyrA gene, strain 9001 was identified as Bacillus amyloliquefaciens. These results indicated that B. amyloliquefaciens 9001 could be a promising agent in biocontrol of apple ring rot on fruit, which might help to minimize the yield loss of apple fruit during the long postharvest period.

  20. Pectobacterium carotovorum subsp. carotovorum – the causal agent of broccoli soft rot in Serbia

    Directory of Open Access Journals (Sweden)

    Katarina Gašić

    2014-12-01

    Full Text Available Soft rot symptoms were observed on broccoli plants in several commercial fields in the western part of Serbia. Six strains of bacteria were isolated from diseased tissues and identified as Pectobacterium carotovorum subsp. carotovorum using conventional bacteriological and molecular methods. All strains were non-fluorescent, gram-negative, facultative anaerobes, oxidase-negative and catalase-positive, causing soft rot on potato and carrot slices and did not induce hypersensitive reaction on tobacco leaves. They grew in 5% NaCl and at 37°C, did not produce acid from α-methyl glucoside, sorbitol and maltose, nor reducing substances from sucrose, but utilized lactose and trehalose, and did not produce indole or lecithinase. The investigated strains showed characteristic growth on Logan’s medium and did not produce blue pigmented indigoidine on GYCA medium nor “fried egg” colonies on PDA. The identity of strains was confirmed by ITS-PCR and ITS-RFLP analyses and by sequence analysis of the 16S rRNA gene. In a pathogenicity assay, all strains caused tissue discoloration and soft rot development on inoculated broccoli head tissue fragments.

  1. Potential worldwide distribution of Fusarium dry root rot in common beans based on the optimal environment for disease occurrence

    Science.gov (United States)

    Macedo, Renan; Sales, Lilian Patrícia; Yoshida, Fernanda; Silva-Abud, Lidianne Lemes

    2017-01-01

    Root rots are a constraint for staple food crops and a long-lasting food security problem worldwide. In common beans, yield losses originating from root damage are frequently attributed to dry root rot, a disease caused by the Fusarium solani species complex. The aim of this study was to model the current potential distribution of common bean dry root rot on a global scale and to project changes based on future expectations of climate change. Our approach used a spatial proxy of the field disease occurrence, instead of solely the pathogen distribution. We modeled the pathogen environmental requirements in locations where in-situ inoculum density seems ideal for disease manifestation. A dataset of 2,311 soil samples from commercial farms assessed from 2002 to 2015 allowed us to evaluate the environmental conditions associated with the pathogen’s optimum inoculum density for disease occurrence, using a lower threshold as a spatial proxy. We encompassed not only the optimal conditions for disease occurrence but also the optimal pathogen’s density required for host infection. An intermediate inoculum density of the pathogen was the best disease proxy, suggesting density-dependent mechanisms on host infection. We found a strong convergence on the environmental requirements of both the host and the disease development in tropical areas, mostly in Brazil, Central America, and African countries. Precipitation and temperature variables were important for explaining the disease occurrence (from 17.63% to 43.84%). Climate change will probably move the disease toward cooler regions, which in Brazil are more representative of small-scale farming, although an overall shrink in total area (from 48% to 49% in 2050 and 26% to 41% in 2070) was also predicted. Understanding pathogen distribution and disease risks in an evolutionary context will therefore support breeding for resistance programs and strategies for dry root rot management in common beans. PMID:29107985

  2. Specificity of monoclonal antibodies to strains of Dickeya sp. that cause bacterial heart rot of pineapple.

    Science.gov (United States)

    Peckham, Gabriel D; Kaneshiro, Wendy S; Luu, Van; Berestecky, John M; Alvarez, Anne M

    2010-10-01

    During a severe outbreak of bacterial heart rot that occurred in pineapple plantations on Oahu, Hawaii, in 2003 and years following, 43 bacterial strains were isolated from diseased plants or irrigation water and identified as Erwinia chrysanthemi (now Dickeya sp.) by phenotypic, molecular, and pathogenicity assays. Rep-PCR fingerprint patterns grouped strains from pineapple plants and irrigation water into five genotypes (A-E) that differed from representatives of other Dickeya species, Pectobacterium carotovorum and other enteric saprophytes isolated from pineapple. Monoclonal antibodies produced following immunization of mice with virulent type C Dickeya sp. showed only two specificities. MAb Pine-1 (2D11G1, IgG1 with kappa light chain) reacted to all 43 pineapple/water strains and some reference strains (D. dianthicola, D. chrysanthemi, D. paradisiaca, some D. dadantii, and uncharacterized Dickeya sp.) but did not react to reference strains of D. dieffenbachiae, D. zeae, or one of the two Malaysian pineapple strains. MAb Pine-2 (2A7F2, IgG3 with kappa light chain) reacted to all type B, C, and D strains but not to any A or E strains or any reference strains except Dickeya sp. isolated from Malaysian pineapple. Pathogenicity tests showed that type C strains were more aggressive than type A strains when inoculated during cool months. Therefore, MAb Pine-2 distinguishes the more virulent type C strains from less virulent type A pineapple strains and type E water strains. MAbs with these two specificities enable development of rapid diagnostic tests that will distinguish the systemic heart rot pathogen from opportunistic bacteria associated with rotted tissues. Use of the two MAbs in field assays also permits the monitoring of a known subpopulation and provides additional decision tools for disease containment and management practices.

  3. Crown sheath rot of rice: host-range and varietal resistance to Gaeumannomyces graminis var. graminis

    Directory of Open Access Journals (Sweden)

    Cecília do Nascimento Peixoto

    2014-09-01

    Full Text Available Several gramineous plants occurring in rice fields show symptoms of crown sheath rot of rice, caused by Gaeumannomyces graminis var. graminis (Ggg, under natural conditions of infection. The pathogenicity of the Ggg-a 01 isolate, collected from rice, was tested on seven grass species and eight cereals, under greenhouse conditions, in order to get information on host-range and resistance of rice genotypes to crown sheath rot. The inoculation tests showed that the rice isolate was pathogenic to weeds such as Echinochloa crusgalli, Pennisetum setosum, Brachiaria sp., Digitaria horizontalis, Brachiaria plantaginea, Eleusine indica and Cenchrus echinatus, and that these species are potential hosts to the pathogen. Winter cereals such as wheat, oat, rye, barley and triticale, as well as sorghum, maize and millet, presented different degrees of susceptibility to the Ggg-a isolate. Significant differences were observed in relation to lesion height and production of hyphopodia and perithecia on culms. Perithecia were not observed on millet, sorghum, southern sandbur and maize. The resistance of 58 upland rice genotypes was tested, and the SCIA16 and SCIA08 genotypes presented lesion height significantly smaller, being considered resistant, when compared to the highly susceptible CNAS10351 genotype.

  4. Potential of Epicoccum purpurascens Strain 5615 AUMC as a Biocontrol Agent of Pythium irregulare Root Rot in Three Leguminous Plants.

    Science.gov (United States)

    Koutb, Mostafa; Ali, Esam H

    2010-12-01

    Epicoccum purpurascens stain 5615 AUMC was investigated for its biocontrol activity against root rot disease caused by Pythium irregulare. E. purpurascens greenhouse pathogenicity tests using three leguminous plants indicated that the fungus was nonpathogenic under the test conditions. The germination rate of the three species of legume seeds treated with a E. purpurascens homogenate increased significantly compared with the seeds infested with P. irregulare. No root rot symptoms were observed on seeds treated with E. purpurascens, and seedlings appeared more vigorous when compared with the non-treated control. A significant increase in seedling growth parameters (seedling length and fresh and dry weights) was observed in seedlings treated with E. purpurascens compared to pathogen-treated seedlings. Pre-treating the seeds with the bioagent fungus was more efficient for protecting seeds against the root rot disease caused by P. irregulare than waiting for disease dispersal before intervention. To determine whether E. purpurascens produced known anti-fungal compounds, an acetone extract of the fungus was analyzed by gas chromatography mass spectrometry. The extract revealed a high percentage of the cinnamic acid derivative (trimethylsiloxy) cinnamic acid methyl ester. The E. purpurascens isolate grew more rapidly than the P. irregulare pathogen in a dual culture on potato dextrose agar nutrient medium, although the two fungi grew similarly when cultured separately. This result may indicate antagonism via antibiosis or competition.

  5. Application of Amplified Fragment Length Polymorphism Fingerprinting for Taxonomy and Identification of the Soft Rot Bacteria Erwinia carotovora and Erwinia chrysanthemi

    OpenAIRE

    Avrova, Anna O.; Hyman, Lizbeth J.; Toth, Rachel L.; Toth, Ian K.

    2002-01-01

    The soft rot bacteria Erwinia carotovora and Erwinia chrysanthemi are important pathogens of potato and other crops. However, the taxonomy of these pathogens, particularly at subspecies level, is unclear. An investigation using amplified fragment length polymorphism (AFLP) fingerprinting was undertaken to determine the taxonomic relationships within this group based on their genetic relatedness. Following cluster analysis on the similarity matrices derived from the AFLP gels, four clusters (c...

  6. Incidence of root rot diseases of soybean in Multan Pakistan and its management by the use of plant growth promoting rhizobacteria

    International Nuclear Information System (INIS)

    Haq, M.I.; Tahir, M.I.; Mahmood, S.

    2012-01-01

    Eight villages in Multan district were surveyed to record incidence of disease and losses of soybean (Glycine max L.) caused by root rot fungi. The root incidence ranged 10-17% and losses ranged 6.75-15.5%. The evaluation of four PGPR isolates was used in combination with organic amendment for the management of root-rot disease incidence and to reduce the population of root pathogenic fungi and to increase the yield in field. This study demonstrated effective biological control by the PGPR isolates tested, thereby indicating the possibility of application of rhizobacteria for control of soil bor ne diseases of soybean in Pakistan and other countries. (author)

  7. Effect of essential oil of Satureja hortensis against Bacillus pumilus, which cause of soft rot on some plants

    Science.gov (United States)

    Dadaşoǧlu, Fatih

    2017-04-01

    In this study, it is aimmed to be determined the antimicrobial effects of the essential oil in vitro conditions, extracted from wild forms of plant which is known as Satureja hortensis around the world and grows naturally at Erzurum province of Turkey against Bacillus pumilus isolates, which are the agent of Soft Rot for some fruits and vegetables. For this purpose, 18 isolates of B. pumilus which have been determined as the agent of Soft Rot in previous studies performed in plants such as potatos, onions, strawberries, melons and watermelons. As the positive control, Streptomycin antibiotics sold as ready produce were used. According to the obtained results, the essential oil have the antibactericidal effect of 19-29 mm against 18 isolates of B. pumilus. It has been observed that the antibiotics used as the positive control has the antibacterial effect of 16-22 mm. In conclusion, the essential oil has the lethal effect against 18 B. pumilus isolates which are agents of Soft Rot. It is assesed that these essential oil extracted from Satureja hortensis can be used against these Soft Rot pathogens.

  8. Transgenic Amorphophallus konjac expressing synthesized acyl-homoserine lactonase (aiiA) gene exhibit enhanced resistance to soft rot disease.

    Science.gov (United States)

    Ban, Huifang; Chai, Xinli; Lin, Yongjun; Zhou, Ying; Peng, Donghai; Zhou, Yi; Zou, Yulan; Yu, Ziniu; Sun, Ming

    2009-12-01

    Amorphophallus konjac is an important economic crop widely used in health products and biomaterials. However, this monocotyledonous plant's production is seriously restricted by soft rot disease. Some Bacillus thuringiensis strains generate an endocellular acyl homoserine lactonase (AiiA), which has inhibitory effect on soft rot pathogen through disrupting the signal molecules (N-acylhomoserine lactones, AHL) of their Quorum Sensing system. The aim of our study is to obtain transgenic A. konjac expressing AiiA protein and exhibiting resistance to soft rot. But till now, there is not any report about exogenous gene transformation in A. konjac. In this research, an Agrobacterium-mediated genetic transformation system was constructed. An aiiA gene was synthesized according to the codon usage in A. konjac. Embryogenic callus was infected with the A. tumefaciens strain EHA105 harboring the plant transformation plasmid pU1301 plus synthesized aiiA gene. After antibiotics screening, 34 plants were obtained. PCR analysis showed that positive amplified fragments were present in 21 out of these 34 lines. Southern blot analysis indicated that aiiA gene had integrated into the genome of A. konjac. Western blotting demonstrated that the target protein of interest was reactive with the antibody against AiiA. Further disease resistance detection revealed that all of the tested transgenic A. konjac lines exhibited high resistance to soft rot bacteria Erwinia carotovora subsp. Carotovora (Ecc) SCG1. The protocol is useful for the quality improvement of A. konjac through genetic transformation.

  9. Biological characteristics of Bacillus amyloliquefaciens AK-0 and suppression of ginseng root rot caused by Cylindrocarpon destructans.

    Science.gov (United States)

    Kim, Y S; Balaraju, K; Jeon, Y H

    2017-01-01

    The effect of Bacillus amyloliquefaciens AK-0 (AK-0) on ginseng root rot disease caused by Cylindrocarpon destructans was investigated. From 190 ginseng rhizosphere bacteria, AK-0 was selected for further analysis; its morphological characteristics were investigated by microscopy. AK-0 was identified as B. amyloliquefaciens using the Biolog system, 16S rRNA gene sequence analysis and examination of morphological and biochemical characteristics. Bacterial population and media optimization were estimated by the bacterial growth curve. The number of AK-0 cells was relatively higher in brain-heart infusion (BHI) medium than in other media. The potential antifungal effect of AK-0 culture filtrate on the in vitro conidial germination of C. destructans and root rot development on root discs and 4-year-old ginseng roots were assessed. Polymerase chain reaction (PCR) analysis of antibiotic biosynthesis gene expression suggested that the release of antibiotic compounds is involved in the antifungal effect of AK-0 and the suppression of ginseng root rot. These results indicate that the CF of AK-0 has antifungal effects on fungal pathogens of ginseng, resulting in the suppression of root rot disease caused by C. destructans. AK-0 is a potential source of novel bioactive metabolites. AK-0 CF exhibited antifungal effects against C. destructans on ginseng roots. PCR analysis indicated that the AK-0 harbours genes involved in the biosynthesis of antimicrobial compounds. © 2016 The Society for Applied Microbiology.

  10. Improvement of resistance to Fusarium root rot through gene ...

    African Journals Online (AJOL)

    Fusarium root rot (FRR), caused by Fusarium solani f.sp. , is one of the most serious root rot diseases of common bean (Phaseolus vulgaris L.) throughout the world. Yield losses of up to 84% have been attributed to the disease. Development and deployment of resistant materials is the most feasible approach to managing ...

  11. ( Azadirachta Indica ) Leaf Extracts on the Rot Fungus ( Fusarium ...

    African Journals Online (AJOL)

    The storage lifespan of kola nuts is challenged by the problem of decay of nuts in storage as a result of the attack by the rot fungus (Fusarium spp). The effect of the neem leaf (Azadirachta indica) extracts on the rot fungus was investigated in order to aid extended kola nuts storage. The aqueous and ethanolic leaf extracts of ...

  12. RESISTANCE TO POST-HARVEST MICROBIAL ROT IN YAM ...

    African Journals Online (AJOL)

    ACSS

    Rot from microbial infection of healthy yam tubers reduces their table quality and renders them unappealing to consumers. A study was carried out at Bimbilla in the Nanumba North District of Ghana to evaluate possible interactions of yam genotypes and storage methods for controlling internal rot in yam. Four local varieties.

  13. Impact of management strategies in the basal rot, charcoal rots epidemiology and Phaseolus vulgaris L. yield.

    Directory of Open Access Journals (Sweden)

    Ulacio Osorio Dilcia

    2013-02-01

    Full Text Available The effect of chemical, physical, biologycal and cultural strategies individually or combinated were evaluated in the epidemiology of the basal rot (Sclerotium rolfsii, charcoal rot (Macrophomina phaseolina and the Phaseolus vulgaris cv Tacarigua yield at Barinas state from Venezuela. In the experiment, Tebuconazole (Teb was applicated at seed (1 L/Ton and at soil, a los 30 y 60 days after of the sow (1 L/ha; Trichoderma harzianum (Tri was applicated at seed (15 g for each 1.5 k and to 15, 30, 45 y 60 days after of the sow (30 g/10 L of water. On the other hand, soil was solarizated (Sol during 15 days and calcium nitrate (Ca (60 g/10 L of water was applicated each 15 days until 60 days of growth of cultivated plants. Basal rot was registered as far as 42 days after of the sow, showing less of 5.3% in Teb y the combination SolTeb. The hightest incidence of this disease was observed in the treatment Tri with 28.5%, being highter that control (14.5%. Last to 42 days predominated the charcoal rot in the rest of the plants for a total of 100% of incidente in everything the treatments. Nevertheless, Teb showed the hightest yield with 555 k/ha, being different estatistically at treatment TriCa, which showed the lowest yield with 31 k/ha, however, the roots not formed nodules nitrogen uptake in these replications with the fungicide and Ca. It is concluded that S. rolfsii was sensible at action of some of the treatments; but not M. phaseolina; nevertheless, the plants were capables to produce seeds health apparently in treatments in which observed less severity of charcoal rot.

  14. Endophytic fungal diversity in Theobroma cacao (cacao) and T. grandiflorum (cupuaçu) trees and their potential for growth promotion and biocontrol of black-pod disease.

    Science.gov (United States)

    Hanada, Rogério Eiji; Pomella, Alan William V; Costa, Heron Salazar; Bezerra, José Luiz; Loguercio, Leandro L; Pereira, José O

    2010-01-01

    The endophytic niches of plants are a rich source of microbes that can directly and indirectly promote plant protection, growth and development. The diversity of culturable endophytic fungi from stems and branches of Theobroma cacao (cacao) and Theobroma grandiflorum (cupuaçu) trees growing in the Amazon region of Brazil was assessed. The collection of fungal endophytic isolates obtained was applied in field experiments to evaluate their potential as biocontrol agents against Phytophthora palmivora, the causal agent of the black-pod rot disease of cacao, one of the most important pathogens in cocoa-producing regions worldwide. The isolated endophytic fungi from 60 traditional, farmer-planted, healthy cacao and 10 cupuaçu plants were cultured in PDA under conditions inducing sporulation. Isolates were classified based upon the morphological characteristics of their cultures and reproductive structures. Spore suspensions from a total of 103 isolates that could be classified at least up to genus level were tested against P. palmivora in pods attached to cacao trees in the field. Results indicated that ∼70% of isolates showed biocontrol effects to a certain extent, suggesting that culturable endophytic fungal biodiversity in this system is of a mostly mutualistic type of interaction with the host. Eight isolates from genera Trichoderma (reference isolate), Pestalotiopsis, Curvularia, Tolypocladium and Fusarium showed the highest level of activity against the pathogen, and were further characterized. All demonstrated their endophytic nature by colonizing axenic cacao plantlets, and confirmed their biocontrol activity on attached pods trials by showing significant decrease in disease severity in relation to the positive control. None, however, showed detectable growth-promotion effects. Aspects related to endophytic biodiversity and host-pathogen-endophyte interactions in the environment of this study were discussed on the context of developing sustainable strategies

  15. Diagnostic of dry rot in living trees

    International Nuclear Information System (INIS)

    Schaetzler, H.P.

    1978-01-01

    The γ-desorption method has been used in the early diagnosis of dry rot in trees. The attenuation of a 60 keV γ-beam ( 241 Am) has been measured on eleven healthy spruce disks. It is seen that early diagnostic of rotten trees is limited by natural density variation of the wood itself, but for a 95% confidence level that the wood is diseased, a tree must have an average of less than 0.59 g./cm 3 . (Auth/C.F.)

  16. Medical Council of India : the rot within.

    Science.gov (United States)

    Pandya, Sunil K

    2009-01-01

    The Medical Council of India is a statutory national agency charged with several responsibilities. Sadly, it is plagued by inefficiency, arbitrariness and lack of transparency. It has been functioning for some years as the fiefdom of one person--Dr Ketan Desai. He has been re-elected president of the council despite strictures against him by the High Court of New Delhi. This essay provides data that may help the reader identify the rot within the Council. Permitted optimism, we may hope that this essay and similar observations by others will prompt a change for the better. At present such optimism is not justified.

  17. Rhizoctonia disease of tulip : characterization and dynamics of the pathogens

    NARCIS (Netherlands)

    Schneider, J.H.M.

    1998-01-01

    Rhizoctonia disease causes severe losses during the production cycle of tulip. The complex nature of the disease requires a precise characterization of the causal pathogens. Typical bare patches are caused by R. solani AG 2-t. Bulb rot symptoms are, apart from AG 2-t isolates, caused by R.

  18. Temporal Occurrence and Niche Preferences of Phytophthora spp. Causing Brown Rot of Citrus in the Central Valley of California.

    Science.gov (United States)

    Hao, Wei; Miles, Timothy D; Martin, Frank N; Browne, Gregory T; Förster, Helga; Adaskaveg, James E

    2018-03-01

    Brown rot of citrus fruit is caused by several species of Phytophthora and is currently of serious concern for the California citrus industry. Two species, Phytophthora syringae and P. hibernalis, are quarantine pathogens in China, a major export market for California citrus. To maintain trade and estimate the risk of exporting a quarantine pathogen, the distribution and frequency of Phytophthora spp. causing brown rot of orange in major growing areas of California was investigated. Symptomatic fruit were collected from navel (winter to late spring) and Valencia (late spring to summer) orange orchards from 2013 to 2015. Species identification of isolates was based on morphological characteristics, random amplified polymorphic DNA banding patterns, and sequencing of the internal transcribed spacer and the partial cox2/spacer/cox1 regions from axenic cultures, or directly on DNA from fruit tissue using a multiplex TaqMan quantitative polymerase chain reaction assay. In winter samplings, the incidence of P. syringae based on the number of fruit with Phytophthora spp. detection ranged from 73.6 to 96.1% for the two counties surveyed. The remaining isolates were identified as P. citrophthora. In late spring or summer, only P. citrophthora was recovered. P. hibernalis and P. nicotianae were not detected in any fruit with brown rot symptoms. These results indicate that P. syringae is currently an important brown rot pathogen of citrus fruit in California during the cooler seasons of the year. In winter 2016 and 2017, P. syringae was recovered by pear baiting at a high incidence from leaf litter and from a small number of rhizosphere soil or root samples but not from living leaves on the tree. In contrast, P. citrophthora was rarely found in leaf litter but was commonly detected in the rhizosphere. Thus, leaf litter is a major inoculum source for P. syringae and this species occupies a distinct ecological niche.

  19. ANTAGONISTIC EFFECT OF FOUR FUNGAL ISOLATES TO GANODERMA BONINENSE, THE CAUSAL AGENT OF BASAL STEM ROT OF OIL PALM

    Directory of Open Access Journals (Sweden)

    OKKY SETYAWATI DHARMAPUTRA

    1990-01-01

    Full Text Available Four fungal isolates from soils obtained from three sites of the oil palm plantations in North Sumatra were found antagonistic to Ganoderma boninense, the causal agent of basal stem rot of oil palm. Penicillium citrinum inhibited the growth of the pathogen and formed a zone of inhibition on the agar media. Trichoderma harzianum BIO - 1 as well as BIO - 2 and T. viride not only repressed the growth of the pathogen but also caused lysis of the hyphae, and the colony was totally overgrown by the antagonists.

  20. Screening preharvest/postharvest strategies to prevent fruit rot decay.

    Science.gov (United States)

    Vorstermans, B; Creemers, P

    2007-01-01

    In fruit growing preharvest sprayings in the orchard are mainly applied to protect fruit from decaying. Next to multisite fungicides (captan, thiram, tolylfluanid) the most commonly used products recognized for the Belgium market are Bellis (pyraclostrobin & boscalid) and the combination of Topsin M (thiophanate-methyl) and Frugico (diethofencarb). In general the spraying schedule varies depending on weather conditions (infection risk), preharvest interval of available fungicides, fruitgrower and cultivar of pome fruit (apple/pear). Facing the climatological conditions before picking the residue loading on the fruit surface can differ enormously. Also wet (pre)grading is considered to decrease the product residue resulting to fruits which are less protected before entering the cold storage room. In this context a partially replacement of the preharvest treatments by one postharvest application could offer a reliable alternative to the PPP reduction program (Plant Protection Products) in the orchard. A standardized application method by dipping or drenching will cover the fruits homogenically resulting in a rationalized fungicide use compared to the preharvest sprayings in the orchard. For the Belgium market Philabuster (imazalil & pyrimethanil) is registered for postharvest treatments since for this product a proper solution for the waste water of postharvest uses was developed to protect surface waters (Funds technology). Philabuster provides an advanced mould control towards fruit rot pathogens Gloeosporium spp., Botrytis cinerea and Penicillium spp. In this context several trials were set up to evaluate the biological efficacy of Philabuster alone or in combination with preharvest sprayings in the orchard. In concrete different preharvest spraying schedules were applied in the last six weeks before harvest on apple and pear facing parameters as rational fungicide use, antifungal effectiveness and cost price. The purpose was to select the optimal combination in

  1. Molecular Basis of Resistance to Fusarium Ear Rot in Maize

    Directory of Open Access Journals (Sweden)

    Alessandra Lanubile

    2017-10-01

    Full Text Available The impact of climate change has been identified as an emerging issue for food security and safety, and the increased incidence of mycotoxin contamination in maize over the last two decades is considered a potential emerging hazard. Disease control by chemical and agronomic approaches is often ineffective and increases the cost of production; for this reason the exploitation of genetic resistance is the most sustainable method for reducing contamination. The review focuses on the significant advances that have been made in the development of transcriptomic, genetic and genomic information for maize, Fusarium verticillioides molds, and their interactions, over recent years. Findings from transcriptomic studies have been used to outline a specific model for the intracellular signaling cascade occurring in maize cells against F. verticillioides infection. Several recognition receptors, such as receptor-like kinases and R genes, are involved in pathogen perception, and trigger down-stream signaling networks mediated by mitogen-associated protein kinases. These signals could be orchestrated primarily by hormones, including salicylic acid, auxin, abscisic acid, ethylene, and jasmonic acid, in association with calcium signaling, targeting multiple transcription factors that in turn promote the down-stream activation of defensive response genes, such as those related to detoxification processes, phenylpropanoid, and oxylipin metabolic pathways. At the genetic and genomic levels, several quantitative trait loci (QTL and single-nucleotide polymorphism markers for resistance to Fusarium ear rot deriving from QTL mapping and genome-wide association studies are described, indicating the complexity of this polygenic trait. All these findings will contribute to identifying candidate genes for resistance and to applying genomic technologies for selecting resistant maize genotypes and speeding up a strategy of breeding to contrast disease, through plants

  2. Chemical Characterization of Different Sumac and Pomegranate Extracts Effective against Botrytis cinerea Rots

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    Flora V. Romeo

    2015-06-01

    Full Text Available Pomegranate (Punica granatum L. peel and sumac (Rhus coriaria L. fruit and leaf extracts were chemically characterized and their ability to inhibit table grape (cv. Italia rots caused by Botrytis cinerea was evaluated on artificially inoculated berries. Different extraction methods were applied and extracts were characterized through Ultra Fast High Performance Liquid Chromatography coupled to Photodiode array detector and Electrospray ionization Mass spectrometer (UPLC-PDA-ESI/MSn for their phenol and anthocyanin contents. The concentrated pomegranate peel extract (PGE-C was the richest in phenols (66.97 g gallic acid equivalents/kg while the concentrated sumac extract from fruits (SUF-C showed the highest anthocyanin amount (171.96 mg cyanidin 3-glucoside equivalents/kg. Both phenolic and anthocyanin profile of pomegranate and sumac extracts were quite different: pomegranate extract was rich in cyanidin 3-glucoside, pelargonidin 3-glucoside and ellagic acid derivatives, while sumac extract was characterized by 7-methyl-cyanidin 3-galactoside and gallic acid derivatives. The concentrated extracts from both pomegranate peel and sumac leaves significantly reduced the development of Botrytis rots. In particular, the extract from pomegranate peel completely inhibited the pathogen at different intervals of time (0, 12, and 24 h between treatment and pathogen inoculation on fruits maintained at 22–24 °C and high relative humidity (RH. This extract may represent a valuable alternative to control postharvest fungal rots in view of its high efficacy because of the low cost of pomegranate peel, which is a waste product of processing factories.

  3. RECONSTRUCTING THE EVOLUTIONARY HISTORY OF THE FOREST FUNGAL PATHOGEN, ARMILLARIA MELLEA, IN A TEMPERATE WORLDWIDE POPULATIONS

    Science.gov (United States)

    The forest pathogen Armillaria mellea s.s. (Basidiomycota, Physalacriaceae) is among the most significant forest pathogens causing root rot in northern temperate forest trees worldwide. Phylogenetic reconstructions for A. mellea show distinct European, Asian and North American lineages. The North Am...

  4. Black to Black

    DEFF Research Database (Denmark)

    Langkjær, Michael Alexander

    2012-01-01

    Pop musicians performing in black stage costume take advantage of cultural traditions relating to matters black. Stylistically, black is a paradoxical color: although a symbol of melancholy, pessimism, and renunciation, black also expresses minimalist modernity and signifies exclusivity (as is hi...... suggested that appreciation of the highly personal motives of both Siouxsie Sioux and Janelle Monáe in wearing black may be achieved via analogies with the minimalist sublime of American artists Frank Stella’s and Ad Reinhardt’s black canvasses.......Pop musicians performing in black stage costume take advantage of cultural traditions relating to matters black. Stylistically, black is a paradoxical color: although a symbol of melancholy, pessimism, and renunciation, black also expresses minimalist modernity and signifies exclusivity (as...... is hinted by Rudyard Kipling’s illustration of ‘The [Black] Cat That Walked by Himself’ in his classic children’s tale). It was well understood by uniformed Anarchists, Fascists and the SS that there is an assertive presence connected with the black-clad figure. The paradox of black’s abstract elegance...

  5. SOIL MYCOFLORA OF BLACK PEPPER RHIZOSPHERE IN THE PHILIPPINES AND THEIR IN VITRO ANTAGONISM AGAINST Phytophthora capsici L.

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    Rita Noveriza

    2016-10-01

    Full Text Available Foot rot disease of black pepper caused by Phytophthora capsici had been reported in Batangas and Laguna, Philippines. The plant was recovered following the application of crop residue (organic substrate and intercropping with other crops. This study was aimed to isolate, identify, and determine the soil mycoflora from the rhizosphere of black pepper grown on various cropping patterns in Batangas and Laguna. Antagonistic activity of mycoflora isolates was tested against P. capsici using dual culture technique. The result showed that 149 colonies of soil mycoflora isolated were belonging to 14 genera; three of them, i.e. Penicillium, Paecilomyces and Aspergillus, were the most dominant. All of the mycoflora isolates were able to inhibit the growth of the pathogen. Eighteen of them were the most promising antagonists, based on their inhibition growth of more than 60%. It is suggested that antagonistic mechanism of Mucor isolate (1001, Trichoderma (125, 170, 171, 179, 180, 181, Gliocladium (109, Cunninghamella (165, 168, Mortierella (177, and Aspergillus (106 was space competitor (competition for nutrient since they rapidly overgrew the pathogen. Aspergillus (67, 79, 81, 83, 108, and 202 isolates inhibited the pathogen apparently by producing antibiotic, whereas Trichoderma (125, 170, 171, 179, 180, and 181 isolates were able to penetrate the hyphae of the pathogen. The organic matter percentage in the soil was significantly correlated with the number of antagonistic mycoflora in rhizosphere (R2 = 0.1094, but the cropping pattern was negatively correlated. This study suggests that organic matter increased antagonistic mycoflora in black pepper rhizosphere, which will reduce severity of the disease.

  6. Efficacy of Oryza sativa husk and Quercus phillyraeoides extracts for the in vitro and in vivo control of fungal rot disease of white yam (Dioscorea rotundata Poir).

    Science.gov (United States)

    Dania, Victor Ohileobo; Fadina, Olubunmi Omowunmi; Ayodele, Maria; Kumar, P Lava

    2014-01-01

    Tuber rot disease is a major constraint to white yam (Dioscorea rotundata) production, accounting for 50-60% of annual yield losses in Nigeria. The main method of control using synthetic fungicides is being discouraged due to human and environmental health hazards. The potential of Oryza sativa husk (OSH) and Quercus phillyraeoides (QP) extracts for the in vitro and in vivo control of six virulent rot-causing fungal pathogens, Lasiodiplodia theobromae, Aspergillus niger, Rhizoctonia solani, Penicillium oxalicum, Sclerotium rolfsii, and Fusarium oxysporum was evaluated, using five different extract concentrations of 0.5%, 1.0%, 1.5%, 2.5%, and 3.5% w/v. These fungi were isolated from rotted tubers of D. rotundata, across three agroecological zones in Nigeria-the Humid rainforest, Derived savanna, and southern Guinea savanna. All treatments were subjected to three methods of inoculation 48 hours before the application of both extracts and stored at 28 ± 2°C for 6 months. Radial mycelial growth of the test pathogens was effectively inhibited at concentrations ≤ 3.5% w/v in vitro for both OSH and QP extracts. Rotting was significantly reduced (P ≤ 0.05) to between 0 to 18.8% and 0% to 20.9% for OSH and QP extracts respectively. The extracts significantly (P ≤ 0.05) inhibited percent rot of the test pathogens at 3.5% concentration w/v in vivo. Rot incidence was, however, lower in replicate tubers that were inoculated, treated with extracts and exposed than treatments that were covered. Phytochemical analysis of OSH and QP extracts revealed the presence of secondary metabolites such as alkaloids, flavonoids, saponins, tannins, ferulic acid, phlobatanins, Terpenoids, phenols, anthraquinone and pyroligneous acid. The efficacy of both extracts in reducing rot in this study recommends their development as prospective biopesticide formulation and use in the management of post-harvest rot of yam tubers.

