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Oral: Pathogen Diversity


Phylogenetic and population analyses of the brown root-rot pathogen (Phellinus noxius) highlight the existence of two distinct populations
J. STEWART (1), N. Sahashi (2), T. Hattori (2), Y. Ota (2), L. Shuey (3), R. Schlub (4), N. Atibalentia (5), F. Brooks (6), A. Tang (7), R. Lam (7), M. Leung (8), L. Chu (9), H. Kwan (9), A. Mohd Farid (10), S. Lee (10), C. Chung (11), H. Lee (11), Y. Hua

Phellinus noxius is a vastly destructive, fast-growing fungal pathogen that affects a wide range of woody hosts in pan-tropical areas, including Asia, Oceania, and Africa. This pathogen causes brown root-rot on diverse hosts, with little indication of host specificity. Pathogenic symptoms of P. noxius infection can include reduced tree growth, defoliation, and branch dieback; however, P. noxius can survive as a saprophyte. Understanding the genetic diversity and evolutional history of P. noxius populations worldwide well help assess the evolutionary origins, worldwide movement, and potential ecological differences within P. noxius. The objective of this study was to estimate a wide-scale genetic diversity and evolutionary history of P. noxius movement. A total of 158 isolates were included from Japan, Taiwan, Australia, China (Hong Kong), Malaysia, and the Pacific islands of American Samoa, Saipan, Guam, Palau, Pohnpei, and Kosrae were sequenced at four loci including ITS, LSU-rDNA, elongation factor-1 alpha, and RNA polymerase subunit II. The results show two distinct clades of P. noxius. Currently, sequencing data are generating by Illumina sequencing of double-digest reduced representation libraries (ddRAD). Continued analyses will assess regional population structure, gene flow among populations, diversity in recently observed populations, and potential suitable climate space for specific genotypes.