Abstract:
Phyllosticta spp. are important pathogens of citrus plants. Several Phyllosticta species
associated with Citrus species grown in China have been reported; however, the relative prevalences
of individual species and the distributions of their genotypes among host Citrus species remain
largely unknown. In this study, we conducted an extensive survey of Phyllosticta species across
11 citrus-producing provinces in southern China. From fruits and leaves with black spots or blackspot-
like symptoms, a total of 461 Phyllosticta strains were isolated. Based on molecular (ITS, actA, tef1,
gapdh, LSU, and rpb2 sequences) and morphological data, the strains were systematically identified as
belonging to five species: P. capitalensis, P. citrichinaensis, P. citriasiana, P. citricarpa, and P. paracitricarpa.
To further understand intraspecific genetic diversity and relationships, strains of five species from
different geographic and host sources were analyzed based on the multilocus sequence data. Our
population genetic analyses revealed that all five Phyllosticta species on citrus showed evidence
for clonal dispersals within and among geographic regions. In addition, pathogenicity tests using
representative strains showed that all five species can cause disease on the tested Citrus spp. We
discuss the implications of our results for the control and management of Citrus Black Spot and
related diseases.
Description:
SUPPLEMENTARY MATERIALS : FIGURE S1: Symptoms of citrus fruit spots from which the Phyllostitca isolates were obtained; FIGURES S2–S7: Maximum likelihood phylogeny of Phyllostica isolates related to citrus. S2. 194 isolates of ITS tree, S3. 183 isolates of actA tree, S4. 176 isolates of tef1 tree, S5. 166 isolates of gapdh tree, S6. 164 isolates of LSU tree, S7. 116 isolates of rpb2 tree; FIGURE S8. Column chart indicating the average lesion area produced each isolate of Phyllosticta spp. TABLE S1: Isolates information sequenced in this study; TABLE S2: GenBank Accession number of the isolates used for phylogenetic analysis in this study. TABLE S3: Datasets used and statistics resulting from phylogenetic analyses. TABLE S4: Comparison of morphology of two novel Phyllosticta species and their related sister species. TABLE S5: Nucleotide differences observed among P. paracitriasiana and P. citriasiana isolates used in this study. TABLE S6: Nucleotide differences observed among P. paracitrichinaensis and P. citrichinaensis isolates used in this study. TABLE S7: Fst values among provincial or/and host subpopulations of five Phyllostitca spp. in China.