  7. Impact of armillaria root rot in intensively managed white spruce/aspen stands

    Energy Technology Data Exchange (ETDEWEB)

    Blenis, P.V.; Mallet, K.I.; Titus, S.J.

    1995-12-31

    The Western Boreal Growth and Yield (WESBOGY) experiment was initiated to determine the growth and yield of aspen and white spruce when the two species occur in mixtures at different densities. Armillaria root rot may play an important role in mixedwood management because the fungus can attack both spruce and aspen, and the spatial distribution of trees influences the spread of these pathogens. The ultimate objective of WESBOGY is to determine the effect of the different densities on the impact of Armillaria root rot. However, as Armillaria may be distributed irregularly across the landscape, it is necessary to know the initial pathogen population so that it can be used as a covariate to adjust estimated treatment effects to account for different starting levels of Armillaria. This paper reports on a project to determine the distribution of Armillaria in two replicates of the WESBOGY trial. Armillaria distribution was determined by inserting trap logs into the soil between the planted spruces in July 1993 and examining the logs a year later for the distinctive white mycelium typical of Armillaria.

  8. Fusarium oxysporum as Causal Agent of Tomato Wilt and Fruit Rot

    Directory of Open Access Journals (Sweden)

    Maja Ignjatov

    2012-01-01

    Full Text Available Tomatoes are parasitized by a number of pathogens, including Fusarium oxysporum f. sp. lycopersici, causal agent of fusarium wilt. Fresh vegetable fruits can be contaminated with variousfungi that produce mycotoxins, which is an important issue for human health. The objective of this paper was to isolate, determine, and identify causal organisms of tomato wilt and fruit rot, based on the pathogens morphological and molecular characteristics. Samples ofdiseased plants showing symptoms of tomato wilt were collected from different localities in the production region of Vojvodina. Fruits with symptoms of fusarium rot were collected from storage and warehouses. The isolation and morphological determination of the fungus were performed on PDA and Czapek’s nutrient media. Isolates from diseased plants growing in field,designated as TFW1-TFW12 and seven isolates from diseased tomato fruits (TFM1-TFM7 were chosen for further investigation. For identification of the fungal solates, the polymerase chain reaction (PCR was also used. The EF1/EF2 primer pair was used for molecular identification of Fusarium sp. Nine analyzed samples were found to contain DNA fragments 700 bp in size.

  9. The 'Dr Jekyll and Mr Hyde fungus': noble rot versus gray mold symptoms of Botrytis cinerea on grapes.

    Science.gov (United States)

    Fournier, Elisabeth; Gladieux, Pierre; Giraud, Tatiana

    2013-09-01

    Many cryptic species have recently been discovered in fungi, especially in fungal plant pathogens. Cryptic fungal species co-occurring in sympatry may occupy slightly different ecological niches, for example infecting the same crop plant but specialized on different organs or having different phenologies. Identifying cryptic species in fungal pathogens of crops and determining their ecological specialization are therefore crucial for disease management. Here, we addressed this question in the ascomycete Botrytis cinerea, the agent of gray mold on a wide range of plants. On grape, B. cinerea causes severe damage but is also responsible for noble rot used for processing sweet wines. We used microsatellite genotyping and clustering methods to elucidate whether isolates sampled on gray mold versus noble rot symptoms in three French regions belong to genetically differentiated populations. The inferred population structure matched geography rather than the type of symptom. Noble rot symptoms therefore do not seem to be caused by a specific B. cinerea population but instead seem to depend essentially on microclimatic conditions, which has applied consequences for the production of sweet wines.

  10. Integrated Management of Causal Agents of Postharvest Fruit Rot of Apple

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    Mila Grahovac

    2011-01-01

    Full Text Available One of the major causes of poor quality and fruit loss (during storage and transportare diseases caused by phytopathogenic fungi. Economic losses which are the consequenceof the phytopathogenic fungus activity after harvest exceed the losses in the field.Themost important postharvest fungal pathogens of apple fruits are: Botrytis cinerea Pers. exFr., Penicillium expansum (Lk. Thom., Cryptosporiopsis curvispora (Peck. Grem., Colletotrichumgloeosporioides (Penz. Sacc., Monilinia sp., Gloeosporium album Osterw, Alternaria alternata(Fr. Keissler, Cladosporium herbarium Link., Cylindrocarpon mali (Alles. Wollenw., Stemphyliumbotryosum Wallr. The use of available protection technologies can significantly reducelosses caused by pathogens in storage. The concept of integrated pest management (IPMin apple fruits i.e. sustainable approach in control of causal agents of postharvest fruit rot,using cultural, physical, biological and chemical measures, to minimize economic, healthand risks to consumers and environment, is presented in the paper.

  11. FIRST REPORT OF Phytophthora nicotianae CAUSING ROOT ROT OF SOURSOP IN NORTHEASTERN BRAZIL

    Directory of Open Access Journals (Sweden)

    JAQUELINE FIGUEREDO DE OLIVEIRA COSTA

    Full Text Available ABSTRACT In 2013, soursop trees showing symptoms of root rot were observed in a field in Maceió, state of Alagoas, Brazil. It was isolated Phytophthora sp. which pathogenicity was confirmed in the host seedlings. Morphological and physiological characteristics in carrot-agar modified medium were consistent with Phytophthora nicotianae description. The PCR sequences products obtained with ITS1/ITS4 primers were compared to sequences of ribosomal DNA of Phytophthora species from the GenBank database observing high identity with other P. nicotianae isolates. A phylogenetic tree was performed to compare the isolate with other sequences of P. nicotianae, which clustering has been verified with 99% of bootstrap, confirming the morphophysiological studies. This is the first report of this pathogen on annonaceous plants in the Northeastern Brazil.

  12. Induced resistance in tomato fruit by γ-aminobutyric acid for the control of alternaria rot caused by Alternaria alternata.

    Science.gov (United States)

    Yang, Jiali; Sun, Cui; Zhang, Yangyang; Fu, Da; Zheng, Xiaodong; Yu, Ting

    2017-04-15

    The study investigated the effect of γ-aminobutyric acid (GABA) on the control of alternaria rot in tomato fruit and the possible mechanism involved. Our results showed exogenous GABA could stimulate remarkable resistance to the alternaria rot, while it had no direct antifungal activity against Alternaria alternata. Moreover, the activities of antioxidant enzymes, including peroxidase, superoxide dismutase and catalase, along with the expression of these corresponding genes, were significantly induced in the GABA treatment. The obtained data suggested GABA induced resistance against the necrotrophic pathogen A. alternata, at least in part by activating antioxidant enzymes, restricting the levels of cell death caused by reactive oxygen species. Meanwhile, the key enzyme genes of GABA shunt, GABA transaminase and succinic-semialdehyde dehydrogenase, were found up-regulated in the GABA treatment. The activation of the GABA shunt might play a vital role in the resistance mechanism underpinning GABA-induced plant immunity. Copyright © 2016 Elsevier Ltd. All rights reserved.

  13. Biological Control of Fusarium Stalk Rot of Maize Using Bacillus spp

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    Joon-Hee Han

    2015-12-01

    Full Text Available Maize (Zea mays L. is an economically important crop in worldwide. While the consumption of the maize is steadily increasing, the yield is decreasing due to continuous mono-cultivation and infection of soil-borne fungal pathogens such as Fusarium species. Recently, stalk rot disease in maize, caused by F. subglutinans and F. temperatum has been reported in Korea. In this study, we isolated bacterial isolates in rhizosphere soil of maize and subsequently tested for antagonistic activities against F. subglutinans and F. temperatum. A total of 1,357 bacterial strains were isolated from rhizosphere. Among them three bacterial isolates (GC02, GC07, GC08 were selected, based on antagonistic effects against Fusarium species. The isolates GC02 and GC07 were most efficient in inhibiting the mycelium growth of the pathogens. The three isolates GC02, GC07 and GC08 were identified as Bacillus methylotrophicus, B. amyloliquefaciens and B. thuringiensis using 16S rRNA sequence analysis, respectively. GC02 and GC07 bacterial suspensions were able to suppress over 80% conidial germination of the pathogens. GC02, GC07 and GC08 were capable of producing large quantities of protease enzymes, whereas the isolates GC07 and GC08 produced cellulase enzymes. The isolates GC02 and GC07 were more efficient in phosphate solubilization and siderophore production than GC08. Analysis of disease suppression revealed that GC07 was most effective in suppressing the disease development of stalk rot. It was also found that B. methylotrophicus GC02 and B. amyloliquefaciens GC07 have an ability to inhibit the growth of other plant pathogenic fungi. This study indicated B. methylotrophicus GC02 and B. amyloliquefaciens GC07 has potential for being used for the development of a biological control agent.

  14. Experimental infection of highly and low pathogenic avian influenza viruses to chickens, ducks, tree sparrows, jungle crows, and black rats for the evaluation of their roles in virus transmission.

    Science.gov (United States)

    Hiono, Takahiro; Okamatsu, Masatoshi; Yamamoto, Naoki; Ogasawara, Kohei; Endo, Mayumi; Kuribayashi, Saya; Shichinohe, Shintaro; Motohashi, Yurie; Chu, Duc-Huy; Suzuki, Mizuho; Ichikawa, Takaya; Nishi, Tatsuya; Abe, Yuri; Matsuno, Keita; Tanaka, Kazuyuki; Tanigawa, Tsutomu; Kida, Hiroshi; Sakoda, Yoshihiro

    2016-01-01

    Highly pathogenic avian influenza viruses (HPAIVs) have spread in both poultry and wild birds. Determining transmission routes of these viruses during an outbreak is essential for the control of avian influenza. It has been widely postulated that migratory ducks play crucial roles in the widespread dissemination of HPAIVs in poultry by carrying viruses along with their migrations; however close contacts between wild migratory ducks and poultry are less likely in modern industrial poultry farming settings. Therefore, we conducted experimental infections of HPAIVs and low pathogenic avian influenza viruses (LPAIVs) to chickens, domestic ducks, tree sparrows, jungle crows, and black rats to evaluate their roles in virus transmission. The results showed that chickens, ducks, sparrows, and crows were highly susceptible to HPAIV infection. Significant titers of virus were recovered from the sparrows and crows infected with HPAIVs, which suggests that they potentially play roles of transmission of HPAIVs to poultry. In contrast, the growth of LPAIVs was limited in each of the animals tested compared with that of HPAIVs. The present results indicate that these common synanthropes play some roles in influenza virus transmission from wild birds to poultry. Copyright © 2015 Elsevier B.V. All rights reserved.

  15. Creation of initial breeding material of potato with complex resistance to Fusarium dry rot and tuber late blight

    Directory of Open Access Journals (Sweden)

    В. В. Гордієнко

    2017-09-01

    Full Text Available Purpose. To select the initial breeding material with complex resistance to Fusarium dry rot and tuber late blight among the created potato of secondary interspecific hyb­rids. Methods. Interspecific hybridization, laboratory test, analytical approach. Results. Based on the interspecific hybridization, the initial breeding material was created and the degree of its resistance to the above pathogens was determined by way of artificial infection of tubers with the inoculum of such fungi as Fusarium sambucinum Fuck and Phytophthora infestans (Mont. De Bary. During interspecific hybridization based on schemes of saturating and enriching crosses, using forms of various species with a high phenotypic expression of resistance to Fusarium dry rot, the result of the cumulative effect of genes that control resistance to the pathogen was observed. Crossing combinations differed significantly for the degree of population average manifestation of resistance to the diseases. Conclusions. Combinations В54, В53, В61 with a mean resistance (above 7 grades to Fusarium dry rot have been selected. Such combinations as B52, B50 and B54 had increased resistance to tuber late blight. It was found that the combination В54 is characterized by complex resistance to both diseases. For further work, the following samples with complex resistance to Fusarium dry rot and tuber late blight (7 grades or more were selected: В59с42, В59с43, В50с16, В50с19, В50с44, В51с1, В51с26, В51с28, В52с11, В52с23, В52с24, В52с29, В53с1, В53с11, В53с17 , В53с23, В54с13, В54с14.

  16. Co-inoculation with rhizobia and AMF inhibited soybean red crown rot: from field study to plant defense-related gene expression analysis.

    Directory of Open Access Journals (Sweden)

    Xiang Gao

    Full Text Available Soybean red crown rot is a major soil-borne disease all over the world, which severely affects soybean production. Efficient and sustainable methods are strongly desired to control the soil-borne diseases.We firstly investigated the disease incidence and index of soybean red crown rot under different phosphorus (P additions in field and found that the natural inoculation of rhizobia and arbuscular mycorrhizal fungi (AMF could affect soybean red crown rot, particularly without P addition. Further studies in sand culture experiments showed that inoculation with rhizobia or AMF significantly decreased severity and incidence of soybean red crown rot, especially for co-inoculation with rhizobia and AMF at low P. The root colony forming unit (CFU decreased over 50% when inoculated by rhizobia and/or AMF at low P. However, P addition only enhanced CFU when inoculated with AMF. Furthermore, root exudates of soybean inoculated with rhizobia and/or AMF significantly inhibited pathogen growth and reproduction. Quantitative RT-PCR results indicated that the transcripts of the most tested pathogen defense-related (PR genes in roots were significantly increased by rhizobium and/or AMF inoculation. Among them, PR2, PR3, PR4 and PR10 reached the highest level with co-inoculation of rhizobium and AMF.Our results indicated that inoculation with rhizobia and AMF could directly inhibit pathogen growth and reproduction, and activate the plant overall defense system through increasing PR gene expressions. Combined with optimal P fertilization, inoculation with rhizobia and AMF could be considered as an efficient method to control soybean red crown rot in acid soils.

  17. Energy balance associated with the degradation of lignocellulosic material by white-rot and brown-rot fungi.

    Science.gov (United States)

    Derrien, Delphine; Bédu, Hélène; Buée, Marc; Kohler, Annegret; Goodell, Barry; Gelhaye, Eric

    2017-04-01

    Forest soils cover about 30% of terrestrial area and comprise between 50 and 80% of the global stock of soil organic carbon (SOC). The major precursor for this forest SOC is lignocellulosic material, which is made of polysaccharides and lignin. Lignin has traditionally been considered as a recalcitrant polymer that hinders access to the much more labile structural polysaccharides. This view appears to be partly incorrect from a microbiology perspective yet, as substrate alteration depends on the metabolic potential of decomposers. In forest ecosystems the wood-rotting Basidiomycota fungi have developed two different strategies to attack the structure of lignin and gain access to structural polysaccharides. White-rot fungi degrade all components of plant cell walls, including lignin, using enzymatic systems. Brown-rot fungi do not remove lignin. They generate oxygen-derived free radicals, such as the hydroxyl radical produced by the Fenton reaction, that disrupt the lignin polymer and depolymerize polysaccharides which then diffuse out to where the enzymes are located The objective of this study was to develop a model to investigate whether the lignin relative persistence could be related to the energetic advantage of brown-rot degradative pathway in comparison to white-rot degradative pathway. The model simulates the changes in substrate composition over time, and determines the energy gained from the conversion of the lost substrate into CO2. The energy cost for the production of enzymes involved in substrate alteration is assessed using information derived from genome and secretome analysis. For brown-rot fungus specifically, the energy cost related to the production of OH radicals is also included. The model was run, using data from the literature on populous wood degradation by Trametes versicolor, a white-rot fungus, and Gloeophyllum trabeum, a brown-rot fungus. It demonstrates that the brown-rot fungus (Gloeophyllum trabeum) was more efficient than the white-rot

  18. Molecular identification of Neofabraea species associated with bull's-eye rot on apple using rolling-circle amplification of partial EF-1α sequence.

    Science.gov (United States)

    Lin, Huijiao; Jiang, Xiang; Yi, Jianping; Wang, Xinguo; Zuo, Ranling; Jiang, Zide; Wang, Weifang; Zhou, Erxun

    2018-01-01

    A rolling-circle amplification (RCA) method with padlock probes targeted on EF-1α regions was developed for rapid detection of apple bull's-eye rot pathogens, including Neofabraea malicorticis, N. perennans, N. kienholzii, and N. vagabunda (synonym: N. alba). Four padlock probes (PLP-Nm, PLP-Np, PLP-Nk, and PLP-Nv) were designed and tested against 28 samples, including 22 BER pathogen cultures, 4 closely related species, and 2 unrelated species that may cause serious apple decays. The assay successfully identified all the bull's-eye rot pathogenic fungi at the level of species, while no cross-reaction was observed in all target species and no false-positive reaction was observed with all strains used for reference. This study showed that the use of padlock probes and the combination of probe signal amplification by RCA provided an effective and sensitive method for the rapid identification of Neofabraea spp. The method could therefore be a useful tool for monitoring bull's-eye rot pathogens in port quarantine and orchard epidemiological studies.

  19. Erwinia carotovora extracellular proteases : characterization and role in soft rot

    OpenAIRE

    Kyöstiö, Sirkka R. M.

    1990-01-01

    Erwinia carotovora subsp. carotovora (Ecc) strain EC14, a Gram-negative bacterium, causes soft rot on several crops, including potato. Maceration of potato tuber tissue is caused by secreted pectolytic enzymes. Other cell-degrading enzymes may also have roles in pathogenesis, including cellulases, phospholipases, and protease(s). The objectives of this research were to (1) characterize Ecc extracellular protease (Prt) and (2) elucidate its role in potato soft rot. A gene enc...

  20. Development of biocontrol agents from food microbial isolates for controlling post-harvest peach brown rot caused by Monilinia fructicola.

    Science.gov (United States)

    Zhou, Ting; Schneider, Karin E; Li, Xiu-Zhen

    2008-08-15

    An unconventional strategy of screening food microbes for biocontrol activity was used to develop biocontrol agents for controlling post-harvest peach brown rot caused by Monilinia fructicola. Forty-four microbial isolates were first screened for their biocontrol activity on apple fruit. Compared with the pathogen-only check, seven of the 44 isolates reduced brown rot incidence by >50%, including four bacteria: Bacillus sp. C06, Lactobacillus sp. C03-b and Bacillus sp. T03-c, Lactobacillus sp. P02 and three yeasts: Saccharomyces delbrueckii A50, S. cerevisiae YE-5 and S. cerevisiae A41. Eight microbial isolates were selected for testing on peaches by wound co-inoculation with mixtures of individual microbial cultures and conidial suspension of M. fructicola. Only two of them showed significant biocontrol activity after five days of incubation at 22 degrees C. Bacillus sp. C06 suppressed brown rot incidence by 92% and reduced lesion diameter by 88% compared to the pathogen-only check. Bacillus sp.T03-c reduced incidence and lesion diameter by 40% and 62%, respectively. The two isolates were compared with Pseudomonas syringae MA-4, a biocontrol agent for post-harvest peach diseases, by immersing peaches in an aliquot containing individual microbial isolates and the pathogen conidia. Treatments with isolates MA-4, C06 and T03-c significantly controlled brown rot by 91, 100, and 100% respectively. However, only isolates MA-4 and C06 significantly reduced brown rot by 80% and 15%, respectively when bacterial cells alone were applied. On naturally infected peaches, both the bacterial culture and its cell-free filtrate of the isolate C06 significantly controlled peach decay resulting in 77 and 90% reduction, respectively, whereas the treatment using only the bacterial cells generally had no effect. Isolate C06 is a single colony isolate obtained from a mesophilic cheese starter, and has been identified belonging to Bacillus amyloliquefaciens. The results have clearly

  1. Catecholamine biosynthesis pathway potentially involved in banana defense mechanisms to crown rot disease.

    Science.gov (United States)

    Lassois, L; De Clerck, C; Frettinger, P; De Lapeyre De Bellaire, L; Lepoivre, P; Haïssam Jijakli, M

    2011-01-01

    Variations in Cavendish bananas susceptibility to crown rot disease have been observed (Lassois et al., 2010a), but the molecular mechanisms underlying these quantitative host-pathogen relationships were still unknown. The present study was designed to compare gene expression between bananas (Musa acuminata, AAA, 'Grande-Naine') showing a high post-harvest susceptibility (S+) and bananas showing a low post-harvest susceptibility (S-) to crown rot disease. This comparison was performed between crowns (S+ and S-) collected one hour before standardized artificial inoculations with Colletotrichum musae. Fruit susceptibility was evaluated through lesion size on the crown 13 days later. Gene expression comparisons were performed with the cDNA-AFLP technique (Lassois et al., 2009). This revealed that a gene showing a strong homology with a dopamine-beta-monooxygenase (DoH) is differently expressed between S+ and S (Lassois et al., 2011). Furthermore, semi-quantitative real-time RT-PCR analyses between S+ and S- were applied to confirm the differential expression results for DoH obtained by cDNA-AFLP. Two biological replicates were tested. These semi-quantitative analyses were performed not only on tissues collected one hour before C. musae inoculation but also on crown tissues collected 13 days after inoculation. The real-time RT-PCR confirmed that DoH was upregulated in the S tissues collected at harvest, just before C. musae inoculation. This gene was also highly upregulated in the S- tissues collected 13 days after crown inoculation. Similar results were obtained for both biological replicates. Our results suggest that catecholamine's could play a role in banana defense mechanisms to crown rot disease.

  2. Identification, characterization and mycotoxigenic ability of Alternaria spp. causing core rot of apple fruit in Greece.

    Science.gov (United States)

    Ntasiou, Panagiota; Myresiotis, Charalampos; Konstantinou, Sotiris; Papadopoulou-Mourkidou, Euphemia; Karaoglanidis, George S

    2015-03-16

    Alternaria core rot is a major postharvest disease of apple fruit in several countries of the world, including Greece. The study was conducted aiming to identify the disease causal agents at species level, investigate the aggressiveness of Alternaria spp. isolates and the susceptibility of different apple varieties and determine the mycotoxigenic potential of Alternaria spp. isolates from apple fruit. Seventy-five Alternaria spp. isolates obtained from apple fruit showing core rot symptoms were identified as either Alternaria tenuissima or Alternaria arborescens at frequencies of 89.3 and 11.7%, respectively, based on the sequence of endopolygalacturonase (EndoPG) gene. Artificial inoculations of fruit of 4 different varieties (Fuji, Golden Delicious, Granny Smith and Red Delicious) and incubation at two different temperatures (2 and 25°C) showed that fruit of Fuji variety were the most susceptible and fruit of Golden Delicious the most resistant to both pathogens. In addition, the production of 3 mycotoxins, alternariol (AOH), alternariol monomethyl ether (AME) and tentoxin (TEN) was investigated in 30 isolates of both species. Mycotoxin determination was conducted both in vitro, on artificial nutrient medium and in vivo on artificially inoculated apple fruit, using a high performance liquid chromatography with diode array detector (HPLC-DAD). The results showed that most of the isolates of both species were able to produce all the 3 metabolites both in vivo and in vitro. On apple fruit A. tenuissima isolates produced more AOH than A. arborescens isolates, whereas the latter produced more TEN than the former. Such results indicate that Alternaria core rot represents a major threat of apple fruit production not only due to quantitative yield losses but also for qualitative deterioration of apple by-products. Copyright © 2014 Elsevier B.V. All rights reserved.

  3. Comparative studies on thermochemical characterization of corn stover pretreated by white-rot and brown-rot fungi.

    Science.gov (United States)

    Zeng, Yelin; Yang, Xuewei; Yu, Hongbo; Zhang, Xiaoyu; Ma, Fuying

    2011-09-28

    The effects of white-rot and brown-rot fungal pretreatment on the chemical composition and thermochemical conversion of corn stover were investigated. Fungus-pretreated corn stover was analyzed by Fourier transform infrared spectroscopy and X-ray diffraction analysis to characterize the changes in chemical composition. Differences in thermochemical conversion of corn stover after fungal pretreatment were investigated using thermogravimetric and pyrolysis analysis. The results indicated that the white-rot fungus Irpex lacteus CD2 has great lignin-degrading ability, whereas the brown-rot fungus Fomitopsis sp. IMER2 preferentially degrades the amorphous regions of the cellulose. The biopretreatment favors thermal decomposition of corn stover. The weight loss of IMER2-treated acid detergent fiber became greater, and the oil yield increased from 32.7 to 50.8%. After CD2 biopretreatment, 58% weight loss of acid detergent lignin was achieved and the oil yield increased from 16.8 to 26.8%.

  4. Draft Genome Sequence of the Plant Pathogen Dickeya zeae DZ2Q, Isolated from Rice in Italy.

    Science.gov (United States)

    Bertani, Iris; Passos da Silva, Daniel; Abbruscato, Pamela; Piffanelli, Pietro; Venturi, Vittorio

    2013-11-07

    Dickeya zeae is an emerging rice (Oryza sativa) pathogen causing bacterial foot rot. Related pathogens affect maize (Zea mays) and potato (Solanum tuberosum) and a variety of important ornamental and floral plants. Here, we present the draft genome sequence of D. zeae DZ2Q, an isolate obtained from rice grown in Italy.

  5. Draft Genome Sequence of the Plant Pathogen Dickeya zeae DZ2Q, Isolated from Rice in Italy

    OpenAIRE

    Bertani, Iris; Passos da Silva, Daniel; Abbruscato, Pamela; Piffanelli, Pietro; Venturi, Vittorio

    2013-01-01

    Dickeya zeae is an emerging rice (Oryza sativa) pathogen causing bacterial foot rot. Related pathogens affect maize (Zea mays) and potato (Solanum tuberosum) and a variety of important ornamental and floral plants. Here, we present the draft genome sequence of D. zeae DZ2Q, an isolate obtained from rice grown in Italy.

  6. Etiology and Population Genetics of Colletotrichum spp. Causing Crown and Fruit Rot of Strawberry.

    Science.gov (United States)

    Ureña-Padilla, A R; Mackenzie, S J; Bowen, B W; Legard, D E

    2002-11-01

    ABSTRACT Isolates of Colletotrichum spp. from diseased strawberry fruit and crowns were evaluated to determine their genetic diversity and the etiology of the diseases. Isolates were identified to species using polymerase chain reaction primers for a ribosomal internal transcribed spacer region and their pathogenicity was evaluated in bioassays. Isolates were scored for variation at 40 putative genetic loci with random amplified polymorphic DNA and microsatellite markers. Only C. acutatum was recovered from diseased fruit. Nearly all isolates from crowns were C. gloeosporioides. In crown bioassays, only isolates of C. gloeosporioides from strawberry caused collapse and death of plants. A dendrogram generated from the genetic analysis identified several primary lineages. One lineage included isolates of C. acutatum from fruit and was characterized by low diversity. Another lineage included isolates of C. gloeosporioides from crowns and was highly polymorphic. The isolates from strawberry formed distinctive clusters separate from citrus isolates. Evaluation of linkage disequilibrium among polymorphic loci in isolates of C. gloeosporioides from crowns revealed a low level of disequilibrium as would be expected in sexually recombining populations. These results suggest that epidemics of crown rot are caused by Glomerella cingulata (anamorph C. gloeosporioides) and that epidemics of fruit rot are caused by C. acutatum.

  7. The Effect and Action Mechanisms of Oligochitosan on Control of Stem Dry Rot of Zanthoxylum bungeanum.

    Science.gov (United States)

    Li, Peiqin; Cao, Zhimin; Wu, Zhou; Wang, Xing; Li, Xiuhong

    2016-06-30

    In this report, the effects of two oligochitosans, i.e., oligochitosan A (OCHA) and oligochitosan B (OCHB), on control of dry rot of Zanthoxylum bungeanum (Z. bungeanum) caused by Fusarium sambucinum (F. sambucinum) were evaluated. First, both oligochitosans show desirable ability to decrease the infection of F. sambucinum. Second, the oligochitosans strongly inhibit the radial colony and submerged biomass growth of F. sambucinum. Lastly, these oligochitosans are capable of increasing the activities of phenylalanine ammonia lyase (PAL), polyphenoloxidase (PPO) and peroxidase (POD) significantly, as well as enhancing the content of total phenolics in Z. bungeanum stems. These findings indicate that the protective effects of OCHA and OCHB on Z. bungeanum stems against dry rot may be associated with the direct fungitoxic function against pathogen and the elicitation of biochemical defensive responses in Z. bungeanum stems. The outcome of this report suggests that oligochitosans may serve as a promising natural fungicide to substitute, at least partially, for synthetic fungicides in the disease management of Z. bungeanum.

  8. Basal Root Rot, a new Disease of Teak (Tectona grandis in Malaysia caused by Phellinus noxius

    Directory of Open Access Journals (Sweden)

    Mohd Farid, A.

    2005-01-01

    Full Text Available Basal root rot of teak was first reported from Sabak Bernam, Selangor making this the first report of the disease on teak in Peninsular Malaysia. The fungus found associated with the disease was Phellinus noxious. The disease aggressively killed its host irrespective of the host health status. Bark depression at the root collar which was visible from a distance was the characteristic symptom and the main indicator in identifying the disease in the plantation since above ground symptoms of the canopy could not be differentiated from crowns of healthy trees. However, although above ground symptoms were not easily discernible, the disease was already advanced and the trees mostly beyond treatment; 3.4 % of the trees in the plantation were affected and the disease occurred both on solitary trees and in patches. Below ground, infected trees had rotted root systems, mainly below and around the collar region with brown discolored wood and irregular golden-brown honeycomb-like pockets of fungal hyphae in the wood. Pathogenicity tests showed that the fungus produced symptoms similar to those observed in the plantation and killed two year-old teak plants. The disease killed all the inoculated hosts within three months, irrespective of wounded or unwounded treatments.

  9. The Effect and Action Mechanisms of Oligochitosan on Control of Stem Dry Rot of Zanthoxylum bungeanum

    Directory of Open Access Journals (Sweden)

    Peiqin Li

    2016-06-01

    Full Text Available In this report, the effects of two oligochitosans, i.e., oligochitosan A (OCHA and oligochitosan B (OCHB, on control of dry rot of Zanthoxylum bungeanum (Z. bungeanum caused by Fusarium sambucinum (F. sambucinum were evaluated. First, both oligochitosans show desirable ability to decrease the infection of F. sambucinum. Second, the oligochitosans strongly inhibit the radial colony and submerged biomass growth of F. sambucinum. Lastly, these oligochitosans are capable of increasing the activities of phenylalanine ammonia lyase (PAL, polyphenoloxidase (PPO and peroxidase (POD significantly, as well as enhancing the content of total phenolics in Z. bungeanum stems. These findings indicate that the protective effects of OCHA and OCHB on Z. bungeanum stems against dry rot may be associated with the direct fungitoxic function against pathogen and the elicitation of biochemical defensive responses in Z. bungeanum stems. The outcome of this report suggests that oligochitosans may serve as a promising natural fungicide to substitute, at least partially, for synthetic fungicides in the disease management of Z. bungeanum.

  10. Investigating the efficacy of Bacillus subtilis SM21 on controlling Rhizopus rot in peach fruit.

    Science.gov (United States)

    Wang, Xiaoli; Wang, Jing; Jin, Peng; Zheng, Yonghua

    2013-06-17

    The efficacy of Bacillus subtilis SM21 on controlling Rhizopus rot caused by Rhizopus stolonifer in postharvest peach fruit and the possible mechanisms were investigated. The results indicated B. subtilis SM21 treatment reduced lesion diameter and disease incidence by 37.2% and 26.7% on the 2nd day of inoculation compared with the control. The in vitro test showed significant inhibitory effect of B. subtilis SM21 on mycelial growth of R. stolonifer with an inhibition rate of 48.9%. B. subtilis SM21 treatment significantly enhanced activities of chitinase and β-1,3-glucanase, and promoted accumulation of H2O2. Total phenolic content and 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical-scavenging activity were also increased by this treatment. Transcription of seven defense related genes was much stronger in fruit treated with B. subtilis SM21 or those both treated with B. subtilis SM21 and inoculated with R. stolonifer compared with fruit inoculated with R. stolonifer alone. These results suggest that B. subtilis SM21 can effectively inhibit Rhizopus rot caused by R. stolonifer in postharvest peach fruit, possibly by directly inhibiting growth of the pathogen, and indirectly inducing disease resistance in the fruit. Copyright © 2013 Elsevier B.V. All rights reserved.

