Article

First record of Ceratocystis fimbriata on Carapa guianensis

New Disease Reports 12/2012; 26:13. DOI: 10.5197/j.2044-0588.2012.026.013

ABSTRACT Crabwood or andiroba (Carapa guianensis) is a medium to large tree belonging to the family Meliaceae, widespread in tropical South America, used for timber, furniture, and oil from seeds for cosmetic and ethnomedicinal purposes. Despite its economic importance only one disease caused by Pestalotiopsis macrochaeta has been reported (Halfeld-Vieira & Nechet, 2006). In August 2008, during the course of surveys in a native forest in São João da Baliza municipality in Roraima state, Brazil, dying seedlings of C. guianensis were observed with symptoms of a fungal infection on stems (Fig. 1) and petioles. Only one fungus species was isolated from perithecia present in infected tissue, forming olive brown cultures on potato dextrose agar (PDA). The following morphological features were observed. Perithecia were dark brown, globose, 112-200 μm, neck erect, 431-680 μm, with divergent ostiolar hyphae (Fig. 2A, 2B); perithecial width at the base was 27-34 μm and 20 μm at the apex. Acospores were "hat" shaped, hyaline, 5-7 x 4-5 μm (Fig. 2C). The anamorph corresponded to Chalara with hyaline, cylindrical, catenulate endoconidia with truncate ends, 10-20 x 3.7-5 µm; chlamydospores were pale to dark brown, ovoid, thick-walled, 10-15 x 10-12 µm (Fig. 2D). Based on these morphological characteristics the fungus was identified as Ceratocystis fimbriata (Wingfield et al., 1993). To confirm the identity of the pathogen, the internal transcribed spacer (ITS) region of a representative isolate was amplified using ITS 1 and ITS 4 universal primers and sequenced (GenBank Accession No. JN051277). Ribosomal DNA-ITS sequence data were found to have up to 98% identity with C. fimbriata. To fulfil Koch's postulates, pathogenicity tests were performed in a greenhouse on two-month-old C. guianensis seedlings. Stems were wounded with one superficial puncture with a needle tip, a mycelium plug inserted and the wound covered with Parafilm. A PDA disk was used as control and each treatment consisted of six plants kept under greenhouse conditions. Seven days later the Parafilm was removed and the progress of the symptoms was evaluated. After 10 days, the pathogen was re-isolated from the stem lesions only on plants inoculated with mycelium

