TreeBASE Search-Analyses for study 14609

@ARTICLE{TreeBASE2Ref22295, author = {Chris Frederik Jakobus Spies and Julia C. Meitz-Hopkins and Shaun D. Langenhoven and M. C. Pretorius and Adele McLeod}, title = {Two clonal lineages of Phytophthora citrophthora from citrus in South Africa represent a single phylogenetic species}, year = {2014}, keywords = {intraspecific variation, phylogeny, RAMS, RAPDs}, doi = {}, url = {http://}, pmid = {}, journal = {Mycologia}, volume = {}, number = {}, pages = {}, abstract = {Phytophthora citrophthora, a serious pathogen of citrus, is comprised of distinct clonal lineages on citrus in Eastern Corsica and Spain, with the G1 lineage dominating. In South Africa, the extent of genetic variation among citrus associated P. citrophthora isolates is unknown. This was therefore investigated using isolates from South Africa (n=60), Spain (n=10), and six reference isolates representing three P. citrophthora groups CTR1, CTR2 and CTR3 previously identified by Mchau & Coffey (1994) using isozyme polymorphisms. Isolates from South Africa and Spain belonged to two lineages (G1 and G2) based on an internal transcribed spacer (ITS) phylogeny and random amplified microsatellites (RAMS) and random amplified polymorphic DNA (RAPD) profiling. Although the combined RAMS and RAPD data identified 14 genotypes among these isolates, unweighted pair group method with arithmetic mean (UPGMA) analyses grouped the isolates into two distinct clusters that corresponded to the G1 and G2 lineages. The G1 lineage predominated among isolates from South Africa (92 %) and Spain (100 %). Phylogenetic analyses of the ?-tubulin, cytochrome c oxidase subunit I (COX1) and ITS regions did not support the hypothesis that the two lineages represent distinct phylogenetic species, but suggested that isozyme group CTR2 and possibly CTR3 should be redescribed as species distinct from P. citrophthora (South African, Spanish and CTR1 reference isolates). Mating type analyses, using tester strains from groups CTR2 and CTR3 revealed that most G1 isolates were sterile (n = 57) but that a few were of the A1 mating type (n = 8), whereas all G2 isolates were A2 mating type (n = 5). The mating type designation was confirmed using P. capsici tester strains. However, when the A1 (G1 lineage) and A2 (G2 lineage including CTR1 reference isolates) mating type isolates were paired in all possible combinations with each other, no oogonia or antheridia were produced. This suggests that only the tester P. capsici, CTR2 and CTR3 strains were able to produce sexual structures and that the G1 and G2 lineages are sterile and reproductively isolated, which is supported by the molecular data.} }