Phytophthora palmivora from Sulawesi and Java Islands, Indonesia, reveals high genotypic diversity and lack of population structure. Issue 4 (April 2022)

• Record Type: Journal Article
• Authors: Brugman, Eirene; Wibowo, Arif; Widiastuti, Ani
• Is Part Of: Fungal biology. Volume 126:Issue 4(2022)
• Page Start: 267
• Page End: 276
• Publication Date: 2022-04
• Subjects: Cocoa -- Black pod disease -- Population genetic -- Microsatellites; Mycology -- Periodicals; Fungi -- Periodicals; 579.505
• DOI: 10.1016/j.funbio.2022.02.004
• Languages: English
• ISSNs: 1878-6146

Abstract

Abstract: Phytophthora palmivora is the causal agent of cocoa black pod disease, one of the primary diseases of cocoa in Indonesia. A better understanding of P. palmivora population genetics is needed to aid the development of relevant disease management strategies. This study is the first population genetic study of P. palmivora in Indonesia using microsatellite markers based on the alleles genotyping method. The microsatellite markers were used to determine the genotype of 44 P. palmivora isolates from Sulawesi (24) and Java (20) islands. The total number of observed multilocus genotypes (MLG) from both populations was 34. The genotypic diversity of P. palmivora from Sulawesi (2.90; 16.0; 0.938) and Java (2.76; 14.3; 0.930) islands was high as seen from Shannon's diversity index (H), Stoddart and Taylor's Index (G), and Simpson's Index (λ) respectively. Evenness and Nei's unbiased gene diversity exhibited similarly high levels from both populations. The linkage disequilibrium test indicated that sexual recombination occurred in the Java population (P = 0.312). Analysis of molecular variance (AMOVA) and Bayesian clustering revealed five genetic clusters, and isolates from both islands were evenly distributed across the five gene clusters. All genetic diversity was from within individuals. P. palmivora from Sulawesi and Java showed a high genotypic diversity but a lack of genetic differentiation among populations (Fst = 0.006). Both populations formed one highly diverse group. Minimum spanning network analysis showed no particular grouping of MLGs, and shared MLGs from both populations indicated long-distance migration of P. palmivora facilitated by human activities. Highlights: High genotypic diversities with average Simpson index (λ) 0.934 and Evenness (E5 ) 0.883. 70% of the multilocus genotype from Sulawesi and 70.5% of the multilocus genotypes from Java were observed only once. No genetic differentiation between populations collected from both islands. The same multilocus genotype found in both populations indicates pathogen migration mediated by human activities.