scholarly journals Pathogenic and Nonpathogenic Lifestyles in Colletotrichum acutatum from Strawberry and Other Plants

2001 ◽  
Vol 91 (10) ◽  
pp. 986-992 ◽  
Author(s):  
Stanley Freeman ◽  
Sigal Horowitz ◽  
Amir Sharon

Anthracnose is one of the major fungal diseases of strawberry occurring worldwide. In Israel, the disease is caused primarily by the species Colletotrichum acutatum. The pathogen causes black spot on fruit, root necrosis, and crown rot resulting in mortality of transplants in the field. The host range and specificity of C. acutatum from strawberry was examined on pepper, eggplant, tomato, bean, and strawberry under greenhouse conditions. The fungus was recovered from all plant species over a 3-month period but caused disease symptoms only on strawberry. Epiphytic and endophytic (colonization) fungal growth in the different plant species was confirmed by reisolation from leaf tissues and by polymerase chain reaction (PCR)-specific primer amplification. C. acutatum was also isolated from healthy looking, asymptomatic plants of the weed genera Vicia and Conyza. Isolates that were recovered from the weeds caused disease symptoms on strawberry and were positively identified as C. acutatum by PCR. The habitation of a large number of plant species, including weeds, by C. acutatum suggests that, although it causes disease only on strawberry and anemone in Israel, this fungus can persist on many other plant species. Therefore, plants that are not considered hosts of C. acutatum may serve as a potential inoculum source for strawberry infection and permit survival of the pathogen between seasons.

HortScience ◽  
2008 ◽  
Vol 43 (1) ◽  
pp. 66-68 ◽  
Author(s):  
Stanley Freeman

Colletotrichum spp. are broad-range pathogens, meaning that many species can infect a single host and a single species can infect diverse hosts. For example, Colletotrichum acutatum J.H. Simmonds affects a wide range of crops, causing disease symptoms on apple, almond, anemone, citrus, lupin, peach, pecan, strawberry, and others, whereas Colletotrichum gloeosporioides Penz. (Penz. & Sacc.) can affect many of the previous hosts as well. Anthracnose is one of the major fungal diseases of strawberry occurring worldwide. In Israel, the disease is caused primarily by the species C. acutatum. The pathogen causes irregular leaf spot, bud rot, petiole and stolon necrosis, and black spot on fruit. The pathogen is most destructive when it causes root necrosis and crown rot, which usually kill the plants in nurseries and transplants in the field. To maintain a disease-free crop, nuclear and foundation stock material, as well as field nurseries, must be routinely monitored and tested for presence of the pathogen. Strawberry cultivation using plasticulture as an overhead cover of the crop can significantly control anthracnose disease incidence by reducing inoculum spread and infection, both in nurseries and in production fields. C. acutatum from strawberry can survive on several cultivated plant species, such as pepper, eggplant, tomato, bean, and weed species, without causing disease symptoms. This indicated that they may serve as a potential inoculum reservoir for strawberry infection between seasons. Although C. acutatum survives in soil under certain conditions, no specific resting structures have been observed indicating that the pathogen does not behave as a typical soilborne fungus.


2006 ◽  
Vol 59 ◽  
pp. 141-145 ◽  
Author(s):  
K.R. Everett ◽  
J. Rees-George

The plant pathogen Guignardia citricarpa causes citrus black spot and is not considered to be present in New Zealand Speciesspecific polymerase chain reaction (PCR) primers were designed to identify G citricarpa and G mangiferae a closely related saprotroph that is present in New Zealand These PCR primers were tested against a range of other saprotrophic and pathogenic fungi viz Botrytis cinerea Botryosphaeria dothidea B parva Cladosporium sp Colletotrichum acutatum C gloeosporioides Cryptosporiopsis sp Epicoccum sp Nigrospora sp Penicillium sp Pestalotia sp Phialophora sp Phlyctema sp Phoma sp Phomopsis sp Stemphylium sp and Venturia inaequalis The primers JRGGc were specific to G citricarpa and JRGGm to G mangiferae A 226 bp product was amplified from G mangiferae DNA using JRGGm primers and a 501 bp product was amplified from G citricarpa DNA using JRGGc primers These primers thus distinguished G citricarpa from G mangiferae and can be used to rapidly identify incursions by citrus black spot


Plant Disease ◽  
2002 ◽  
Vol 86 (10) ◽  
pp. 1178-1178 ◽  
Author(s):  
S. G. Bobev ◽  
A. Zveibil ◽  
S. Freeman

