Colletotrichum Sp Research Articles

Diversity in antifungal activity of strains of Chromobacterium violaceum from the Brazilian Amazon

Chromobacterium violaceum is a free-living Gram-negative bacterium found in soil and aquatic habitats; abundantly present in the Brazilian Amazon, it is an important example of exploitable microbial diversity of the tropics. In this study, 24 strains from the Brazilian Amazon and ATCC 12472(T) were investigated for biocontrol potential of seven fungi pathogenic to soybean [Glycine max (L.) Merril] seed. Both cells and the supernatants of two Brazilian strains, 07-1 and 27-1, together with ATCC 12472(T) were strongly antagonistic to six out of the seven fungi. The antifungal activity of the Brazilian strains to Fusarium sp., Phomopsis sp. and Cercospora kikuchi was consistently stronger than that of ATCC 12472(T). In addition, the two Brazilian strains, but not ATCC 12472(T), were effective against Corynespora sp., and all three strains and their supernatants were equally effective against Aspergillus sp. and Colletotrichum sp. None of the strains had antifungal activity against Botroyodiplodia sp. Three potential mechanisms related to the antibiosis were investigated: violacein toxicity, cyanide production and chitinolytic activity; however, it was not possible to associate any of them with the antifungal activity. The results highlight the biotechnological potential still to be explored within the poorly characterized microbial biodiversity of the tropics.

Determination of enzymes from Colletotrichum sp. AHU9748 essential for lepidimoide production from okra polysaccharide

The allelopathic substance lepidimoide (Lp), which exhibits multiple functions in the growth and development of plants, was produced by Colletotrichum sp. AHU9748 from okra polysaccharide. Okra polysaccharide has the repeating structure (1-->4)-O-alpha-(d-galactopyranosyluronic acid)-(1-->2)-O-alpha-l-rhamnopyranose in its hexasaccharide repeating unit of its main chain. To determine the enzymes essential for Lp production, the supernatant of a culture broth was fractionated by repeated column chromatographies to identify two serial fractions responsible for Lp production and non-Lp production by measuring Lp production together with beta-galactosidase (beta-gal), rhamnogalacturonan lyase (RG-lyase) and acetylesterase (AE) activities, which we hypothesized to be necessary for Lp production from the structure of Lp. We confirmed the presence of these three enzymatic activities in the highest-Lp-producing fraction. The addition of purified RG-lyase to fractions producing no or a small amount of Lp demonstrated that beta-gal and RG-lyase activities are necessary for Lp production. The N-terminal amino acid sequences of the three separated proteins on SDS-PAGE confirmed the presence of enzymes identical to beta-gal, RG-lyase and AE in the Lp-producing fractions.

Germinação e sanidade de sementes de Bauhinia variegata

As bauínias são consideradas pioneiras tardias na escala de sucessão vegetal, pois têm crescimento moderadamente rápido. Podem ser utilizadas como planta forrageira, ornamental, para papel e celulose, madeira serrada e roliça e também para recuperação de áreas degradadas. Buscando-se alternativas por meio de métodos de escarificação, para uma germinação rápida e uniforme, sementes de Bauhinia variegata foram submetidas aos seguintes tratamentos pré-germinativos: escarificação mecânica com lixa 220; imersão em água quente a 80 ºC; imersão em água fria a 10 ºC durante 2 h; corte com tesoura na região oposta à micrópila; imersão em ácido sulfúrico concentrado por 5 min seguida de lavagem em água corrente; e imersão em ácido sulfúrico concentrado por 20 min, seguida de lavagem em água corrente. Em seguida, as sementes foram colocadas para germinar em caixas plásticas tipo gerbox em substrato de vermiculita sob temperatura constante de 30 ºC, com avaliações aos sete e 14 dias, e semeadas em bandejas de isopor em areia em casa de vegetação. Avaliaram-se, em casa de vegetação, a porcentagem final de emergência aos 32 dias após a semeadura e o índice de velocidade de emergência. Foi realizado, ainda, o teste de sanidade (Blotter Test) com 400 sementes, pelo método de papel-filtro (Blotter test). Para o teste de germinação e índice de velocidade de emergência foram utilizadas cinco subamostras de 30 sementes de cada tratamento, sendo o experimento conduzido em delineamento inteiramente casualizado, em comparação com as médias pelo teste de Tukey (P>0,05). Constatou-se que a escarificação mecânica (lixa e corte com tesoura) e a imersão em água fria promoveram a germinação das sementes. No entanto, os valores foram semelhantes, estatisticamente, à testemunha; a velocidade de germinação em laboratório foi maior quando as sementes foram escarificadas com lixa ou imersas em água fria por 2 h; o tratamento com ácido sulfúrico (20 min) prejudicou o índice de velocidade de emergência em bandejas; os fungos detectados nas sementes foram Trichothecium sp, Aspergillus sp, Cladosporium sp, Colletotrichum sp, Fusarium sp., Penicillium sp e Rhizopus sp, mas não exerceram efeito na germinação e vigor das sementes.

