78,548 research outputs found

    A Detection Method for Tropical Race 4 of the Banana Pathogen Fusarium oxysporum f. sp. cubense

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    Fusarium oxysporum f. sp. cubense (Foc) is the causal agent of Fusarium wilt, the devastating disease that ruined the ‘Gros Michel’ (AAA)-based banana production in the first half of the 20th century. The occurrence of a new variant in Southeast Asia that overcomes the resistance in Cavendish clones such as ‘Grand Naine’ (AAA) is a major concern to current banana production worldwide. The threat posed by this new variant, called tropical race 4 (TR4), may be overcome by the introduction of resistant cultivars. However, the identification of new resistant sources or breeding for resistance is a long-term effort. Currently, the only option to control the disease is to avoid or reduce the spread of the pathogen by eradication of infected plants and isolation of infested plantations. This requires sensitive and highly specific diagnostics that enable early detection of the pathogen. A two-locus database of DNA sequences, from over 800 different isolates from multiple formae speciales of F. oxysporum, was used to develop a molecular diagnostic tool that specifically detects isolates from the vegetative compatibility group (VCG) 01213, which encompasses the Foc TR4 genotype. This diagnostic tool was able to detect all Foc TR4 isolates tested, while none of the Foc isolates from 19 VCGs other than 01213 showed any reaction. In addition, the developed diagnostic tool was able to detect Foc TR4 when using DNA samples from different tissues of ‘Grand Naine’ plants inoculated with TR4 isolate

    Space station accommodations for life sciences research facilities: Phase A conceptual design and programmatics studies for Missions SAAX0307, SAAX0302 and the transition from SAAX0307 to SAAX0302. Volume 1: Executive summary

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    The conceptual designs and programmatics for a Space Station Nonhuman Life Sciences Research Facility (LSRF) are highlighted. Conceptual designs and programmatics encompass an Initial Orbital Capability (IOC) LSRF, a growth or Follow-on Orbital Capability (FOC), and the transitional process required to modify the IOC LSRF to the FOC LSRF

    Pathogenic and Molecular Characterization of Fusarium oxysporum f.sp. ciceri Causing Chickpea Wilt through ISSR Markers

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    In the present investigation the pathogenic and genetic variability was assayed, amongst the seven isolates of Fusarium oxysporum f.sp. ciceri (Foc) collected from different agro-climatic zones of Maharashtra State, India. The isolates of Fusarium oxysporum f.sp.ciceri were confirmed by SCAR marker which yielded 1.5 KD band. The pathogenicity of each isolate was confirmed using the wilt susceptible chickpea genotype JG-62. On the basis of pathogenic ability the isolates were grouped as highly pathogenic (FOC-2, FOC-5, FOC-6), strongly pathogenic (FOC-1,FOC-3) and moderately pathogenic (FOC-4,FOC-7). Eight Inter Simple Sequence Repeats primers (ISSRs) were used to determine the genetic variability in seven isolates Fusarium oxysporum f.sp. ciceri. The seven primers produced 80 scorable bands. Off 80 bands, 73 bands were polymorphic and average level of polymorphism was 91.25 per cent. In UPGMA analysis, Foc-1 (Wardha) was found to have higher value of similarity coefficient (0.8375) whereas Foc-2 (Lonar) was found to have lower value of similarity coefficient (0.4625). The isolates of Fusarium oxysporum f.sp.ciceri were grouped into two major clusters. First group, cluster-A includes isolates belonging to Wardha, Washim and Lonar. Second group, cluster-B includes Nashik, Ahmednagar, Rahuri and Pune. It shows that Foc-1 (Wardha) have higher value of similarity coefficient with Foc-3 (Washim) whereas Foc-2 (Lonar) have lower value of similarity coefficient with Foc-5 (Ahmednagar).The similarity matrix indicated that seven isolates of Fusarium oxysporum f.sp.ciceri exhibited in between 46-84 per cent similarity coefficient

    What do “residuals” from first-order conditions reveal about DGE models?

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    The first-order condition (FOC) associated with labour in many dynamic general equilibrium models involves only current period variables. Residuals constructed from this FOC are inconsistent with aggregate US data in that they are very large and highly persistent. The persistence suggests that models which introduce dynamic terms in the labour FOC may be more consistent with the data. Three such models (one with learning by doing, one with habit formation, and one with labour adjustment costs) confirm that they can reduce the persistence in the residuals making the models more consistent with the joint dynamics of consumption, output and hours.dynamic general equilibrium models, real business cycles, first-order conditions.

