Phylogenetic species recognition and hybridisation in Lasiodiplodia: A case study on species from baobabs.
Lasiodiplodia species (Botryosphaeriaceae, Ascomycota) infect a wide range of typically woody plants on which they are associated with many different disease symptoms. In this study, we determined the identity of Lasiodiplodia isolates obtained from baobab (Adansonia species) trees in Africa and reviewed the molecular markers used to describe Lasiodiplodia species. Publicly available and newly produced sequence data for some of the type strains of Lasiodiplodia species showed incongruence amongst phylogenies of five nuclear loci. We conclude that several of the previously described Lasiodiplodia species are hybrids of other species. Isolates from baobab trees in Africa included nine species of Lasiodiplodia and two hybrid species. Inoculation trials with the most common Lasiodiplodia species collected from these trees produced significant lesions on young baobab trees. There was also variation in aggressiveness amongst isolates from the same species. The apparently widespread tendency of Lasiodiplodia species to hybridise demands that phylogenies from multiple loci (more than two and preferably four or more) are compared for congruence prior to new species being described. This will avoid hybrids being incorrectly described as new taxa, as has clearly occurred in the past.
Department of Plant and Soil Sciences, DST-NRF Centre of Excellence in Tree Health Biotechnology (CTHB), Forestry and Agricultural Biotechnology Institute (FABI), Faculty of Natural and Agricultural Sciences, University of Pretoria, Pretoria 0083, South Africa. Electronic address: elsie.cruwyagen@fabi.up.ac.za.
Elsie M
EM
Cruywagen
Department of Genetics, CTHB, FABI, University of Pretoria, Pretoria 0083, South Africa. Electronic address: bernard.slippers@fabi.up.ac.za.
Bernard
B
Slippers
Department of Plant and Soil Sciences, DST-NRF Centre of Excellence in Tree Health Biotechnology (CTHB), Forestry and Agricultural Biotechnology Institute (FABI), Faculty of Natural and Agricultural Sciences, University of Pretoria, Pretoria 0083, South Africa. Electronic address: jolanda.roux@fabi.up.ac.za.
Jolanda
J
Roux
Department of Plant and Soil Sciences, DST-NRF Centre of Excellence in Tree Health Biotechnology (CTHB), Forestry and Agricultural Biotechnology Institute (FABI), Faculty of Natural and Agricultural Sciences, University of Pretoria, Pretoria 0083, South Africa. Electronic address: mike.wingfield@fabi.up.ac.za.
Michael J
MJ
Wingfield
D035162:Adansonia / Q000382:microbiology*; D000349:Africa; D001203:Ascomycota / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification*; D004271:DNA, Fungal / Q000235:genetics*; D010802:Phylogeny; D010935:Plant Diseases / Q000382:microbiology; D011995:Recombination, Genetic; D017422:Sequence Analysis, DNA
D004271:DNA, Fungal
Barcoding; Botryosphaeriaceae; Fungal hybrids; Phylogenetic species concept; Taxonomy