First Report of Colletotrichum acutatum Causing a Leaf Spot on Myrica cerifera in Florida.

Wax myrtle (Morella cerifera (synonym Myrica cerifera) (L.) Small) is a native tree used in Florida landscapes. In the summer of 2005 and spring of 2006, small necrotic spots were observed on young leaves in two commercial nurseries in central Florida. Lesions were dark brown-to-black and eventually coalesced to form large, irregular necrotic areas. Leaves with large lesions abscised prematurely, defoliating the entire plant. Conidia formed on acervuli were observed on the surface of the largest lesions and were tentatively identified as a Colletotrichum sp. Isolations from the edges of lesions were made on potato dextrose agar (PDA) after surface disinfestation of leaf pieces in 0.6% NaOCl for 30 sec. Red chromogenic colonies developed after 5 days of incubation at 24°C. Colonies produced hyaline, oblong conidia with pointed ends averaging 14 × 4 μm and were identified as Colletotrichum acutatum J.H. Simmonds (1). The sequence from internal transcribed spacer regions 1 and 2 and the 5.8s rRNA gene of the rDNA repeat for an isolate (GenBank Accession No. DQ839609) was 100% identical to sequence from the same region of 36 C. acutatum isolates in the NCBI database. These isolates came from at least 16 different hosts, including seven ornamental hosts. There were three isolates from blueberry among the matches (Accession Nos. AB219029, AJ301911, and AJ301905), and the rDNA sequence was also identical to the sequence obtained in our laboratory for a chromogenic C. acutatum isolate from blueberry. Three single-spore isolates were tested for pathogenicity on potted plants in the greenhouse. Two young shoots were spray inoculated with a suspension (1 × 106 conidia/ml) of each isolate. Shoots were covered with a plastic bag for 24 h and maintained at 26.5°C. Two shoots were sprayed with sterile water as a control and similarly covered. All isolates produced brown spots on the youngest leaves 3 to 5 days after inoculation; no symptoms developed on control shoots. The fungus was reisolated from all inoculated shoots. To our knowledge, this is the first report of C. acutatum on wax myrtle in Florida. The disease has a potential to spread and become a significant problem for the cultivation of this species in ornamental nurseries in Florida. Reference: (1) J. H. Simmonds. Qld. J. Agric. Anim. Sci. 22:437, 1965.

Sm1, a Proteinaceous Elicitor Secreted by the Biocontrol Fungus Trichoderma virens Induces Plant Defense Responses and Systemic Resistance

The soilborne filamentous fungus Trichoderma virens is a biocontrol agent with a well-known ability to produce antibiotics, parasitize pathogenic fungi, and induce systemic resistance in plants. Even though a plant-mediated response has been confirmed as a component of bioprotection by Trichoderma spp., the molecular mechanisms involved remain largely unknown. Here, we report the identification, purification, and characterization of an elicitor secreted by T. virens, a small protein designated Sm1 (small protein 1). Sm1 lacks toxic activity against plants and microbes. Instead, native, purified Sm1 triggers production of reactive oxygen species in monocot and dicot seedlings, rice, and cotton, and induces the expression of defense-related genes both locally and systemically in cotton. Gene expression analysis revealed that SM1 is expressed throughout fungal development under different nutrient conditions and in the presence of a host plant. Using an axenic hydroponic system, we show that SM1 expression and secretion of the protein is significantly higher in the presence of the plant. Pretreatment of cotton cotyledons with Sm1 provided high levels of protection to the foliar pathogen Colletotrichum sp. These results indicate that Sm1 is involved in the induction of resistance by Trichoderma spp. through the activation of plant defense mechanisms.