  11. Biocontrol mechanisms of Trichoderma harzianum against soybean charcoal rot caused by Macrophomina phaseolina

    Directory of Open Access Journals (Sweden)

    Khaledi Nima

    2016-01-01

    Full Text Available Throughout the world, charcoal rot, caused by Macrophomina phaseolina, is one of the most destructive and widespread diseases of crop plants such as soybean. In this study, the biological control capability of 11 Trichoderma spp. isolates against M. phaseolina was investigated using screening tests. Among all the tested Trichoderma spp. isolates, inhibition varied from 20.22 to 58.67% in dual culture tests. Dual culture, volatile and non-volatile tests revealed that two isolates of Trichoderma harzianum (including the isolates T7 and T14 best inhibited the growth of M. phaseolina in vitro. Therefore, these isolates were selected for biocontrol of M. phaseolina in vivo. The results of greenhouse experiments revealed that disease severity in the seed treatment with T. harzianum isolates was significantly lower than that of the soil treatment. In most of the cases, though, soil treatment with T. harzianum resulted in higher plant growth parameters, such as root and shoot weight. The effects of T. harzianum isolates on the activity of peroxidase enzyme and phenolic contents of the soybean root in the presence and absence of M. phaseolina were determined in greenhouse conditions. Our results suggested that a part of the inhibitory effect of T. harzianum isolates on soybean charcoal rot might be related to the indirect influence on M. phaseolina. Plant defense responses were activated as an elicitor in addition to the direct effect on the pathogen growth.

  12. Screening bactericidal effect of Pectobacterium carotovorum subsp. carotovorum strains against causal agent of potato soft rot.

    Science.gov (United States)

    Kazemi-Zaromi, Samaneh; Baghaee-Ravari, Sareh; Khodaygan, Pejman; Falahati-Rastegar, Mahrokh

    2016-02-01

    This study focuses on the potential of Pectobacterium carotovorum subsp. carotovorum (Pcc) strains producing bacteriocin as a tool to control potato soft rot disease. Thirty out of 48 purified bacterial strains were characterized as Pcc using specific PCR and phenotypic tests. The pathogenicity and pectate degrading assays were recorded positive for 13 strains. Bacteriocin typing clustered producers into three groups according to their antimicrobial spectra. Majority of the producers except strains of group II showed antibacterial activity toward relative genus and the role of UV or mitomycin C was inductive. In addition, none of the distant genus was sensitive to Pcc bacteriocins except Rhizobium vitis. Molecular detection of four bacteriocins including carotovoricin, carosin S1, S2 and carosin D was performed. Overall, 54.5% of group I, 47.3 and 70% of groups II and III strains carried carotovoricin and four strains harbored gene corresponding to carosin S1. According to our data divers antimicrobial patterns obtained by Pcc strains and existence of new bateriocines could be possible. Moreover, our findings recommended that direct application of P29 or expression of corresponding genes of Pog22 or P21 in a nonpathogenic strain as a biocontrol agent may improve soft rot disease control. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. A combination of biocontrol agents improves the management of dry root rot (Macrophomina phaseolina in greengram

    Directory of Open Access Journals (Sweden)

    R. Thilagavathi

    2007-08-01

    Full Text Available The biocontrol agents Trichoderma viride (strains Tv1 and Tv13, Pseudomonas fluorescens (Pf1 and Py15 and Bacillus subtilis (Bs16 were tested individually and in combination for their effectiveness against root rot of greengram caused by Macrophomina phaseolina. As regards the compatibility of the biocontrol agents with each other, T. viride strains were not compatible with B. subtilis (Bs16, but P. fluorescens strains were compatible with B. subtilis and T. viride. Of the biocontrol agents tested in vitro against M. phaseolina, combinations of P. fluorescens+T. viride (Pf1+Tv1, Pf1+Tv13 and Py15+Tv1 inhibited mycelial growth of the pathogen and they also promoted the growth of the greengram seedlings. A combination of Pf1+Tv1 was most effective in reducing root rot incidence under glass-house and field conditions as compared with other single or combined treatments or the untreated control. The activity of the defense-related enzymes peroxidase, polyphenol oxidase and phenyl alanine ammonia lyase was significantly greater in greengram plants treated with a talc based formulation containing Pf1+Tv1 followed by Pf1+Tv13 and Py15+Tv1, than in plants receiving other treatments or the untreated control. Moreover, a combination of Pf1+Tv1 followed by Pf1+Tv13 and Py15+Tv1 significantly increased yield under glass house and field conditions.

  14. Drug Target Identification and Prioritization for Treatment of Ovine Foot Rot: An In Silico Approach

    Directory of Open Access Journals (Sweden)

    Abhishek Acharya

    2016-01-01

    Full Text Available Ovine foot rot is an infection of the feet of sheep, mainly caused by Dichelobacter nodosus. In its virulent form, it is highly contagious and debilitating, causing significant losses in the form of decline in wool growth and quality and poor fertility. Current methods of treatment are ineffective in complete eradication. Effective antibiotic treatment of foot rot is hence necessary to ensure better outcomes during control phases by reduction in culling count and the possibility of carriers of the infection. Using computational approaches, we have identified a set of 297 proteins that are essential to the D. nodosus and nonhomologous with sheep proteins. These proteins may be considered as potential vaccine candidates or drug targets for designing antibiotics against the bacterium. This core set of drug targets have been analyzed for pathway annotation to identify 67 proteins involved in unique bacterial pathways. Choke-point analysis on the drug targets identified 138 choke-point proteins, 29 involved in unique bacterial pathways. Subcellular localization was also predicted for each target to identify the ones that are membrane associated or secreted extracellularly. In addition, a total of 13 targets were identified that are common in at least 10 pathogenic bacterial species.

  15. Unconventional alternatives for control of tomato root rot caused by Rhizoctonia solani under greenhouse conditions

    Directory of Open Access Journals (Sweden)

    Hamza Amany

    2016-07-01

    Full Text Available This study was done to assess the antifungal effect of some biocontrol agents effective microorganisms (EMs1, Pseudomonas fluorescens, and Bacillus pumilus, titanium dioxide (TiO2 nanoparticles, black cumin and wheat germ oils as well as the recommended fungicide (flutolanil against root rot of tomato. Moreover, gas chromatography-mass spectrometry (GC-MS examination was completed to identify the bioactive compounds in plant oils (dark cumin and wheat germ. Also the impact of these medicines on some biochemical and growth parameters of tomato was examined. Flutolanil was the best treatment followed by dark cumin, TiO2, EMs1, Pseudomonas fluorescens, Bacillus pumilus and wheat germ oil, individually in both test seasons. The outcomes demonstrated a marked increase in each biochemical character (chlorophyll substance, peroxidase and polyphenoloxidase and plant development (height and fresh and dry weight under all the tried treatments in comparison to the controls.

  16. Postharvest biological control of brown rot in peaches after cold storage preceded by preharvest chemical control 1

    Directory of Open Access Journals (Sweden)

    Elizandra Pivotto Pavanello

    2015-12-01

    Full Text Available ABSTRACT Pathogenic fungi cause skin darkening and peach quality depreciation in post harvest. Therefore, alternative techniques to chemical treatment are necessary in order to reduce risks to human health. The aim of this study was to evaluate the effect of the application of Trichoderma harzianum in association with different fungicides applied before harvest to 'Eldorado' peaches for brown rot control and other quality parameters during storage. The treatments consisted of five preharvest fungicide applications (control, captan, iprodione, iminoctadine and tebuconazole associated with postharvest application of T. harzianum, after cold storage (with and without application, in three evaluation times (zero, two and four days at 20 °C, resulting in a 5x2x3 factorial design. The application of T. harzianum only brought benefits to the control of brown rot when combined with the fungicide captan, at zero day shelf life. After two days, there was a greater skin darkening in peaches treated with T. harzianum compared with peaches without the treatment, except for peaches treated with the fungicide iprodione and T. harzianum The application of T. harzianum during postharvest showed no benefits for the control of brown rot, however, the association with fungicides reduced the incidence of Rhizopus stolonifer during the shelf life.

  17. Fusarium proliferatum - Causal agent of garlic bulb rot in Spain: Genetic variability and mycotoxin production.

    Science.gov (United States)

    Gálvez, Laura; Urbaniak, Monika; Waśkiewicz, Agnieszka; Stępień, Łukasz; Palmero, Daniel

    2017-10-01

    Fusarium proliferatum is a world-wide occurring fungal pathogen affecting several crops included garlic bulbs. In Spain, this is the most frequent pathogenic fungus associated with garlic rot during storage. Moreover, F. proliferatum is an important mycotoxigenic species, producing a broad range of toxins, which may pose a risk for food safety. The aim of this study is to assess the intraspecific variability of the garlic pathogen in Spain implied by analyses of translation elongation factor (tef-1α) and FUM1 gene sequences as well as the differences in growth rates. Phylogenetic characterization has been complemented with the characterization of mating type alleles as well as the species potential as a toxin producer. Phylogenetic trees based on the sequence of the translation elongation factor and FUM1 genes from seventy nine isolates from garlic revealed a considerable intraspecific variability as well as high level of diversity in growth speed. Based on the MAT alleles amplified by PCR, F. proliferatum isolates were separated into different groups on both trees. All isolates collected from garlic in Spain proved to be fumonisin B 1 , B 2 , and B 3 producers. Quantitative analyses of fumonisins, beauvericin and moniliformin (common secondary metabolites of F. proliferatum) showed no correlation with phylogenetic analysis neither mycelial growth. This pathogen presents a high intraspecific variability within the same geographical region and host, which is necessary to be considered in the management of the disease. Copyright © 2017 Elsevier Ltd. All rights reserved.

  18. Symptomology and etiology of a new disease, yellow stunt, and root rot of standing milkvetch caused by Embellisia sp. in Northern China.

    Science.gov (United States)

    Li, Yan Zhong; Nan, Zhi Biao

    2007-06-01

    An Embellisia sp. has been established as the cause of a new disease of the herbaceous perennial forage legume, 'standing milkvetch' (Astragalus adsurgens Pall.) in Northern China, which severely reduces plant density and degrades A. adsurgens stands. The disease was common at an experimental location in Gansu Province where it was recognized by the occurrence of stunted plants with reddish-brown stems and yellow and necrotic leaf blades. An Embellisia sp. was isolated from symptomatic stem, leaf blade, petiole, and root tissues at varying frequencies of up to 90%. Single-spore isolates grew very slowly on PCA, PDA, V-8 and, wheat hay decoction agar. Pathogenicity was confirmed by inoculation of seeds, dipping 2-day-old pre-germinated seedlings in inoculum and spraying inoculum on 6-month-old plants. Symptoms on test plants included yellow leaf lesions, brown lesions on stems and petioles, stunted side-shoots with yellow, small, distorted and necrotic leaves, shoot blight, bud death, crown rot, root rot, and plant death. The disease is named as 'yellow stunt and root rot' of A. adsurgens to distinguish it from diseases caused by other known pathogens. Embellisia sp. is also pathogenic to A. sinicus but not to 11 other tested plant species.

  19. The Growth of Root Rot Disease on Pepper Seed Applied by Trichoderma Harzianum Inoculum

    Directory of Open Access Journals (Sweden)

    S. Sofian

    2013-06-01

    Full Text Available Normal 0 false false false IN X-NONE X-NONE MicrosoftInternetExplorer4 Root rot disease on pepper caused by Phytophthora capsici is one of the most important diseases on pepper. The using of antagonistic fungus of Trichoderma harzianum as a biological control agent of the pathogen is one of the important alternatives in controlling P. capsici without causing negative effects on the environment. The objectives of the research were to study about the ability of T. harzianum inoculum application in inhibiting the development of root-rot disease, influenced the growth of pepper seed, to studythe effective length time application of T. harzianum inoculum in inhibiting the development of root rot disease, and increased the growth of pepper seedlings. This research was arranged in a completely randomized design, with five treatments of length time application of T. harzianum inoculum i.e. control treatment without applicationtime of T. harzianum inoculum (K, application time of T. harzianum inoculum for 0 week (S0, application time of T. harzianum inoculum for 1 week (S1, application time of T. harzianum inoculum for two weeks (S2, application time of T. harzianum inoculum for three weeks (S3, and application time of T. harzianum inoculum for 4 weeks (S4 before planting. Each treatment was repeated15 times. The observed parameterswere disease percentage, the inhibition of antagonistic fungus, disease infection rate, plant height, number of leaves, wet and dry weight of plant, stem and leaves on pepper seed, and P. capsici population density. The result showed that application time of T. harzianum inoculumfor 4 weeks (S4 before planting is the most effective time in inhibiting the development of root rot disease than the other treatment sand also had significant effect on increasing the growth of pepper seed. The antagonism test showed that T. harzianum could inhibit P. capsiciin vitro. This result proves that application time of T. harzianum inoculums

  20. ROTS: An R package for reproducibility-optimized statistical testing.

    Science.gov (United States)

    Suomi, Tomi; Seyednasrollah, Fatemeh; Jaakkola, Maria K; Faux, Thomas; Elo, Laura L

    2017-05-01

    Differential expression analysis is one of the most common types of analyses performed on various biological data (e.g. RNA-seq or mass spectrometry proteomics). It is the process that detects features, such as genes or proteins, showing statistically significant differences between the sample groups under comparison. A major challenge in the analysis is the choice of an appropriate test statistic, as different statistics have been shown to perform well in different datasets. To this end, the reproducibility-optimized test statistic (ROTS) adjusts a modified t-statistic according to the inherent properties of the data and provides a ranking of the features based on their statistical evidence for differential expression between two groups. ROTS has already been successfully applied in a range of different studies from transcriptomics to proteomics, showing competitive performance against other state-of-the-art methods. To promote its widespread use, we introduce here a Bioconductor R package for performing ROTS analysis conveniently on different types of omics data. To illustrate the benefits of ROTS in various applications, we present three case studies, involving proteomics and RNA-seq data from public repositories, including both bulk and single cell data. The package is freely available from Bioconductor (https://www.bioconductor.org/packages/ROTS).

  1. Relative Efficacy of On-Farm Weeds as Soil-Amendement for Managing Dry Root Rot of Clusterbean in an Arid Environment

    Directory of Open Access Journals (Sweden)

    R. Mawar

    2006-12-01

    Full Text Available The effectiveness of certain on-farm weeds as soil amendments was ascertained against Macrophomina phaseolina, a soil-borne pathogen causing dry root rot of crops grown under rainfed conditions in arid regions. Population changes in M. phaseolina were determined in soils amended separately with residues (1%, w:w of Aerva persica, Celosia argentea, Corchorus depressus, Euphorbia hirta, Heliotropium subulatum and Polycarpaea corymbosa, for a period of 90 days. Significant reductions by 90.4–100% in the population of M. phaseolina were achieved with all the weed residues except P. corymbosa. Celosia and Euphorbia residues completely eradicated viable propagules of M. phaseolina. A strong increase (44–61% in the population of antagonistic actinomycetes was also found in soil amended with Corchorus and Euphorbia. In field tests, soil amended (50 g m2 with Euphorbia, Aerva and Celosia residues significantly reduced dry root rot incidence on clusterbean and also reduced M. phaseolina propagules in the soil. However, dry root rot incidence in Polycarpaea-amended soil (5.8–24.6% was not significantly different from that in non-amended soil (4.3–25.3% in both years of the experiment. P. corymbosa also increased the number of propagules of M. phaseolina in the soil. The results demonstrate that dry root rot of rainfed-cultivated annual crops in arid land can be managed with certain weeds as a soil amendment.

  2. Diaporthaceae associated with root rot of maize

    NARCIS (Netherlands)

    Lamprecht, S.C.; Crous, P.W.; Groenewald, J.Z.; Tewoldemedhin, Y.T.; Marasas, W.F.O.

    2011-01-01

    We investigated the identity and genetic diversity of more than 100 isolates belonging to Phyllosticta (teleomorph Guignardia), with particular emphasis on Phyllosticta citricarpa and Guignardia mangiferae s.l. occurring on Citrus. Phyllosticta citricarpa is the causal agent of Citrus Black Spot and

  3. Genetic variation between Phytophthora cactorum isolates differing in their ability to cause crown rot in strawberry

    OpenAIRE

    Eikemo, H.; Klemsdal, S.S.; Riisberg, I.; Bonants, P.J.M.; Stensvand, A.; Tronsmo, A.M.

    2004-01-01

    Analysis of 44 isolates of Phytophthora cactorum, isolated from strawberry and other hosts, by AFLP showed that the crown rot pathotype is different from leather rot isolates and from P. cactorum isolated from other hosts. 16 of 23 crown rot isolates, including isolates from Europe, Japan, Australia, and New Zealand, were identical in an analysis based on 96 polymorphic bands from seven primer combinations. Leather rot isolates of strawberry could not be distinguished from isolates from other...

  4. Black holes

    International Nuclear Information System (INIS)

    Feast, M.W.

    1981-01-01

    This article deals with two questions, namely whether it is possible for black holes to exist, and if the answer is yes, whether we have found any yet. In deciding whether black holes can exist or not the central role in the shaping of our universe played by the forse of gravity is discussed, and in deciding whether we are likely to find black holes in the universe the author looks at the way stars evolve, as well as white dwarfs and neutron stars. He also discusses the problem how to detect a black hole, possible black holes, a southern black hole, massive black holes, as well as why black holes are studied

  5. First report of Fusarium proliferatum causing dry rot in Michigan commercial potato (Solanum tuberosum) production

    Science.gov (United States)

    Fusarium dry rot of potato is a postharvest disease caused by several Fusarium spp. and is of worldwide importance. Thirteen Fusarium spp. have been implicated in fungal dry rots of potatoes worldwide. Among them, 11 species have been reported causing potato dry rot of seed tubers in the northern Un...

  6. Fusarium spp. causing dry rot of seed potato tubers in Michigan and their sensitivity to fungicides

    Science.gov (United States)

    Fusarium dry rot of potato (Solanum tuberosum L.) is a postharvest disease that can be caused by several Fusarium spp. A survey was conducted to establish the composition of Fusarium species causing dry rot of seed tubers in Michigan. A total of 370 dry rot symptomatic tubers were collected in 2009 ...

  7. Occurrence of wood-and root- rot basidiomycetes on trees in Bayero ...

    African Journals Online (AJOL)

    Several death and decays or rots of tropical trees are as result of infection caused by wood and root rot 'parasitic basidiomycetes. In the present study, survey of parasitic homobasidiomycetes causing wood and root rot on woody trees in Bayero University, Kano (two campuses) was carried out between April – September ...

  8. Genetic variation between Phytophthora cactorum isolates differing in their ability to cause crown rot in strawberry

    NARCIS (Netherlands)

    Eikemo, H.; Klemsdal, S.S.; Riisberg, I.; Bonants, P.J.M.; Stensvand, A.; Tronsmo, A.M.

    2004-01-01

    Analysis of 44 isolates of Phytophthora cactorum, isolated from strawberry and other hosts, by AFLP showed that the crown rot pathotype is different from leather rot isolates and from P. cactorum isolated from other hosts. 16 of 23 crown rot isolates, including isolates from Europe, Japan,

  9. Occurrence of black Aspergilli in indoor environments of six countries

    NARCIS (Netherlands)

    Varga, János; Kocsubé, Sándor; Szigeti, Gyöngyi; Baranyi, Nikolett; Vágvölgyi, Csaba; Jakšić Despot, Daniela; Magyar, Donát; Meijer, Martin; Samson, Robert A; Segvić Klarić, Maja

    Black Aspergilli (Aspergillus section Nigri) are widely distributed in various habitats. They act as food spoilage organisms, human pathogens, and mycotoxin producers and are frequently encountered in indoor environments. Black Aspergilli, specifically A. niger, A. welwitschiae, and A. carbonarius,

  10. In vitro and in vivo antagonism of actinomycetes isolated from Moroccan rhizospherical soils against Sclerotium rolfsii: a causal agent of root rot on sugar beet (Beta vulgaris L.).

    Science.gov (United States)

    Errakhi, R; Lebrihi, A; Barakate, M

    2009-08-01

    To evaluate the ability of the isolated actinomycetes to inhibit in vitro plant pathogenic fungi and the efficacy of promising antagonistic isolates to reduce in vivo the incidence of root rot induced by Sclerotium rolfsii on sugar beet. Actinomycetes isolated from rhizosphere soil of sugar beet were screened for antagonistic activity against a number of plant pathogens, including S. rolfsii. Ten actinomycetes out of 195 screened in vitro were strongly inhibitory to S. rolfsii. These isolates were subsequently tested for their ability to inhibit sclerotial germination and hyphal growth of S. roflsii. The most important inhibitions were obtained by the culture filtrate from the isolates J-2 and B-11, including 100% inhibition of sclerotial germination and 80% inhibition of hyphal growth. These two isolates (J-2 and B-11) were then screened for their ability to protect sugar beet against infection of S. rolfsii induced root rot in a pot trial. The treatment of S. rolfsii infested soil with a biomass and culture filtrate mixture of the selected antagonists reduced significantly (P sugar beet. Isolate J-2 was most effective and allowed a high fresh weight of sugar beet roots to be obtained. Both antagonists J-2 and B-11 were classified as belonging to the genus Streptomyces species through morphological and chemical characteristics as well as 16S rDNA analysis. Streptomyces isolates J-2 and B-11 showed a potential for controlling root rot on sugar beet and could be useful in integrated control against diverse soil borne plant pathogens. This investigation showed the role, which actinomycete bacteria can play to control root rot caused by S. rolfsii, in the objective to reduce treatments with chemical fungicides.

  11. Occurrence OF Pectobacterium carotovorum strains isolated from potato soft rot in Morocco.

    Science.gov (United States)

    Terta, M; El Karkouri, A; Ait M'hand, R; Achbani, E; Barakate, M; Amdan, M; Annajar, B; El Hassouni, M; Val, F; Bouteau, F; Ennaji, M M

    2010-09-11

    Pectobacterium carotovorum subsp. carotovorum, Pectobacterium astrosepticum and Pectobacterium chrysanthemi are the soft rot tuber of potatoes pathogens (Solanum tuberosum). The aim of this study was to determine the occurrence of these pathogens in Moroccan regions producing potatoes. Fifty three isolates of Pectobacterium were isolated on medium Crystal Violet Pectate. The comparison of their bacteriological characteristics with standard strains allowed us to conclude that all the isolates belonged to the Pectobacterium. With regard to phenotype characteristics, the variability that was found included 32 typical Pectobacetrium carotovorum subsp. carotovorum, 3 typical Pectobacterium atrosepticum, and 18 atypical Pectobacterium carotovorum subsp. carotovorum. Three strains of the atypical group; showed that the biochemical properties overlap among the Pectobacterium carotovorum and Pectobacterium chrysanthemi. These data were needed molecular characterization. However, the PCR amplification of total genomic DNA of 53 isolates with the two primers Y1/Y2 and P143/P145 yielded an amplified fragment of the expected size (434 bp) only with Y1/Y2, indicated that all the isolates collected and tested belonged to the Pectobacterium carotovorum species. On the basis the pathogenicity tests, these strains revealed that they were pectinolytic, and showed differences in aggressiveness against potato and leaves of tobacco.

  12. Black Alcoholism.

    Science.gov (United States)

    Watts, Thomas D.; Wright, Roosevelt

    1988-01-01

    Examines some aspects of the problem of alcoholism among Blacks, asserting that Black alcoholism can best be considered in an ecological, environmental, sociocultural, and public health context. Notes need for further research on alcoholism among Blacks and for action to reduce the problem of Black alcoholism. (NB)

  13. Black Culture

    Science.gov (United States)

    Brown, Angela Khristin

    2013-01-01

    The migration of blacks in North America through slavery became united. The population of blacks passed down a tradition of artist through art to native born citizens. The art tradition involved telling stories to each generation in black families. The black culture elevated by tradition created hope to determine their personal freedom to escape…

  14. Aggressive root pathogen Phellinus noxius and implications for western Pacific Islands

    Science.gov (United States)

    Sara M. Ashiglar; Phil G. Cannon; Ned B. Klopfenstein

    2015-01-01

    Phellinus noxius is an aggressive root rot pathogen affecting tropical and subtropical forests. Causing much damage in tropical Asia, Africa, Taiwan, Japan and the Pacific Islands, its wide host range encompasses more than 200 plant species representing 59 families (Ann et al. 2002). It can devastate agricultural plantations of tea, rubber, cocoa, avocados,...

  15. Identification of Rhizopus stolonifer as a Pre-emergence Seedling Disease Pathogen of Beta vulgaris

    Science.gov (United States)

    Rhizopus stolonifer, a common soil borne fungus in Michigan, is a known root rot pathogen on mature sugar beet. In 2008, Rs was isolated from a sugar beet seed lot showing consistently low germination rates in both the field and lab, and Rs was morphologically identified on malt extract agar. Much o...

  16. Toward The identification Of candidate genes involved in black pod disease resistance in Theobroma cacao L.

    Science.gov (United States)

    Increasing yield, quality and disease resistance are important objectives for cacao breeding programs. Some of the diseases, such as black pod rot (Phytophtora spp), frosty pod (Moniliophthora roreri) and witches’ broom (M. perniciosa), produce significant losses in all or in some of the various pro...

  17. Combination of RNAseq and SNP nanofluidic array reveals the center of genetic diversity of cacao pathogen Moniliophthora roreri in the upper Magdalena Valley of Colombia and its clonality

    Science.gov (United States)

    Moniliophthora roreri is the fungal pathogen that causes frosty pod rot (FPR) disease of Theobroma cacao L., the source of chocolate. FPR occurs in most of the cacao producing countries in the Western Hemisphere, causing yield losses up to 80%. Genetic diversity within the FPR pathogen population ma...

  18. in vitro technique for selecting onion for white rot disease

    African Journals Online (AJOL)

    ACSS

    and Simmonds, D.H. 2003. Partial resistance to white mold in a transgenic soybean line. Crop Science 43: 92-95. Coventry, E., Noble, R., Mead, A. and Whipps,. J.M. 2005. Suppression of Allium white rot. (Sclerotium cepivorum) in different soils using vegetable wastes. European Journal of Plant Pathology 111: 101-112.

  19. Evaluation of common bean (Phaseolus vulgaris) response to charcoal rot

    Science.gov (United States)

    Charcoal rot in common beans (Phaseolus vulgaris L.), caused by Macrophomina phaseolina (Tassi) Gold. (Mph), is an endemic disease in the prevailing hot and dry conditions in southern Puerto Rico. This study evaluated the 120 bean genotypes that compose the BASE 120 panel under screenhouse conditio...

  20. improvement of resistance to fusarium root rot through gene

    African Journals Online (AJOL)

    Prof. Adipala Ekwamu

    PhD. Thesis. University of KwaZulu-Natal, Pietmeritzburg,. South Africa. Navarro, F., Sass, M.E. and Nienhuis, J. 2003. Identification and mapping bean root rot resistance in an 'Eagle x Puebla 152' population. Annual Report of the Bean. Improvement Cooperative 47:83–84. Park, S.J. and Tu, J.C. 1994. Genetic segregation.

  1. Biodegrading effects of some rot fungi on Pinus caribaea wood

    African Journals Online (AJOL)

    STORAGESEVER

    2008-05-16

    May 16, 2008 ... degradation was peculiar with each fungus. Wood decay varied along the tree bole but was not related to height above the ground. The results indicated that biodegradation by rot fungi differs in intensity according to the fungus species and this suggested that preservative impregnation and retention may.

  2. Physiological studies of Sclerotium rolfsii Sacc. causing collar rot of ...

    African Journals Online (AJOL)

    In vitro studies were conducted on the effect of temperature, pH levels, carbon, nitrogen and amino acids on the mycelial growth and biomass production of Sclerotium rofsii Sacc. causing collar rot of mint. The results reveal that the growth of S. rolfsii was maximum at 30°C which was reduced significantly below 20°C and ...

  3. Botanicals to Control Soft Rot Bacteria of Potato

    Directory of Open Access Journals (Sweden)

    M. M. Rahman

    2012-01-01

    Full Text Available Extracts from eleven different plant species such as jute (Corchorus capsularis L., cheerota (Swertia chiraita Ham., chatim (Alstonia scholaris L., mander (Erythrina variegata, bael (Aegle marmelos L., marigold (Tagetes erecta, onion (Allium cepa, garlic (Allium sativum L., neem (Azadiracta indica, lime (Citrus aurantifolia, and turmeric (Curcuma longa L. were tested for antibacterial activity against potato soft rot bacteria, E. carotovora subsp. carotovora (Ecc P-138, under in vitro and storage conditions. Previously, Ecc P-138 was identified as the most aggressive soft rot bacterium in Bangladeshi potatoes. Of the 11 different plant extracts, only extracts from dried jute leaves and cheerota significantly inhibited growth of Ecc P-138 in vitro. Finally, both plant extracts were tested to control the soft rot disease of potato tuber under storage conditions. In a 22-week storage condition, the treated potatoes were significantly more protected against the soft rot infection than those of untreated samples in terms of infection rate and weight loss. The jute leaf extracts showed more pronounced inhibitory effects on Ecc-138 growth both in in vitro and storage experiments.

  4. Fungi associated with base rot disease of aloe vera (Aloe ...

    African Journals Online (AJOL)

    STORAGESEVER

    2008-12-17

    Dec 17, 2008 ... Fungi associated with base rot disease of Aloe vera (syn. Aloe barbadensis) were investigated in Niger. Delta Area of Nigeria. Fungi and their percentage frequency were Aspergillus verocosa 28.03%,. Fusarium oxysporium 24.24%, Plectosphaerella cucumerina 16.67%, Mammeria ehinobotryoides 15.91 ...

  5. Inflorescence rot disease of date palm is caused by Fusarium ...

    African Journals Online (AJOL)

    Zulfiqar-Ali

    2012-05-01

    May 1, 2012 ... inflorescence rot disease in southern part of Iraq is Fusarium proliferatum. Pathogenecity test confirmed the ... Key words: Fusarium proliferatum, ITS1, ITS4, pathogenecity, PCR, isolates, phylogeny. INTRODUCTION ..... ITS rRNA Region for Identification of Fusarium spp. from Ocular. Sources. Investigative ...

  6. Advancing our understanding of charcoal rot in soybeans

    Science.gov (United States)

    Charcoal rot (Macrophomina phaseolina (Tassi) Goid ) of soybean [Glycine max (L.) Merr.], is an important but commonly misidentified disease, and very few summary articles exist on this pathosystem. Research conducted over the last 10 years has improved our understanding of the environment conducive...

  7. Production and optimization of ligninolytic enzymes by white rot ...

    African Journals Online (AJOL)

    The present study deals with production of ligninolytic enzymes from an indigenous white rot fungus Schizophyllum commune IBL-06 by using banana stalk as substrate through the process of solid state fermentation. The production process was further improved by optimizing a number of physical parameters such as ...

  8. Fungi associated with base rot disease of aloe vera ( Aloe ...

    African Journals Online (AJOL)

    Fungi associated with base rot disease of Aloe vera (syn. Aloe barbadensis) were investigated in Niger Delta Area of Nigeria. Fungi and their percentage frequency were Aspergillus verocosa 28.03%, Fusarium oxysporium 24.24%, Plectosphaerella cucumerina 16.67%, Mammeria ehinobotryoides 15.91% and Torula ...

  9. Inflorescence rot disease of date palm caused by Fusarium ...

    African Journals Online (AJOL)

    Date palm is one of the important income sources for many farmers in different parts of several countries, including Iraq, Iran, Saudi Arabia, North Africa etc. Inflorescence rot is a serious disease of date palm which limits its yield. The identification of the causal organism is a key step to tackling this disease, and such studies ...

  10. Detecting cotton boll rot with an electronic nose

    Science.gov (United States)

    South Carolina Boll Rot is an emerging disease of cotton, Gossypium hirsutum L., caused by the opportunistic bacteria, Pantoea agglomerans (Ewing and Fife). Unlike typical fungal diseases, bolls infected with P. agglomerans continue to appear normal externally, complicating early and rapid detectio...

  11. Factors contributing to bacterial bulb rots of onion

    Science.gov (United States)

    The incidence of bacterial rots of onion bulbs is increasing and has become a serious problem for growers. This increase is likely due to a combination of factors, such as high bacterial populations in soils and irrigation water, heavy rains flooding production fields, higher temperatures, etc. It m...

  12. Evaluation of antagonistic fungi against charcoal rot of sunflower ...

    African Journals Online (AJOL)

    user

    Results showed reduction in disease incidence of charcoal rot on sunflower cultivar G-66 with antagonist, A. flavus (100%) followed by A. niger (64.86%) P. capsulatum (63.79%) and T. viride (31.89%) over control. Decrease in disease incidence over control was 100% where seed was treated with combination of A. niger ...

  13. OXIDATION OF PERSISTANT ENVIRONMENTAL POLLUTANTS BY A WHITE ROT FUNGUS

    Science.gov (United States)

    The white rot fungus Phanerochaete chrysosporium degraded DDT [1,1,-bis(4-chlorophenyl)-2,2,2-trichloroethane], 3,4,3',4'-tetrachlorobiphenyl, 2,4,5,2',-4',5'-hexachlorobiphenyl, 2,3,7,8-tetrachlorodibenzo-p-dioxin, lindane (1,2,3,4,5,6-hexachlorocylohexane), and benzo[a]pyrene t...

  14. Calonectria species associated with cutting rot of Eucalyptus

    NARCIS (Netherlands)

    Lombard, L.; Zhou, X.D.; Crous, P.W.; Wingfield, B.D.; Wingfield, M.J.

