oalib
Search Results: 1 - 10 of 100 matches for " "
All listed articles are free for downloading (OA Articles)
Page 1 /100
Display every page Item
Induction of Defense-Related Enzymes in Banana Plants: Effect of Live and Dead Pathogenic Strain of Fusarium oxysporum f. sp. cubense  [PDF]
Janki N. Thakker,Samiksha Patel,Pinakin C. Dhandhukia
ISRN Biotechnology , 2013, DOI: 10.5402/2013/601303
Abstract: The aim of the present study was to scrutinize the response of banana (Grand Naine variety) plants when interacting with dead or live pathogen, Fusarium oxysporum f.sp. cubense, a causative agent of Panama disease. Response of plants was evaluated in terms of induction of defense-related marker enzyme activity, namely, peroxidase (POX), polyphenol oxidase (PPO), -1,3 glucanase, chitinase, and phenolics. Plant's interaction with live pathogen resulted in early induction of defense to restrain penetration as well as antimicrobial productions. However, pathogen overcame the defense of plant and caused disease. Interaction with dead pathogen resulted in escalating defense response in plants. Later on plants inoculated with dead pathogen showed resistance to even forced inoculation of live pathogen. Results obtained in the present study suggest that dead pathogen was able to mount defense response in plants and provide resistance to Panama disease upon subsequent exposure. Therefore, preparation from dead pathogen could be a potential candidate as a biocontrol agent or plant vaccine to combat Panama disease. 1. Introduction Musa acuminata (Banana) is one of the most important fruit crops of world as well as of India. Banana could be considered poor man’s apple, and it is the cheapest among all other fruits in the country. Fusarium wilt caused by Fusarium oxysporum f.sp. cubense (Foc) is the most destructive disease of banana [1]. The pathogen is soil-borne and remains viable up to several years and cause 20%–80% loss of banana. Several disease management strategies can be used such as crop rotation, burning infected plants or plant parts, and application of carbendazim [2]. Methods mentioned have limited success, and the application of synthetic fungicides may result in undesirable effects on the environment. An alternative to above strategies for managing fusarium wilt is the use of biological control. Biocontrol agent can be a beneficial organism (live or dead) or its part such as cell wall, protein, and oligosaccharides [3]. While using live organisms as a biocontrol agent, appropriate conditions for maintaining it should be strictly followed. Nevertheless, if part of the organism such as cell wall, protein, oligosaccharide, or attenuated/killed organism is used then strict conditions are not required. Plants, humans, and animals give instantaneous response to the pathogen or its part. Animals and humans produce antibodies against pathogen or vaccine, similarly plants response to pathogen attack by producing PR-proteins, defense-related enzymes [4],
Biochemical characterization of Fusarium oxysporum f. sp. cubense isolates from India
KH Bhuvanendra, SAC Udaya, C Nayaka, SR Kini, HS Shetty, HS Prakash
African Journal of Biotechnology , 2010,
Abstract: The Fusarium wilt caused by Fusarium oxyspoum f. sp. cubense (Foc) is a major biotic constraint for banana production. The characteristics of F. oxyspoum f. sp. cubense isolates were investigated using electrophoretic studies of isozyme and whole-cell protein. The morphological characteristics of the isolates were very similar to each other. All the Foc isolates were pathogenic to banana cultivar ‘Nanjangud Rasabale’ but they did not induce any disease symptoms on cultivar ‘Cavendish’. F. oxyspoum (Isolate 6) did not induce wilt symptoms on either ‘Nanjangud’ or ‘Cavendish’ cultivar. Isozyme banding patterns showed 46 scoreable markers and cluster analysis with UPGMA using genetic distance showed that the isolates belonged to three main groups. Group 1 contained isolates 1, 2, 4, 5, 7 and isolate 3 and 6 were placed in group 2 and 3. Results indicated that the estimated intraspecific variation may be more pronounced with isozyme analysis than with protein markers. The level of isozyme variability detected within F. oxysporum f.sp. cubense suggested that it is reliable, efficient and effective in determining genetic relationships among Foc isolates.