Download full-text

Full-text

Available from: Bernardo Halfeld-Vieira, Jun 30, 2015
1 Follower
 · 
113 Views
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Carapa guianensis (Meliaceae) is a tree which occurs naturally in Central and South America, but which is also planted as ornamental. It has attracted much attention because its seeds contain an oil with medicinal properties. The common name of C. guianensis in Brazil is andiroba, hence andiroba oil, while in Guyana it is known a karaba and crabwood oil. In 2003 a foliar blight was observed in the lower canopy of trees in the state of Roraima, Brazil (Fig. 1). Closer examination revealed punctiform acervuli (Fig. 2), which contained conidia typical of Pestalotiopsis (Nag Raj, 1993). These were smooth, long-fusiform, 4-septate, with three intermediate cells almost concolorous and 2 to 3 apical appendages. They measured 24-34 x 5-8 µm, with median cells 16-21 µm, apical appendage 16-34 µm long and a single basal appendage 5-8 µm long. Mycelial growth on potato dextrose agar media was cottony white and conidia were produced in ink-like fruiting bodies (Fig. 3). Based on these observations the fungus was identified as Pestalotiopsis macrochaeta (Zhang et al., 2003).
    Plant Pathology 04/2006; 55:304. DOI:10.1111/j.1365-3059.2005.01274.x · 2.97 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Teak (Tectona grandis) is a species native to the wetlands of the Indian subcontinent and Southeast Asia. Currently, it is cultivated in almost all tropical regions. Teak was introduced to Brazil 80 years ago, into Mato Grosso (MT) among other states. MT has the largest planted area (about 50,000 hectares) with potential for future expansion due to its favourable climate. In September 2009, teak plants were found with wilt symptoms in the region of Cáceres, MT, Brazil. Stem fragments with characteristic symptoms were collected and placed on carrot baits (Moller & DeVay, 1968) in a humid chamber and incubated at 25 ± 2°C under an alternate 12 hour photoperiod. After perithecium formation, a portion of the ascospore mass was transferred to malt extract agar medium (MEA) to allow the formation of colonies which were incubated under the above-mentioned conditions. After 10 days, observed perithecia were black, globose (233.12 x 277.74 µm) and showed a long rostrum (729 µm). Ascospores had the typical format of a "hat" with dimensions of 3.62 x 4.68 µm. Chlamydospores (10.76 x 14.03 µm) and cylindrical endoconidia (19.89 x 3.12 µm) were observed (Fig. 1). Barrel-shaped endoconidia were not found. The morphological characteristics indicated that the isolate belonged to the species Ceratocystis fimbriata (Engelbrecht & Harrington, 2005). The ITS1 and ITS4 sequenced region of the isolate (JQ354938) showed 98% similarity to the isolate of C. fimbriata strain CMW5312 (AF395687.1). The inoculation of plants was performed according to Silveira et al. (2006), with some modifications. One-centimetre mycelial discs of the fungus (from 10-day-old colonies on MEA) were placed onto the injured stems of six-month-old healthy teak plants. The inoculation site was wrapped with cotton cloth (moistened with sterile distilled water) and plastic film. Some plants were inoculated with MEA disc as negative control. The inoculated plants were kept in greenhouse (average temperature of 27°C). Wilt symptoms caused by C. fimbriata were observed 90 days after inoculation and plant death at 120 days (Fig. 2). The fungus was again isolated in culture from the stem of these inoculated teak plants, confirming the pathogenicity. This is the first report of C. fimbriata in teak in Mato Grosso, Brazil.
    06/2012; 25. DOI:10.5197/j.2044-0588.2012.025.024
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Mating studies showed that isolates of the insect-associated wilt pathogen Ceratocystis fimbriata from Eucalyptus spp., mango, fig, inhame (Colocasia esculenta), Gmelina arborea and sweet potato were interfertile, and progeny from those crosses showed normal segregation for microsatellite markers. Genetic diversity was compared among 13 populations of C. fimbriata collected from six states in Brazil using 15 highly polymorphic microsatellite markers. The gene diversity values of most eucalyptus and mango populations from Minas Gerais, Bahia, Rio de Janeiro and São Paulo states were similar to putatively native populations of Ceratocystis platani and C. cacaofunesta, two other species in the C. fimbriata complex that are homothallic. Index of association values indicated substantial asexual reproduction or selfing in populations on mango and eucalyptus. Most of these eucalyptus and mango populations were not highly differentiated from each other, and these populations and genotypes appeared to be more closely related to each other than to other populations by upgma analyses. By contrast, the G. arborea population from Pará and the fig and inhame populations from São Paulo had relatively low levels of diversity and were highly differentiated from each other and all other studied populations, suggesting that they were from different origins and had gone through genetic bottlenecks. One of the eucalyptus populations in Bahia consisted of a single genotype and may have been introduced to the site in infected cuttings from another Bahia location. Similarly, a mango population from Mato Grosso do Sul consisted of a single genotype, which was identical to one of the genotypes found on mango in São Paulo. Aside from introductions by humans, mating studies and genetic analyses suggest that limited dispersal distance and a high degree of selfing or asexual reproduction lead to local populations of C. fimbriata that have limited diversity but are highly differentiated from other populations.
    Plant Pathology 07/2010; 59(4):721 - 735. DOI:10.1111/j.1365-3059.2010.02275.x · 2.97 Impact Factor