    2010-01-01

    Decline in the productivity of Eucalyptus hybrid cutting production in the Guangdong Province of China is linked to cutting rot associated with several Calonectria spp. The aim of this study was to identify these fungi using morphological and DNA sequence comparisons. Two previously undescribed

  15. Autochthonous white rot fungi from the tropical forest: Potential of ...

    African Journals Online (AJOL)

    Autochthonous white rot fungi from the tropical forest: Potential of Cuban strains for dyes and textile industrial effluents decolourisation. MI Sánchez-López, SF Vanhulle, V Mertens, G Guerra, SH Figueroa, C Decock, A Corbisier, MJ Penninckx ...

  16. The influence of root rot incidence on cassava genotype on ...

    African Journals Online (AJOL)

    28 panelists were asked to indicate their degree of preference for the colour, odour and taste of each gari sample by choosing the appropriate category in the hedonic scale. The results were compared with the tuberous root rot incidence and severity of genotypes in the field. All experiments were repeated and the data ...

  17. Root rot of sugarbeet in the Vojvodina Province

    Directory of Open Access Journals (Sweden)

    Stojšin Vera B.

    2006-01-01

    Full Text Available Large changes introduced in the sugar beet production technology in the Vojvodina Province over last 40 years resulted in changes in the etiology and harmfulness of different agents of sugar beet root diseases. Improvements in cultivation practices reduced the harmfulness of some diseases while increased the harmfulness of others. Some disease agents became obsolete, but others gained importance. New agents of root diseases were found. The most frequent damages, persisting over long periods of time were caused by seedling damping-off, Fusarium root rot, charcoal root rot, parasitic (Rhizomania and non-parasitic root bearding. The parasitic damping-off caused by several fungal species but most frequently by Phoma betae occurred at the time when multigerm seeds were used in combination with extensive cultural practices. The agents of seedling diseases completely lost their significance as the consequence of switching to fungicide - treated monogerm seeds, earlier planting and improved soil tillage. In the period of intensive use of agricultural chemicals, seedling damping-off occurred frequently due to the phytotoxic action of chemicals (insecticides, herbicides and mineral fertilizers. In some years, frosts caused damping- off of sugar beet seedlings on a large scale in the Vojvodina Province. Poor sugar beet germination and emergence were frequently due to spring droughts. Sometimes they were due to strong winds. The occurrence of Fusarium root rot and charcoal root rot intensified on poor soils. Fusariosis symptoms were exhibited as plant wilting and different forms of root rot. In recent years root tip rot has occurred frequently in the first part of the growing season causing necrosis and dying of plants. Lateral roots tended to proliferate from the healthy tissue, giving the root a bearded appearance similar to Rhizomania. Fusarium oxysporum was the most frequent agent of this fusariosis. F. graminearum, F. equiseti, F. solani have also been

  18. Nosocomial pathogens

    African Journals Online (AJOL)

    remains an important problem in intensive care units. Hospital wards had been shown to act as reservoirs of pathogenic microorganisms associated with infection. To assess the prevalence of pathogenic organisms in the environment of the neonatal unit, 92 swabs were randomly collected from cots, incubators and various ...

  19. [Screening of three novel antimicrobial peptides with antifungal pathogens].

    Science.gov (United States)

    Lan, Jinping; Li, Liyun; Wang, Yang; Wang, Xianyun; Liu, Lijuan; Liu, Gouzhen; Cheng, Xiongying

    2011-12-01

    In order to discover novel antimicrobial peptides against important crop pathogens, we designed and screened a high capacity random peptide library and isolated a number of clones expressing peptides with antifungal activity. We selected 96 peptides from the library and synthesized their sequence, which were used to assay their activity against crop fungal pathogens. Using agar diffusion assay, these peptides were assayed for their activity against pathogens that cause cotton Fusarium wilt (Fusarium f. sp, vasinfecum), cotton red rot (Fusarium moniliforme), wheat spot blotch (Bipolaris sorokiniana) and potato early blight (Alternaria solani). The three random peptides, A6, D4 and F10, showed the strongest activity against the above four crop fungal pathogens. Through Blastp analysis, we did not find they have homologous sequences with known antimicrobial peptides. The novel antimicrobial peptides will provide gene resources for preventing important crop pathogens.

  20. Pathogens of potato (Solanum tuberosum L. tuber (Phytophtora infestans occurring in treatments with foliar fertilization

    Directory of Open Access Journals (Sweden)

    Bożena Cwalina-Ambroziak

    2012-10-01

    Full Text Available The paper presents the results of a three-year exact plot experiment (2008-2010 established in Bałcyny (NE Poland. Three potato cultivars were grown: medium-early ‘Adam’, medium-late ‘Pasja Pomorska’, and late ‘Ślęza’. The experimental factors were foliar fertilizers applied alone or in combination (Basfoliar 12-4-6, ADOB Mn, Solubor DF and two levels of soil mineral fertilization (N1P1K1-80 kg N × ha-1, 80 kg P × ha-1, 120 K × ha-1; N2P2K2-120 kg N × ha-1, 144 kg P × ha-1, 156 K × ha-1. The experimental materials comprised potato tubers. The symptoms of soft rot (Pectobacterium carotovorum subsp. carotovorum, late blight (Phytophthora infestans and dry rot (Fusarium spp. were evaluated in 5 kg potato samples, and were expressed as the percentage mass of infected tubers. The rates of common scab (Streptomyces scabies and black scurf (Rhizoctonia solani infection were estimated on 100 tubers collected randomly after harvest, according to a nine-point scale, and were presented as a percentage infection index. In the laboratory, fungi were isolated on PDA medium from potato tubers immediately after harvest and after five-month storage. The incidence of tuber diseases depended on potato cultivars affected. The severity of tuber diseases varied between treatments with two levels of NPK fertilization and foliar fertilization. The lowest number of Fusarium-infected tubers was obtained from treatments where three foliar fertilizers were applied in combination, which was confirmed by the lowest abundance of fungal isolates. More fungi were isolated from potato tubers after harvest than after storage, but pathogens were more frequently isolated from stored tubers. After harvest, the lowest number of pathogenic fungi was isolated from the tubers of cv. ‘Adam’ in the non-fertilized treatment, and after storage – from the tubers of the late cultivars in the treatment with three foliar fertilizers applied in combination.

  1. Control of postharvest soft rot caused by Erwinia carotovora of vegetables by a strain of Bacillus amyloliquefaciens and its potential modes of action.

    Science.gov (United States)

    Zhao, Yancun; Li, Pengxia; Huang, Kaihong; Wang, Yuning; Hu, Huali; Sun, Ya

    2013-03-01

    Erwinia carotovora subsp. carotovora (Ecc), the causal agent of bacterial soft rot, is one of the destructive pathogens of postharvest vegetables. In this study, a bacterial isolate (BGP20) from the vegetable farm soil showed strong antagonistic activity against Ecc in vitro, and its twofold cell-free culture filtrate showed excellent biocontrol effect in controlling the postharvest bacterial soft rot of potatoes at 25 °C. The anti-Ecc metabolites produced by the isolate BGP20 had a high resistance to high temperature, UV-light and protease K. Based on the colonial morphology, cellular morphology, sporulation, and partial nucleotide sequences of 16S rRNA and gyrB gene, the isolate BGP20 was identified as Bacillus amyloliquefaciens subsp. plantarum. Further in vivo assays showed that the BGP20 cell culture was more effective in controlling the postharvest bacterial soft rot of green peppers and Chinese cabbages than its twofold cell-free culture filtrate. In contrast, the biocontrol effect and safety of the BGP20 cell culture were very poor on potatoes. In the wounds of potatoes treated with both the antagonist BGP20 and the pathogen Ecc, the viable count of Ecc was 31,746 times that of BGP20 at 48 h of incubation at 25 °C. But in the wounds of green peppers, the viable count of BGP20 increased 182.3 times within 48 h, and that of Ecc increased only 51.3 %. In addition, the treatment with both BGP20 and Ecc induced higher activity of phenylalanine ammonia-lyase (PAL) than others in potatoes. But the same treatment did not induce an increase of PAL activity in green peppers. In conclusion, the present study demonstrated that the isolate BGP20 is a promising candidate in biological control of postharvest bacterial soft rot of vegetables, but its main mode of action is different among various vegetables.

  2. Genome sequence of the model plant pathogen Pectobacterium carotovorum SCC1.

    Science.gov (United States)

    Niemi, Outi; Laine, Pia; Koskinen, Patrik; Pasanen, Miia; Pennanen, Ville; Harjunpää, Heidi; Nykyri, Johanna; Holm, Liisa; Paulin, Lars; Auvinen, Petri; Palva, E Tapio; Pirhonen, Minna

    2017-01-01

    Bacteria of the genus Pectobacterium are economically important plant pathogens that cause soft rot disease on a wide variety of plant species. Here, we report the genome sequence of Pectobacterium carotovorum strain SCC1, a Finnish soft rot model strain isolated from a diseased potato tuber in the early 1980's. The genome of strain SCC1 consists of one circular chromosome of 4,974,798 bp and one circular plasmid of 5524 bp. In total 4451 genes were predicted, of which 4349 are protein coding and 102 are RNA genes.

  3. Improved horticultural practices against leaf wilting, root rot and nutrient uptake in mango (mangiferaindica l.)

    International Nuclear Information System (INIS)

    Nafees, M.; Ahmad, I.; Ahmad, S.; Anwar, R.; Maryyam, A.; Hussnain, R.R.

    2013-01-01

    Poor plant health condition due to various known biotic and abiotic stresses; becoming a disaster in each mango growing country of the world including Pakistan. On the basis of previous researches on the identification of pathogen and several abiotic factors; Soil drenching and foliar spray of various concentrations of Topsin M (TMIC), Aliette (ATP) and Ridomil Gold (ACE) in combination with CuSO/sub 4/(Copper sulphate) was done on mango plants of cv. S.B. (Samar Bahist) Chaunsa showing wilting of leaves and shoots. Foliar application of micro-nutrients (Fe, B and Zn) (Iron, Boron and Zinc) was also practiced to improve general health of experimental plants Month-wise emergence of flushes was significantly higher in all treated plants compared with control. Percentage of wilted leaves and root rot in plants, which received drenching and foliar treatments, was significantly reduced (50%) compared with untreated plants. Nitrogen, phosphorus and potassium (N, P and K) levels in leaves were significantly improved in treated plants compared with control. Sigmoid relatioship was observed between fungicides and copper sulphate concentrations and uptake of N, P and K in treated plants. Application of 250g ATP fungicide by foliar spray plus 125g by soil drench, each along with 50g CuSO/sub 4/proved to be the best against leaf wilting and it improved the N and P level in leaves. While, application of 250g TMIC by foliar spray and 125g by soil drench, each with 50g CuSO/sub 4/, was found to be the best to reduce the spread of root rot in experimental plants. Preliminary spray of TMIC along with Copper sulphate is effective to improve plant health of mango cv. S.B. Chounsa. (author)

  4. Two previously unknown Phytophthora species associated with brown rot of Pomelo (Citrus grandis fruits in Vietnam.

    Directory of Open Access Journals (Sweden)

    Ivana Puglisi

    Full Text Available Two distinct Phytophthora taxa were found to be associated with brown rot of pomelo (Citrus grandis, a new disease of this ancestral Citrus species, in the Vinh Long province, Mekong River Delta area, southern Vietnam. On the basis of morphological characters and using the ITS1-5.8S-ITS2 region of the rDNA and the cytochrome oxidase subunit 1 (COI as barcode genes, one of the two taxa was provisionally named as Phytophthora sp. prodigiosa, being closely related to but distinct from P. insolita, a species in Phytophthora Clade 9, while the other one, was closely related to but distinct from the Clade 2 species P. meadii and was informally designated as Phytophthora sp. mekongensis. Isolates of P. sp. prodigiosa and P. sp. mekongensis were also obtained from necrotic fibrous roots of Volkamer lemon (C. volkameriana rootstocks grafted with 'King' mandarin (Citrus nobilis and from trees of pomelo, respectively, in other provinces of the Mekong River Delta, indicating a widespread occurrence of both Phytophthora species in this citrus-growing area. Koch's postulates were fulfilled via pathogenicity tests on fruits of various Citrus species, including pomelo, grapefruit (Citrus x paradisi, sweet orange (Citrus x sinensis and bergamot (Citrus x bergamia as well as on the rootstock of 2-year-old trees of pomelo and sweet orange on 'Carrizo' citrange (C. sinensis 'Washington Navel' x Poncirus trifoliata. This is the first report of a Phytophthora species from Clade 2 other than P. citricola and P. citrophthora as causal agent of fruit brown rot of Citrus worldwide and the first report of P. insolita complex in Vietnam. Results indicate that likely Vietnam is still an unexplored reservoir of Phytophthora diversity.

  5. Two previously unknown Phytophthora species associated with brown rot of Pomelo (Citrus grandis) fruits in Vietnam.

    Science.gov (United States)

    Puglisi, Ivana; De Patrizio, Alessandro; Schena, Leonardo; Jung, Thomas; Evoli, Maria; Pane, Antonella; Van Hoa, Nguyen; Van Tri, Mai; Wright, Sandra; Ramstedt, Mauritz; Olsson, Christer; Faedda, Roberto; Magnano di San Lio, Gaetano; Cacciola, Santa Olga

    2017-01-01

    Two distinct Phytophthora taxa were found to be associated with brown rot of pomelo (Citrus grandis), a new disease of this ancestral Citrus species, in the Vinh Long province, Mekong River Delta area, southern Vietnam. On the basis of morphological characters and using the ITS1-5.8S-ITS2 region of the rDNA and the cytochrome oxidase subunit 1 (COI) as barcode genes, one of the two taxa was provisionally named as Phytophthora sp. prodigiosa, being closely related to but distinct from P. insolita, a species in Phytophthora Clade 9, while the other one, was closely related to but distinct from the Clade 2 species P. meadii and was informally designated as Phytophthora sp. mekongensis. Isolates of P. sp. prodigiosa and P. sp. mekongensis were also obtained from necrotic fibrous roots of Volkamer lemon (C. volkameriana) rootstocks grafted with 'King' mandarin (Citrus nobilis) and from trees of pomelo, respectively, in other provinces of the Mekong River Delta, indicating a widespread occurrence of both Phytophthora species in this citrus-growing area. Koch's postulates were fulfilled via pathogenicity tests on fruits of various Citrus species, including pomelo, grapefruit (Citrus x paradisi), sweet orange (Citrus x sinensis) and bergamot (Citrus x bergamia) as well as on the rootstock of 2-year-old trees of pomelo and sweet orange on 'Carrizo' citrange (C. sinensis 'Washington Navel' x Poncirus trifoliata). This is the first report of a Phytophthora species from Clade 2 other than P. citricola and P. citrophthora as causal agent of fruit brown rot of Citrus worldwide and the first report of P. insolita complex in Vietnam. Results indicate that likely Vietnam is still an unexplored reservoir of Phytophthora diversity.

  6. Rhamnolipid Biosurfactant against Fusarium verticillioides to Control Stalk and Ear Rot Disease of Maize

    Directory of Open Access Journals (Sweden)

    Siddhartha Narayan Borah

    2016-09-01

    Full Text Available Antifungal activity of rhamnolipids (RLs has been widely studied against many plant pathogenic fungi, but not against Fusarium verticillioides, a major pathogen of maize (Zea mays L.. F. verticillioides causes stalk and ear rot of maize or asymptomatically colonizes the plant and ears resulting in moderate to heavy crop loss throughout the world. F. verticillioides produces fumonisin mycotoxins, reported carcinogens, which makes the contaminated ears unsuitable for consumption. In this study, the RL produced using glucose as sole carbon source was characterized by FTIR and LCMS analyses and its antifungal activity against F. verticillioides was evaluated in vitro on maize stalks and seeds. Further, the effect of RL on the mycelia of F. verticillioides was investigated by scanning electron microscopy which revealed visible damage to the mycelial structure as compared to control samples. In planta, treatment of maize seeds with a RL concentration of 50 mg l-1 resulted in improved biomass and fruiting compared to those of healthy control plants and complete suppression of characteristic disease symptoms and colonization of maize by F. verticillioides. The study highlights the potential of RLs to be used for an effective biocontrol strategy against colonization of maize plant by F. verticillioides.

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

    Science.gov (United States)

    Raoul des Essarts, Yannick; Cigna, Jérémy; Quêtu-Laurent, Angélique; Caron, Aline; Munier, Euphrasie; Beury-Cirou, Amélie; Hélias, Valérie; Faure, Denis

    2015-10-23

    Development of protection tools targeting Dickeya species 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 several Dickeya sp. and/or Pectobacterium sp. pathogens. Most of them belonged to the Pseudomonas and Bacillus genera. In vitro assays revealed a fitness decrease of the tested Dickeya sp. and Pectobacterium sp. 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 with Dickeya dianthicola revealed that a mix of three biocontrol agents, namely, Pseudomonas putida PA14H7 and Pseudomonas fluorescens PA3G8 and PA4C2, repeatedly decreased the severity of blackleg symptoms as well as the transmission of D. dianthicola to 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 by D. dianthicola on potato plants and tubers. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

  8. Conjunctively screening of biocontrol agents (BCAs) against fusarium root rot and fusarium head blight caused by Fusarium graminearum.

    Science.gov (United States)

    Wang, Lu-Yao; Xie, Yue-Shen; Cui, Yuan-Yu; Xu, Jianjun; He, Wei; Chen, Huai-Gu; Guo, Jian-Hua

    2015-08-01

    Fusarium root-rot and fusarium head blight are plant diseases caused by Fusarium sp. in different growth periods of wheat, bring heavy losses to crop production in China. This research is aiming to screen biocontrol agents conjunctively for controlling these two diseases at the same time, as well as evaluate our previous BCAs (Biological Control Agents) screening strategies in more complex situation, considering biocontrol is well concerned as an environmental-friendly plant disease controlling method. Totally 966 bacterial isolates were screened from different parts of wheat tissues, of which potential biocontrol values were detected according to their abilities in antagonism inhibition and secreting extracellular hydrolytic enzyme. Biocontrol tests against fusarium root rot and fusarium head blight were carried out on 37 bacterial isolates with potential biocontrol capacity after pre-selection through ARDRA- and BOX-PCR analysis on strains with high assessment points. We acquired 10 BCAs with obvious biocontrol efficacy (more than 40%) in greenhouse and field tests. Pseudomonas fluorescens LY1-8 performed well in both two tests (biocontrol efficacy: 44.62% and 58.31%), respectively. Overall, correlation coefficient is 0.720 between assessment values of 37 tested BCA strains and their biocontrol efficacy in trails against fusarium root rot; correlation coefficient is 0.806 between their assessment values and biocontrol efficacy in trails against fusarium head blight. We acquired 10 well-performed potential BCAs, especially P. fluorescens LY1-8 displayed good biocontrol capacity against two different diseases on wheat. Biocontrol efficacies results in both greenhouse and field tests showed high positive correlation with assessment values (0.720 and 0.806), suggesting that the BCAs screening and assessing strategy previously developed in our lab is also adaptable for conjunctively screening BCAs for controlling both root and shoot diseases on wheat caused by same

  9. Increased delignification by white rot fungi after pressure refining Miscanthus.

    Science.gov (United States)

    Baker, Paul W; Charlton, Adam; Hale, Mike D C

    2015-01-01

    Pressure refining, a pulp making process to separate fibres of lignocellulosic materials, deposits lignin granules on the surface of the fibres that could enable increased access to lignin degrading enzymes. Three different white rot fungi were grown on pressure refined (at 6 bar and 8 bar) and milled Miscanthus. Growth after 28 days showed highest biomass losses on milled Miscanthus compared to pressure refined Miscanthus. Ceriporiopsis subvermispora caused a significantly higher proportion of lignin removal when grown on 6 bar pressure refined Miscanthus compared to growth on 8 bar pressure refined Miscanthus and milled Miscanthus. RM22b followed a similar trend but Phlebiopsis gigantea SPLog6 did not. Conversely, C. subvermispora growing on pressure refined Miscanthus revealed that the proportion of cellulose increased. These results show that two of the three white rot fungi used in this study showed higher delignification on pressure refined Miscanthus than milled Miscanthus. Copyright © 2015 Elsevier Ltd. All rights reserved.

  10. Biological Control of White Rot in Garlic Using Burkholderia pyrrocinia CAB08106-4

    Directory of Open Access Journals (Sweden)

    Kwang Seop Han

    2013-03-01

    Full Text Available White rot caused by Sclerotium cepivorum was reported to be severe soil-born disease on garlic. Disease progress of white rot of garlic (Allium sativum L. was investigated during the growing season of 2009 to 2011 at Taean and Seosan areas. The white rot disease on bulb began to occur from late April and peaked in late May. The antifungal bacteria, Burkholderia pyrrocinia CAB08106-4 was tested in field bioassay for suppression of white rot disease. As a result of the nucleotide sequence of the gene 16S rRNA, CAB008106-4 strain used in this study has been identified as B. pyrrocinia. B. pyrrocinia CAB080106-4 isolate suppressed the white rot with 69.6% control efficacy in field test. These results suggested that B. pyrrocinia CAB08106-4 isolate could be an effective biological control agent against white rot of garlic.

  11. Removal of phenanthrene in contaminated soil by combination of alfalfa, white-rot fungus, and earthworms.

    Science.gov (United States)

    Deng, Shuguang; Zeng, Defang

    2017-03-01

    The aim of this study was to investigate the removal of phenanthrene by combination of alfalfa, white-rot fungus, and earthworms in soil. A 60-day experiment was conducted. Inoculation with earthworms and/or white-rot fungus increased alfalfa biomass and phenanthrene accumulation in alfalfa. However, inoculations of alfalfa and white-rot fungus can significantly decrease the accumulation of phenanthrene in earthworms. The removal rates for phenanthrene in soil were 33, 48, 66, 74, 85, and 93% under treatments control, only earthworms, only alfalfa, earthworms + alfalfa, alfalfa + white-rot fungus, and alfalfa + earthworms + white-rot fungus, respectively. The present study demonstrated that the combination of alfalfa, earthworms, and white-rot fungus is an effective way to remove phenanthrene in the soil. The removal is mainly via stimulating both microbial development and soil enzyme activity.

  12. Fungal hydroquinones contribute to brown rot of wood

    Science.gov (United States)

    Melissa R. Suzuki; Christopher G. Hunt; Carl J. Houtman; Zachary D. Dalebroux; Kenneth E. Hammel

    2006-01-01

    The fungi that cause brown rot of wood initiate lignocellulose breakdown with an extracellular Fenton system in which Fe2+ and H2O2 react to produce hydroxyl radicals (•OH), which then oxidize and cleave the wood holocellulose. One such fungus, Gloeophyllum trabeum, drives Fenton chemistry on defined media by reducing Fe3+ and O2 with two extracellular hydroquinones,...

  13. Trichoderma spp. decrease Fusarium root rot in common bean

    Directory of Open Access Journals (Sweden)

    Hudson Teixeira

    2012-12-01

    Full Text Available The effectiveness of six Trichoderma-based commercial products (TCP in controlling Fusarium root rot (FRR in common bean was assessed under field conditions. Three TCP, used for seed treatment or applied in the furrow, increased seedling emergence as much as the fungicide fludioxonil. FRR incidence was not affected, but all TCP and fludioxonil reduced the disease severity, compared to control. Application of Trichoderma-based products was as effective as that of fludioxonil in FRR management.

  14. The presence and survival of soft rot (Erwinia) in flower bulb production systems

    OpenAIRE

    Doorn, van, J.; Vreeburg, P.J.M.; Leeuwen, van, P.J.; Dees, R.H.L.

    2011-01-01

    Soft rot is causing increasing damage in the flower bulb industry. Bulbous ornamentals such as Hyacinthus, Dahlia, Iris, Muscari, Freesia and Zantedeschia can be infected. Soft rot in flower bulbs is mainly caused by Dickeya spp. (Dickeya spp.) and Erwinia carotovora subsp. carotovora (Pectobacterium carotovorum spp. carotovorum).To identify and detect these soft rot bacterial species in several bulbous ornamentals, standard PCR methods were used. During the last four years, research was dire...

  15. Cellulose Degradation by Cellulose-Clearing and Non-Cellulose-Clearing Brown-Rot Fungi

    OpenAIRE

    Highley, Terry L.

    1980-01-01

    Cellulose degradation by four cellulose-clearing brown-rot fungi in the Coniophoraceae—Coniophora prasinoides, C. puteana, Leucogyrophana arizonica, and L. olivascens—is compared with that of a non-cellulose-clearing brown-rot fungus, Poria placenta. The cellulose- and the non-cellulose-clearing brown-rot fungi apparently employ similar mechanisms to depolymerize cellulose; most likely a nonenzymatic mechanism is involved.

  16. Etiology and epidemiology of Pythium root rot in hydroponic crops: current knowledge and perspectives

    Directory of Open Access Journals (Sweden)

    John Clifford Sutton

    2006-09-01

    Full Text Available The etiology and epidemiology of Pythium root rot in hydroponically-grown crops are reviewed with emphasis on knowledge and concepts considered important for managing the disease in commercial greenhouses. Pythium root rot continually threatens the productivity of numerous kinds of crops in hydroponic systems around the world including cucumber, tomato, sweet pepper, spinach, lettuce, nasturtium, arugula, rose, and chrysanthemum. Principal causal agents include Pythium aphanidermatum, Pythium dissotocum, members of Pythium group F, and Pythium ultimum var. ultimum. Perspectives are given of sources of initial inoculum of Pythium spp. in hydroponic systems, of infection and colonization of roots by the pathogens, symptom development and inoculum production in host roots, and inoculum dispersal in nutrient solutions. Recent findings that a specific elicitor produced by P. aphanidermatum may trigger necrosis (browning of the roots and the transition from biotrophic to necrotrophic infection are considered. Effects on root rot epidemics of host factors (disease susceptibility, phenological growth stage, root exudates and phenolic substances, the root environment (rooting media, concentrations of dissolved oxygen and phenolic substances in the nutrient solution, microbial communities and temperature and human interferences (cropping practices and control measures are reviewed. Recent findings on predisposition of roots to Pythium attack by environmental stress factors are highlighted. The commonly minor impact on epidemics of measures to disinfest nutrient solution as it recirculates outside the crop is contrasted with the impact of treatments that suppress Pythium in the roots and root zone of the crop. New discoveries that infection of roots by P. aphanidermatum markedly slows the increase in leaf area and whole-plant carbon gain without significant effect on the efficiency of photosynthesis per unit area of leaf are noted. The platform of

  17. Biological control of Black Pod Disease and Seedling Blight of cacao caused by Phytophthora Species using Trichoderma from Aceh Sumatra

    Science.gov (United States)

    The cocoa tree, Theobroma cacao L., suffers large yield losses in Aceh Indonesia to the disease black pod rot, caused by Phytophthora spp. Despite having the largest area under cacao production in Sumatra, farmers in the Aceh region have low overall production because of losses to insect pests and b...

  18. Development of a rapid and simple Agrobacterium tumefaciens mediated transformation system for the fungal pathogen Heterobasidion annosum

    Science.gov (United States)

    Nicklas Samils; Malin Elfstrand; Daniel L. Lindner Czederpiltz; Jan Fahleson; Ake Olson; Christina Dixelius; Jan Stenlid

    2006-01-01

    Heterobasidion annosum causes root and butt-rot in trees and is the most serious forest pathogen in the northern hemisphere. We developed a rapid and simple Agrobacterium-mediated method of gene delivery into H. annosum to be used in functional studies of candidate genes and for visualization of mycelial interactions. Heterobasidion annosum TC 32-1 was cocultivated at...

  19. Detection of bacterial soft-rot of crown imperial caused by Pectobacterium carotovorum subsp. carotovorum using specific PCR primers

    Directory of Open Access Journals (Sweden)

    E. Mahmoudi

    2007-08-01

    Full Text Available Pectobacterium is one of the major destructive causal agent in most crop plants throughout the world. During a survey in spring of 2005 in the rangeland of Kermanshah and Isfahan, provinces of Iran, samples of bulbs and stems of crown imperial with brown spot and soft rot were collected. Eight strains of pectolytic Erwinia were isolated and purified from these samples. Phenotypic tests indicated that the strains were gram-negative, facultative anaerobic, rod shaped, motile with peritrichous flagella. They were oxidase negative, catalase positive and also able to macerate potato slices. Pathogenicity of all the strains were confirmed on corn, philodendron and crown imperial by inoculation of these crops with a bacterial suspension and reisolation of the strain from symptomatic tissues. A pair of specific PCR primers was used to detect these bacterial strains. The primer set (EXPCCF/EXPCCR amplified a single fragment of the expected size (0.55 kb from genomic DNA of all strains used in this study. In nested PCR, the primer set (INPCCR/INPCCF amplified the expected single fragment (0.4 kb from the PCR product of first PCR amplification. On the basis of the biochemical and phenotypic characteristics and PCR amplification by the specific PCR primers, these strains were identified as Pectobacterium carotovorum subsp. carotovorum. This is the first report of occurrence of crown imperial bacterial soft-rot in Iran.

  20. Effect of corn steep liquor on lettuce root rot (Fusarium oxysporum f.sp. lactucae) in hydroponic cultures.

    Science.gov (United States)

    Chinta, Yufita D; Kano, Kazuki; Widiastuti, Ani; Fukahori, Masaru; Kawasaki, Shizuka; Eguchi, Yumi; Misu, Hideyuki; Odani, Hiromitsu; Zhou, Songying; Narisawa, Kazuhiko; Fujiwara, Kazuki; Shinohara, Makoto; Sato, Tatsuo

    2014-08-01

    Recent reports indicate that organic fertilisers have a suppressive effect on the pathogens of plants grown under hydroponic systems. Furthermore, microorganisms exhibiting antagonistic activity to diseases have been observed in organic hydroponic systems. This study evaluated the effect of corn steep liquor (CSL) on controlling lettuce root rot disease [Fusarium oxysporum f.sp. lactucae (FOL)] in a hydroponic system. The effect of CSL and Otsuka A (a chemical fertiliser) on the inhibition of FOL in terms of mycelial growth inhibition was tested in vivo. Addition of CSL suppressed FOL infection rates. CSL inhibited FOL infection by 26.3-42.5% from 2 days after starting incubation. In comparison, Otsuka A inhibited FOL growth by 5.5-19.4%. In addition, four of 10 bacteria isolated from the nutrient media containing CSL exhibited inhibition zones preventing FOL mycelial growth. We found that CSL suppressed FOL in lettuce via its antifungal and biostimulatory effects. We suggest that activation of beneficial microorganisms present in CSL may be used to decrease lettuce root rot disease and contribute to lettuce root growth. © 2014 Society of Chemical Industry.

  1. Control of root rot of chickpea caused by Sclerotium rolfsii by different agents and gamma radiation

    International Nuclear Information System (INIS)

    Rasha Mohammed Fathy El- Said, R.M.F.

    2012-01-01

    Sclerotium rolfsii causes root rot disease in several crops including chickpea that result in low yield. Artificial infection of chickpea seedlings by S. rolfsii in vitro demonstrated that different tissues of the plant completely disintegrated by fungal infection. In vitro and green house pot experiments demonstrated that inducers in combination with fungicides, oils and bio agents resulted in about 80 % suppression of root rot disease. Treatments have no phyto toxic effect on chickpea seedlings at low doses. Gliocladium virens and Gliocladium deliquescens were effective as biocontrol agents against Sclerotium rolfsii. The percent of survival plants, fresh weight, dry weight and plant height of chickpea plants increased with different treatments with inducers compared with the control. Chlorophyll a, b, and total chlorophyll amounts increased to the maximum values. The activity of two plant enzymes, peroxidase and polyphenol oxidase increased. In this study, gamma irradiation of chickpea seeds at doses 5, 10, 15, 20, 25 and 30 Gy have negative effect on survival, plant height, fresh weight and dry weight of chickpea. The effect of gamma irradiation at doses 0.25, 0.5, 1.0, 1.5, 2.0, 2.5 and 3.0 kGy on the antagonistic effect of Gliocladium virens and Gliocladium deliquescens against S. rolfsii were investigated. The results revealed that gamma irradiation increase the antagonistic effect of Gliocladium virens and Gliocladium deliquescens against S. rolfsii . Effect of gamma irradiation at doses of 0, 0.25, 0.5, 1.0, 1.5, 2.0, 2.5, 3.0 and 5 kGy on the mycelial growth and pathogenicity of S. rolfsii were investigated. The results revealed that gamma irradiation at doses 0.25 up to 3.0 kGy increase the pathogenicity of S. rolfsii but gamma irradiation at dose 5.0 kGy completely inhibited the growth of S. rolfsii. Extracellular polygalacturonase was characterized and purified by precipitation with 70 % ammonium sulfate, dialysis and gel filtration through Sephadex 75

  2. Black Culture

    Directory of Open Access Journals (Sweden)

    Angela Khristin Brown

    2013-07-01

    Full Text Available The migration of blacks in North America through slavery became united.  The population of blacks past downs a tradition of artist through art to native born citizens. The art tradition involved telling stories to each generation in black families. The black culture elevated by tradition created hope to determine their personal freedom to escape from poverty of enslavement and to establish a way of life through tradition. A way of personal freedoms was through getting a good education that lead to a better foundation and a better way of life.