Effects of Fusarium oxysporum f.sp.cubense Toxin on the Ultrastructure of Banana Leaves
香蕉枯萎病菌毒素对香蕉叶片超微结构的影响

LI Chi,LI Yong-jian,YU Li,HUANG Bing-zhiGuangdong Ocean University,Zhanjiang,China,Zhuhai Agricultural Science Research Center,Zhuhai,
李赤
,黎永坚,于莉,黄秉智

吉林农业大学学报 , 2011,
Abstract: The effects of fusaric acid and Fusarium oxysporum f.sp.cubense race 4 toxin on the ultrastructure of Xinbei banana and Baxi banana leaf tissue were studied.The results showed that the leaf ultrastructure of either Xinbei banana or Baxi banana began to appear damages after being treated with toxin in 2 hours,and 12 hours later the damages achieved the most seriously included plasmolysis;reduction of chloroplast and starch granules;appearance of osmiophilic granules;decomposition of chloroplast lamella;reduc...
Efficacy of Micro Nutrients on Banana fusarium Wilt. (Fusarium oxysporum f. sp. cubense) and it's Synergistic Action with Trichoderma viride
K. SANJEEV,A. ESWARAN
Notulae Botanicae Horti Agrobotanici Cluj-Napoca , 2008,
Abstract: In the present investigations, efficacy of micro nutrients viz., (calcium nitrate, ammonium sulphate, copper sulphate, potassium chloride, sodium chloride, borax, ferrous sulphate and zinc sulphate) against Fusarium oxysporum f. sp. cubense causing panama wilt of banana were studied. The results of experiment revealed that among the micro nutrients used, borax @ 500 and 750 ppm completely inhibited the mycelial growth of Fusarium oxysporum f. sp. cubense followed by zinc sulphate (47.3, 42.7, 31.0 and 14.3 mm at 100, 250, 500 and 750 ppm respectively). The incorporation of borax in solid medium at higher concentrations viz., 500 and 750 ppm., significantly decreased the mycelial growth of the T.viride, whereas the sporulation capacity of T.viride (207.48 x 108 spores/ sq.cm @ 500 ppm) was found to be maximised by the addition of borax. In general, the antagonist was compatible with borax at low concentrations. The maximum inhibition of mycelial growth of F. oxysporum f. sp cubense was found in borax and T. viride inoculated medium.
Diversidade genética por marcadores moleculares em Fusarium oxysporum f. sp. cubense no Estado de Santa Catarina
Silva, Cristiane Maria da;Hinz, Robert Harri;Stadnik, Marciel Jo?o;Pereira, Adriana;Tcacenco, Fernando Adami;
Ciência Rural , 2010, DOI: 10.1590/S0103-84782010001200007
Abstract: panama disease, caused by fusarium oxysporum f. sp. cubense (foc), is one of the major disease of banana crop. the use of resistant cultivars is the recommended control method, but the assessment of the pathogen genetic diversity is necessary for the development of long-term management strategies. this study aimed to analyze the genetic variability of isolates of foc in santa catarina state, using rapd and ssr molecular markers. it was evaluated 64 isolates collected in the producing regions of santa catarina state, where 100% of them were pathogenic to banana cv. 'enxerto'. cluster analysis by molecular markers revealed variability among the isolates. both molecular techniques were effective in separating the isolates into tree distinct groups and, in general, led to similar grouping. three isolates (co16, js23 and js26) were genetically more distant in dendograms of similarity.
