RESUMO
In total, 10 populations of Helicotylenchus associated with Musa spp., six from Colombia, and four from Brazil were identified to the species level. Morphological and morphometric data were recorded for each population, performed a principal components analysis (PCA), a conglomerate, along with consensus sequences of D2 to D3 expansion segment of the large subunit of ribosomal DNA (28S) for different populations. Identify of species were performed using the basic local alignment search tool (BLAST), and the evolutionary relationships of species were explored using a phylogeny study. Four species of Helicotylenchus were identified based on morphological and morphometric data: H. multicinctus, H. dihystera, H. erythrinae, and H. californicus. PCA and conglomerate analysis clearly separated these species. BLAST and phylogenetic analysis confirmed the presence of these species associated with Musa spp. crops. This is the first report of these species in Colombia through integrative taxonomy.In total, 10 populations of Helicotylenchus associated with Musa spp., six from Colombia, and four from Brazil were identified to the species level. Morphological and morphometric data were recorded for each population, performed a principal components analysis (PCA), a conglomerate, along with consensus sequences of D2 to D3 expansion segment of the large subunit of ribosomal DNA (28S) for different populations. Identify of species were performed using the basic local alignment search tool (BLAST), and the evolutionary relationships of species were explored using a phylogeny study. Four species of Helicotylenchus were identified based on morphological and morphometric data: H. multicinctus, H. dihystera, H. erythrinae, and H. californicus. PCA and conglomerate analysis clearly separated these species. BLAST and phylogenetic analysis confirmed the presence of these species associated with Musa spp. crops. This is the first report of these species in Colombia through integrative taxonomy.
RESUMO
In Colombia, identification of entomopathogenic nematodes (EPN's) native species is of great importance for pest management programs. The aim of this study was to isolate and identify EPNs and their bacterial symbiont in the department of Cauca-Colombia and then evaluate the susceptibility of two Hass avocado (Persea americana) pests to the EPNs isolated. EPNs were isolated from soil samples by the insect baiting technique. Their bacterial symbiont was isolated from hemolymph of infected Galleria mellonella larvae. Both organisms were molecularly identified. Morphological, and biochemical characterization was done for the bacteria. Susceptibility of Epitrix cucumeris and Pandeleteius cinereus adults was evaluated by individually exposing adults to 50 infective juveniles. EPNs were allegedly detected at two sampled sites (natural forest and coffee cultivation) in 5.8% of the samples analyzed. However, only natural forest EPN's could be isolated and multiplied. The isolate was identified as Steinernema carpocapsae BPS and its bacterial symbiont as Xenorhabus nematophila BPS. Adults of both pests were susceptible to S. carpocapsae indicating this EPN potential for its management. The results of this study constitute the first record of S. carpocapsae in Colombia and the susceptibility of P. cinereus to this EPN.
RESUMO
Three populations, two from Colombia and one from Brazil, of Rotylenchulus reniformis associated with banana and plantain, were characterized using morphological, morphometric, and molecular methods. Morphometric data from these populations were similar to type and reference populations of R. reniformis. Partial sequences of both D2-D3 rDNA and mitochondrial cytochrome oxidase subunit I (COI) regions had a strong affinity (99% similarity) to previously published sequences of R. reniformis. Phylogenetic analyses (maximum likelihood and Bayesian inference) suggested that the Colombian populations of R. reniformis corresponded to the previously described Type A of the species. This is the definitive first report in Colombia of R. reniformis associated with banana and plantain crops.
RESUMO
Ceratobasidium includes orchid mycorrhizal symbionts, plant pathogens and biocontrol agents of soilborne plant pathogens. It is not known to what extent members of the first guild also can participate in the others. Ceratobasidium spp. were isolated from roots of Colombian orchids and identified by phylogeny based on nrITS sequences. Phylogenetic grouping of Ceratobasidium spp. isolates corresponded to orchid host substrate (epiphytic vs. terrestrial). Isolates were tested for virulence on rice and for biocontrol of Rhizoctonia solani, causal agent of sheath blight of rice. All Ceratobasidium spp. isolates caused some signs of sheath blight but significantly less than a pathogenic R. solani used as a positive control. When Ceratobasidium spp. isolates were inoculated on rice seedlings 3 d before R. solani, they significantly reduced disease expression compared to controls inoculated with R. solani alone. The use of Ceratobasidium spp. from orchids for biological control is novel, and biodiverse countries such as Colombia are promising places to look for new biocontrol agents.