Colletotrichum sp: A potential candidate for biocontrol of scentless chamomile (Matricaria perforata) in western Canada

Based on an assessment of 706 fungal isolates obtained from Canada and Europe, a group of Colletotrichum sp. isolates, tentatively identified as C. truncatum, was moderately efficacious for biocontrol of scentless chamomile (Matricaria perforata). In this study, 19 C. truncatum isolates, 11 from Canada and eight from Europe, were compared for virulence, crop safety, and minimum dew requirement for infection to narrow the selection of candidates. Applied at 1×106 spores mL−1, these isolates expressed variable virulence under controlled environments, with slightly higher variations observed on the Canadian isolates. There was also a slight difference in host specificity among the isolates tested; most isolates caused disease only on chamomile species (M. perforata and M. recutita) but two Canadian isolates also infected lentil, flax, or both. At 20°C, most isolates required more than 20 h dew for maximum infection. This requirement can be an impediment for using this fungus as a biocontrol agent in western Canada where the climate is semi-arid. Treatment of scentless chamomile at the 10-leaf stage with the herbicide metribuzin 48 h prior to fungal inoculation increased weed control to 72%, compared to 40 and 47% by the herbicide and fungus applied alone. However, a similar treatment using the herbicide bentazon did not enhance the weed control significantly as compared to the herbicide alone.

Detoxification of fusaric acid by a nonpathogenic Colletotrichum sp.

A wide range of bacterial and fungal isolates was screened for their ability to detoxify the phytotoxin fusaric acid (FA), which is produced by a great number of Fusarium species. Some of the antagonistic fluorescent pseudomonad isolates were resistant to high concentrations of FA (up to 500 ppm). However, the bacterial isolates were unable to degrade or detoxify FA that was added to King's B (KB) liquid medium. A nonpathogenic Colletotrichum sp. isolate was able to completely detoxify FA after 4 days of incubation in malt broth medium containing 200 ppm of FA. At higher concentrations of FA (up to 400 ppm), the fungal isolate did not grow and FA was not degraded by the end of 10 days post-incubation. The Colletotrichum sp. isolate detoxified fusaric acid to 4-butyl-2-carboxy-pyrimidine. The chemical structure of the detoxified compound was identified by LC/DAD, LC-ES +/MS, LC-ES −/MS, GC-EI/MS and 1H NMR analysis. The toxicity of the detoxified compound was tested on tomato seedlings and on spore germination of different fungal isolates. No toxic effects were observed.

Colletotrichum Disease of Mungbean Sprout by Colletotrichum acutatum

Decayed samples of marketed mungbean sprout were collected from Sacheon, Suncheon, and Dangjin cities in Korea. Initial symptom on hypocotyls was dark-brown diamond speck, which developed into enlarged sunken brownish-black spot with irregular margin, followed by softening yellowish decay. Brown speck on cotyledon further developed into irregular lesions. This study isolated the fungus Colletotrichum sp. The fungal colony was pale orange, which turned greenish gray after 1 week at . Colony of reverse side in a petri dish was pink. Neither conidiomata nor setae were present in the culture. Typical fusiform conidia sized 7.5-15.02.5-2.9 were hyaline, aseptate, smooth, and had salmon color in mass. Conidiogenous cells were phialidic, hyaline, smooth, and cylindrical with terminal distinct collarette. Basedon these mycological characteristics, the casual organism was identified as Colletotrichum acutatum. This is first report of Colletotrichum acutatum in Korea.

Characterization of Colletotrichum Isolates from Tamarillo, Passiflora, and Mango in Colombia and Identification of a Unique Species from the Genus

ABSTRACT This study was conducted to identify the species of Colletotrichum infecting tamarillo, mango, and passiflora in Colombia and to assess whether cross-infection between host species is occurring. Isolates of Colletotrichum spp. from tamarillo (n = 54), passiflora (n = 26), and mango (n = 15) were characterized by various molecular methods and by morphological criteria. Morphological characterization grouped the tamarillo isolates as C. acutatum and the passiflora and mango isolates as C. gloeosporioides. Species-specific primer analysis was reliable and confirmed grouping of the tamarillo isolates (besides Tom-6) as C. acutatum and the mango isolates (besides Man-76) as C. gloeosporioides. However, DNA of the passiflora isolates was not amplified by either C. acutatum- or C. gloeosporioides-specific primers, but reacted with a new primer, Col1, designed according to the internal transcribed spacer (ITS) 1 region of these isolates. Isolates Tom-6 and Man-76 also reacted positively with the Col1 primer. All the isolates reacting with the C. acutatum- and C. gloeosporioides-specific primers failed to react with primer Col1. Isolate Pass-35 from passiflora did not react with any of the taxon-specific primers. Arbitrarily primed polymerase chain reaction (ap-PCR), random amplified polymerase DNA (RAPD)-PCR, and A+T-rich DNA analyses delineated representative isolates into subgroups within the designated species. Molecular analyses indicated that the C. acutatum tamarillo isolates were uniform or clonal, whereas the C. gloeosporioides mango isolates and Colletotrichum passiflora isolates were heterogeneous. Likewise, sequence analysis of the complete ITS (ITS1-5.8S-ITS2) region identified certain isolates to their respective species: tamarillo isolates as C. acutatum; mango isolates as C. gloeosporioides; passiflora, Tom-6, and Man-76 isolates as a Colletotrichum sp. as yet undefined; and the Pass-35 isolate as an additional undefined Colletot-richum sp. Molecular analyses of the population of Colletotrichum isolates from passiflora, Tom-6 from tamarillo, and Man-76 from mango indicate that this population may not be host specific.