Contamination of Bananas with Beauvericin and Fusaric Acid Produced by Fusarium oxysporum f. sp. cubense  [PDF]
Chunyu Li, Cunwu Zuo, Guiming Deng, Ruibin Kuang, Qiaosong Yang, Chunhua Hu, Ou Sheng, Sheng Zhang, Lijun Ma, Yuerong Wei, Jing Yang, Siwen Liu, Manosh Kumar Biswas, Altus Viljoen, Ganjun Yi
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0070226
Abstract: Background Fusarium wilt, caused by the fungal pathogen Fusarium oxysporum f. sp. cubense (Foc), is one of the most destructive diseases of banana. Toxins produced by Foc have been proposed to play an important role during the pathogenic process. The objectives of this study were to investigate the contamination of banana with toxins produced by Foc, and to elucidate their role in pathogenesis. Methodology/Principal Findings Twenty isolates of Foc representing races 1 and 4 were isolated from diseased bananas in five Chinese provinces. Two toxins were consistently associated with Foc, fusaric acid (FA) and beauvericin (BEA). Cytotoxicity of the two toxins on banana protoplast was determined using the Alamar Blue assay. The virulence of 20 Foc isolates was further tested by inoculating tissue culture banana plantlets, and the contents of toxins determined in banana roots, pseudostems and leaves. Virulence of Foc isolates correlated well with toxin deposition in the host plant. To determine the natural occurrence of the two toxins in banana plants with Fusarium wilt symptoms, samples were collected before harvest from the pseudostems, fruit and leaves from 10 Pisang Awak ‘Guangfen #1’ and 10 Cavendish ‘Brazilian’ plants. Fusaric acid and BEA were detected in all the tissues, including the fruits. Conclusions/Signficance The current study provides the first investigation of toxins produced by Foc in banana. The toxins produced by Foc, and their levels of contamination of banana fruits, however, were too low to be of concern to human and animal health. Rather, these toxins appear to contribute to the pathogenicity of the fungus during infection of banana plants.
Suspensions Derived from Anaerobically Fermented Tilapia Offal Inhibit Fusarium oxysporum f. sp. cubense in Banana  [PDF]
Yuhan Zhou, Yuelian Liu, Qingfang Lv
Agricultural Sciences (AS) , 2018, DOI: 10.4236/as.2018.911105
Abstract: Effective control strategies are lacking for Fusarium wilt of banana crops worldwide. Here, the inhibitory efficacy of suspensions derived from Tilapia offal by anaerobic fermentation against Fusarium oxysporum f. sp. cubense tropical race 4 (Foc TR4) was evaluated. Two anaerobic fermentation methods were used: 1) natural fermentation of offal (NF) and 2) fermentation of offal supplemented with 5% lime (LF). The suspensions were applied in three treatments: Plate assay, pot system, and in the field. The inhibition rate and disease index were determined. The results showed that the inhibition was significantly greater for LF than for NF on plates. In pot system and in the field, the disease index was lower for the LF group than for the NF group and was significantly lower than that of the control. Therefore, suspensions derived from anaerobically fermented offal provide a new control method for Fusarium wilt in banana.
Variabilidade genética de isolados de Fusarium oxysporum f. sp. cubense obtidos de bananais do norte de Minas Gerais
Santos, Telma Miranda dos;Costa, Marcia Regina;Xavier, Adelica Aparecida;Nietsche, Silvia;Fernandes, Thiago Prates;Pereira, Gleice Viviane Nunes;
Revista Brasileira de Fruticultura , 2011, DOI: 10.1590/S0100-29452011000200014
Abstract: banana is one of the most consumed tropical fruits in the world, accounting for approximately 10% of world trade in fruits. panama disease, caused by fusariumoxysporum f. sp. cubense is a major disease of banana. rapd marker have been used for taxonomic studies, analysis of variability of virulence in pathogenic fungi, characterization of races and variability inter and intra-specific populations from different regions. the objective of present study was to evaluate the genetic variability of 36 isolates of f. oxysporum f. sp. cubense using rapd marker. thirteen rapd primers were selected and data analysis was performed using the similarity coefficient of nei and li. a total of 178 bands were obtained, of which 167 (93.82%) showed polymorphism at least two isolates and only 11 (6.18%) showed monomorphism, demonstrating the high variability among isolates. the genetic distances ranged from 5.7 to 54.6%, and the average distance of 30.2%. according to cluster analysis (upgma) no correlation among isolates were found. the results suggest a high genetic variability among isolates and no correlation between molecular groupings and their geographical origin were observed.
