RESUMEN
Eucalyptus spp. are widely planted in Colombia as an important component of a growing paper and pulp industry. Leaf and shoot blight caused by Calonectria spp. was one of the first disease problems to emerge in these plantations. A survey of Eucalyptus plantations in four forestry regions of Colombia during 2016 resulted in a large number of Calonectria isolates from soil samples collected in the understories of trees having symptoms of Calonectria leaf and shoot blight. The aim of this study was to identify and resolve the phylogenetic relationships for these isolates using DNA sequence comparisons of six gene regions as well as morphological characters. From a collection of 107 isolates, seven Calonectria species residing in three species complexes were identified. Two of these represented undescribed species, namely C.exiguispora sp. nov. and C.guahibo sp. nov. Calonectriaparvispora and C.spathulata were the most commonly isolated species, each of which accounted for approximately 30% of the isolates. The results suggest that Colombia has a wide diversity of Calonectria spp. and that these could challenge Eucalyptus plantation forestry in the future.
RESUMEN
Vietnam and Indonesia have rapidly growing and extensive plantation forestry programs, especially of Acacia spp. and Eucalyptus spp. As these plantations expand, the threat from pests and diseases also increases. Calonectria species are among those pathogens causing diseases of trees in plantations and nurseries in these countries. Extensive surveys were conducted across plantations and nurseries of Vietnam and parts of Indonesia, where a large number of Calonectria isolates were retrieved from diseased leaves and soils associated with symptomatic trees. The aim of this study was to identify and resolve the phylogenetic relationships among these isolates using DNA sequence comparisons of four gene regions as well as morphological characters. From a collection of 165 isolates, the study revealed five known and 10 undescribed species. The relatively high diversity of Calonectria species found in this study supports the view that many more species in this genus remain to be discovered in other areas of Southeast Asia.
Asunto(s)
Variación Genética , Hypocreales/clasificación , Hypocreales/genética , Filogenia , Acacia/microbiología , ADN de Hongos/genética , ADN Espaciador Ribosómico , Eucalyptus/microbiología , Hypocreales/aislamiento & purificación , Indonesia , Enfermedades de las Plantas/microbiología , Hojas de la Planta/microbiología , VietnamRESUMEN
Cylindrocladiella spp. are widely distributed especially in tropical and sub-tropical regions, where they are mainly known as saprobes although some species are plant pathogens. Very little is known about these fungi in South-East Asia. The aim of this study was to identify a collection of Cylindrocladiella isolates from soils collected in forest nurseries and plantations in Vietnam and Malaysia. This was achieved using DNA sequence comparisons and morphological observations. The study revealed two previously described species, Cy. lageniformis and Cy. peruviana as well as five novel taxa, described here as Cy. arbustasp. nov., Cy. malesianasp. nov., Cy. obpyriformissp. nov., Cy. parvisporasp. nov. and Cy. solicolasp. nov. A relatively small collection of isolates from a limited geographic sampling revealed an unexpectedly high level of Cylindrocladiella diversity suggesting that many more species in this genus await discovery in South-East Asia.