Efeito fungistático de Bacillus thuringiensis e de outras bactérias sobre alguns fungos fitopatogênicos

Quatro isolados bacterianos da rizosfera de Drosera villosa var. villosa (B1, B2, B3, B4) e dois isolados de Bacillus thuringiensis (B5 e B6), sendo B6 produtor da toxina bioinseticida Cry1Ab, foram avaliados quanto à capacidade de inibir os fungos fitopatogênicos Fusarium solani f. sp. phaseoli, Fusarium solani f. sp. glycines, Fusarium oxysporum e Colletotrichum sp. A cepa mais efetiva foi B1 que inibiu o crescimento dos quatro fungos até o 26º dia. B. thuringiensis inibiu o crescimento de três destes, o que indica que possui atividade antifúngica e abre um novo campo de estudo para a utilização do B. thuringiensis.

Stimulation of artemisinin production in Artemisia annua hairy roots by the elicitor from the endophytic Colletotrichum sp.

Artemisinin content in hairy roots of Artemisia annua was increased from 0.8 mg g−1 dry wt to 1 mg g−1 dry wt by using elicitor treatment of mycelial extracts from the endophytic fungus Colletotrichum sp. The increase of artemisinin was dependent on the growth stage of hairy roots as well as on the dose of the elicitor applied. When hairy roots of 23-day-old cultures (later growth phase) were exposed to the elicitor at 0.4 mg total sugar ml−1 for 4 days, the maximum production of artemisinin reached to 13 mg l−1, a 44% increase over the control. This is the first report on the stimulation of artemisinin production in hairy roots by the elicitor from an endophytic fungus of A. annua.

Mango Anthracnose: Economic Impact and Current Options For Integrated Managaement.

Mango Anthracnose: Economic Impact and Current Options For Integrated Managaement.

ChemInform Abstract: WF14861, a New Cathepsins B and L Inhibitor Produced by Colletotrichum sp. Part 1. Taxonomy, Production, Purification and Structure Elucidation.

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WF14861, a new cathepsins B and L inhibitor produced by Colletotrichum sp. II. Biological properties.

WF14861, 3-(N-(1-(N-(4-aminobutyl)-N-(3-aminopropyl)carbamoyl)-2-(4-hydroxyphenyl )ethyl)carbamoyl)oxirane-2-carboxylic acid, was obtained from the culture mycelium of Colletotrichum sp. as a novel cathepsins B and L inhibitor. WF14861 also showed inhibitory activities against bone derived crude protease and other cysteine proteases in vitro. The compound ameliorated the tissue damage and the bone destruction models of low-calcium-diet-fed mouse and adjuvant arthritis rat model.

WF14861, a new cathepsins B and L inhibitor produced by Colletotrichum sp. I. Taxonomy, production, purification and structure elucidation.

WF14861, a novel cathepsins B and L inhibitor, was obtained from the culture mycelium of a fungus strain Colletotrichum sp. No. 14861. Spectroscopic analysis showed that WF14861 consisted of trans-epoxysuccinic acid, L-tyrosine and spermidine, WF14861 inhibited cathepsins B and L selectively.

Characterization of Colletotrichum Species Responsible for Anthracnose Diseases of Various Fruits.

