title: Two previously unknown Phytophthora species associated with brown rot of Pomelo (Citrus grandis) fruits in Vietnam.
abstract: Two distinct Phytophthora taxa were found to be associated with brown rot of pomelo (Citrus grandis), a new disease of this ancestral Citrus species, in the Vinh Long province, Mekong River Delta area, southern Vietnam. On the basis of morphological characters and using the ITS1-5.8S-ITS2 region of the rDNA and the cytochrome oxidase subunit 1 (COI) as barcode genes, one of the two taxa was provisionally named as Phytophthora sp. prodigiosa, being closely related to but distinct from P. insolita, a species in Phytophthora Clade 9, while the other one, was closely related to but distinct from the Clade 2 species P. meadii and was informally designated as Phytophthora sp. mekongensis. Isolates of P. sp. prodigiosa and P. sp. mekongensis were also obtained from necrotic fibrous roots of Volkamer lemon (C. volkameriana) rootstocks grafted with 'King' mandarin (Citrus nobilis) and from trees of pomelo, respectively, in other provinces of the Mekong River Delta, indicating a widespread occurrence of both Phytophthora species in this citrus-growing area. Koch's postulates were fulfilled via pathogenicity tests on fruits of various Citrus species, including pomelo, grapefruit (Citrus x paradisi), sweet orange (Citrus x sinensis) and bergamot (Citrus x bergamia) as well as on the rootstock of 2-year-old trees of pomelo and sweet orange on 'Carrizo' citrange (C. sinensis 'Washington Navel' x Poncirus trifoliata). This is the first report of a Phytophthora species from Clade 2 other than P. citricola and P. citrophthora as causal agent of fruit brown rot of Citrus worldwide and the first report of P. insolita complex in Vietnam. Results indicate that likely Vietnam is still an unexplored reservoir of Phytophthora diversity.
authors.affiliation: Department of Agriculture, Food and Environment, University of Catania, Catania, Italy.|Dipartimento di Agraria, Università Mediterranea di Reggio Calabria, Feo di Vito, Reggio Calabria, Italy.
authors.forename: Ivana
authors.initials: I
authors.lastname: Puglisi
authors.affiliation: Department of Agriculture, Food and Environment, University of Catania, Catania, Italy.
authors.forename: Alessandro
authors.initials: A
authors.lastname: De Patrizio
authors.affiliation: Dipartimento di Agraria, Università Mediterranea di Reggio Calabria, Feo di Vito, Reggio Calabria, Italy.
authors.forename: Leonardo
authors.initials: L
authors.lastname: Schena
authors.affiliation: Phytophthora Research Center Mendel University, Zemedelska 1, 613 00 Brno, Czech Republic.|Phytophthora Research and Consultancy, Am Rain 9, Nußdorf, Germany.
authors.forename: Thomas
authors.initials: T
authors.lastname: Jung
authors.affiliation: Department of Agriculture, Food and Environment, University of Catania, Catania, Italy.
authors.forename: Maria
authors.initials: M
authors.lastname: Evoli
authors.affiliation: Department of Agriculture, Food and Environment, University of Catania, Catania, Italy.
authors.forename: Antonella
authors.initials: A
authors.lastname: Pane
authors.affiliation: Southern Horticultural Research Institute, My Tho, Tien Giang, Vietnam.
authors.forename: Nguyen
authors.initials: N
authors.lastname: Van Hoa
authors.affiliation: Southern Horticultural Research Institute, My Tho, Tien Giang, Vietnam.
authors.forename: Mai
authors.initials: M
authors.lastname: Van Tri
authors.affiliation: Department of Electronics, Mathematics and Natural Sciences, University of Gävle, Gävle, Sweden.
authors.forename: Sandra
authors.initials: S
authors.lastname: Wright
authors.affiliation: Department of Forest Mycology and Plant Pathology, Swedish Agricultural University (SLU), Uppsala, Sweden.
authors.forename: Mauritz
authors.initials: M
authors.lastname: Ramstedt
authors.affiliation: Department of Biological and Environmental Sciences, Gothenburg University, Gothenburg, Sweden.
authors.forename: Christer
authors.initials: C
authors.lastname: Olsson
authors.affiliation: Department of Agriculture, Food and Environment, University of Catania, Catania, Italy.
authors.forename: Roberto
authors.initials: R
authors.lastname: Faedda
authors.affiliation: Dipartimento di Agraria, Università Mediterranea di Reggio Calabria, Feo di Vito, Reggio Calabria, Italy.
authors.forename: Gaetano
authors.initials: G
authors.lastname: Magnano di San Lio
authors.affiliation: Department of Agriculture, Food and Environment, University of Catania, Catania, Italy.
authors.forename: Santa Olga
authors.identifier: http://orcid.org/0000-0001-7926-3601
authors.initials: SO
authors.lastname: Cacciola
mesh_terms: D002957:Citrus / Q000235:genetics / Q000254:growth & development / Q000382:microbiology*; D004271:DNA, Fungal / Q000235:genetics; D005638:Fruit / Q000382:microbiology*; D010802:Phylogeny; D010838:Phytophthora / Q000145:classification / Q000302:isolation & purification*; D010935:Plant Diseases / Q000382:microbiology*; D018517:Plant Roots / Q000382:microbiology*; D017422:Sequence Analysis, DNA; D014744:Vietnam
chemical_list: D004271:DNA, Fungal