    Potensi Cendawan Endofit Dalam Mengendalikan Fusarium Oxysporum F.sp. Cubense Dan Nematoda Radopholus Similis Cobb. Pada Tanaman Pisang Barangan (Musa Paradisiaca L.) Di Rumah Kaca

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    Potential of endophytic fungal to control Fusarium oxysporum f.sp. cubense (Foc) andnematode Radopholus similis (Rs) on banana cv. Barangan (Musa paradisiaca L.) crop ongreenhouse. This research aims to intens and find potential endophytic as biocontrol agents tocontrol Foc and Rs on banana cv. Barangan crop. This research used Completely RandomizedDesign (CRD) non factorial consist thrithteen treatments and three replications. Replications;control (without inoculated), inoculated 300 Rs, inoculated Foc, inoculated 300 Rs one week laterinoculated Foc two weeks later inoculated endophytic 5BSBH's isolate, inoculated 300 Rs oneweek later inoculated Foc two weeks later inoculated endophytic 4BSU's isolate, inoculated 300 Rsone week later inoculated Foc two weeks later inoculated endophytic 1BJH's isolate, inoculated 300Rs one week later inoculated Foc two weeks later inoculated endophytic 1BTAH's isolate,inoculated 300 Rs one week later inoculated Foc two weeks later inoculated endophytic 1BSHT'sisolate, inoculated endophytic 5BSBH's isolate one week later inoculated 300 Rs two weeks laterinoculated Foc, inoculated endophytic 4BSU's isolate one week later inoculated 300 Rs two weekslater inoculated Foc, inoculated endophytic 1BJH's isolate one week later inoculated 300 Rs twoweeks later inoculated Foc, inoculated endophytic 5BSBH's isolate one week later inoculated 300Rs two weeks later inoculated Foc, inoculated endophytic 1BSHT's isolate one week laterinoculated 300 Rs two weeks later inoculated Foc. The results showed that endophytic fungal hadthe potency as biocontrol agent in controlling Fusarium wilt of banana cv. Barangan

    First-Order Query Evaluation with Cardinality Conditions

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    We study an extension of first-order logic that allows to express cardinality conditions in a similar way as SQL's COUNT operator. The corresponding logic FOC(P) was introduced by Kuske and Schweikardt (LICS'17), who showed that query evaluation for this logic is fixed-parameter tractable on classes of structures (or databases) of bounded degree. In the present paper, we first show that the fixed-parameter tractability of FOC(P) cannot even be generalised to very simple classes of structures of unbounded degree such as unranked trees or strings with a linear order relation. Then we identify a fragment FOC1(P) of FOC(P) which is still sufficiently strong to express standard applications of SQL's COUNT operator. Our main result shows that query evaluation for FOC1(P) is fixed-parameter tractable with almost linear running time on nowhere dense classes of structures. As a corollary, we also obtain a fixed-parameter tractable algorithm for counting the number of tuples satisfying a query over nowhere dense classes of structures

    Pengendalian Hayati Penyakit Layu Fusarium Pisang (Fusarium Oxysporum F.sp. Cubense) dengan Trichoderma SP.

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    The aim of this research was to study the inhibiting ability of Trichoderma sp. to control fusarium wilt of banana in greenhouse condition. The experiments consisted of the antagonism test between Trichoderma sp. and Fusarium oxysporum f.sp. cubense (Foc) in vitro using dual culture method and glass house experiment which was arranged in 3×3 Factorial Complete Randomized Design. First factor of the latter experiment was the dose of Trichoderma sp. culture (0, 25, and 50 g per polybag), second factor was time of Trichoderma culture application (2 weeks before Foc inoculation, at same time with Foc inoculation and 2 weeks after Foc inoculation). Trichoderma sp. was cultured in mixed rice brand and chaff medium. The disease intensity was observed with scoring system of wilting leaves (0–4). The results showed that Trichoderma sp. was antagonistic against Foc in vitro and inhibited 86% of Foc colony development. Mechanism of antagonism between Trichoderma sp. and Foc was hyperparasitism. Trichoderma hyphae coiled around Foc hyphae. Lysis of Foc hyphae was occurred at the attached site of Trichoderma hyphae on Foc hyphae. Added banana seedling with Trichoderma sp. Culture reduced disease intensity of Fusarium wilt. Suggested dose of Trichoderma culture application in glass house was 25 g/polybag, given at the same time with Foc inoculation. Penelitian ini bertujuan untuk mengetahui kemampuan Trichoderma sp. untuk pengendalian penyakit layu fusarium pisang di rumah kaca. Penelitian meliputi pengujian daya hambat Fusarium oxysporum f.sp. cubense (Foc) in vitro dan kemampuan menekan intensitas penyakit di rumah kaca. Penelitian in vitro meliputi uji antagonisme dan mekanismenya yang dilakukan secara dual culture. Uji pengaruh Trichoderma sp. terhadap penyakit layu Fusarium dilakukan di rumah kaca dengan Rancangan Acak Lengkap Faktorial. Faktor pertama adalah dosis biakan Trichoderma sp., dengan tiga aras (0, 25, 50 g/per bibit dalam polibag). Faktor kedua adalah waktu pemberian dengan tiga aras (dua minggu sebelum, bersamaan, dan dua minggu setelah inokulasi dengan Foc). Tiap perlakuan terdiri atas 10 ulangan. Intensitas penyakit diamati dengan sistem scoring (1–4) terhadap kelayuan daun. Biakan Trichoderma sp. ditumbuhkan dalam medium campuran sekam dan bekatul (2:1, g/g). Hasil penelitian menunjukkan bahwa Trichoderma sp. bersifat antagonistik terhadap Foc in vitro dengan daya hambat terhadap perkembangan koloni Foc 86%. Mekanisme penghambatan berupa hiperparasitisme. Hifa Trichoderma sp. menempel, melilit pada hifa Foc sehingga terjadi lisis hifa. Lisis hifa Foc terjadi pada tempat persinggungan antara hifa Foc dan hifa Trichoderma sp. Hasil pengujian di rumah kaca menunjukkan bahwa penyakit layu Fusarium dapat dihambat dengan pemberian Trichoderma sp. dalam medium campuran dedak dan bekatul sebanyak 25 g pada per polibag yang dilakukan bersamaan dengan waktu inokulasi Foc