ilamentous fungi of the genus Colletotrichum and its teleomorph Glomerella are considered major plant pathogens worldwide. They cause significant economic damage to crops in tropical, subtropical, and temperate regions. Cereals, legumes, ornamentals, vegetables, and fruit trees may be seriously affected by the pathogen (3). Although many cultivated fruit crops are infected by Colletotrichum species, the most significant economic losses are incurred when the fruiting stage is attacked. Colletotrichum species cause typical disease symptoms known as anthracnose, characterized by sunken necrotic tissue where orange conidial masses are produced. Anthracnose diseases appear in both developing and mature plant tissues (4). Two distinct types of diseases occur: those affecting developing fruit in the field (preharvest) and those damaging mature fruit during storage (postharvest). The ability to cause latent or quiescent infections has grouped Colletotrichum among the most important postharvest pathogens. Species of the pathogen appear predominantly on aboveground plant tissues; however, belowground organs, such as roots and tubers, may also be affected. In this article, we deal in particular with methods used to identify and characterize Colletotrichum species and genotypes from almond, avocado, and strawberry, as examples, using traditional and molecular tools. The three pathosystems chosen represent different disease patterns of fruitassociated Colletotrichum. Multiple Species on a Single Host Numerous cases have been reported in which several Colletotrichum species or biotypes are associated with a single host. For example, avocado and mango anthracnose, caused by both C. acutatum and C. gloeosporioides, affect fruit predominantly as postharvest diseases (25,40,41). Strawberry may be infected by three Colletotrichum species, C. fragariae, C. acutatum, and C. gloeosporioides, causing anthracnose of fruit and other plant parts (31). Almond and other deciduous fruits may be infected by C. acutatum or C. gloeosporioides (Table 1) (1,5,46,50). Citrus can be affected by four different Colletotrichum diseases (61): postbloom fruit drop and key lime anthracnose, both caused by C. acutatum, and shoot dieback and leaf spot, and postharvest fruit decay, both caused by C. gloeosporioides. Additional examples of hosts affected by multiple Colletotrichum species include coffee, cucurbits, pepper, and tomato. Single Species on Multiple Hosts It is common to find that a single botanical species of Colletotrichum infects multiple hosts. For example, C. gloeosporioides (Penz.) Penz. & Sacc. in Penz. (teleomorph: Glomerella cingulata (Stoneman) Spauld. & H. Schrenk), which is considered a cumulative species and forms the sexual stage in some instances, is found on a wide variety of fruits, including almond, avocado, apple, and strawberry (Table 2) (6,15,31,46). Likewise, C. acutatum J.H. Simmonds has been reported to infect a large number of fruit crops, including avocado, strawberry, almond, apple, and peach (1,5,16,25,27). Examples of other species with multiple host ranges include C. coccodes, C. capsici, and C. dematium (14,56).

The in vitro effect of allelopathy and various fungi on marsh reed grass (Calamagrostis canadensis)

Allelopathy and endophytic fungi were evaluated as factors affecting the biological control of marsh reed grass, Calamagrostis canadensis (Michx.) Beauv., a weed of boreal reforestation areas. Leachate from marsh reed grass straw inhibited root growth into liquid and agar media and increased foliar necrosis. Most seedlings harboring endophytic species of Fusarium and Chaetomium were healthy in agar controls, but all such seedlings were diseased when grown in agar with straw leachate. The straw leachate and various fungi had distinct impacts on the virulence of Colletotrichum sp., a potential biocontrol agent for marsh reed grass. In comparisons of control and allelopathic media, Colletotrichum sp. stimulated the overall vigor of reed grass while reducing vigor in the allelopathic medium. Individual isolates of fungi in the genera Epicoccum, Drechslera, and Fusarium were uniformly antagonistic to Colletotrichum, whereas antagonism in individual isolates of Chaetomium, Alternaria, and Stemphylium depended on the presence or absence of allelopathy. Another Fusarium isolate increased the virulence of Colletotrichum sp. in both media, as did two applications of Colletotrichum sp. Allelopathic compounds, Fusarium sp., and Colletotrichum sp. are potential components of a strategy for biological control of marsh reed grass. Key words: weed, biological control, bioherbicide, mycoherbicide.

Antifungal Properties of Elephantopus scaber L. (Asteraceae) Against Crop Pathogenic Fungi

Harmful effect of synthetic fungicides towards environment and other organisms have become important issues nowadays. Research on the plant product to be developed as an alternative for synthetic fungicides has attracted interest of many scientists. The aim of this study is to determine the effect of antimicrobial properties of Elephantopus scaber L. from the family Asteraceae against six crop pathogenic fungi viz., Glomerella cingulata (Stoneman) Spauld. & H. Schrenk, Fusarium oxysporum Schltdl., Pyricularia oryzae Cavara, Fusarium solani (Mart.) Sacc., Pestalotiopsis sp., and Colletotrichum sp. Three different concentrations of E. scaber crude extract- 1%, 5% and 15%, were used in fungal growth inhibition test. At 15% (w/v) concentration, the mycelia growth of Colletotrichum sp., F. solani, and P. oryzae were significantly retarded. It indicates that the extract of E. scaber could potentially be used as a biofungicide.