  3. Integrated Management of Damping-off, Root and/or Stem Rot Diseases of Chickpea and Efficacy of the Suggested Formula

    Directory of Open Access Journals (Sweden)

    Montaser Fawzy ABDEL-MONAIM

    2011-08-01

    Full Text Available Eleven fungal isolates were isolated from naturally infected chickpea roots collected from different locations in New Valley Governorate (Egypt. The isolated fungi were purified and identified as Rhizoctonia solani (5 isolates, Fusarium solani (4 isolates and Sclerotinia sclerotiorum (2 isolates. The isolated fungi proved their pathogenicity on cv. Giza 3. Response of chickpea cvs. Giza 1, Giza 2, Giza 3, Giza 4, Giza 88, Giza 195, Giza 531 to infection by the tested fungi was significantly varied. Giza 1 was the most resistant one followed by Giza 531, while the other tested cvs. were highly susceptible. Seven biocontrol agents, namely Bacillus subtilis, B. megaterium, B. cereus, Trichoderma viride, T. harzianum, Aspergillus sp., Penicillium sp. isolated from chickpea rhizosphere, were tested for their antagonistic action against the tested pathogens. B. subtilis isolate BSM1, B. megaterium isolate TVM5, T. viride isolate TVM2 and T. harzianum isolate THM4 were the most antagonistic ones to the tested fungi in vitro, while the other isolates were moderate or weak antagonists. The most antagonistic isolates as well as the commercial biocide Rhizo-N were applied as seed treatment for controlling damping-off, root and/or stem rot diseases caused by the tested fungi under greenhouse conditions. The obtained data showed that all tested antagonistic isolates were able to cause significant reduction of damping-off, root and/or stem rot diseases in chickpea plants. T. viride (isolate TVM2 and B. megaterium (isolate BMM5 proved to be the most effective isolates for controlling the diseases. Under field condition, the obtained data indicated that all the tested antagonistic isolates significantly reduced damping-off, root and/or stem rot. T. viride (isolate TVM2 and B. megaterium (isolate BMM5 recorded the highest reduction of damping-off, root and/or stem rot in all sowing dates. Sowing of treated seeds with bioagents in first of November gave the

  4. Endophytic Bacteria Improve Plant Growth, Symbiotic Performance of Chickpea (Cicer arietinum L. and Induce Suppression of Root Rot Caused by Fusarium solani under Salt Stress

    Directory of Open Access Journals (Sweden)

    Dilfuza Egamberdieva

    2017-09-01

    Full Text Available Salinity causes disturbance in symbiotic performance of plants, and increases susceptibility of plants to soil-borne pathogens. Endophytic bacteria are an essential determinant of cross-tolerance to biotic and abiotic stresses in plants. The aim of this study was to isolate non–rhizobial endophytic bacteria from the root nodules of chickpea (Cicer arietinum L., and to assess their ability to improve plant growth and symbiotic performance, and to control root rot in chickpea under saline soil conditions. A total of 40 bacterial isolates from internal root tissues of chickpea grown in salinated soil were isolated. Four bacterial isolates, namely Bacillus cereus NUU1, Achromobacter xylosoxidans NUU2, Bacillus thuringiensis NUU3, and Bacillus subtilis NUU4 colonizing root tissue demonstrated plant beneficial traits and/or antagonistic activity against F. solani and thus were characterized in more detail. The strain B. subtilis NUU4 proved significant plant growth promotion capabilities, improved symbiotic performance of host plant with rhizobia, and promoted yield under saline soil as compared to untreated control plants under field conditions. A combined inoculation of chickpea with M. ciceri IC53 and B. subtilis NUU4 decreased H2O2 concentrations and increased proline contents compared to the un-inoculated plants indicating an alleviation of adverse effects of salt stress. Furthermore, the bacterial isolate was capable to reduce the infection rate of root rot in chickpea caused by F. solani. This is the first report of F. solani causing root rot of chickpea in a salinated soil of Uzbekistan. Our findings demonstrated that the endophytic B. subtilis strain NUU4 provides high potentials as a stimulator for plant growth and as biological control agent of chickpea root rot under saline soil conditions. These multiple relationships could provide promising practical approaches to increase the productivity of legumes under salt stress.

  5. Influence of Commercial Antibiotics on Biocontrol of Soft Rot and Plant Growth Promotion in Chinese Cabbages by Bacillus vallismortis EXTN-1 and BS07M

    Directory of Open Access Journals (Sweden)

    Mee Kyung Sang

    2015-12-01

    Full Text Available We investigated influence of three commercial antibiotics viz., oxolinic acid, streptomycin, and validamycin A, on biocontrol and plant growth promoting activities of Bacillus vallismortis EXTN-1 and BS07M in Chinese cabbage. Plants were pre-drenched with these strains followed by antibiotics application at recommended and ten-fold diluted concentration to test the effect on biocontrol ability against soft rot caused by Pectobacterium carotovorum SCC1. The viability of the two biocontrol strains and bacterial pathogen SCC1 was significantly reduced by oxolinic acid and streptomycin in vitro assay, but not by validamycin A. In plant trials, strains EXTN- 1 and BS07M controlled soft rot in Chinese cabbage, and there was a significant difference in disease severity when the antibiotics were applied to the plants drenched with the two biocontrol agents. Additional foliar applications of oxolinic acid and streptomycin reduced the disease irrespective of pre-drench treatment of the PGPRs. However, when the plants were pre-drenched with EXTN-1 followed by spray of validamycin A at recommended concentration, soft rot significantly reduced compared to untreated control. Similarly, strains EXTN-1 and BS07M significantly enhanced plant growth, but it did not show synergistic effect with additional spray of antibiotics. Populations of the EXTN-1 or BS07M in the rhizosphere of plants sprayed with antibiotics were significantly affected as compared to control. Taken together, our results suggest that the three antibiotics used for soft rot control in Chinese cabbage could affect bacterial mediated biocontrol and plant growth promoting activities. Therefore, combined treatment of the PGPRs and the commercial antibiotics should be carefully applied to sustain environmental friendly disease management.

  6. Field survey and fungicide screening of fungal pathogens of rambutan (Nephelium lappaceum) fruit rot in Hawaii

    Science.gov (United States)

    Rambutan (Nephelium lappaceum Linn.) is a tropical fruit in Hawaii that has increased in value in the niche market of exotic fruits. The primary limitation to pre-harvest and post-harvest quality is the occurrence of fungal diseases of the fruit. A survey of rambutan disease was conducted in Hilo, H...

  7. Storage rot fungi and seed-borne pathogens of onion | Adongo ...

    African Journals Online (AJOL)

    Rotten onion bulbs obtained from the four markets (Abinchi, Anloga, Kwadaso and Central markets) were infected by five fungal species: Aspergillus niger, A. flavus, Penicillium sp., Rhizopus stolonifer and Fusarium oxysporum. Of these, A. niger and Penicillium sp. were the most frequently isolated fungi. A. flavus was the ...

  8. First report of the root-rot pathogen, Armillaria nabsnona, from Hawaii

    Science.gov (United States)

    J. W. Hanna; N. B. Klopfenstein; M. -S. Kim

    2007-01-01

    The genus Armillaria (2) and Armillaria mellea sensu lato (3) have been reported previously from Hawaii. However, Armillaria species in Hawaii have not been previously identified by DNA sequences, compatibility tests, or other methods that distinguish currently recognized taxa. In August 2005, Armillaria rhizomorphs and mycelial bark fans were collected from two...

  9. Biochemical response and host-pathogen relation of stalk rot fungi ...

    African Journals Online (AJOL)

    Dr. nirupma

    or by cutting off the supply of water and nutrients from the roots. It causes ... distilled water. To this, one drop of Tween-20 was added and spore suspension was stirred continuously to avoid clumping/sticking together of spores on the upper surface of the water. The suspension ..... the pathogenesis-related PRms protein.

  10. T4-related bacteriophage LIMEstone isolates for the control of soft rot on potato caused by 'Dickeya solani'.

    Directory of Open Access Journals (Sweden)

    Evelien M Adriaenssens

    Full Text Available The bacterium 'Dickeya solani', an aggressive biovar 3 variant of Dickeya dianthicola, causes rotting and blackleg in potato. To control this pathogen using bacteriophage therapy, we isolated and characterized two closely related and specific bacteriophages, vB_DsoM_LIMEstone1 and vB_DsoM_LIMEstone2. The LIMEstone phages have a T4-related genome organization and share DNA similarity with Salmonella phage ViI. Microbiological and molecular characterization of the phages deemed them suitable and promising for use in phage therapy. The phages reduced disease incidence and severity on potato tubers in laboratory assays. In addition, in a field trial of potato tubers, when infected with 'Dickeya solani', the experimental phage treatment resulted in a higher yield. These results form the basis for the development of a bacteriophage-based biocontrol of potato plants and tubers as an alternative for the use of antibiotics.

  11. FcStuA from Fusarium culmorum controls wheat foot and root rot in a toxin dispensable manner.

    Science.gov (United States)

    Pasquali, Matias; Spanu, Francesca; Scherm, Barbara; Balmas, Virgilio; Hoffmann, Lucien; Hammond-Kosack, Kim E; Beyer, Marco; Migheli, Quirico

    2013-01-01

    Fusarium culmorum is one of the most harmful pathogens of durum wheat and is the causal agent of foot and root rot (FRR) disease. F. culmorum produces the mycotoxin deoxynivalenol (DON) that is involved in the pathogenic process. The role of the gene FcStuA, a StuA ortholog protein with an APSES domain sharing 98.5% homology to the FgStuA protein (FGSG10129), was determined by functional characterisation of deletion mutants obtained from two F. culmorum wild-type strains, FcUk99 (a highly pathogenic DON producer) and Fc233B (unable to produce toxin and with a mild pathogenic behavior). The ΔFcStuA mutants originating from both strains showed common phenotypic characters including stunted vegetative growth, loss of hydrophobicity of the mycelium, altered pigmentation, decreased activity of polygalacturonic enzymes and catalases, altered and reduced conidiation, delayed conidial germination patterns and complete loss of pathogenicity towards wheat stem base/root tissue. Glycolytic process efficiency [measured as growth on glucose as sole carbon (C) source] was strongly impaired and growth was partially restored on glutamic acid. Growth on pectin-like sources ranked in between glucose and glutamic acid with the following order (the lowest to the highest growth): beechwood xylan, sugarbeet arabinan, polygalacturonic acid, citrus pectin, apple pectin, potato azogalactan. DON production in the mutants originating from FcUK99 strain was significantly decreased (-95%) in vitro. Moreover, both sets of mutants were unable to colonise non-cereal plant tissues, i.e. apple and tomato fruits and potato tubers. No differences between mutants, ectopic and wild-type strains were observed concerning the level of resistance towards four fungicides belonging to three classes, the demethylase inhibitors epoxiconazole and tebuconzole, the succinate dehydrogenase inhibitor isopyrazam and the cytochrome bc1 inhibitor trifloxystrobin. StuA, given its multiple functions in cell regulation

  12. Black Cohosh

    Science.gov (United States)

    ... who have had hormone-sensitive conditions such as breast cancer or for pregnant women or nursing mothers. Black cohosh should not be confused with blue cohosh (Caulophyllum thalictroides) , which has different effects and may not be safe. Black cohosh has ...

  13. Efficacy of plant essential oils on postharvest control of rots caused by fungi on different stone fruits in vivo.

    Science.gov (United States)

    Lopez-Reyes, Jorge Giovanny; Spadaro, Davide; Prelle, Ambra; Garibaldi, Angelo; Gullino, Maria Lodovica

    2013-04-01

    The antifungal activity of plant essential oils was evaluated as postharvest treatment on stone fruit against brown rot and grey mold rot of stone fruit caused by Monilinia laxa and Botrytis cinerea, respectively. The essential oils from basil (Ocimum basilicum), fennel (Foeniculum sativum), lavender (Lavandula officinalis), marjoram (Origanum majorana), oregano (Origanum vulgare), peppermint (Mentha piperita), rosemary (Rosmarinus officinalis), sage (Salvia officinalis), savory (Satureja montana), thyme (Thymus vulgaris), and wild mint (Mentha arvensis) were tested at two different concentrations on apricots (cv. Kyoto and cv. Tonda di Costigliole), nectarines (cv. Big Top and cv. Nectaross) and plums (cv. Italia and cv. TC Sun). The volatile composition of the essential oils tested was determined by gas chromatography-mass spectrometry analysis. The treatments containing essential oils from oregano, savory, and thyme at 1% (vol/vol) controlled both B. cinerea and M. laxa growing on apricots cv. Tonda di Costigliole and plums cv. Italia and cv. TC Sun; however, the same treatments were phytotoxic for the carposphere of nectarines cv. Big Top and cv. Nectaross. Treatments with 10% (vol/vol) essential oils were highly phytotoxic, notwithstanding their efficacy against the pathogens tested. The essential oils containing as major components α-pinene, p-cymene, carvacrol, and thymol showed similar results on stone fruit, so their antimicrobial activity and the phytotoxicity produced could be based on the concentration of their principal compounds and their synergistic activity. The efficacy of the essential oil treatments on control of fungal pathogens in postharvest depended on the fruit cultivar, the composition and concentration of the essential oil applied, and the length of storage.

  14. A transposon-directed epigenetic change in ZmCCT underlies quantitative resistance to Gibberella stalk rot in maize.

    Science.gov (United States)

    Wang, Chao; Yang, Qin; Wang, Weixiang; Li, Yipu; Guo, Yanling; Zhang, Dongfeng; Ma, Xuena; Song, Wei; Zhao, Jiuran; Xu, Mingliang

    2017-09-01

    A major resistance quantitative trait locus, qRfg1, significantly enhances maize resistance to Gibberella stalk rot, a devastating disease caused by Fusarium graminearum. However, the underlying molecular mechanism remains unknown. We adopted a map-based cloning approach to identify the resistance gene at qRfg1 and examined the dynamic epigenetic changes during qRfg1-mediated maize resistance to the disease. A CCT domain-containing gene, ZmCCT, is the causal gene at the qRfg1 locus and a polymorphic CACTA-like transposable element (TE1) c. 2.4 kb upstream of ZmCCT is the genetic determinant of allelic variation. The non-TE1 ZmCCT allele is in a poised state, with predictive bivalent chromatin enriched for both repressive (H3K27me3/H3K9me3) and active (H3K4me3) histone marks. Upon pathogen challenge, this non-TE1 ZmCCT allele was promptly induced by a rapid yet transient reduction in H3K27me3/H3K9me3 and a progressive decrease in H3K4me3, leading to disease resistance. However, TE1 insertion in ZmCCT caused selective depletion of H3K4me3 and enrichment of methylated GC to suppress the pathogen-induced ZmCCT expression, resulting in disease susceptibility. Moreover, ZmCCT-mediated resistance to Gibberella stalk rot is not affected by photoperiod sensitivity. This chromatin-based regulatory mechanism enables ZmCCT to be more precise and timely in defense against F. graminearum infection. © 2017 The Authors. New Phytologist © 2017 New Phytologist Trust.

  15. Characterizing butt-rot fungi on USA-affiliated islands in the western Pacific

    Science.gov (United States)

    Phil Cannon; Ned B. Klopfenstein; Robert L. Schlub; Mee-Sook Kim; Yuko Ota; Norio Sahashi; Roland J. Quitugua; John W. Hanna; Amy L. Ross-Davis; J. D. Sweeney

    2014-01-01

    Ganoderma and Phellinus are genera that commonly cause tree butt-rot on USA-affiliated islands of the western Pacific. These fungal genera can be quite prevalent, especially in older mangrove stands. Although the majority of infections caused by these fungi lead to severe rotting of the heartwood, they typically do not directly kill the living tissues of the sapwood,...

  16. First report of Calonectria hongkongensis causing fruit rot of rambutan (Nephelium lappaceum L.)

    Science.gov (United States)

    Fruit rot is a major pre- and post-harvest disease problem in rambutan orchards. In 2011, fruit rot was observed at the USDA-TARS orchards in Mayaguez, Puerto Rico. Infected fruit were collected and tissue sections (1 mm2) were superficially sterilized with 70% ethanol and 0.5% sodium hypochlorite. ...

  17. First report of Colletotrichum fructicola and C. queenslandicum causing fruit rot of rambutan (Nephelium lappaceum L.)

    Science.gov (United States)

    In rambutan production, fruit rot is the main pre- and post-harvest disease of concern. In a 2008-2013 fruit disease survey, fruit rot was observed in eight orchards in Puerto Rico. Infected fruit were collected and 1 mm2 tissue sections were surface disinfested with 70% ethanol followed by 0.5% sod...

  18. Preparation and Characterization of Novolak Phenol Formaldehyde Resin from Liquefied Brown-Rotted Wood

    Science.gov (United States)

    Gai-Yun Li; Chung-Yun Hse; Te-Fu Qin

    2012-01-01

    The brown-rotted wood was liquefied in phenol with phosphoric acid as catalyst and the resulting liquefied products were condensed with formaldehyde to yield novolak liquefied wood-based phenol formaldehyde resin (LWPF). The results showed that brown-rotted wood could be more easily liquefied than sound wood in phenol. The residue content of liquefied wood decreased...

  19. Enzymatic oxalic acid regulation correlated with wood degradation in four brown-rot fungi

    Science.gov (United States)

    Anne Christine Steenkjær Hastrup; Frederick Green III; Patricia K. Lebow; Bo Jensen

    2012-01-01

    Oxalic acid is a key component in the initiation of brown-rot decay and it has been suggested that it plays multiple roles during the degradation process. Oxalic acid is accumulated to varying degrees among brown-rot fungi; however, details on active regulation are scarce. The accumulation of oxalic acid was measured in this study from wood degraded by the four brown-...

  20. Effect of irradiation and insect pest control on rots and sensory ...

    African Journals Online (AJOL)

    The coffee bean weevil, Araecerus fasciculatus Degeer (Coleoptera: Curculionidae) is associated with rots in stored yam tubers. The current study was designed to assess the effect of irradiation and other insect pest control strategies on rots and sensory quality of stored yams. 450 tubers each of two varieties of white yam ...

  1. Biocontrol of charcoal-rot of sorghum by actinomycetes isolated from ...

    African Journals Online (AJOL)

    use

    2011-12-12

    Dec 12, 2011 ... Streptomyces but with different species in BLAST analysis. This study indicates that the selected actinomycetes have the potential for PGP and control of charcoal-rot disease in sorghum. Key words: Antagonistic actinomycetes, biocontrol, charcoal-rot, Macrophomina phaseolina. INTRODUCTION.

  2. First report of Fusarium redolens causing crown rot of wheat (Triticum spp.) in Turkey

    Science.gov (United States)

    Fusarium crown rot, caused by a complex of Fusarium spp., is a yield-limiting disease of wheat world-wide, especially in dry Mediterranean climates. In order to identify Fusarium species associated with crown rot of wheat, a survey was conducted in summer 2013 in the major wheat growing regions of T...

  3. Potassium and Phosphorus effects on disease severity of charcoal rot of soybean

    Science.gov (United States)

    The effects of potassium (K) and phosphorus (P) fertilizers on charcoal rot of soybean [Glycine max (L.) Merr.] are unknown. Therefore, the severity of charcoal rot was studied at five levels of K (0, 37, 75, 111 and 149 kg K ha-1) and a level that was equal to the recommended fertilizer applicatio...

  4. Potassium and phosphorus have no effects on severity of charcoal rot of soybean

    Science.gov (United States)

    The effects of potassium (K) and phosphorus (P) fertilizers on charcoal rot of soybean [Glycine max (L.) Merr.] are unknown. Therefore, the severity of charcoal rot was studied at five levels of K (0, 37, 75, 111 and 149 kg K ha-1) and a level that was equal to the recommended fertilizer applicatio...

  5. Studies on the epidemiology of spear rot in oil palm (Elaeis guineensis Jacq.) in Suriname

    NARCIS (Netherlands)

    Lande, van de H.L.

    1993-01-01

    The epidemiology of spear rot, an infectious disease of unknown etiology, was studied over 10 years at three government-owned oil palm plantations in Suriname. As with other and similar diseases, amarelecimento fatal in Brazil and pudrición del cogollo in Latin America, which too show rot

  6. First Report of Calonectria hongkongensis Causing Fruit Rot of Rambutan (Nephelium lappaceum)

    NARCIS (Netherlands)

    Serrato-Diaz, L.M.; Latoni-Brailowsky, E.I.; Rivera-Vargas, L.I.; Goenaga, R.J.; Crous, P.W.; French-Monar, R.D.

    2013-01-01

    Fruit rot of rambutan is a pre- and post-harvest disease problem of rambutan orchards. In 2011, fruit rot was observed at USDA-ARS orchards in Mayaguez, Puerto Rico. Infected fruit were collected and 1 mm2 tissue sections were surface disinfested with 70% ethanol followed by 0.5% sodium

  7. Potential of bulb-associated bacteria for biocontrol of hyacinth soft rot caused by Dickeya zeae

    NARCIS (Netherlands)

    Jafra, S.; Przysowa, J.; Gwizdek-Wisniewska, A.; Wolf, van der J.M.

    2009-01-01

    Dickeya zeae is a pectinolytic bacterium responsible for soft rot disease in flower bulb crops. In this study, the possibility of controlling soft rot disease in hyacinth by using antagonistic bacteria isolated from hyacinth bulbs was explored. Bacterial isolates with potential for biocontrol were

  8. The presence and survival of soft rot (Erwinia) in flower bulb production systems

    NARCIS (Netherlands)

    Doorn, van J.; Vreeburg, P.J.M.; Leeuwen, van P.J.; Dees, R.H.L.

    2011-01-01

    Soft rot is causing increasing damage in the flower bulb industry. Bulbous ornamentals such as Hyacinthus, Dahlia, Iris, Muscari, Freesia and Zantedeschia can be infected. Soft rot in flower bulbs is mainly caused by Dickeya spp. (Dickeya spp.) and Erwinia carotovora subsp. carotovora

  9. Fungicide rotation schemes for managing Phytophthora fruit rot of watermelon across southeastern United States

    Science.gov (United States)

    Southeastern states produce about 50% of the watermelons in the United States (U.S.) where conditions are optimal for development of Phytophthora fruit rot prevail. Phytophthora fruit rot significantly limits watermelon production by causing serious yield losses to growers before and after harvest. ...

  10. Conversion of sorghum stover into animal feed with white-rot fungi ...

    African Journals Online (AJOL)

    Treatment of crop residues with some species of white-rot fungi can enhance the nutritive value. After the fungal treatment of sorghum (Sorghum bicolor) stover with two white-rot fungi in a solid state fermentation, the chemical composition and in vitro digestibility of the resultant substrate was determined. The results show a ...

  11. Interaction of Rhizoctonia solani and Rhizopus stolonifer Causing Root Rot of Sugar Beet

    Science.gov (United States)

    In recent years, growers in Michigan and other sugar beet production areas of the United States have reported increasing incidence of root rot with little or no crown or foliar symptoms in sugar beet with Rhizoctonia crown and root rot. In addition, Rhizoctonia-resistant beets have been reported wit...

  12. Conversion of sorghum stover into animal feed with white-rot fungi ...

    African Journals Online (AJOL)

    STORAGESEVER

    2010-03-15

    Mar 15, 2010 ... white-rot fungi: Pleurotus ostreatus and Pleurotus ... the fungal treatment of sorghum (Sorghum bicolor) stover with two white-rot fungi in a solid state ..... Rumen degradation and In vitro gas production parameters in some browse forages, grasses and maize stover from Kenya. J. Food Agric. Environ.

  13. The effect of long term storage on bacterial soft rot resistance in potato

    Science.gov (United States)

    Bacterial soft rot is a serious disease in potato (Solanum tuberosum L.), causing rapid tuber tissue maceration and, consequently, marketable yield loss. Soft rot bacteria, especially Pectobacterium carotovorum subsp. carotovorum (Pbc), are favored by moist conditions, which are prevalent in large p...

  14. Copper tolerance of brown-rot fungi : time course of oxalic acid production

    Science.gov (United States)

    Frederick Green; Carol A. Clausen

    2003-01-01

    The increase in the use of non-arsenical copper-based wood preservatives in response to environmental concerns has been accompanied by interest in copper-tolerant decay fungi. Oxalic acid production by brown-rot fungi has been proposed as one mechanism of copper tolerance. Fifteen brown-rot fungi representing the genera Postia, Wolfiporia, Meruliporia, Gloeophyllum,...

  15. Fungicides reduce Rhododendron root rot and mortality caused by Phytophthora cinnamomi, but not by P. plurivora

    Science.gov (United States)

    Rhododendron root rot, caused by several Phytophthora species, can cause devastating losses in nursery-grown plants. Most research on chemical control of root rot has focused on Phytophthora cinnamomi. However, it is unknown whether treatments recommended for P. cinnamomi are also effective for othe...

  16. Nonchemical, cultural management strategies to suppress phytophthora root rot in northern highbush blueberry

    Science.gov (United States)

    Phytophthora cinnamomi causes root rot of highbush blueberry and decreases plant growth, yield, and profitability for growers. Fungicides can suppress root rot, but cannot be used in certified organic production systems and fungicide resistance may develop. Alternative, non-chemical, cultural manag...

  17. Resistance to post-harvest microbial rot in yam: Integration of ...

    African Journals Online (AJOL)

    Post-harvest microbial rot is an important disease that causes severe losses in yam (Dioscorea spp.) storage. Rot from microbial infection of healthy yam tubers reduces their table quality and renders them unappealing to consumers. A study was carried out at Bimbilla in the Nanumba North District of Ghana to evaluate ...

  18. Insights into molecular and metabolic events associated with fruit response to post-harvest fungal pathogens

    Science.gov (United States)

    Alkan, Noam; Fortes, Ana M.

    2015-01-01

    Due to post-harvest losses more than 30% of harvested fruits will not reach the consumers’ plate. Fungal pathogens play a key role in those losses, as they cause most of the fruit rots and the customer complaints. Many of the fungal pathogens are already present in the unripe fruit but remain quiescent during fruit growth until a particular phase of fruit ripening and senescence. The pathogens sense the developmental change and switch into the devastating necrotrophic life style that causes fruit rotting. Colonization of unripe fruit by the fungus initiates defensive responses that limit fungal growth and development. However, during fruit ripening several physiological processes occur that correlate with increased fruit susceptibility. In contrast to plant defenses in unripe fruit, the defense posture of ripe fruit entails a different subset of defense responses that will end with fruit rotting and losses. This review will focus on several aspects of molecular and metabolic events associated with fleshy fruit responses induced by post-harvest fungal pathogens during fruit ripening. PMID:26539204

  19. First report of in-vitro fludioxonil-resistant isolates of Fusarium spp. causing potato dry rot in Michigan

    Science.gov (United States)

    Fusarium dry rot of potato (Solanum tuberosum) is a postharvest disease caused by several Fusarium species and is of worldwide importance. Measures for controlling dry rot in storage are limited. Dry rot has been managed primarily by reducing tuber bruising, providing conditions for rapid wound heal...

  20. Zinc Induced Enzymatic Defense Mechanisms in Rhizoctonia Root Rot Infected Clusterbean Seedlings

    Directory of Open Access Journals (Sweden)

    Neha Wadhwa

    2014-01-01

    Full Text Available This investigation was planned to determine the effect of different concentrations of zinc (Zn on biochemical constituents of clusterbean, which play an important role in disease resistance mechanisms. Clusterbean seedlings were grown with 0, 10, or 20 mg Zn kg−1 soil treatments in earthen pots filled with 700 g inoculated soil. Soil was inoculated by pretreatment with 250 mg (wet weight of Rhizoctonia inoculums per pot. A similar set was maintained in uninoculated soil. Root rot incidence decreased to 41 and 27 per cent with 10 and 20 mg Zn kg−1 soil treatments, respectively, as compared to 68 percent at control. Antioxidative enzyme activity (polyphenol oxidase, peroxidase, phenylalanine ammonia lyase, and tyrosine ammonia lyase increased in inoculated seedlings and was increased further by 20 mg Zn kg−1 soil treatment. Antioxidative enzymes play an important role against fungal invasion, as peroxidase is involved in the formation of barrier via lignifications at the site of pathogen penetration. PAL and TAL play a key role in phenylpropanoid metabolism and could perform defense-related functions. Zn acts as a cofactor for these enzymes, so it can be concluded that Zn may be used as a soil-nutritive agent to increase resistance in plants against fungal diseases.

  1. Ralstonia solanacearum biovar 1 associated with a new outbreak of potato brown rot in Portugal

    Directory of Open Access Journals (Sweden)

    Leonor Cruz

    2008-10-01

    Full Text Available In May 2007, potato plants exhibiting symptoms possibly of brown rot were collected in some potato fields in the Baixo Mondego region (Center, Portugal, as a part of a nationwide programme to monitor Ralstonia solanacearum. All laboratory procedures laid down in Commission Directive 2006/63/EC, including dilution plating on semi-selective medium SMSA, indirect imunofluorescence (IIF, polymerase chain reaction (PCR using specific primers and bioassays on tomato plants, were strictly followed and the causal agent of the disease was identified as Ralstonia solanacearum. The identity of the pure cultures of the isolated organism was confirmed by PCR, IIF and pathogenicity tests on several other plant species (eggplant, tobacco, pelargonium and eucalyptus. In biovar determination, the failure of the isolates to utilise/oxidise certain carbon sources indicated that the isolates were all biovar 1. This biovar has a broader host range than biovar 2 strains, and affects several crops of economic importance including ornamental plants and forest trees. Comparative analysis of 16S rRNA and endoglucanase (egl gene sequences of these isolates with sequences that have been deposited at the GenBank revealed a similarity higher than 99% for several Ralstonia solanacearum isolates from biovar 1, including isolate DAR 64836 (Accession number DQ011551. This is the first report of Ralstonia solanacearum biovar 1 in Portugal. All control measures specified in the Commission Directive are being implemented.

  2. Carbon Dioxide and Methane Formation in Norway Spruce Stems Infected by White-Rot Fungi

    Directory of Open Access Journals (Sweden)

    Ari M. Hietala

    2015-09-01

    Full Text Available Globally, billions of tons of carbon sequestered in trees are annually recycled back to the atmosphere through wood decomposition by microbes. In Norway, every fifth Norway spruce shows at final harvest infection by pathogenic white-rot fungi in the genera Heterobasidion and Armillaria. As these fungi can mineralize all components of wood, we predicted that they have a significant carbon footprint. Gas samples taken from infected stems were analyzed for CO2 and CH4 concentrations, and wood samples from different parts of the decay columns were incubated under hypoxic (4% O2 and anoxic laboratory conditions. In spring and summer the stem concentrations of CO2 were generally two times higher in trees with heartwood decay than in healthy trees. For most of the healthy trees and trees with heartwood decay, mean stem concentrations of CH4 were comparable to ambient air, and only some Armillaria infected trees showed moderately elevated CH4. Consistently, low CH4 production potentials were recorded in the laboratory experiment. Up-scaling of CO2 efflux due to wood decay in living trees suggests that the balance between carbon sequestration and emission may be substantially influenced in stands with high frequency of advanced root and stem heartwood decay.

  3. Watery rot of pseudo-stem (Dickeya sp. management in banana (Musa sp. under greenhouse conditions

    Directory of Open Access Journals (Sweden)

    Joaquín Guillermo Ramírez

    2014-12-01

    Full Text Available This crop has serious constraints with diseases, including those caused by bacteria, such as Dickeya sp. This research aimed to evaluate the effect of 4 resistance inductors and 3 doses in Chlorine Dioxide in handling watery rot of pseudo-stem (Dickeya sp. in banana. Resistance inducers and their doses were Potassium Phosphite: 1.5 cm 3 .l -1 ; 3-Aminobutanoic Acid: 1.0 g.l -1 ; Methyl Jasmonate: 0.2 g.l -1 ; S-Methyl-Acibenzolar: 0.3 ml.l -1 , all by foliar application, while Chlorine Dioxide was injected into the pseudo-stem, in doses of 10, 20 and 30 mg.l -1 . The evaluated variables were: development of the disease, total biomass and quantification of the bacterium in the inoculated pseudo-stems. Applications of Chlorine Dioxide achieved a reduction of disease by 65.4, 91.99 and 61.5%, in addition to an inhibition of 100% of the pathogen, using 30 and 50 mg.l -1 doses. Meanwhile, the use of resistance inductors reduced up to 60.6% of the disease, but this effect failed to improve plant growth.

  4. The history of research on oil palm bud rot (Elaeis guineensis Jacq. in Colombia

    Directory of Open Access Journals (Sweden)

    Édgar Benítez

    2014-12-01

    Full Text Available This article presents an overview of the main results obtained from research on oil palm bud rot. Aetiologic studies with biotic and abiotic approaches were explored, aiming for a model that would help in the understanding of the ethology of this disease. It also discusses how the results of the studies are contradictory and how the arguments for biological causes have not shown progress. Furthermore, the results of measuring the influence of abiotic factors, where there is greater consensus, are discussed; however, there is controversy due to the fact that different researchers placed different weight on the final model of this disease. This situation has led to controls being directed toward potential pathogens associated with the disease, as determined by circumstantial evidence, wherein the positive or negative response to the control may be confused with extrinsic factors such as disease escape or foci formation. Even the role played by the insect Rhynchophorus palmarum (L. in the death of palms affected by this disease is in doubt. Finally, this paper shows how the process of general disease research has important biases arising from the risk aversion of palm producers or the lack of continuity in results obtained by different research groups.

