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Phomopsis husk rot of macadamia in Australia and South Africa caused by novel Diaporthe species
Author(s) -
Wrona Christopher J.,
Mohankumar Vheena,
Schoeman Maritha H.,
Tan Yu P.,
Shivas Roger G.,
JeffEgo Olumide S.,
Akinsanmi Olufemi A.
Publication year - 2020
Publication title -
plant pathology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.928
H-Index - 85
eISSN - 1365-3059
pISSN - 0032-0862
DOI - 10.1111/ppa.13170
Subject(s) - biology , phomopsis , proteaceae , botany , clade , pathogenicity , phylogenetic tree , husk , gene , microbiology and biotechnology , genetics
Phomopsis husk rot (PHR) in macadamia is a disease of economic importance in major commercial production areas in Australia and South Africa. Effective control of PHR is hindered by limited knowledge about its aetiology and epidemiology. The diversity and pathogenicity of more than 50 isolates of Diaporthe associated with PHR in macadamia orchards in Australia and South Africa was assessed. Multilocus phylogenetic analyses of DNA sequences of the ITS, tef1α , and tub2 gene loci revealed four novel clades that are described as Diaporthe australiana sp. nov., D . drenthii sp. nov., D . macadamiae sp. nov., and D . searlei sp. nov. Pathogenicity tests with representative isolates found that all four species caused PHR of varying severity between and within species, as well as between the two macadamia cultivars HAES 344 and HAES 816. The Australian species, D . australiana , was the most aggressive species compared with the three South African species. This study improves our understanding of the aetiology of PHR in macadamia and paves the way for more effective disease management.