Fig 1.
Fruit of pomelo (Citrus grandis) with symptoms of brown rot caused by mixed infections of P. sp. prodigiosa and P. sp. mekongensis from Vietnam.
Fig 2.
Five-day-old colonies of isolates PF6a2 and PF6f2 of P. sp. mekongensis and isolate PF6e of P. sp. prodigiosa (from left to right) on V8 juice agar (top) and potato-dextrose agar (bottom).
Fig 3.
Morphology of vegetative structures of Phytophthora isolates.
A. Cluster of fusiform, papillate sporangia of P. sp. mekongensis. B. Obpyriform, persistent, nonpapillate sporangium of P. sp. prodigiosa. C. Internal and external extended proliferations of persistent sporangia of P. sp. prodigiosa produced in water. (Scale bar = 20 μm).
Fig 4.
Chlamydospores and hyphal swellings produced by P. sp. prodigiosa.
(A). Globose, small, sessile chlamydospores on V8A, attached laterally to the hypha and with a thin wall. (B-E) Hyphal swellings of P. sp. prodigiosa on V8A with bizarre shapes (Scale bar = 20 μm).
Table 1.
Phytophthora species sampled in the Mekong River delta (Vietnam), source, host, location of recovery and GenBank accession numbers of ITS and COI sequences of representative isolates.
Fig 5.
Molecular phylogenetic analysis of the combined data set ITS and COI among isolates Pf6f2, Pr3 and Pf6a2 of P. sp. mekongensis (indicated by arrows) within Phytophthora major Clade 2 by Maximum Likelihood method, based on the Tamura-Nei model.
The percentage of trees in which the associated taxa clustered together is shown next to the branches. Initial trees for the heuristic search were obtained by applying the Neighbor-Joining method to a matrix of pairwise distances estimated using the Maximum Composite Likelihood (MCL) approach. The tree was drawn to scale, with branch lengths measured in the number of substitutions per site. Bootstrap values were obtained from 1000 replications. Asterisk (*) indicates the ex-type isolate.
Fig 6.
Molecular phylogenetic analysis of the combined data set ITS and COI among isolates PF6e and Pr1 of P. sp. prodigiosa (indicated by arrows) within Phytophthora major Clade 9 by Maximum Likelihood method, based on the Tamura-Nei model.
The percentage of trees in which the associated taxa clustered together is shown next to the branches. Initial trees for the heuristic search were obtained by applying the Neighbor-Joining method to a matrix of pairwise distances estimated using the Maximum Composite Likelihood (MCL) approach. The tree was drawn to scale, with branch lengths measured in the number of substitutions per site. Bootstrap values were obtained from 1000 replications. Asterisk (*) indicates the ex-type isolate.
Table 2.
Area (cm2) of lesions caused by isolates PF6a2, PF6f2, and Pr3 of P. sp. mekongensis and isolates PF6e and Pr1 of P. sp. prodigiosa on fruits of various citrus species and cultivar inoculated with (A) agar plugs on wounded fruits, (B) agar plugs on unwounded fruits and (C) a drop (200 μl) of zoospore water-suspension on unwounded fruits, 6 days after inoculation.
Fig 7.
Gum exudate oozing from the twig of a sweet orange ‘Lane Late’ wound inoculated with isolate PF6f2 of P. sp. mekongensis from Vietnam, 12 days after inoculation.