  5. Essential oils on the control of stem and ear rot in maize

    Directory of Open Access Journals (Sweden)

    Glauco Antonio Teixeira

    2013-11-01

    Full Text Available Stem and ear rot caused by Stenocarpella maydis are responsible for severe losses in maize production. Treatment of seeds with fungicides may induce environmental damage. Hence, this study aimed to evaluate the effects of essential oils extracted from Cymbopogon winterianus, Thymus vulgaris, Cymbopogon citratus, Corymbia citriodora, Cinnamomum zeylanicum, and Syzygium aromaticum on the development of in vitro S. maydis. In addition, maize seeds were treated with these essential oils to determine their possible mode of action and effects. The oils from S. aromaticum, C. zeylanicum, and T. vulgaris inhibited fungal development at concentrations higher than 0.025%. The oils from S. aromaticum and C. zeylanicum showed seed germination rates of 89.0% and 84.5%, which were higher than that of the control. The oils from S. aromaticum and C. zeylanicum reduced the pathogen incidence in the seeds to 39.0% and 28.0%, respectively. Further, these oils as well as that from T. vulgaris produced lower reduction of maize stand. Scanning electron microscopy examination revealed that essential oils from S. aromaticum and T. vulgaris acted directly on the conidia, impeding germination. The findings suggest that the oils from S. aromaticum, C. zeylanicum, and T. vulgaris are potential alternatives for maize seed treatment in the control of S. maydis.

  6. Identification of volatile markers in potato brown rot and ring rot by combined GC-MS and PTR-MS techniques: study on in vitro and in vivo samples.

    Science.gov (United States)

    Blasioli, Sonia; Biondi, Enrico; Samudrala, Devasena; Spinelli, Francesco; Cellini, Antonio; Bertaccini, Assunta; Cristescu, Simona M; Braschi, Ilaria

    2014-01-15

    Ralstonia solanacearum (Rs) and Clavibacter michiganensis subsp. sepedonicus (Cms) are the bacterial causal agents of potato brown and ring rot, respectively, and are included in the A2 list of quarantine pathogens in Europe. Identification by GC-MS analysis of volatile organic compounds from Rs or Cms cultured on different nutrient media was performed. GC-MS and PTR-MS analysis were carried out also on unwounded potato tubers infected with the same pathogens. Infected tubers were produced by experimental inoculations of the plants. In in vitro experiments, Rs or Cms emitted volatile compounds, part of which were specific disease markers of potato (2-propanol and 3-methylbutanoic acid), mainly originating from bacterial metabolism (i.e., amino acid degradation, carbohydrate and fatty acid oxidation). In potato tubers, pathogen metabolism modified the volatile compound pattern emitted from healthy samples. Both bacteria seem to accelerate metabolic processes ongoing in potatoes and, in the case of Rs, disease markers (1-hepten-3-ol, 3,6-dimethyl-3-octanone, 3-ethyl-3-methylpentane, 1-chloroctane, and benzothiazole) were identified.

  7. Perfect Undetectable Acoustic Device from Fabry-Pérot Resonances

    Science.gov (United States)

    Chen, Huanyang; Zhou, Yangyang; Zhou, Mengying; Xu, Lin; Liu, Qing Huo

    2018-02-01

    Transformation acoustics is a method to design novel acoustic devices, while the complexity of the material parameters hinders its progress. In this paper, we analytically present a three-dimensional perfect undetectable acoustic device from Fabry-Pérot resonances and confirm its functionality from Mie theory. Such a mechanism goes beyond the traditional transformation acoustics. In addition, such a reduced version can be realized by holey-structured metamaterials. Our theory paves a way to the implementation of three-dimensional transformation acoustic devices.

  8. Serpula lacrymans, The Dry Rot Fungus and Tolerance Towards Copper-Based Wood Preservatives

    DEFF Research Database (Denmark)

    Hastrup, Anne Christine Steenkjær; Jensen, Bo; Clausen, Carol

    2005-01-01

    -rot fungi is thought to be due in part to oxalic acid production and accumulation. Oxalic acid has been implicated in copper tolerance by the formation of copper oxalate crystals. Twelve isolates of the dry rot fungus, S. lacrymans and four other brown rot species were evaluated for weight loss on wood......Serpula lacrymans (Wulfen : Fries) Schröter, the dry rot fungus, is considered the most (Wulfen : Fries) Schröterthe dry rot fungus, is considered the most economically important wood decay fungus in temperate regions of the world i.e. northern Europe, Japan and Australia. Previously copper based...... wood preservatives were the most commonly used preservatives for pressure treatment of wood for building constructions. Because of a suspicion about tolerance toward copper components, a soil block test was undertaken to clarify the effect of two copper based preservatives, copper citrate and ACQ...

  9. Role of Rot in bacterial autolysis regulation of Staphylococcus aureus NCTC8325.

    Science.gov (United States)

    Chu, Xinmin; Xia, Rui; He, Nianan; Fang, Yuting

    2013-09-01

    Autolysis is an important process in cell wall turnover in Staphylococcus aureus, performed by several peptidoglycan hydrolases or so-called autolysins and controlled by many regulators. Rot is a global regulator that regulates numerous virulence genes, including genes encoding lipase, hemolysins, proteases and genes related to cell surface adhesion. The aim of our study was to determine whether Rot has the ability to regulate autolysis. We compared Triton-X-100-induced autolysis of S. aureus NCTC8325 and its rot knock-out mutant. We found that the rot mutant showed increased autolysis rates. By examining the transcript level of several autolysins and some known regulators responsible for regulating autolysis using real-time RT-PCR assays, we found that transcription of two autolysins (lytM, lytN) and one regulatory operon (lrgAB) was changed in the rot mutant. An in vitro approach was undertaken to determine which of these genes are directly controlled by Rot. Rot proteins were overproduced in Escherichia coli and purified. Gel mobility shift DNA binding assays were used and showed that in-vitro-purified Rot can directly bind to the promoter region of lytM, lytN, lrgA and lytS. We also tested biofilm formation of the rot mutant, and it showed enhancement in biofilm formation. Taken together, our results reveal that Rot affects autolysis by directly regulating autolysins LytM and LytN, and, via a regulatory system, LrgAB. Copyright © 2013 Institut Pasteur. Published by Elsevier Masson SAS. All rights reserved.

  10. Vegetative compatibility group of Fusarium solani pathogenic to tobacco plant in peninsular Malaysia

    Directory of Open Access Journals (Sweden)

    Mohd Norhafeez bin Jusoh

    2013-12-01

    Full Text Available Five strains of Fusarium solani isolated from root rot of tobacco from Kelantan and Terengganu, Malaysia were tested for the pathogenicity on tobacco seedlings by root dipping method. All 5 isolates showed discoloration on the roots. The nitrate non-utilizing (nit mutants were generated from these pathogenic strains of F. solani and a compatible nit1 and NitM pair was obtained in each strain. Vegetative Compatible Groups (VCGs by nit mutants were determined. All 5 strains of F. solani were assigned to the independent VCGs. Non-pathogenic strains of F. solani previously isolated from root rot of tobacco in Malaysia also generated nit mutants and were assigned to 10 different VCGs. However, complementation of nit mutants between 5 pathogenic strains and 7 non-pathogenic strains of F. solani was not achieved. Both pathogenic and nonpathogenic strains were assigned to the independent VCGs. This suggested that the isolates of F. solani pathogenic to tobacco were derived from the progenies of crossing in the field. However, perithecium formation was not observed in their cultures.

  11. Efficient xylose fermentation by the brown rot fungus Neolentinus lepideus.

    Science.gov (United States)

    Okamoto, Kenji; Kanawaku, Ryuichi; Masumoto, Masaru; Yanase, Hideshi

    2012-02-10

    The efficient production of bioethanol on an industrial scale requires the use of renewable lignocellulosic biomass as a starting material. A limiting factor in developing efficient processes is identifying microorganisms that are able to effectively ferment xylose, the major pentose sugar found in hemicellulose, and break down carbohydrate polymers without pre-treatment steps. Here, a basidiomycete brown rot fungus was isolated as a new biocatalyst with unprecedented fermentability, as it was capable of converting not only the 6-carbon sugars constituting cellulose, but also the major 5-carbon sugar xylose in hemicelluloses, to ethanol. The fungus was identified as Neolentinus lepideus and was capable of assimilating and fermenting xylose to ethanol in yields of 0.30, 0.33, and 0.34 g of ethanol per g of xylose consumed under aerobic, oxygen-limited, and anaerobic conditions, respectively. A small amount of xylitol was detected as the major by-product of xylose metabolism. N. lepideus produced ethanol from glucose, mannose, galactose, cellobiose, maltose, and lactose with yields ranging from 0.34 to 0.38 g ethanol per g sugar consumed, and also exhibited relatively favorable conversion of non-pretreated starch, xylan, and wheat bran. These results suggest that N. lepideus is a promising candidate for cost-effective and environmentally friendly ethanol production from lignocellulosic biomass. To our knowledge, this is the first report on efficient ethanol fermentation from various carbohydrates, including xylose, by a naturally occurring brown rot fungus. Copyright © 2011 Elsevier Inc. All rights reserved.

  12. Pathogenicity of fungal species in aroid ( Colocasia and Xanthosoma rhizomes

    Directory of Open Access Journals (Sweden)

    Amaurys Dávila Martínez

    2016-07-01

    Full Text Available Among the diseases affecting aroids is rhizome rot caused by various pathogen fungi. These rots usually appear in poorly drained heavy soils with high organic matter content. These diseases appear more during the rainy season because it is a fungus complex living in the soil and is favored by high humidity. In order to know the virulence of different pathogens involved in this syndrome, cross-species inoculations were performed. Species of Rhizoctonia solani Kühn and Sclerotiun rolfsii Sacc were used in croos inoculations as they showed a higher percentage of appearance in the analyzed samples. The pathogenicity of the major fungal species was confirmed in Xanthosoma: S. rolfsii, F. sulphureum and F. chlamydosporum and in Colocasia: Phoma sp, Diplodia sp.and S. rolfsii. In the combined inoculations, Rhizoctonia solani showed synergism in the fungus Phoma sp in Xanthosoma and F. chlamydosporum in Colocasia and an antagonistic effect with the rest of the species. S. rolfsii showed synergism with all fungi in Colocasia except with Diplodia sp. and Phoma sp. while in Xanthosoma it showed antagonism with all species.

  13. Black Tea

    Science.gov (United States)

    ... leaves of the same plant, has some different properties. Black tea is used for improving mental alertness ... that slow blood clotting include aspirin, clopidogrel (Plavix), diclofenac (Voltaren, Cataflam, others), ibuprofen (Advil, Motrin, others), naproxen ( ...

  14. The chemical inducer, BTH (benzothiadiazole) and root colonization by mycorrhizal fungi (Glomus spp.) trigger resistance against white rot (Sclerotinia sclerotiorum) in sunflower.

    Science.gov (United States)

    Bán, Rita; Baglyas, Gellért; Virányi, Ferenc; Barna, Balázs; Posta, Katalin; Kiss, József; Körösi, Katalin

    2017-03-01

    White rot caused by Sclerotinia sclerotiorum (SS) is one of the most devastating plant diseases of sunflower. Controlling this pathogen by available tools hardly result in acceptable control. The aim of this study was to elucidate the effects of plant resistance inducers, BTH (benzothiadiazole in Bion 50 WG) and arbuscular mycorrhizal fungi (AMF) on disease development of white rot in three sunflower genotypes. Defence responses were characterized by measuring the disease severity and identifying cellular/histological reactions (e.g. autofluorescence) of host plants upon infection. Depending on the host genotype, a single application of inducers reduced disease symptoms. Histological examination of host responses revealed that BTH and/or AMF pre-treatments significantly impeded the development of pathogenic hyphae in Iregi szürke csíkos and P63LE13 sunflower plants and it was associated with intensive autofluorescence of cells. Both localized and systemic induction of resistance was observed. Importantly, the frequency of mycorrhization of hybrid P63LE13 and PR64H41 was significantly increased upon BTH treatment, so it had a positive effect on the formation of plant-mycorrhiza interactions in sunflower. To our knowledge, this is the first report on the additive effect of BTH on mycorrhization and the positive effect of these inducers against SS in sunflower.

  15. Application of amplified fragment length polymorphism fingerprinting for taxonomy and identification of the soft rot bacteria Erwinia carotovora and Erwinia chrysanthemi.

    Science.gov (United States)

    Avrova, Anna O; Hyman, Lizbeth J; Toth, Rachel L; Toth, Ian K

    2002-04-01

    The soft rot bacteria Erwinia carotovora and Erwinia chrysanthemi are important pathogens of potato and other crops. However, the taxonomy of these pathogens, particularly at subspecies level, is unclear. An investigation using amplified fragment length polymorphism (AFLP) fingerprinting was undertaken to determine the taxonomic relationships within this group based on their genetic relatedness. Following cluster analysis on the similarity matrices derived from the AFLP gels, four clusters (clusters 1 to 4) resulted. Cluster 1 contained Erwinia carotovora subsp. carotovora (subclusters 1a and 1b) and Erwinia carotovora subsp. odorifera (subcluster 1c) strains, while cluster 2 contained Erwinia carotovora subsp. atroseptica (subcluster 2a) and Erwinia carotovora subsp. betavasculorum (subcluster 2b) strains. Clusters 3 and 4 contained Erwinia carotovora subsp. wasabiae and E. chrysanthemi strains, respectively. While E. carotovora subsp. carotovora and E. chrysanthemi showed a high level of molecular diversity (23 to 38% mean similarity), E. carotovora subsp. odorifera, E. carotovora subsp. betavasculorum, E. carotovora subsp. atroseptica, and E. carotovora subsp. wasabiae showed considerably less (56 to 76% mean similarity), which may reflect their limited geographical distributions and/or host ranges. The species- and subspecies-specific banding profiles generated from the AFLPs allowed rapid identification of unknown isolates and the potential for future development of diagnostics. AFLP fingerprinting was also found to be more differentiating than other techniques for typing the soft rot erwinias and was applicable to all strain types, including different serogroups.

  16. The roles of arbuscular mycorrhizal fungi in the intensity of the foot rot disease on pepper plant from the infected soil

    Directory of Open Access Journals (Sweden)

    Norma Fauziyah

    2017-07-01

    Full Text Available Pepper (Piper nigrum L. is an important spice plant of  Indonesia. In Bangka Belitung Province, the main pepper producer, pepper has been the most commonly cultivated commodity. However, the production has declined from time to time. One of the causes of the decline is Pepper Fot Rot, caused by Phytophthora capsici. The rapid spread and development of the disease is mainly due to utilization of diseased plant materials for pepper cuttings and infested or diseased plantation soil. The materials used in this research included the infected soil taken from the infectedpepper plantation at Bangka Island with disease intensity of pepper foot rot 60%, inoculum of Arbuscular Mycorrhizal fungi in the zeolite medium, compost, and pepper seedling from Natar variety. This research was done by planting pepper seedling on infected soil and observing plant height, disease intensity, and infection of AM fungi on the roots. The results showed that soil from diseased pepper plants harbored high population of plant pathogens inoculum and caused the death of 9 week-old cuttings and retarded growth of the survivors. Sterilization of the infected soil with hot water vapor for 3 hours still could not control the pathogen. Good growth was observed on one node cutting planted in sterile soil amended with arbuscular mycorrhizal fungi.

  17. Foodborne pathogens

    Directory of Open Access Journals (Sweden)

    Thomas Bintsis

    2017-06-01

    Full Text Available Foodborne pathogens are causing a great number of diseases with significant effects on human health and economy. The characteristics of the most common pathogenic bacteria (Bacillus cereus, Campylobacter jejuni, Clostridium botulinum, Clostridium perfringens, Cronobacter sakazakii, Esherichia coli, Listeria monocytogenes, Salmonella spp., Shigella spp., Staphylococccus aureus, Vibrio spp. and Yersinia enterocolitica, viruses (Hepatitis A and Noroviruses and parasites (Cyclospora cayetanensis, Toxoplasma gondii and Trichinella spiralis, together with some important outbreaks, are reviewed. Food safety management systems based on to classical hazard-based approach has been proved to be inefficient, and risk-based food safety approach is now suggested from leading researchers and organizations. In this context, a food safety management system should be designed in a way to estimate the risks to human health from food consumption and to identify, select and implement mitigation strategies in order to control and reduce these risks. In addition, the application of suitable food safety education programs for all involved people in the production and consumption of foods is suggested.

  18. Phytophthora megakarya and P. palmivora, closely related causal agents of cacao black pod induce similar reactions when infecting pods of a susceptible cacao genotype

    Science.gov (United States)

    Phytophthora megakarya (Pmeg) and Phytophthora palmivora (Ppal) cause black pod rot of Theobroma cacao. Of these two clade 4 species; Pmeg is more virulent and is displacing Ppal on cacao in many cacao production areas in Africa. To understand the advantages Pmeg has over Ppal, we compared symptom...

  19. The Phytopathogen Dickeya dadantii (Erwinia chrysanthemi 3937) Is a Pathogen of the Pea Aphid†

    OpenAIRE

    Grenier, Anne-Marie; Duport, Gabrielle; Pagès, Sylvie; Condemine, Guy; Rahbé, Yvan

    2006-01-01

    Dickeya dadantii (Erwinia chrysanthemi) is a phytopathogenic bacterium causing soft rot diseases on many crops. The sequencing of its genome identified four genes encoding homologues of the Cyt family of insecticidal toxins from Bacillus thuringiensis, which are not present in the close relative Pectobacterium carotovorum subsp. atrosepticum. The pathogenicity of D. dadantii was tested on the pea aphid Acyrthosiphon pisum, and the bacterium was shown to be highly virulent for this insect, eit...

  20. APPLICATION METHOD OF ANTIMICROBIAL SUB -STANCES FOR THE CONTROL OF schiZophyllum commuN e FR. CAUSING BROWN GERM AND SEED ROT OF OIL PALM

    Directory of Open Access Journals (Sweden)

    ANTARIO DIKIN

    2008-01-01

    Full Text Available Biological seed treatment promotes to save the environment from toxic chemicals in the agricultural practices. Schizophyllum commune is one of the important seedborne pathogenic fungi causing brown germ and seed rot of oil palm which required effective and efficient treat -ment based on environmental friendly approaches. Anti-microbial substances are extracted from antagonistic bacteria of B. multivorans and M. testaceum after mass production in the liquid media. Application method of anti-microbial substances for the control of Schizophylllum commune was done by seed dipping for 30 minutes and vacuum infiltration at 400 mm Hg. vac. for 2 min. in supernatant of anti-microbial substances diluted in sterilized distilled water with concentra -tion ratio of 1:4. Application method using anti-microbial substances from antagonistic bacteria inhibited the growth of pathogenic fungus, enhanced seed germination, and without causing any abnormal growth of oil palm seedlings.

  1. Impact of transgenic potatoes expressing anti-bacterial agents on bacterial endophytes is comparable with the effects of plant genotype, soil type and pathogen infection

    NARCIS (Netherlands)

    Rasche, F; Velvis, H; Zachow, C; Berg, G; Van Elsas, JD; Sessitsch, A

    1. Blackleg and soft rot disease of potatoes Solanum tuberosum L., mainly caused by the bacterial pathogen Erwinia carotovora ssp. atrospetica (Eca), lead to enormous yield losses world-wide. Genetically modified (GM) potatoes producing anti-bacterial agents, such as cecropin/attacin and T4

  2. Impact of transgenic potatoes expressing anti-bacterial agents on bacterial endophytes is comparable with the effects of plant genotype, soil type and pathogen infection

    NARCIS (Netherlands)

    Rasche, F.; Velvis, H.; Zachow, C.; Berg, G.; Elsas, van J.D.; Sessitsch, A.

    2006-01-01

    1. Blackleg and soft rot disease of potatoes Solanum tuberosum L., mainly caused by the bacterial pathogen Erwinia carotovora ssp. atrospetica (Eca), lead to enormous yield losses world-wide. Genetically modified (GM) potatoes producing anti-bacterial agents, such as cecropin/attacin and T4

  3. Metabolites produced by antagonistic microbes inhibit the principal avocado pathogens in vitro

    Directory of Open Access Journals (Sweden)

    Sara Ramírez R.

    2015-04-01

    Full Text Available The demand for Hass avocado in the global market exceeds the supply by over 50%. Colombia has a remarkable advantage as a producer in the region due to its high yields. However, the productivity of this crop can be seriously affected by diseases such as root rot, caused by Phytophthora cinnamomi, postharvest body rot and stem end rot, caused by Colletotrichum sp. and Phomopsis sp., respectively. The potential of 76 bacterial isolates obtained from avocado rhizosphere to produce inhibitory metabolites against avocado's pathogens was evaluated. The antagonistic effect of the rhizobacteria against P. cinnamomi, Colletotrichum sp. and Phomopsis sp. was tested through dual cultures. Thirty-six percent of the tested isolates presented inhibition halos against P. cinnamomi, 36% against Colletotrichum sp. and 67% against Phomopsis sp. Additionally, three isolates were selected for fermentation tests using different broth cultures. The extracts obtained from fermentations in the minimal medium of isolates ARP5.1 and AED06 showed inhibitory activity against the evaluated pathogens, but this effect was not observed with the AED26 extract. The media supplemented with copper chloride did not enhance activity of the extracts. These results suggest that using microbial metabolic extracts is a viable alternative for controlling avocado pathogens in vitro.

  4. Control of Ralstonia Solanacearum The Causal Agent of Brown Rot in Potato Using Essential Oils

    International Nuclear Information System (INIS)

    Salem, E.A.

    2011-01-01

    Five essential oils, namely peppermint (Mentha piperita L.), caraway (Carium carvum L.), fennel (Foeniculum vulgare Mill.), lemongrass (Cymbopogon citratus Staph.) and thyme (Thymus vulgaris), were used separately against Ralstonia solanacearum; the causal agent of brown rot in potato. The most two effective oils (peppermint and thyme) were used in vitro and in vivo after testing their effects on potato tubers buds germination. Peppermint inhibited buds germination but thyme have no effects on buds germination. In vivo, the control of brown rot using thyme oil in glass house experiment reduced the percentage of brown rot infection to 30.6% and reduced the severity of disease from 5 to 3.

  5. Plasmonic coaxial Fabry-Pérot nanocavity color filter

    Science.gov (United States)

    Si, G. Y.; Leong, E. S. P.; Danner, A. J.; Teng, J. H.

    2010-08-01

    Plamonic coaxial structures have drawn considerable attetion recently because of their unique properties. They exhibit different mechanisms of extraordinary optical transmission observed from subwavelength holes and they can support localized Fabry-Pérot plasmon modes. In this work, we experimentally demonstrate color filters based on coaxial structures fabricated in optically thick metallic films. Using nanogaps with different apertures from 160 nm down to only 40 nm, we show varying color outputs when the annular aperture arrays are illuminated with a broadband light source. Effective color-filter function is demonstrated in the optical regime. Different color outputs are observed and optical spectra are measured. In such structures, it is the propagating mode playing an important role rather than the evanescent. Resonances depend strongly on ring apertures, enabling devices with tunability of output colors using simple geometry control.

  6. Combination of RNAseq and SNP nanofluidic array reveals the center of genetic diversity of cacao pathogen Moniliophthora roreri in the upper Magdalena Valley of Colombia and its clonality

    OpenAIRE

    Ali, Shahin S.; Shao, Jonathan; Strem, Mary D.; Phillips-Mora, Wilberth; Zhang, Dapeng; Meinhardt, Lyndel W.; Bailey, Bryan A.

    2015-01-01

    Moniliophthora roreri is the fungal pathogen that causes frosty pod rot (FPR) disease of Theobroma cacao L., the source of chocolate. FPR occurs in most of the cacao producing countries in the Western Hemisphere, causing yield losses up to 80%. Genetic diversity within the FPR pathogen population may allow the population to adapt to changing environmental conditions and adapt to enhanced resistance in the host plant. The present study developed single nucleotide polymorphism (SNP) markers fro...

  7. Animal vectors of eastern dwarf mistletoe of black spruce.

    Science.gov (United States)

    Michael E. Ostry; Thomas H. Nicholls; D.W. French

    1983-01-01

    Describes a study to determine the importance of animals in the spread of eastern dwarf mistletoe of black spruce. Radio telemetry, banding, and color-marking techniques were used to study vectors of this forest pathogen.

  8. Stem base rot of winter wheat by Fusarium spp. - causes and effects

    Directory of Open Access Journals (Sweden)

    Małgorzata Narkiewicz-Jodko

    2012-12-01

    Full Text Available The aim of the work was to determine the influence of weather conditions and a degree of weed infestation on the incidence of stem bases rot (Fusarium spp. of winter wheat cultivars as well as their yield. The winter wheat cultivars (Kobra, Korweta, Mikon, Zyta were investigated (2000-2002 in the field where the following herbicides: Apyros 75 WG + Atpolan, Affinity 50,75 WG, Attribut 70 WG were applied. It has been shown the occurrence of stem base rot (Fusarium spp. depended mainly on weather conditions. The application of the herbicides improved the plant health. The stem base rot on winter wheat was caused by Fusarium spp., specially F. culmorum. The decrease in winter wheat yield depended on weather conditions, weed infestation and the occurrence of stem base rot (Fusarium spp..

  9. CHARACTERIZATION OF WOOD DECAY BY ROT FUNGI USING COLORIMETRY AND INFRARED SPECTROSCOPY

    Directory of Open Access Journals (Sweden)

    Mírian de Almeida Costa

    2011-09-01

    Full Text Available Wood samples of marupá (Simarouba amara and andiroba (Carapa guianenis were submitted to Trametes versicolor (white rot and Gloeophylum trabeum (brown rot fungi attack. Colorimetry was used to determine the color of the wood before and after wood decaying fungi. To evaluate the changes in chemical compounds levels in the wood samples, the diffuse reflectance medium infrared spectroscopy was used. Both wood were non resistant against white rot fungus, while with brown rot attack andiroba was resistant and marupá was not. After Gloeophyllum trabeum attack both woods changed to a darken color, and after Trametes versicolor attack andiroba changed to a lighter color and marupá darkened slightly, The analysis showed a reduction in the peak intensity of cellulose, hemicellulose and lignin, for both species, after Trametes versicolor attack and a reduction in the peak intensity of cellulose after Gloeophyllum trabeum attack.

  10. Efficacy of four plant extracts in the control of root rot disease of ...

    African Journals Online (AJOL)

    Garcinia cola) and neem (Azadirachta indica) extracts in the control of root rot of cowpea caused by Pythium aphanidermatum was carried out in vitro and in the field (in vivo). They were evaluated for their antifungal activity over P.

  11. Biodegradation of hazardous waste using white rot fungus: Project planning and concept development document

    International Nuclear Information System (INIS)

    Luey, J.; Brouns, T.M.; Elliott, M.L.

    1990-11-01

    The white rot fungus Phanerochaete chrysosporium has been shown to effectively degrade pollutants such as trichlorophenol, polychlorinated biphenyls (PCBs), dioxins and other halogenated aromatic compounds. These refractory organic compounds and many others have been identified in the tank waste, groundwater and soil of various US Department of Energy (DOE) sites. The treatment of these refractory organic compounds has been identified as a high priority for DOE's Research, Development, Demonstration, Testing, and Evaluation (RDDT ampersand E) waste treatment programs. Unlike many bacteria, the white rot fungus P. chrysosporium is capable of degrading these types of refractory organics and may be valuable for the treatment of wastes containing multiple pollutants. The objectives of this project are to identify DOE waste problems amenable to white rot fungus treatment and to develop and demonstrate white rot fungus treatment process for these hazardous organic compounds. 32 refs., 6 figs., 7 tabs

  12. Zwalczanie zgnilizny powodowanej przez grzyby z rodzaju Penicillium [Control of Penicillium apple rot

    Directory of Open Access Journals (Sweden)

    H. Borecka

    2015-06-01

    Full Text Available Control of Pezicula spp. fungi reduced Penicillium apple rot. The Penicillium apple rot process began slowly under the modified atmosphere of 5% CO2 and 3% O2. The lower concentration of Benlate – 0.05% did not influence this fungicide's effectiveness, The lower concentration– 0.05% of Topsin M decreased the effectiveness of this fungicide. The resistant strains of Penicillium spp. to benzimidazole fungicides under laboratory conditions were obtained.

  13. Molecular diagnosis of Phytophthora cinnamomi associated with root rot in avocado producing areas of Ecuador

    OpenAIRE

    Diana Elizabeth Toapanta-Gallegos; Luis Eduardo Morillo-Velastegui; William Fernando Viera-Arroyo

    2017-01-01

    One of the most damaging diseases in cultivation of avocado (Persea americana Mill.) is root rot associated with Phytophthora cinnamomi Rands. This disease causes progressive wilt and even death of the tree. The objective of this study was to identify the presence of P. cinnamomi in two productive areas of avocado in Ecuador using the molecular technique PCR-RFLP. Tree root samples were obtained with root rot symptoms in the production areas,...

  14. Identification of Quorum Quenching Bacteria and Its Biocontrol Potential Against Soft Rot Disease Bacteria, Dickeya Dadantii

    OpenAIRE

    Khoiri, Syaiful; Damayanti, Tri Asmira; Giyanto, Giyanto

    2017-01-01

    Dickeya dadantii is one of newly found bacteria causing soft rot on orchids in Indonesia. Infected plants showed severe rot rapidly only in few days. An effort to control the bacteria was conducted by utilizing selected quorum quenching (QQ) inducer bacteria which produce AHL-lactonase by aiiA gene. The aims of this research were to screen and identify of quorum quenching bacteria, and also assayed their biocontrol potential ability against D. dadantii in laboratory. The screening of QQ bacte...

  15. Effectiveness of Neutral Electrolyzed Water on Incidence of Fungal Rot on Tomato Fruits ( Solanum lycopersicum L.).

    Science.gov (United States)

    Vásquez-López, Alfonso; Villarreal-Barajas, Tania; Rodríguez-Ortiz, Gerardo

    2016-10-01

    We assessed the effect of neutral electrolyzed water (NEW) on the incidence of rot on tomato ( Solanum lycopersicum L.) fruits inoculated with Fusarium oxysporum , Galactomyces geotrichum , and Alternaria sp. at sites with lesions. The inoculated fruits were treated with NEW at 10, 30, and 60 mg liter -1 active chlorine, with copper oxychloride fungicide, and with sterile distilled water (control) for 3, 5, and 10 min. In the experiment with F. oxysporum , 50 to 80% of the control fruits and 50 to 60% of the fruits treated with the fungicide exhibited symptoms of rot at the inoculated sites. The lowest incidence recorded was 30% for fruits treated with NEW at 60 mg liter -1 active chlorine with an immersion time of 5 min. In the experiment with G. geotrichum , incidence of rot on control fruits was 70 to 90%, and for treatment with fungicide rot incidence was 50 to 90%. NEW at 60 mg liter -1 active chlorine significantly reduced incidence of symptomatic fruit: only 30% of the inoculated fruits washed for 5 min had damage from rot. In the experiment with Alternaria sp., 60 to 90% of the fruits in the control group and 60 to 70% of the fruits in the fungicide group were symptomatic. The lowest incidence was recorded for the treatment in which the fruits were submerged in NEW with 60 mg liter -1 active chlorine for 3 min. In this group, 40 to 50% of the fruits exhibited symptoms of rot. These results were obtained 8 days after inoculation. NEW, with 60 mg liter -1 active chlorine, significantly reduced incidence of rot symptoms on fruits inoculated with one of the experimental fungi relative to the control (P ≤ 0.05). NEW at 60 mg liter -1 is effective in the control of fungal rot in tomatoes.

  16. Zwalczanie zgnilizny powodowanej przez grzyby z rodzaju Penicillium [Control of Penicillium apple rot

    OpenAIRE

    H. Borecka

    2015-01-01

    Control of Pezicula spp. fungi reduced Penicillium apple rot. The Penicillium apple rot process began slowly under the modified atmosphere of 5% CO2 and 3% O2. The lower concentration of Benlate – 0.05% did not influence this fungicide's effectiveness, The lower concentration– 0.05% of Topsin M decreased the effectiveness of this fungicide. The resistant strains of Penicillium spp. to benzimidazole fungicides under laboratory conditions were obtained.

  17. Detection of a pathogen shift among the pectolytic bacterial pathogens of potato in Washington State

    Science.gov (United States)

    Bacterial tuber soft rot, aerial stem rot and blackleg are significant diseases of potatoes in Washington State. These diseases are caused by Pectobacterium carotovorum subsp. carotovorum, Pectobacterium atrosepticum, and Dickeya chrysanthemi, all characterized by the ability to produce pectolytic ...

  18. Black Willow

    Science.gov (United States)

    R. M. Krinard

    1980-01-01

    Black willow and other species of Salix together comprise a majority of the stocking. Cottonwood is the chief associate, particularly in the early stages, but green ash, sycamore, pecan, persimmon, waterlocust, American elm, baldcypress, red maple, sugarberry, box-elder, and in some areas, silver maple are invaders preceding the next successional stage.

  19. Counseling Blacks

    Science.gov (United States)

    Vontress, Clemmont E.