Recently, there has been increasing interest in growing strawberries (Fragaria × ananassa) in Bulgaria. During the spring seasons of 2001 and 2002, progressive fruit damage in some producers' plots was observed in the Plovdiv Region. Appearance and development of symptoms were typical of anthracnose on aboveground plant structures. On immature fruits, lesions were single or in groups of two or three, circular, small (1 to 3 mm), sunken, and dark brown to black. Lesions on ripe fruits were similar in shape and color, larger (10 to 15 mm), and when coalesced, they covered most or the entire surface. Elliptical, sunken lesions with lighter centers were also found on petioles and stolons, and blighted flowers and infected immature fruits became dark in color. Under wet conditions, salmon-colored masses of conidia were produced mainly on mature but also on unripe fruits, and on petioles and stolons. Conidia were hyaline, cylindrical, and attenuated at both ends measuring 11.5 (9.2 to 13.3) × 4.5 (4.2 to 5.0) μm (2). Colonies of the isolated fungus growing on potato dextrose agar were white with mycelium becoming gray and aerial. Symptoms were reproduced by artificial inoculation of healthy, ripe strawberry fruits. Fruits were wounded with a sterile scalpel, and 5-mm plugs of agar cultures of two isolates were placed on each wound (12 fruits per isolate). An equal number of wounded and noninoculated fruits were used as a control. Fruits were kept in a humidity chamber at 25°C, and 3 to 5 days later, necrotic sunken zones containing acervuli were observed around the wounds of inoculated fruits, and the pathogen was subsequently reisolated. Identical symptoms were obtained after inoculation of raspberry fruits. Intact strawberry stolons and stalks were also successfully inoculated in the lab with two additional isolates using the same technique and tightly covering wounds with adhesive tape. No symptoms were found in the controls of all tests. On the basis of symptoms and pathogen characteristics, the disease was confirmed as anthracnose (black spot) caused by Colletotrichum acutatum. Additionally, the identity of six isolates was confirmed as C. acutatum by species-specific polymerase chain reaction amplification resulting in a single fragment of 490 bp using primers ITS4 and CaInt2 (1). To our knowledge this is the first report of C. acutatum on strawberry in Bulgaria. References: (1) S. Freeman et al. Pathogenic and non-pathogenic lifestyles in Colletotrichum acutatum from strawberry and other plants. Phytopathology 91:986, 2001. (2) P. S. Gunnell, and W. D. Gubler. Taxonomy and morphology of Colletotrichum species pathogenic to strawberry. Mycologia 84:157, 1992.


2017 ◽  
Vol 23 (1) ◽  
Author(s):  
N.NANDHA KUMAR ◽  
K. SOURIANATHA SUNDARAM ◽  
D. SUDHAKAR ◽  
K.K. KUMAR

Excessive presence of polysaccharides, polyphenol and secondary metabolites in banana plant affects the quality of DNA and it leads to difficult in isolating good quality of DNA. An optimized modified CTAB protocol for the isolation of high quality and quantity of DNA obtained from banana leaf tissues has been developed. In this protocol a slight increased salt (NaCl) concentration (2.0M) was used in the extraction buffer. Polyvinylpyrrolidone (PVP) and Octanol were used for the removal of polyphenols and polymerase chain reaction (PCR) inhibitors. Proteins like various enzymes were degraded by Proteinase K and removed by centrifugation from plant extract during the isolation process resulting in pure genomic DNA, ready to use in downstream applications including PCR, quantitative polymerase chain reaction (qPCR), ligation, restriction and sequencing. This protocol yielded a high molecular weight DNA isolated from polyphenols rich leaves of Musa spp which was free from contamination and colour. The average yields of total DNA from leaf ranged from 917.4 to 1860.9 ng/ìL. This modified CTAB protocol reported here is less time consuming 4-5h, reproducible and can be used for a broad spectrum of plant species which have polyphenol and polysaccharide compounds.


Plants ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 335
Author(s):  
Daniel Lizzi ◽  
Alessandro Mattiello ◽  
Alessio Adamiano ◽  
Guido Fellet ◽  
Emanuele Gava ◽  
...  

Most current studies on the relationships between plans and engineered nanomaterials (ENMs) are focused on food crops, while the effects on spontaneous plants have been neglected so far. However, from an ecological perspective, the ENMs impacts on the wild plants could have dire consequences on food webs and ecosystem services. Therefore, they should not be considered less critical. A pot trial was carried out in greenhouse conditions to evaluate the growth of Holcus lanatus L. (monocot) and Diplotaxis tenuifolia L. DC. (dicot) exposed to cerium oxide nanoparticles (nCeO2). Plants were grown for their entire cycle in a substrate amended with 200 mg kg−1nCeO2 having the size of 25 nm and 50 nm, respectively. nCeO2 were taken up by plant roots and then translocated towards leaf tissues of both species. However, the mean size of nCeO2 found in the roots of the species was different. In D. tenuifolia, there was evidence of more significant particle aggregation compared to H. lanatus. Further, biomass variables (dry weight of plant fractions and leaf area) showed that plant species responded differently to the treatments. In the experimental conditions, there were recorded stimulating effects on plant growth. However, nutritional imbalances for macro and micronutrients were observed, as well.


2021 ◽  
Vol 22 (5) ◽  
pp. 2435
Author(s):  
Marzia Beccaccioli ◽  
Manuel Salustri ◽  
Valeria Scala ◽  
Matteo Ludovici ◽  
Andrea Cacciotti ◽  
...  