Effect of endophytic Fusarium oxysporum on paralysis and mortality of Pratylenchus goodeyi
P Mwaura, T Dubois, T Losenge, D Coyne, E Kahangi
African Journal of Biotechnology , 2010,
Abstract: Three bioassays were conducted to investigate the antagonistic effect of secondary metabolites produced by 5 endophytic Fusarium oxysporum isolates from banana (Musa spp.) plants in Kenya, against Pratylenchus goodeyi. Percentage paralyses were recorded 3, 6 and 24 h after exposure to culture filtrates. Percentage mortality was evaluated after 48 h. All isolates caused significantly higher percentage paralysis (17.5 - 25.9%) and percentage mortality (62.3 - 72.8%) of P. goodeyi motile stages compared to the control (8.4 - 10.9% and 17.3 - 34.6%, respectively). Percentage paralysis of motile stages of P. goodeyi decreased as the length of time exposure to culture filtrates increased, while mortality increased as length of nematodes exposure to culture filtrates increased. Kenyan isolates performed equally as good as the Ugandan isolate (V5W2) in causing paralysis and mortality. Results from this study demonstrated that endophytic F. oxysporum antagonizes P. goodeyi through production of secondary metabolites.
Isolation and characterization of an exopolygalacturonase from Fusarium oxysporum f.sp. cubense race 1 and race 4
Zhangyong Dong, Zhenzhong Wang
BMC Biochemistry , 2011, DOI: 10.1186/1471-2091-12-51
Abstract: An exopolygalacturonase (PGC2) was isolated and purified from the supernatant of the plant pathogen Fusarium oxysporum f.sp. cubense race 4 (FOC4). PGC2 had an apparent Mr of 63 kDa by SDS-PAGE and 51.7 kDa by mass spectrometry. The enzyme was N-glycosylated. PGC2 hydrolyzed polygalacturonic acid in an exo-manner, as demonstrated by analysis of degradation products. To obtain adequate amounts of protein for functional studies between the PGC2 proteins of two races of the pathogen, pgc2 genes encoding PGC2 from race 4 (FOC4) and race 1 (FOC1), both 1395 bp in length and encoding 465 amino acids with a predicted amino-terminal signal sequence of 18 residues, were cloned into the expression vector pPICZaA and then expressed in Pichia pastoris strains of SMD1168. The recombinant PGC2 products, r-FOC1-PGC2 and r-FOC4-PGC2, were expressed and purified as active extracellular proteins. Optimal PGC2 activity was observed at 50°C and pH 5. The Km and Vmax values of purified r-FOC1-PGC2 were 0.43 mg.mL-1 and 94.34 units mg protein-1 min-1, respectively. The Km and Vmax values of purified r-FOC4-PGC2 were 0.48 mg.mL-1 and 95.24 units mg protein-1 min-1, respectively. Both recombinant PGC2 proteins could induce tissue maceration and necrosis in banana plants.Collectively, these results suggest that PGC2 is the first exoPG reported from the pathogen FOC, and we have shown that fully functional PGC2 can be produced in the P. pastoris expression system.The banana (Musa spp.) is one of the world's most popular fruits and is regarded as the fourth most important crop in developing countries [1]. It suffers from several diseases, the most famous being Fusarium wilt disease (Panama disease), which is regarded as one of the most significant threats to banana production worldwide [2]. This disease is caused by the fungus Fusarium oxysporum f. sp. cubense (FOC) and has been reported in all banana-growing regions of the world, including Australia, Asia, Africa and Central and South Americ
Page 1 /100
Display every page Item


Home
Copyright © 2008-2017 Open Access Library. All rights reserved.