    1970-01-01

    Blacks have developed unique environmental perceptions, values, and attitudes, making it difficult for counselors to establish and maintain positive rapport. This article examines attitudinal ingredients posited by Carl Rogers for relevance to this problem, and suggests in-service training to help counselors and other professionals relate…

  20. Black Psyllium

    Science.gov (United States)

    ... by mouth for up to 6 weeks reduces blood sugar in people with type 2 diabetes. Cancer. Diarrhea. Irritable bowel syndrome (IBS). Other conditions. ... with the dose. Diabetes: Black psyllium can lower blood sugar levels ... with type 2 diabetes by slowing down absorption of carbohydrates. Monitor blood ...

  1. Cellulase activity as a mechanism for suppression of phytophthora root rot in mulches.

    Science.gov (United States)

    Richter, Brantlee Spakes; Ivors, Kelly; Shi, Wei; Benson, D M

    2011-02-01

    Wood-based mulches are used in avocado production and are being tested on Fraser fir for reduction of Phytophthora root rot, caused by Phytophthora cinnamomi. Research with avocado has suggested a role of microbial cellulase enzymes in pathogen suppression through effects on the cellulosic cell walls of Phytophthora. This work was conducted to determine whether cellulase activity could account for disease suppression in mulch systems. A standard curve was developed to correlate cellulase activity in mulches with concentrations of a cellulase product. Based on this curve, cellulase activity in mulch samples was equivalent to a cellulase enzyme concentration of 25 U ml(-1) or greater of product. Sustained exposure of P. cinnamomi to cellulase at 10 to 50 U ml(-1) significantly reduced sporangia production, but biomass was only reduced with concentrations over 100 U ml(-1). In a lupine bioassay, cellulase was applied to infested soil at 100 or 1,000 U ml(-1) with three timings. Cellulase activity diminished by 47% between 1 and 15 days after application. Cellulase applied at 100 U ml(-1) 2 weeks before planting yielded activity of 20.08 μmol glucose equivalents per gram of soil water (GE g(-1) aq) at planting, a level equivalent to mulch samples. Cellulase activity at planting ranged from 3.35 to 48.67 μmol GE g(-1) aq, but no treatment significantly affected disease progress. Based on in vitro assays, cellulase activity in mulch was sufficient to impair sporangia production of P. cinnamomi, but not always sufficient to impact vegetative biomass.

  2. Essential plant oils in reducing the intensity of soft rot in Chinese cabbage

    Directory of Open Access Journals (Sweden)

    Myrzânia de Lira Guerra

    Full Text Available The action of essential oils in reducing soft rot in Chinese cabbage, and their influence on the colorimetry and physicochemical characteristics of the vegetable were evaluated. In the greenhouse, plants of the cultivar Natsume were sprayed with 11 oils selected in preliminary tests for phytotoxicity: bergamot, lemongrass, copaiba, Eucalyptus citriodora, blue gum, fennel, ginger, spearmint, sweet orange, lemon and clary sage (0.5% and also the antibiotic Mycoshield® (3 g L-1. After 72 hours the plants were inoculated with Pectobacterium carotovorum subsp. carotovorum (Pcc-c. The oils and the Mycoshield® significantly reduced (P<0.05 the severity (SEV and the area under the disease progress curve (AUDPC. The oils of bergamot, copaiba, E. citriodora, spearmint and sweet orange were then tested for the stability of their effectiveness in the control of three isolates of P. carotovora subsp. carotovorum. These oils reduced the SEV (30.5 to 38.6% and the AUDPC (23.1 to 26.6% with no differences between them or the Mycoshield® (SEV 45.2 and AUDPC 32.8%, except for the copaiba (20.3% which was less effective than the antibiotic in the reduction of the AUDPC. In vitro, only Mycoshield® inhibited the pathogen. None of the treatments altered the colorimetry, levels of ascorbic acid or pH of the leaves of the Chinese cabbage. The spearmint oil increased the total titratable acidity in the same way as the oils of sweet orange, E. citriodora and bergamot increased the total soluble solids. Therefore, spraying with the oils of bergamot, copaiba, E. citriodora, spearmint and sweet orange has potential in the control of this disease.

  3. Soft rot decay capabilities and interactions of fungi and bacteria from fumigated utility poles

    Energy Technology Data Exchange (ETDEWEB)

    Wang, C.J.K.; Worrall, J.J. (State Univ. of New York, Syracuse, NY (United States). Coll. of Environmental Science and Forestry)

    1992-11-01

    The objectives were to (1) identify microfungi and bacterial associates isolated from fumigated southern pine poles from EPRI project RP 1471-72, (2) study the soft-rot capabilities of predominant fungi, and (3) study interactions among microorganisms in relation to wood decay. Methods for identification followed standard techniques using morphological and physiological criteria. Soft-rot by microfungi alone and with bacteria was determined as weight loss and anatomical examination of wood blocks using light microscopy and limited electron microscopy. Acinetobacter calcoaceticus was the predominant bacterium. Twenty-one species of microfungi were identified including four new species. A book entitled IDENTIFICATION MANUAL FOR FUNGI FROM UTILITY POLES IN THE EASTERN UNITED STATES was published. An improved soft-rot test was devised. Fifty-one of 84 species (60%) of microfungi from poles tested were soft-rot positive; that is much greater than previously reported. Three types of anatomical damage of wood of pine or birch caused by soft-rot fungi were described. Interaction tests showed that, in some cases, there was a strong synergism between bacteria and fungi in causing weight loss, but results were inconsistent. Although soft rot is often most apparent under conditions of very high moisture, intermediate moisture levels appear to be optimal, as with basidiomycete decayers.

  4. Soft rot decay capabilities and interactions of fungi and bacteria from fumigated utility poles

    International Nuclear Information System (INIS)

    Wang, C.J.K.; Worrall, J.J.

    1992-11-01

    The objectives were to (1) identify microfungi and bacterial associates isolated from fumigated southern pine poles from EPRI project RP 1471-72, (2) study the soft-rot capabilities of predominant fungi, and (3) study interactions among microorganisms in relation to wood decay. Methods for identification followed standard techniques using morphological and physiological criteria. Soft-rot by microfungi alone and with bacteria was determined as weight loss and anatomical examination of wood blocks using light microscopy and limited electron microscopy. Acinetobacter calcoaceticus was the predominant bacterium. Twenty-one species of microfungi were identified including four new species. A book entitled IDENTIFICATION MANUAL FOR FUNGI FROM UTILITY POLES IN THE EASTERN UNITED STATES was published. An improved soft-rot test was devised. Fifty-one of 84 species (60%) of microfungi from poles tested were soft-rot positive; that is much greater than previously reported. Three types of anatomical damage of wood of pine or birch caused by soft-rot fungi were described. Interaction tests showed that, in some cases, there was a strong synergism between bacteria and fungi in causing weight loss, but results were inconsistent. Although soft rot is often most apparent under conditions of very high moisture, intermediate moisture levels appear to be optimal, as with basidiomycete decayers

  5. Black hole astrophysics

    International Nuclear Information System (INIS)

    Blandford, R.D.; Thorne, K.S.

    1979-01-01

    Following an introductory section, the subject is discussed under the headings: on the character of research in black hole astrophysics; isolated holes produced by collapse of normal stars; black holes in binary systems; black holes in globular clusters; black holes in quasars and active galactic nuclei; primordial black holes; concluding remarks on the present state of research in black hole astrophysics. (U.K.)

  6. Quantum black holes

    CERN Document Server

    Calmet, Xavier; Winstanley, Elizabeth

    2014-01-01

    Written by foremost experts, this short book gives a clear description of the physics of quantum black holes. The reader will learn about quantum black holes in four and higher dimensions, primordial black holes, the production of black holes in high energy particle collisions, Hawking radiation, black holes in models of low scale quantum gravity and quantum gravitational aspects of black holes.

  7. Evaluation of the biocontrol efficacy of a Serratia marcescens strain indigenous to tea rhizosphere for the management of root rot disease in tea.

    Science.gov (United States)

    Dhar Purkayastha, Gargee; Mangar, Preeti; Saha, Aniruddha; Saha, Dipanwita

    2018-01-01

    The aim of the present study is to evaluate plant growth promoting and biocontrol efficacy of a Serratia marcescens strain ETR17 isolated from tea rhizosphere for the effective management of root rot disease in tea. Isolated bacterial culture ETR17 showed significant level of in vitro antagonism against nine different foliar and root pathogens of tea. The phenotypic and molecular characterization of ETR17 revealed the identity of the bacterium as Serratia marcescens. The bacterium was found to produce several hydrolytic enzymes like chitinase, protease, lipase, cellulase and plant growth promoting metabolites like IAA and siderophore. Scanning electron microscopic studies on the interaction zone between pathogen and antagonistic bacterial isolate revealed severe deformities in the fungal mycelia. Spectral analyses (LC-ESI-MS, UV-VIS spectrophotometry and HPLC) and TLC indicated the presence of the antibiotics pyrrolnitrin and prodigiosin in the extracellular bacterial culture extracts. Biofilm formation by ETR17 on polystyrene surface was also observed. In vivo application of talc-based formulations prepared with the isolate ETR17 in tea plantlets under green house conditions revealed effective reduction of root-rot disease as well as plant growth promotion to a considerable extent. Viability studies with the ETR17 talc formulation showed the survivability of the isolate up to six months at room temperature. The sustenance of ETR17 (concentration of 8-9x108 cfu g-1) in the soil after the application of talc formulation was recorded by ELISA. Safety studies revealed that ETR17 did not produce hemolysin as observed in pathogenic Serratia strains. The biocontrol strain reported in this study can be used for field application in order to minimize the use of chemical fungicides for disease control in tea gardens.

  8. Evaluation of the biocontrol efficacy of a Serratia marcescens strain indigenous to tea rhizosphere for the management of root rot disease in tea.

    Directory of Open Access Journals (Sweden)

    Gargee Dhar Purkayastha

    Full Text Available The aim of the present study is to evaluate plant growth promoting and biocontrol efficacy of a Serratia marcescens strain ETR17 isolated from tea rhizosphere for the effective management of root rot disease in tea. Isolated bacterial culture ETR17 showed significant level of in vitro antagonism against nine different foliar and root pathogens of tea. The phenotypic and molecular characterization of ETR17 revealed the identity of the bacterium as Serratia marcescens. The bacterium was found to produce several hydrolytic enzymes like chitinase, protease, lipase, cellulase and plant growth promoting metabolites like IAA and siderophore. Scanning electron microscopic studies on the interaction zone between pathogen and antagonistic bacterial isolate revealed severe deformities in the fungal mycelia. Spectral analyses (LC-ESI-MS, UV-VIS spectrophotometry and HPLC and TLC indicated the presence of the antibiotics pyrrolnitrin and prodigiosin in the extracellular bacterial culture extracts. Biofilm formation by ETR17 on polystyrene surface was also observed. In vivo application of talc-based formulations prepared with the isolate ETR17 in tea plantlets under green house conditions revealed effective reduction of root-rot disease as well as plant growth promotion to a considerable extent. Viability studies with the ETR17 talc formulation showed the survivability of the isolate up to six months at room temperature. The sustenance of ETR17 (concentration of 8-9x108 cfu g-1 in the soil after the application of talc formulation was recorded by ELISA. Safety studies revealed that ETR17 did not produce hemolysin as observed in pathogenic Serratia strains. The biocontrol strain reported in this study can be used for field application in order to minimize the use of chemical fungicides for disease control in tea gardens.

  9. Evaluation of the biocontrol efficacy of a Serratia marcescens strain indigenous to tea rhizosphere for the management of root rot disease in tea

    Science.gov (United States)

    Mangar, Preeti; Saha, Aniruddha

    2018-01-01

    The aim of the present study is to evaluate plant growth promoting and biocontrol efficacy of a Serratia marcescens strain ETR17 isolated from tea rhizosphere for the effective management of root rot disease in tea. Isolated bacterial culture ETR17 showed significant level of in vitro antagonism against nine different foliar and root pathogens of tea. The phenotypic and molecular characterization of ETR17 revealed the identity of the bacterium as Serratia marcescens. The bacterium was found to produce several hydrolytic enzymes like chitinase, protease, lipase, cellulase and plant growth promoting metabolites like IAA and siderophore. Scanning electron microscopic studies on the interaction zone between pathogen and antagonistic bacterial isolate revealed severe deformities in the fungal mycelia. Spectral analyses (LC-ESI-MS, UV-VIS spectrophotometry and HPLC) and TLC indicated the presence of the antibiotics pyrrolnitrin and prodigiosin in the extracellular bacterial culture extracts. Biofilm formation by ETR17 on polystyrene surface was also observed. In vivo application of talc-based formulations prepared with the isolate ETR17 in tea plantlets under green house conditions revealed effective reduction of root-rot disease as well as plant growth promotion to a considerable extent. Viability studies with the ETR17 talc formulation showed the survivability of the isolate up to six months at room temperature. The sustenance of ETR17 (concentration of 8-9x108 cfu g-1) in the soil after the application of talc formulation was recorded by ELISA. Safety studies revealed that ETR17 did not produce hemolysin as observed in pathogenic Serratia strains. The biocontrol strain reported in this study can be used for field application in order to minimize the use of chemical fungicides for disease control in tea gardens. PMID:29466418

  10. Morphoanatomy and histochemistry analyses of cassava roots do not discriminate resistant from susceptible genotypes to soft root rot

    OpenAIRE

    SILVA, Jonny Lucio Sousa; MOURA, Elisa Ferreira; ILKIU-BORGES, Fernanda; GALVÃO, Jessivaldo Rodrigues; FARIAS-NETO, João Tomé de; SILVA, Gisele Barata da; RÊGO, Marcela Cristiane Ferreira; CUNHA, Roberto Lisboa

    2017-01-01

    ABSTRACT Cassava is an important culture in Brazil and in the North of the country, and soft root rot has affected root production. The aim of this work was to identify root morphoanatomic and histochemical characters associated with root rot resistance. In areas with no occurrence of the disease, nine cassava genotypes were tested, four of which were resistant, and five were susceptible to root rot. Root harvest was carried out twelve months after sowing, and thickness of suber, suber and co...

  11. Emerging Pathogens Initiative (EPI)

    Data.gov (United States)

    Department of Veterans Affairs — The Emerging Pathogens Initiative (EPI) database contains emerging pathogens information from the local Veterans Affairs Medical Centers (VAMCs). The EPI software...

  12. Comparative analysis of genome sequences of the conifer tree pathogen, Heterobasidion annosum s.s.

    Directory of Open Access Journals (Sweden)

    Jaeyoung Choi

    2017-12-01

    Full Text Available The causal agent of root and butt rot of conifer trees, Heterobasidion annosum, is widespread in boreal forests and economically responsible for annual loss of approximately 50 million euros to forest industries in Finland alone and much more at European level. In order to further understand the pathobiology of this fungus at the genome level, a Finnish isolate of H. annosum sensu stricto (isolate 03012 was sequenced and analyzed with the genome sequences of 23 white-rot and 13 brown-rot fungi. The draft genome assembly of H. annosum has a size of 31.01 Mb, containing 11,453 predicted genes. Whole genome alignment showed that 84.38% of H. annosum genome sequences were aligned with those of previously sequenced H. irregulare TC 32-1 counterparts. The result is further supported by the protein sequence clustering analysis which revealed that the two genomes share 6719 out of 8647 clusters. When sequencing reads of H. annosum were aligned against the genome sequences of H. irregulare, six single nucleotide polymorphisms were found in every 1 kb, on average. In addition, 98.68% of SNPs were found to be homo-variants, suggesting that the two species have long evolved from different niches. Gene family analysis revealed that most of the white-rot fungi investigated had more gene families involved in lignin degradation or modification, including laccases and peroxidase. Comparative analysis of the two Heterobasidion spp. as well as white-/brown-rot fungi would provide new insights for understanding the pathobiology of the conifer tree pathogen.

  13. The chaperone ClpX stimulates expression of Staphylococcus aureus protein A by rot dependent and independent pathways

    DEFF Research Database (Denmark)

    Jelsbak, Lotte; Ingmer, Hanne; Valihrach, Lukás

    2010-01-01

    at pinpointing the role of ClpX in Rot synthesis revealed that ClpX is required for translation of Rot. Interestingly, translation of the spa mRNA was, like the rot mRNA, enhanced by ClpX. These data demonstrate that ClpX performs dual roles in regulating Protein A expression, as ClpX stimulates transcription...... of spa by enhancing translation of Rot, and that ClpX additionally is required for full translation of the spa mRNA. The current findings emphasize that ClpX has a central role in fine-tuning virulence regulation in S. aureus....

  14. FcStuA from Fusarium culmorum controls wheat foot and root rot in a toxin dispensable manner.

    Directory of Open Access Journals (Sweden)

    Matias Pasquali

    Full Text Available Fusarium culmorum is one of the most harmful pathogens of durum wheat and is the causal agent of foot and root rot (FRR disease. F. culmorum produces the mycotoxin deoxynivalenol (DON that is involved in the pathogenic process. The role of the gene FcStuA, a StuA ortholog protein with an APSES domain sharing 98.5% homology to the FgStuA protein (FGSG10129, was determined by functional characterisation of deletion mutants obtained from two F. culmorum wild-type strains, FcUk99 (a highly pathogenic DON producer and Fc233B (unable to produce toxin and with a mild pathogenic behavior. The ΔFcStuA mutants originating from both strains showed common phenotypic characters including stunted vegetative growth, loss of hydrophobicity of the mycelium, altered pigmentation, decreased activity of polygalacturonic enzymes and catalases, altered and reduced conidiation, delayed conidial germination patterns and complete loss of pathogenicity towards wheat stem base/root tissue. Glycolytic process efficiency [measured as growth on glucose as sole carbon (C source] was strongly impaired and growth was partially restored on glutamic acid. Growth on pectin-like sources ranked in between glucose and glutamic acid with the following order (the lowest to the highest growth: beechwood xylan, sugarbeet arabinan, polygalacturonic acid, citrus pectin, apple pectin, potato azogalactan. DON production in the mutants originating from FcUK99 strain was significantly decreased (-95% in vitro. Moreover, both sets of mutants were unable to colonise non-cereal plant tissues, i.e. apple and tomato fruits and potato tubers. No differences between mutants, ectopic and wild-type strains were observed concerning the level of resistance towards four fungicides belonging to three classes, the demethylase inhibitors epoxiconazole and tebuconzole, the succinate dehydrogenase inhibitor isopyrazam and the cytochrome bc1 inhibitor trifloxystrobin. StuA, given its multiple functions in cell

  15. FcStuA from Fusarium culmorum Controls Wheat Foot and Root Rot in a Toxin Dispensable Manner

    Science.gov (United States)

    Scherm, Barbara; Balmas, Virgilio; Hoffmann, Lucien; Hammond-Kosack, Kim E.; Beyer, Marco; Migheli, Quirico

    2013-01-01

    Fusarium culmorum is one of the most harmful pathogens of durum wheat and is the causal agent of foot and root rot (FRR) disease. F. culmorum produces the mycotoxin deoxynivalenol (DON) that is involved in the pathogenic process. The role of the gene FcStuA, a StuA ortholog protein with an APSES domain sharing 98.5% homology to the FgStuA protein (FGSG10129), was determined by functional characterisation of deletion mutants obtained from two F. culmorum wild-type strains, FcUk99 (a highly pathogenic DON producer) and Fc233B (unable to produce toxin and with a mild pathogenic behavior). The ΔFcStuA mutants originating from both strains showed common phenotypic characters including stunted vegetative growth, loss of hydrophobicity of the mycelium, altered pigmentation, decreased activity of polygalacturonic enzymes and catalases, altered and reduced conidiation, delayed conidial germination patterns and complete loss of pathogenicity towards wheat stem base/root tissue. Glycolytic process efficiency [measured as growth on glucose as sole carbon (C) source] was strongly impaired and growth was partially restored on glutamic acid. Growth on pectin-like sources ranked in between glucose and glutamic acid with the following order (the lowest to the highest growth): beechwood xylan, sugarbeet arabinan, polygalacturonic acid, citrus pectin, apple pectin, potato azogalactan. DON production in the mutants originating from FcUK99 strain was significantly decreased (−95%) in vitro. Moreover, both sets of mutants were unable to colonise non-cereal plant tissues, i.e. apple and tomato fruits and potato tubers. No differences between mutants, ectopic and wild-type strains were observed concerning the level of resistance towards four fungicides belonging to three classes, the demethylase inhibitors epoxiconazole and tebuconzole, the succinate dehydrogenase inhibitor isopyrazam and the cytochrome bc1 inhibitor trifloxystrobin. StuA, given its multiple functions in cell

  16. Antagonismo direto e biocontrole da podridão-mole-do-tomateiro pelo uso de procariotas Direct antagonism and biocontrol of tomato soft rot using prokaryotes

    Directory of Open Access Journals (Sweden)

    Victor Rafael Barra

    2009-03-01

    Full Text Available O objetivo deste trabalho foi avaliar procariotas quanto ao potencial de antagonismo direto para o biocontrole da podridão-mole-do-tomateiro (Pectobacterium carotovorum subsp. carotovorum. Avaliaram-se 45 isolados bacterianos pelo teste de antibiose contra o patógeno. Foram feitos dois ensaios em que sementes de tomate (Lycopersicon esculentum Mill. cv. Santa Clara foram infectadas com isolados antagônicos. As mudas foram transplantadas para solos infestados com suspensões de propágulos P. carotovorum com OD540 de 0,45 e 0,65. Os antagonistas UFV-0005, UFV-043, UFV-BF112 e UFV-0006 foram eficientes em proteger plantas de tomateiro contra a podridão-mole.This work aimed to evaluate prokaryotes to provide direct antagonism and biocontrol of tomato soft rot (Pectobacterium carotovorum subsp. carotovorum. Forty-five bacterial isolates previously selected for biological control of several tomato (Lycopersicon esculentum Mill. diseases were evaluated using an antibiosis test. 'Santa Clara' tomato seeds were inoculated with potential antagonist isolates and transplanted to a soil infested with the pathogen, in two asseys, at a propagule concentration of OD540 0.45 and 0.65. Antagonists UFV-0005, UFV-043, UFV-BF112, and UFV-0006 protected tomato plants against soft rot disease.

  17. Fusarium species as pathogen on orchids.

    Science.gov (United States)

    Srivastava, Shikha; Kadooka, Chris; Uchida, Janice Y

    2018-03-01

    The recent surge in demand for exotic ornamental crops such as orchids has led to a rise in international production, and a sharp increase in the number of plant and plant products moving between countries. Along with the plants, diseases are also being transported and introduced into new areas. Fusarium is one of the major diseases causing pathogens infecting orchids that is spreading through international trade. Studies have identified several species of Fusarium associated with orchids, some are pathogenic and cause symptoms such as leaf and flower spots, leaf or sheath blights, pseudostem or root rots, and wilts. Infection and damage caused by Fusarium reduces the quality of plants and flowers, and can cause severe economic losses. This review documents the current status of the Fusarium-orchid interaction, and illustrates challenges and future perspectives based on the available literature. This review is the first of Fusarium and orchid interactions, and integrates diverse results that both furthers the understanding and knowledge of this disease complex, and will enable the development of effective disease management practices. Copyright © 2017 Elsevier GmbH. All rights reserved.

  18. Burkholderia glumae: next major pathogen of rice?

    Science.gov (United States)

    Ham, Jong Hyun; Melanson, Rebecca A; Rush, Milton C

    2011-05-01

    Burkholderia glumae causes bacterial panicle blight of rice, which is an increasingly important disease problem in global rice production. Toxoflavin and lipase are known to be major virulence factors of this pathogen, and their production is dependent on the TofI/TofR quorum-sensing system, which is mediated by N-octanoyl homoserine lactone. Flagellar biogenesis and a type III secretion system are also required for full virulence of B. glumae. Bacterial panicle blight is thought to be caused by seed-borne B. glumae; however, its disease cycle is not fully understood. In spite of its economic importance, neither effective control measures for bacterial panicle blight nor rice varieties showing complete resistance to the disease are currently available. A better understanding of the molecular mechanisms underlying B. glumae virulence and of the rice defence mechanisms against the pathogen would lead to the development of better methods of disease control for bacterial panicle blight. Bacteria; Proteobacteria; Betaproteobacteria; Burkholderiales; Burkholderiaceae; Burkholderia. Gram-negative, capsulated, motile, lophotrichous flagella, pectolytic. Aborted seed, empty grains as a result of failure of grain filling, brown spots on panicles, seedling rot. Seed sterilization, planting partially resistant lines (no completely resistant line is available). KNOWN VIRULENCE FACTORS: Toxoflavin, lipase, type III effectors. © 2010 LSU AGCENTER. MOLECULAR PLANT PATHOLOGY © 2010 BSPP AND BLACKWELL PUBLISHING LTD.

  19. Enhanced bioprocessing of lignocellulose: Wood-rot fungal saccharification and fermentation of corn fiber to ethanol

    Science.gov (United States)

    Shrestha, Prachand

    This research aims at developing a biorefinery platform to convert corn-ethanol coproduct, corn fiber, into fermentable sugars at a lower temperature with minimal use of chemicals. White-rot (Phanerochaete chrysosporium), brown-rot (Gloeophyllum trabeum) and soft-rot (Trichoderma reesei) fungi were used in this research to biologically break down cellulosic and hemicellulosic components of corn fiber into fermentable sugars. Laboratory-scale simultaneous saccharification and fermentation (SSF) process proceeded by in-situ cellulolytic enzyme induction enhanced overall enzymatic hydrolysis of hemi/cellulose from corn fiber into simple sugars (mono-, di-, tri-saccharides). The yeast fermentation of hydrolyzate yielded 7.1, 8.6 and 4.1 g ethanol per 100 g corn fiber when saccharified with the white-, brown-, and soft-rot fungi, respectively. The highest corn-to-ethanol yield (8.6 g ethanol/100 g corn fiber) was equivalent to 42 % of the theoretical ethanol yield from starch and cellulose in corn fiber. Cellulase, xylanase and amylase activities of these fungi were also investigated over a week long solid-substrate fermentation of corn fiber. G. trabeum had the highest activities for starch (160 mg glucose/mg protein.min) and on day three of solid-substrate fermentation. P. chrysosporium had the highest activity for xylan (119 mg xylose/mg protein.min) on day five and carboxymethyl cellulose (35 mg glucose/mg protein.min) on day three of solid-substrate fermentation. T. reesei showed the highest activity for Sigma cell 20 (54.8 mg glucose/mg protein.min) on day 5 of solid-substrate fermentation. The effect of different pretreatments on SSF of corn fiber by fungal processes was examined. Corn fiber was treated at 30 °C for 2 h with alkali [2% NaOH (w/w)], alkaline peroxide [2% NaOH (w/w) and 1% H2O 2 (w/w)], and by steaming at 100 °C for 2 h. Mild pretreatment resulted in improved ethanol yields for brown- and soft-rot SSF, while white-rot and Spezyme CP SSFs showed

  20. Differences in crystalline cellulose modification due to degradation by brown and white rot fungi.

    Science.gov (United States)

    Hastrup, Anne Christine Steenkjær; Howell, Caitlin; Larsen, Flemming Hofmann; Sathitsuksanoh, Noppadon; Goodell, Barry; Jellison, Jody

    2012-10-01

    Wood-decaying basidiomycetes are some of the most effective bioconverters of lignocellulose in nature, however the way they alter wood crystalline cellulose on a molecular level is still not well understood. To address this, we examined and compared changes in wood undergoing decay by two species of brown rot fungi, Gloeophyllum trabeum and Meruliporia incrassata, and two species of white rot fungi, Irpex lacteus and Pycnoporus sanguineus, using X-ray diffraction (XRD) and (13)C solid-state nuclear magnetic resonance (NMR) spectroscopy. The overall percent crystallinity in wood undergoing decay by M. incrassata, G. trabeum, and I. lacteus appeared to decrease according to the stage of decay, while in wood decayed by P. sanguineus the crystallinity was found to increase during some stages of degradation. This result is suggested to be potentially due to the different decay strategies employed by these fungi. The average spacing between the 200 cellulose crystal planes was significantly decreased in wood degraded by brown rot, whereas changes observed in wood degraded by the two white rot fungi examined varied according to the selectivity for lignin. The conclusions were supported by a quantitative analysis of the structural components in the wood before and during decay confirming the distinct differences observed for brown and white rot fungi. The results from this study were consistent with differences in degradation methods previously reported among fungal species, specifically more non-enzymatic degradation in brown rot versus more enzymatic degradation in white rot. Copyright © 2012 The British Mycological Society. Published by Elsevier Ltd. All rights reserved.

  1. Resistance mechanisms to toxin-mediated charcoal rot infection in maturity group III soybean: role of seed phenol lignin soflavones sugars and seed minerals in charcoal rot resistance

    Science.gov (United States)

    Charcoal rot is a disease caused by the fungus Macrophomina phaseolina (Tassi) Goid, and thought to infect the plants through roots by a toxin-mediated mechanism, resulting in yield loss and poor seed quality, especially under drought conditions. The mechanism by which this infection occurs is not y...

  2. Microsomal transformation of organophosphorus pesticides by white rot fungi.

    Science.gov (United States)

    Jauregui, Juan; Valderrama, Brenda; Albores, Arnulfo; Vazquez-Duhalt, Rafael

    2003-12-01

    The enzymatic mechanism for the transformation of organophosphorus pesticides (OPPs) by different white-rot fungi strains was studied. With the exception of Ganoderma applanatum 8168, all strains from a collection of 17 different fungi cultures were able to deplete parathion. Three strains showing the highest activities were selected for further studies: Bjerkandera adusta 8258, Pleurotus ostreatus 7989 and Phanerochaete chrysosporium 3641. These strains depleted 50 to 96% of terbufos, azinphos-methyl, phosmet and tribufos after four-days exposure to the pesticides. In order to identify the cellular localization of the transformation activity, the extracellular and microsomal fractions of Pleuronts ostreatus 7989 were evaluated in vitro. While the activities of ligninolytic enzymes (lignin peroxidase, manganese peroxidase and laccase) were detected in the extracellular fraction, no enzymatic modification of any of the five pesticides tested could be found, suggesting the intracellular origin of the transformation activity. In accordance with this observation the microsomal fraction was found able to transform three OPPs with the following rates: 10 micromol mg prot(-1) h(-1) for phosmet, 5.7 micromol mg prot(-1) h(-1) for terbufos, and 2.2 micromol mg prot(-1) h(-1) for azinphos-methyl. The products from these reactions and from the transformation of trichlorfon and malathion, were identified by mass-spectrometry. These results, supported by specific inhibition experiments and the stringent requirement for NADPH during the in vitro assays suggest the involvement of a cytochrome P450.

  3. Solubilization and Mineralization of Lignin by White Rot Fungi

    Science.gov (United States)

    Boyle, C. David; Kropp, Bradley R.; Reid, Ian D.

    1992-01-01

    The white rot fungi Lentinula edodes, Phanerochaete chrysosporium, Pleurotus sajor-caju, Flammulina velutipes, and Schizophyllum commune were grown in liquid media containing 14C-lignin-labelled wood, and the formation of water-soluble 14C-labelled products and 14CO2, the growth of the fungi, and the activities of extracellular lignin peroxidase, manganese peroxidase, and laccase were measured. Conditions that affect the rate of lignin degradation were imposed, and both long-term (0- to 16-day) and short-term (0- to 72-h) effects on the production of the two types of product and on the activities of the enzymes were monitored. The production of 14CO2-labelled products from the aqueous ones was also investigated. The short-term studies showed that the different conditions had different effects on the production of the two products and on the activities of the enzymes. Nitrogen sources inhibited the production of both products by all species when differences in growth could be discounted. Medium pH and manganese affected lignin degradation by the different species differently. With P. chrysosporium, the results were consistent, with lignin peroxidase playing a role in lignin solubilization and manganese peroxidase being important in subsequent CO2 production. PMID:16348781

  4. Biodegradation of pentachlorophenol by the white rot fungus Phanerochaete chrysosporium

    International Nuclear Information System (INIS)

    Mileski, G.J.; Bumpus, J.A.; Jurek, M.A.; Aust, S.D.

    1988-01-01

    Extensive biodegradation of pentachlorophenol (PCP) by the white rot fungus Phanerochaete chrysosporium was demonstrated by the disappearance and mineralization of [ 14 C]PCP in nutrient nitrogen-limited culture. Mass balance analyses demonstrated the formation of water-soluble metabolites of [ 14 C]PCP during degradation. Involvement of the lignin-degrading system of this fungus was suggested by the fact that the time of onset, time course, and eventual decline in the rate of PCP mineralization were similar to those observed for [ 14 C]lignin degradation. Also, a purified ligninase was shown to be able to catalyze the initial oxidation of PCP. Although biodegradation of PCP was decreased in nutrient nitrogen-sufficient (i.e., nonligninolytic) cultures of P. chrysosporium, substantial biodegradation of PCP did occur, suggesting that in addition to the lignin-degrading system, another degradation system may also be responsible for some of the PCP degradation observed. Toxicity studies showed that PCP concentrations above 4 mg/liter (15 μM) prevented growth when fungal cultures were identified by inoculation with spores. The lethal effects of PCP could, however, be the circumvented by allowing the fungus to establish a mycelial mat before adding PCP. With this procedure, the fungus was able to grow and mineralize [ 14 C]PCP at concentrations as high as 500 mg/liter (1.9 mM)

  5. Fis is a global regulator critical for modulation of virulence factor production and pathogenicity of Dickeya zeae

    OpenAIRE

    Lv, Mingfa; Chen, Yufan; Liao, Lisheng; Liang, Zhibin; Shi, Zurong; Tang, Yingxin; Ye, Sixuan; Zhou, Jianuan; Zhang, Lianhui

    2018-01-01

    Dickeya zeae is the causal agent of rice foot rot disease, which has recently become a great threat to rice planting countries and regions. The pathogen produces a family of phytotoxins named zeamines that is critical for bacterial virulence, but little is known about the signaling pathways and regulatory mechanisms that govern zeamine production. In this study, we showed that a conserved transcriptional regulator Fis is involved in the regulation of zeamine production in D. zeae strain EC1. ...

