G. Q. Furtado

Infection of Curvularia gladioli on different gladiolus genotypes

In this study the susceptibility of different genotypes of gladiolus (Gladiolus callianthus and the genotypes of G. grandiflorum T-704, Red Beauty, Tradehorn, Veronica, Amsterdam, Yester Gold, and Rose Friendship) was evaluated and correlated with the development of Curvularia gladioli infective structures. The plants were inoculated with a 3 x 104 conidial suspension of the pathogen, and the severity of infection was assessed eight days after inoculation. Leaf samples of G. callianthus and G. grandiflorum vars. Amsterdam, Red Beauty, and T-704 were collected 24 hours after inoculation. They were cleared and the rates of spore germination and appressorium formation of C. gladioli were quantified. G. grandiflorum vars. T-704 and Red Beauty were the most susceptible genotypes, followed by G. callianthus and G. grandiflorum var. Tradehorn. The remaining genotypes did not differentiate among them. No differences related to the conidial germination (93.5%) were found for the genotypes. However, the highest values for appressorium formation were observed for G. callianthus (66.5%) and G. grandiflorus var. Amsterdam (55.7%), and the lowest values were observed for T-704 (32.4%). Thus, appressorium formation of C. gladioli was higher on leaf surfaces of resistant genotypes.

Etiology and pathogenicity of two different isolates of Colletotrichum spp. obtained from physic nut seeds

The species known as physic nut (Jatropha curcas L.) has become important as one of main sources of feedstock for biodiesel production. The aims of this study were characterizing two different isolates of Colletotrichum spp. obtained from seeds of this species, through morphological, cultural, and molecular analyses; as well as assessing pathogenicity of both isolates on leaves and fruit of this plant species. For morphological analysis, length and width of 30 spores of each isolate, produced on medium Malt Extract-Agar (MEA), at 25 ± 1 oC, and under constant light, were measured. Cultural analysis was performed by the fungus growth on PDA medium, through daily measurements of the mycelial growth, and the color of colonies after seven days incubation. DNA of the isolates was extracted and specific oligonucleotides primers (region ITS4) were identified by PCR and used to identify C. capsici (CcInt) and C. gloeosporioides (CgInt). Pathogenicity of isolates was assessed on plants aged 10, 20, 30, 40, 50, and 60 days after sowing and fruits at six maturation stages. Based on these analyses, isolates were identified as C. gloeosporioides and C. capsici. Young plants and the older fruits were more susceptible to infection by the two fungus species.

A novel species of Diaporthe causing leaf spot in Pachira glabra

Pachira glabra (Malvaceae) occurs naturally in Brazil’s Atlantic Forest and is used to recover degraded areas of permanent preservation. Symptoms of leaf spot caused by Diaporthe spp. have been observed in P. glabra saplings in a Brazilian forest nursery. The aim of this study was to identify the fungal species employing morphological characteristics, pathogenicity tests, and DNA sequence comparisons for the internal transcribed spacer region (ITS), β-tubulin (TUB), translation elongation factor 1-α (TEF1), and calmodulin (CAL) gene regions. A novel species was identified and described, named here as Diaporthe pachirae. Furthermore, this is the first report of a species belonging to Diaporthe on P. glabra in Brazil. The current study revealed that documentation of new fungi is a relevant forerunner to any research with natural forests.

First report of Botrytis cinerea on Miconia cinnamomifolia

Miconia cinnamomifolia is a forest species with occurrence in Brazilian Atlantic rainforest. Seedlings from a nursery located in Viçosa (State of Minas Gerais, Brazil) presented symptoms of damping-off. Based on morphology and the ITS sequence, the fungus was identified as belonging to the species Botrytis cinerea. This is the first record of this host-pathogen relationship in Brazil.