Fusarium verticillioides causes multiple diseases of Zea mays (maize) including ear and seedling rots, contaminates seeds and seed products worldwide with toxic chemicals called fumonisins. The role of fumonisins in disease is unclear because, although they are not required for ear rot, they are required for seedling diseases. Disease symptoms may be due to the ability of fumonisins to inhibit ceramide synthase activity, the expected cause of lipids (fatty acids, oxylipins, and sphingolipids) alteration in infected plants. In this study, we explored the impact of fumonisins on fatty acid, oxylipin, and sphingolipid levels in planta and how these changes affect F. verticillioides growth in maize. The identity and levels of principal fatty acids, oxylipins, and over 50 sphingolipids were evaluated by chromatography followed by mass spectrometry in maize infected with an F. verticillioides fumonisin-producing wild-type strain and a fumonisin-deficient mutant, after different periods of growth. Plant hormones associated with defense responses, i.e., salicylic and jasmonic acid, were also evaluated. We suggest that fumonisins produced by F. verticillioides alter maize lipid metabolism, which help switch fungal growth from a relatively harmless endophyte to a destructive necrotroph.


1996 ◽  
Vol 42 (6) ◽  
pp. 533-538 ◽  
Author(s):  
A. R. Podile ◽  
A. P. Prakash

A biocontrol rhizobacterial strain of Bacillus subtilis AF 1 grown for 6 h was coinoculated with Aspergillus niger at different time intervals and microscopic observations revealed adherence of bacterial cells to the fungal mycelium. Bacterial cells multiplied in situ and colonized the mycelial surface. Growth of AF 1 resulted in damage to the cell wall, followed by lysis. AF 1 inoculation into media containing A. niger at 0, 6, and 12 h suppressed >90% fungal growth, while in 18- and 24-h cultures fungal growth inhibition was 70 and 56%, respectively, in terms of dry weight. In dual culture the fungal growth was not accompanied by formation of spores. The mycelial preparation of A. niger as principal carbon source supported the growth of B. subtilis, as much as chitin. Extracellular protein precipitate from B. subtilis culture filtrate had a significant growth-retarding effect on A. niger. Groundnut seeds bacterized with B. subtilis showed a reduced incidence of crown rot in A. niger infested soil, suggesting a possible role of B. subtilis in biological control of A. niger.Key words: mycolytic bacteria, Bacillus subtilis, Aspergillus niger, biological control.


The logarithm of island area accounts for 70 % of the variance in the number of plant species occurring on 100 lagoon islands. Two components of island altitude (altitude of the island rim and the logarithm of the island’s inland altitude) are also of importance, and account for 9 % of the variation in species numbers. A further 13 variables account for only an extra 5 % of the variance in the mixed model. These results resemble the findings of other island studies. In the equation S = K A z , z = 0.345 and falls within the range of expected values. The species-area curve gives little indication of the ‘small island effect’ found for other small islands; this may reflect, among other factors, the richness of the Aldabran flora when compared with those of the small island ecosystems already studied. The curve is also compared with that compiled by Williams (1964) and a discrepancy between the two is discussed. Woody plants are largely responsible for the increase of species numbers with increasing area. Species that are restricted to islands of particular sizes are listed and the characteristics of the frequencies of occurrence of the more common species are summarized.


2008 ◽  
Vol 8 (2) ◽  
pp. 217-229 ◽  
Author(s):  
Vellaisamy Ramamoorthy ◽  
Edgar B. Cahoon ◽  
Mercy Thokala ◽  
Jagdeep Kaur ◽  
Jia Li ◽  
...  

ABSTRACT The C-9-methylated glucosylceramides (GlcCers) are sphingolipids unique to fungi. They play important roles in fungal growth and pathogenesis, and they act as receptors for some antifungal plant defensins. We have identified two genes, FgMT1 and FgMT2, that each encode a putative sphingolipid C-9 methyltransferase (C-9-MT) in the fungal pathogen Fusarium graminearum and complement a Pichia pastoris C-9-MT-null mutant. The ΔFgmt1 mutant produced C-9-methylated GlcCer like the wild-type strain, PH-1, whereas the ΔFgmt2 mutant produced 65 to 75% nonmethylated and 25 to 35% methylated GlcCer. No ΔFgmt1ΔFgmt2 double-knockout mutant producing only nonmethylated GlcCer could be recovered, suggesting that perhaps C-9-MTs are essential in this pathogen. This is in contrast to the nonessential nature of this enzyme in the unicellular fungus P. pastoris. The ΔFgmt2 mutant exhibited severe growth defects and produced abnormal conidia, while the ΔFgmt1 mutant grew like the wild-type strain, PH-1, under the conditions tested. The ΔFgmt2 mutant also exhibited drastically reduced disease symptoms in wheat and much-delayed disease symptoms in Arabidopsis thaliana. Surprisingly, the ΔFgmt2 mutant was less virulent on different host plants tested than the previously characterized ΔFggcs1 mutant, which lacks GlcCer synthase activity and produces no GlcCer at all. Moreover, the ΔFgmt1 and ΔFgmt2 mutants, as well as the P. pastoris strain in which the C-9-MT gene was deleted, retained sensitivity to the antifungal plant defensins MsDef1 and RsAFP2, indicating that the C-9 methyl group is not a critical structural feature of the GlcCer receptor required for the antifungal action of plant defensins.


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