  6. Biological control of strawberry soil-borne pathogens Macrophomina phaseolina and Fusarium solani, using Trichoderma asperellum and Bacillus spp.

    Directory of Open Access Journals (Sweden)

    Ana María PASTRANA

    2016-05-01

    Full Text Available In south-western Spain, Macrophomina phaseolina and Fusarium solani were found to be associated in strawberry plants with, respectively, charcoal rot, and crown and root rot symptoms. For management of both fungal diseases, the antagonistic effects of two commercial formulations, one based on Trichoderma asperellum T18 strain (Prodigy® and the other on Bacillus megaterium and B. laterosporus (Fusbact®, were evaluated in vitro and under controlled environment and field conditions. Two inoculation methods (root-dipping and soil application and two application times (pre- and post-pathogen inoculation, as preventive and curative treatments, respectively were assessed. Dual plate confrontation experiments demonstrated the antagonistic effects of T. asperellum and Bacillus spp. by inhibiting radial growth of M. phaseolina and F. solani by more than 36%. Preventive application of T. asperellum by root-dipping reduced the incidence of charcoal rot (up to 44% in a growth chamber and up to 65% under field conditions and also reduced disease progression, the percentage of crown necrosis, as well as the level of infection measured as ng of pathogen DNA g-1 plant by quantitative real-time PCR. This treatment was also the most effective for reduction of crown and root rot caused by F. solani (up to 100% in a greenhouse and up to 81% under field conditions. These results were nearly comparable with the control achieved using chemical fungicides. The Bacillus spp.-based formulation was also effective for control of charcoal rot and showed variable results for control of F. solani, depending on the growth conditions.

  7. Molecular techniques for characterisation of pathogens

    DEFF Research Database (Denmark)

    Kampmann, Marie-Louise

    Pathogens have always had a major interest to humans due to their central role in sickness and death. Influenza A annually kills at least 250,000 humans, and has been the cause of millions of further deaths during pandemic years in the past. Plague (Yersinia pestis) has been the cause of the Black...... capture for the detection of Y. pestis in samples from the Justinian plague (600 AD) as an attempt to detect this pathogen as a cause of death in the victims....

  8. Evaluation of the Effect of Two Volatile Organic Compounds on Barley Pathogens

    Directory of Open Access Journals (Sweden)

    Amine Kaddes

    2016-08-01

    Full Text Available This study aimed to determine the effect of Volatile Organic Compounds (VOCs on some pathogens, these VOCs were emitted during interactions of barley with Fusarium culmorum Schltdl and/or Cochliobolus sativus Shoemaker, two common root rot pathogens. Our work shows that two organic esters: methyl propanoate (MP and methyl prop-2-enoate (MA significantly reduced the development of fungi in vitro. Additional tests showed that the esters significantly inhibited spore germination of these pathogens. The activity of these VOCs on a wide range of fungal and bacterial pathogens was also tested in vitro and showed inhibitory action. The effect of the VOCs on infected barley seeds also showed plantlets growing without disease symptoms. MA and MP seem to have potential value as alternative plant protection compounds against barley bioagressors.

  9. Production of Ligninolytic Enzymes by White-Rot Fungus Datronia sp. KAPI0039 and Their Application for Reactive Dye Removal

    Directory of Open Access Journals (Sweden)

    Pilanee Vaithanomsat

    2010-01-01

    Full Text Available This study focused on decolorization of 2 reactive dyes; Reactive Blue 19 (RBBR and Reactive Black 5 (RB5, by selected white-rot fungus Datronia sp. KAPI0039. The effects of reactive dye concentration, fungal inoculum size as well as pH were studied. Samples were periodically collected for the measurement of color unit, Laccase (Lac, Manganese Peroxidase (MnP, and Lignin Peroxidase (LiP activity. Eighty-six percent of 1,000 mg L−1 RBBR decolorization was achieved by 2% (w/v Datronia sp. KAPI0039 at pH 5. The highest Lac activity (759.81 UL−1 was detected in the optimal condition. For RB5, Datronia sp. KAPI0039 efficiently performed (88.01% decolorization at 2% (w/v fungal inoculum size for the reduction of 600 mg L−1 RB5 under pH 5. The highest Lac activity (178.57 UL−1 was detected, whereas the activity of MnP and LiP was absent during this hour. The result, therefore, indicated that Datronia sp. KAPI0039 was obviously able to breakdown both reactive dyes, and Lac was considered as a major lignin-degradation enzyme in this reaction.

  10. Developmental and Metabolic Plasticity of White-Skinned Grape Berries in Response to Botrytis cinerea during Noble Rot1[OPEN

    Science.gov (United States)

    Collins, Thomas S.; Vicente, Ariel R.; Doyle, Carolyn L.; Ye, Zirou; Allen, Greg; Heymann, Hildegarde

    2015-01-01

    Noble rot results from exceptional infections of ripe grape (Vitis vinifera) berries by Botrytis cinerea. Unlike bunch rot, noble rot promotes favorable changes in grape berries and the accumulation of secondary metabolites that enhance wine grape composition. Noble rot-infected berries of cv Sémillon, a white-skinned variety, were collected over 3 years from a commercial vineyard at the same time that fruit were harvested for botrytized wine production. Using an integrated transcriptomics and metabolomics approach, we demonstrate that noble rot alters the metabolism of cv Sémillon berries by inducing biotic and abiotic stress responses as well as ripening processes. During noble rot, B. cinerea induced the expression of key regulators of ripening-associated pathways, some of which are distinctive to the normal ripening of red-skinned cultivars. Enhancement of phenylpropanoid metabolism, characterized by a restricted flux in white-skinned berries, was a common outcome of noble rot and red-skinned berry ripening. Transcript and metabolite analyses together with enzymatic assays determined that the biosynthesis of anthocyanins is a consistent hallmark of noble rot in cv Sémillon berries. The biosynthesis of terpenes and fatty acid aroma precursors also increased during noble rot. We finally characterized the impact of noble rot in botrytized wines. Altogether, the results of this work demonstrated that noble rot causes a major reprogramming of berry development and metabolism. This desirable interaction between a fruit and a fungus stimulates pathways otherwise inactive in white-skinned berries, leading to a greater accumulation of compounds involved in the unique flavor and aroma of botrytized wines. PMID:26450706

  11. Developmental and Metabolic Plasticity of White-Skinned Grape Berries in Response to Botrytis cinerea during Noble Rot.

    Science.gov (United States)

    Blanco-Ulate, Barbara; Amrine, Katherine C H; Collins, Thomas S; Rivero, Rosa M; Vicente, Ariel R; Morales-Cruz, Abraham; Doyle, Carolyn L; Ye, Zirou; Allen, Greg; Heymann, Hildegarde; Ebeler, Susan E; Cantu, Dario

    2015-12-01

    Noble rot results from exceptional infections of ripe grape (Vitis vinifera) berries by Botrytis cinerea. Unlike bunch rot, noble rot promotes favorable changes in grape berries and the accumulation of secondary metabolites that enhance wine grape composition. Noble rot-infected berries of cv Sémillon, a white-skinned variety, were collected over 3 years from a commercial vineyard at the same time that fruit were harvested for botrytized wine production. Using an integrated transcriptomics and metabolomics approach, we demonstrate that noble rot alters the metabolism of cv Sémillon berries by inducing biotic and abiotic stress responses as well as ripening processes. During noble rot, B. cinerea induced the expression of key regulators of ripening-associated pathways, some of which are distinctive to the normal ripening of red-skinned cultivars. Enhancement of phenylpropanoid metabolism, characterized by a restricted flux in white-skinned berries, was a common outcome of noble rot and red-skinned berry ripening. Transcript and metabolite analyses together with enzymatic assays determined that the biosynthesis of anthocyanins is a consistent hallmark of noble rot in cv Sémillon berries. The biosynthesis of terpenes and fatty acid aroma precursors also increased during noble rot. We finally characterized the impact of noble rot in botrytized wines. Altogether, the results of this work demonstrated that noble rot causes a major reprogramming of berry development and metabolism. This desirable interaction between a fruit and a fungus stimulates pathways otherwise inactive in white-skinned berries, leading to a greater accumulation of compounds involved in the unique flavor and aroma of botrytized wines. © 2015 American Society of Plant Biologists. All Rights Reserved.

  12. Oxygen-Dependent Globin Coupled Sensor Signaling Modulates Motility and Virulence of the Plant Pathogen Pectobacterium carotovorum.

    Science.gov (United States)

    Burns, Justin L; Jariwala, Parth B; Rivera, Shannon; Fontaine, Benjamin M; Briggs, Laura; Weinert, Emily E

    2017-08-18

    Bacterial pathogens utilize numerous signals to identify the presence of their host and coordinate changes in gene expression that allow for infection. Within plant pathogens, these signals typically include small molecules and/or proteins from their plant hosts and bacterial quorum sensing molecules to ensure sufficient bacterial cell density for successful infection. In addition, bacteria use environmental signals to identify conditions when the host defenses are weakened and potentially to signal entry into an appropriate host/niche for infection. A globin coupled sensor protein (GCS), termed PccGCS, within the soft rot bacterium Pectobacterium carotovorum ssp. carotovorum WPP14 has been identified as an O 2 sensor and demonstrated to alter virulence factor excretion and control motility, with deletion of PccGCS resulting in decreased rotting of a potato host. Using small molecules that modulate bacterial growth and quorum sensing, PccGCS signaling also has been shown to modulate quorum sensing pathways, resulting in the PccGCS deletion strain being more sensitive to plant-derived phenolic acids, which can function as quorum sensing inhibitors, and exhibiting increased N-acylhomoserine lactone (AHL) production. These findings highlight a role for GCS proteins in controlling key O 2 -dependent phenotypes of pathogenic bacteria and suggest that modulating GCS signaling to limit P. carotovorum motility may provide a means to decrease rotting of plant hosts.

  13. Black holes

    International Nuclear Information System (INIS)

    Carter, B.

    1980-01-01

    In years 1920 as a result of quantum mechanics principles governing the structure of ordinary matter, a sudden importance for a problem raised a long time ago by Laplace: what happens when a massive body becomes so dense that even light cannot escape from its gravitational field. It is difficult to conceive how could be avoided in the actual universe the accumulation of important masses of cold matter having been submitted to gravitational breaking down followed by the formation of what is called to day a black hole [fr

  14. Sour rot-damaged grapes are sources of wine spoilage yeasts.

    Science.gov (United States)

    Barata, André; González, Sara; Malfeito-Ferreira, Manuel; Querol, Amparo; Loureiro, Virgílio

    2008-11-01

    Yeast species of sound and sour rot-damaged grapes were analysed during fermentation and grape ripening in the vineyard, using general and selective culture media. During 2003 and 2004 vintages, microvinifications were carried out with sound grapes to which different amounts of grapes with sour rot were added. The wine spoilage species Zygosaccharomyces bailii was only recovered during fermentations with sour rot, reaching 5.00 log CFU mL(-1) (2003) and 2.48 log CFU mL(-1) (2004) at the end of fermentation. The study of yeast populations during the sour rot ripening process (2005 vintage) showed that the veraison-damaged grapes always exhibited higher total yeast counts and a much greater diversity of species. From a total of 22 ascomycetous species, 17 were present only in damaged grapes. The most frequent species were Issatchenkia occidentalis and Zygoascus hellenicus. The spoilage species Z. bailii and Zygosaccharomyces bisporus were consistently isolated exclusively from damaged grapes. This work demonstrates that one of the most dangerous wine spoilage species, Z. bailii, is strongly associated with sour rot grapes and survives during fermentation with Saccharomyces cerevisiae. The use of selective media provides a more accurate characterization of grape contamination species.

  15. Phenotypic and genotypic characteristics of Iranian soft rot bacteria isolates from different hosts

    Directory of Open Access Journals (Sweden)

    Rasool REZAEI

    2010-09-01

    Full Text Available During 2005–2006, 42 soft rot bacterial strains were isolated from the infected tubers of potato, roots of carrot, sugar beet and turnip, and the leaves of lettuce and cabbage with soft rot symptoms in Iran. The isolates were rod-shaped, motile with peritrichous flagella, gram negative, facultative anaerobe, oxidase and urease negative and they rotted potato tuber slices. Of the 42 isolates, 20 were identified as Pectobacterium carotovorum subsp. carotovorum (Pcc, 6 as P. carotovorum subsp. odoriferum (Pco, 4 as P. betavasculorum (Pb and 12 strains as Dickeya dadantii (Dda. PCR amplification of fingerprints of repetitive bacterial DNA elements using the REP, ERIC and BOX primers differentiated the soft rot bacteria to the species and subspecieslevel. Strains of Pcc and Dda were phenotypically and genotypically highly variable, but Pb and Pco strains had low variability. REP-PCR was found to be a promising genotypic tool for the rapid and reliable speciation and typing of soft rot bacteria.

  16. Controlling the root and stem rot of cucumber, caused by Pythium aphanidermatum, using resistance cultivars and grafting onto the cucurbit rootstocks

    Directory of Open Access Journals (Sweden)

    Fatemeh Rostami

    2015-02-01

    Full Text Available Cucumber damping off caused by Pythium aphanidermatum is the most important root and stem rot that limits greenhouse cultivations. In this study, relative susceptibility of grafting commercial cucumber cultivars including Alpha, Caspian 340, Storm 5910, Shalim 616, Delta scar, Janette 810, Festibal C5, Royal, Negyn, Soltan and Fadia on two Cucurbita rootstocks were evaluated against P. aphanidermatum . Disease severity, survival and seedling growth were used for the evaluation. The results showed significant differences between the studied cultivars (p≤0.01. Caspian 340 and Alpha with 15.7% and 100% disease severity had more and less tolerant to P. aphanidermatum, respectively. Cucurbita maxima rootstock was more resistant than Cucurbita pepo to P. aphanidermatum. C. pepo had less compatibility with the cucumber and showed little resistance to the pathogen. The study revealed that grafting Caspian340 on the resistant cucurbit rootstock i.e. Cucurbita maxima could be used as disease control strategies in greenhouses.

  17. Some new and noteworthy diseases of poplars in India. [Botryodiplodia sett-rot; Alternaria tip blight; Cladosporium leaf spot; Fusarium pink incrustation

    Energy Technology Data Exchange (ETDEWEB)

    Singh, S.

    1983-09-01

    Four new diseases of poplars namely Botryodiplodia sett-rott, Alternaria tip blight, Cladosporium leaf spot and Fusarium pink incrustation are described in this paper. Botryodiplodia palmarum causes sett-rott of poplars both at pre-sprouting and post-sprouting stage. The pathogen also causes mortality of poplar plants in the field within 4-6 weeks after planting. Alternaria stage of Pleuspora infectoria has been found as the cause of blackening and dying of growing tips and young leaves of a Populus sp. and P. deltoides in nurseries. Cladosporium humile has been recorded as the cause of brown spot followed by crumpling and premature shedding of leaves in P. ciliata, P. nigra and P. alba. The cause of Fusarium incrustation disease on P. cilata has been identified as Fusarium sp. of Gibbosum group. Pathogenicity of Botryodiplodia palmarum and Alternaria stage of Pleospora infectoria was confirmed by artificial inoculations. Brief descriptions of Alternaria, Cladosporium and Fusarium are also given. The paper also gives a short account of some noteworthy diseases recorded on poplars namely Ganoderma root rot, foliage ruts and stem cankers. Ganoderma root-rot is found to reach alarming proportions in closely spaced poplar plantations. Melampsora ciliata, an indigenous rust, is found to attack mainly clones of P. deltoides, P. yunnanensis, P. trichocarpa, P. alba and some cultivars of P. x euramericana in nurseries. A brief account of three types of stem cankers i.e. cankers due to pink disease fungus, Corticium salmonicolor, sun-scaled cankers and cankers associated with slime flux on various clones of P. deltoides is also given.

  18. Characterizing forest root‐ and butt‐rot fungi in Yap, Palau, Pohnpei, Kosrae, Guam and Saipan [Chapter III

    Science.gov (United States)

    Phil Cannon; Ned B. Klopfenstein; Mee-Sook Kim; Yuko Ota; Norio Sahashi; Robert L. Schlub; Roger Brown; Sara M. Ashiglar; Amy L. Ross-Davis; John W. Hanna

    2014-01-01

    Ganoderma and Phellinus are two common fungal genera causing butt-rot on trees growing on USA-affiliated islands of the western Pacific. Although these fungi can be quite prevalent, especially in some older mangrove stands, it appears that the majority of infections caused by these fungi leads to severe rotting of the heartwood but do not kill the living...

  19. Degradation of lipophilic wood extractive constituents in Pinus sylvestris by the white-rot fungi Bjerkandera sp. and Trametes versicolor

    NARCIS (Netherlands)

    Dorado, J.; Beek, van T.A.; Claassen, F.W.; Sierra-Alvarez, R.

    2001-01-01

    The white-rot fungi Trametes versicolor and Bjerkandera spp. are among the most frequent decomposers of angiosperm wood in forest ecosystems and in wood products in service. Wood extractives have a major impact on wood properties and wood utilization. This work evaluated the ability of two white-rot

  20. Formation of dry gram-negative bacteria biocontrol products and small pilot tests against potato dry rot

    Science.gov (United States)

    Pseudomonas fluorescens strains S11:P:12, P22:Y:05, and S22:T:04 reduce important potato maladies in storage including dry rot, late blight, pink rot, and sprouting. Experiments were conducted to identify methods for producing a dried, efficacious biological control product from one or more of these...

  1. Detection, identification and differentiation of Pectobacterium and Dickeya species causing potato blackleg and tuber soft rot: a review

    NARCIS (Netherlands)

    Czajkowski, R.L.; Pérombelon, M.C.M.; Jafra, S.; Lojkowska, E.; Potrykus, M.; Wolf, van der J.M.; Sledz, W.

    2015-01-01

    The soft rot Enterobacteriaceae (SRE) Pectobacterium and Dickeya species (formerly classified as pectinolytic Erwinia spp.) cause important diseases on potato and other arable and horticultural crops. They may affect the growing potato plant causing blackleg and are responsible for tuber soft rot in

  2. rDNA-based characterization of a new binucleate Rhizoctonia spp. causing root rot on kale in Brazil

    NARCIS (Netherlands)

    Kuramae, E.E.; Buzeto, A.L.; Nakatani, A.K.; Souza, N.L.

    2007-01-01

    In this paper we present the first report of the occurrence of a binucleate Rhizoctonia spp. causing hypocotyl and root rot in kale in Brazil. Rhizoctonia spp. were isolated from kale (Brassica oleracea var. acephala) with symptoms of hypocotyl and root rot. The isolates, characterized as binucleate

  3. Pathogenicity of «Phytophthora nicotianae» Isolates to Tobacco and Tomato Cultivars

    OpenAIRE

    Kalomira Elena

    2000-01-01

    Sixty-one isolates of Phytophthora nicotianae were tested for pathogenicity to tobacco and tomato. All the isolates but one from tobacco were pathogenic to tobacco but none of the isolates from tobacco were pathogenic to tomato. Of the 53 isolates from non tobacco hosts, 19 proved pathogenic to tomato. Seven isolates from different non tobacco hosts colonized the tobacco stem and produced necrosis but not black shank. Five isolates colonized the tomato stem without causing disease...

  4. VOLATILE COMPOUNDS IN THE AROMA OF THREE SPECIES OF WOOD-ROTTING BASIDIOMYCETES AND THEIR ANTIFUNGAL POTENTIAL

    Directory of Open Access Journals (Sweden)

    Cristiana Virginia PETRE

    2017-12-01

    Full Text Available This study aims to determine the volatile organic compounds synthesized by three species of wood-rotting basidiomycetes: Coriolopsis gallica, Megacollybia platyphylla and Lentinus arcularius and test their antifungal potential. The species were cultivated on liquid media and kept for 25 days at 25 °C. The surface cultures were then homogenized, filtrated and extracted using solid-phase extraction and analyzed by GC-MS. The volatile compounds identified were mainly alcohols, ketones, aldehydes and terpenes. The most common volatiles identified in the experiment are: 1-octen-3-ol, 3-hexanol, 3-methyl-1-butanol, 3-octanone, 2-hexanone, benzaldehyde, and limonene. The volatiles metabolites of these species were tested for their antifungal activity using the bi-compartmented Petri dishes method against two species of plant pathogenic fungi: Fusarium solani and Sclerotinia sclerotiorum, on three media. The volatiles produced by Coriolopsis gallica showed the highest antifungal potential against the phytopathogens. The results revealed the importance of media composition in the synthesis of antifungal volatile compounds.

  5. Molecular diagnosis of Phytophthora cinnamomi associated with root rot in avocado producing areas of Ecuador

    Directory of Open Access Journals (Sweden)

    Diana Elizabeth Toapanta-Gallegos

    2017-05-01

    Full Text Available One of the most damaging diseases in cultivation of avocado (Persea americana Mill. is root rot associated with Phytophthora cinnamomi Rands. This disease causes progressive wilt and even death of the tree. The objective of this study was to identify the presence of P. cinnamomi in two productive areas of avocado in Ecuador using the molecular technique PCR-RFLP. Tree root samples were obtained with root rot symptoms in the production areas, from which 10 isolates were morphologically identified with Phytophthora spp. infection. To distinguish among the various Phytophthora species, a molecular analysis was performed using molecular markers in the ITSregion of the ribosomal DNA (rDNA. The ITSdigestion fragment obtained by PCR with the Ta qI enzyme confirmed the presence of Phytophthora cinnamomi in the isolated samples, and its association with root rot in the sampled production areas.

  6. Making Blackness, Making Policy

    OpenAIRE

    Geller, Peter

    2012-01-01

    Too often the acknowledgment that race is a social construction ignores exactly how this construction occurs. By illuminating the way in which the category of blackness and black individuals are made, we can better see how race matters in America. Antidiscrimination policy, social science research, and the state's support of its citizens can all be improved by an accurate and concrete definition of blackness. Making Blackness, Making Policy argues that blackness and black people are literally...

  7. Black hole critical phenomena without black holes

    Indian Academy of Sciences (India)

    Black holes; numerical relativity; nonlinear sigma. Abstract. Studying the threshold of black hole formation via numerical evolution has led to the discovery of fascinating nonlinear phenomena. ... Theoretical and Computational Studies Group, Southampton College, Long Island University, Southampton, NY 11968, USA ...

  8. Black Urine

    Directory of Open Access Journals (Sweden)

    Rahim Vakili

    2016-06-01

    Full Text Available A 2-year-old boy was born at term of healthy, non-consanguineous Iranian parents. His mother attended in the clinic with the history of sometimes discoloration of diapers after passing urine. She noticed that first at the age of one month with intensified in recent months. His Physical examination and growth parameters were normal. His mother denied taking any medication (sorbitol, nitrofurantoin, metronidazole, methocarbamol, sena and methyldopa (5. Qualitative urine examination showed dark black discoloration. By this history, alkaptonuria was the most clinical suspicious. A 24-hour-urine sample was collected and sent for quantitative measurements. The urine sample was highly positive for homogentisic acid and negative for porphyrin metabolites.

  9. Model of Fabry-Pérot-type electromagnetic modes of a cylindrical nanowire

    DEFF Research Database (Denmark)

    Bordo, Vladimir

    2010-01-01

    The rigorous theory of normal electromagnetic modes of a cylindrical nanowire of finite length is developed. The exact integral equation which determines the solution of Maxwell's equations obeying the boundary conditions at the whole nanowire surface is derived. The nanowire normal (Fabry......-Pérot) modes are defined as non-trivial solutions of the source-free equation. The approach is considered in more detail for elongated nanowires whose length is much larger than their diameter. The resonance condition obtained for a single-mode nanowire resembles the formula for the Fabry-Pérot resonator...

  10. Functional Genomics of Lignocellulose Degradation in the Basidiomycete White Rot Schizophyllum commune

    Energy Technology Data Exchange (ETDEWEB)

    Ohm, Robin A. [Joint Genome Inst., Walnut Creek, CA (United States); Tegelaar, Martin [Utrecht Univ. (Netherlands); Henrissat, Bernard [Univ. of Marseille (France); Brewer, Heather M. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Purvine, Samuel O. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Baker, Scott [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Wosten, Han A. B. [Utrecht Univ. (Netherlands); Grigoriev, Igor V. [Joint Genome Inst., Walnut Creek, CA (United States); Lugones, Luis G. [Utrecht Univ. (Netherlands)

    2013-03-01

    White and brown rot fungi are among the most important wood decayers in nature. Although more than 50 genomes of Basidiomycete white and brown rots have been sequenced by the Joint Genome Institute, there is still a lot to learn about how these fungi degrade the tough polymers present in wood. In particular, very little is known about how these fungi regulate the expression of genes involved in lignocellulose degradation. Here, we used transcriptomics, proteomics, and promoter analysis in an effort to gain insight into the process of lignocellulose degradation.

  11. New record of Phytophthora root and stem rot of Lavandula angustifolia

    Directory of Open Access Journals (Sweden)

    Leszek B. Orlikowski

    2013-12-01

    Full Text Available Phytophthora cinnamomi was isolated from rotted root and stem parts of lavender as well as from soil taken from containers with diseased plants. Additionally Botrytis cinerea, Fusarium spp. and Sclerotinia sclerotiorum were often isolated from diseased tissues. P. cinnamomi colonised leaves and stem parts of 4 lavender species in laboratory trials and caused stem rot of plants in greenhouse experiments. Cardinal temperature for in vitro growth were about 7,5 and 32°C with optimum 25-27,5°C. The species colonised stem tissues at temperature ranged from 10° to 32°C.

  12. Pathological and rhizospherical studies on root-rot disease of ...

    African Journals Online (AJOL)

    Isolations from diseased squash roots revealed the presence of Alternaria tenuis, Aspergillus niger, Fusarium oxysporum, F. solani and Rhizoctonia solani. The last two fungi were more frequent than any of the other fungi. Pathogenicity tests proved that squash plants were highly vulnerable to attack by Fusarium solani and ...

  13. Molecular techniques for characterisation of pathogens

    DEFF Research Database (Denmark)

    Kampmann, Marie-Louise

    Pathogens have always had a major interest to humans due to their central role in sickness and death. Influenza A annually kills at least 250,000 humans, and has been the cause of millions of further deaths during pandemic years in the past. Plague (Yersinia pestis) has been the cause of the Black...... Death that was leading to the desertion of whole cities, and as a result was for centuries one of the most feared events in human life. For both of these organisms we generally have situations with only very small amounts of pathogen nucleic acids available, usually because many interesting samples...... capture for the detection of Y. pestis in samples from the Justinian plague (600 AD) as an attempt to detect this pathogen as a cause of death in the victims....

  14. Abalone farm discharges the withering syndrome pathogen into the wild

    Directory of Open Access Journals (Sweden)

    Kevin eLafferty

    2013-12-01

    Full Text Available An intracellular bacterium Candidatus Xenohaliotis californiensis, also called Withering-Syndrome Rickettsia-Like Organism (WS-RLO, is the cause of mass mortalities that are the chief reason for endangerment of black abalone (Haliotis cracherodii. Using a real-time PCR assay, we found that a shore-based abalone farm in Santa Barbara, California, discharged WS-RLO DNA into the ocean. Several other shore-based abalone farms discharge effluent into critical habitat for black abalone in California and this might affect the recovery of wild black abalone. Existing regulatory frameworks exist that could help protect wild species from pathogens released from shore-based aquaculture.

  15. Extensive sampling of basidiomycete genomes demonstrates inadequacy of the white-rot/brown-rot paradigm for wood decay fungi

    Science.gov (United States)

    Fungi of the phylum Basidiomycota (basidiomycetes) make up some 37% of the described fungi and are important in forestry, agriculture, medicine, and bioenergy. This diverse phylum includes symbionts, pathogens, and saprotrophs including the majority of wood decaying and ectomycorrhizal species. To b...

  16. Phytophthora Root and Crown Rot on Apples in Bulgaria

    Directory of Open Access Journals (Sweden)

    Mariana Nakova

    2010-01-01

    Full Text Available Phytophthora is a genus of Oomycota responsible for some of the most serious diseases with great economic impact (Judelson and Blanco, 2005. While 54 species were found in the 20th century (Erwin and Ribeiro, 1996 another 51-54 new species have been identified(Brasier, 2008 since the year 2000. They are spread worldwide and have broad range of host plants – fruit trees, citrus, forest and park species. Phytophthora can cause serious damages in orchards and nurseries of apples, cherries, etc. In Bulgaria they have been found first on young apples and cherries (1998-1999 in Plovdiv region (Nakova, 2003. Surveys have been done for discovering disease symptoms in Plovdiv and Kjustendil regions. Isolates have been obtained from infected plant material (roots and stem bases applying baiting bioassay (green apples, variety Granny Smith and/or PARP 10 selective media. Phytophthora strains were identified based on standard morphology methods – types of colonies on PDA, CMA, V 8, type and size of sporangia, oogonia and antheridia, andoospores. Cardial temperatures for their growth were tested on CMA and PDA.For molecular studies, DNA was extracted from mycelium using the DNA extraction kit.DNA was amplified using universal primers ITS 6 and ITS 4. Amplification products concentrations were estimated by comparison with the standard DNA. Sequencing was done at the Scottish Crop Research Institute (SCRI, Dundee, Scotland. Phytophthora root and crown rot symptoms first appear in early spring. Infected trees show bud break delay, have small chlorotic leaves, and branches die all of a sudden. Later symptoms are found in August-September. Leaves of the infected trees show reddish discoloration and drop down. Both symptoms are connected with lesions (wet, necrotic in appearance at stem bases of the trees.Disease spread was 2-3% in most gardens, only in an apple orchard in Bjaga (Plovdiv region it was up to 8-10%. Morphologically, the isolates acquired from

  17. Black Silicon Solar Cells with Black Ribbons

    DEFF Research Database (Denmark)

    Davidsen, Rasmus Schmidt; Tang, Peter Torben; Mizushima, Io

    2016-01-01

    We present the combination of mask-less reactive ion etch (RIE) texturing and blackened interconnecting ribbons as a method for obtaining all-black solar panels, while using conventional, front-contacted solar cells. Black silicon made by mask-less reactive ion etching has total, average...... reflectance below 0.5% across a 156x156 mm2 silicon (Si) wafer. Black interconnecting ribbons were realized by oxidizing copper resulting in reflectance below 3% in the visible wavelength range. Screen-printed Si solar cells were realized on 156x156 mm2 black Si substrates with resulting efficiencies...... in the range 15.7-16.3%. The KOH-textured reference cell had an efficiency of 17.9%. The combination of black Si and black interconnecting ribbons may result in aesthetic, all-black panels based on conventional, front-contacted silicon solar cells....

  18. Black Silicon Solar Cells with Black Ribbons

    DEFF Research Database (Denmark)

    Davidsen, Rasmus Schmidt; Tang, Peter Torben; Mizushima, Io

    2016-01-01

    We present the combination of mask-less reactive ion etch (RIE) texturing and blackened interconnecting ribbons as a method for obtaining all-black solar panels, while using conventional, front-contacted solar cells. Black silicon made by mask-less reactive ion etching has total, average...... in the range 15.7-16.3%. The KOH-textured reference cell had an efficiency of 17.9%. The combination of black Si and black interconnecting ribbons may result in aesthetic, all-black panels based on conventional, front-contacted silicon solar cells....... reflectance below 0.5% across a 156x156 mm2 silicon (Si) wafer. Black interconnecting ribbons were realized by oxidizing copper resulting in reflectance below 3% in the visible wavelength range. Screen-printed Si solar cells were realized on 156x156 mm2 black Si substrates with resulting efficiencies...

  19. Black holes. Chapter 6

    International Nuclear Information System (INIS)

    Penrose, R.

    1980-01-01

    Conditions for the formation of a black hole are considered, and the properties of black holes. The possibility of Cygnus X-1 as a black hole is discussed. Einstein's theory of general relativity in relation to the formation of black holes is discussed. (U.K.)

  20. Black Eye: First Aid

    Science.gov (United States)

    First aid Black eye Black eye: First aid By Mayo Clinic Staff A black eye is caused by bleeding under the skin around the eye. Most injuries that cause a ... 13, 2018 Original article: http://www.mayoclinic.org/first-aid/first-aid-black-eye/basics/ART-20056675 . Mayo ...