    Karakterisasi Ras Fusarium Oxysporum F. SP. Cubense dengan Metode Vegetative Compatibility Group Test dan Identifikasi Kultivar Pisang yang Terserang

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    Beberapa isolat Fusarium oxysporum f. sp. cubense (Foc) di Sumatera Barat telah dikoleksi untuk mengkaji karakterisasi, distribusi, serta kultivar-kultivar pisang yang terserang. Penelitian dilakukan dari bulan Mei 1999 sampai dengan bulan Maret 2000 di enam dari 14 Daerah Tingkat II, yaitu Solok, Tanah Datar, Agam, Bukit Tinggi, Padang, dan Sawahlunto Sijunjung. Isolat Foc dikumpulkan dari tanaman pisang yang memperlihatkan gejala luar terserang Foc. Isolat-isolat ini selanjutnya dimurnikan dengan teknik spora tunggal dan ras Foc diidentifikasi secara vegetative compatibility group (VCG). Gejala layu fusarium ditemukan di semua lokasi penelitian pada 15 kultivar pisang, baik pisang buah meja seperti pisang buai (AAA), pisang raja serai/sereh (AAB), dan pisang ambon (AAA), maupun pisang olahan seperti pisang kepok (ABB/BBB). Tiga puluh tujuh isolat Foc dikoleksi dari jaringan vaskular pisang yang memperlihatkan gejala luar serangan Foc. Isolat-isolat tersebut terkelompok ke dalam vegetative com- patibility group 0120, 0124, 0125, 01213, 01215, 01216, 0128, dan 01219. Tiga puluh dua dari 37 isolat Foc yang dikoleksi ini diidentifikasi sebagai Foc ras 4, yaitu VGC 0120, 01213, 01215, 01216, dan 01219. Sedangkan lima isolat lainnya termasuk ke dalam VCG 0124 dan 01218 Foc ras 1. Isolat VCG 01216 ditemukan di semua lokasi pengamatan pada 14 dari 15 kultivar terserang Foc. Sedangkan VCG 0120 hanya di temukan di Padang. Distribusi dari VCG lainnya lebih bervariasi di setiap daerah pengamatan. Kultivar cavendish (buai, AAA) yang dinyatakan resisten terhadap ras 1, ternyata ditemukan diserang oleh Foc ras 1 VCG 01218. Kultivar kepok yang diakui tahan terhadap Foc ras 4 dan merupakan salah satu kultivar andalan di Sumatera Barat, ditemukan diserang oleh Foc ras 4 VCG 0120, 01215, 01216, dan 01219, kultivar ini bahkan juga diserang oleh Foc ras 1 VCG 0124

    Reaction of banana cultivars to the Meloidogyne javanica X Fusarium oxysporum f. sp. cubense complex.

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    The interaction Fusarium oxysporum f. sp. cubense (Foc) x nematode and the genetic variability of Foc are the main problems with potential to affect the use of resistant varieties in the management of the Panama disease. The objective of this work was to evaluate the interaction between Foc and Meloidogyne javanica on the banana of the Prata Anã, Grande Naine and BRS Princesa cultivars. The experiment was conducted in a randomized block design, with six treatments and ten replications, which differed in the inoculation time of each pathogen. Simultaneous inoculation with Foc and M. javanica, inoculation with Foc one week before inoculation with M. javanica, and inoculation with M. javanica one week before inoculation with Foc. In addition to the controls, Foc isolated, M. javanica isolated, and cultivars without the pathogens. The seedlings were transplanted in 3-liter pots with sterile soil infested with 40 grams of Foc inoculum at the concentration of 1x106CFU/gram and 1000 eggs and J2 of M. javanica. At the end of 56 days, the treatments with 'Grande Naine' presented the highest reproduction factors of M. javanica. In the 'Prata Anã' no interaction was observed between Foc x M. javanica. The treatments with simultaneous inoculation of the two pathogens, and with Foc a week before, in the 'BRS Princesa', presented the highest external disease indices (DI), which promoted the highest AUDPC. The highest internal DI were observed in the treatments Foc+Mj+Grande Naine, Foc+Mj+BRS Princesa, Mj+Grande Naine+Foc and Foc+BRS Princesa+Mj. The simultaneous presence of M. javanica and Foc increases the severity of the Panama disease in Grande Naine and BRS Princesa cultivars
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