The Myrtle rust pathogen, Puccinia psidii, discovered in Africa

Abstract

Puccinia psidii, the cause of a disease today commonly referred to as Myrtle rust, is considered a high priority quarantine threat globally. It has a wide host range in the Myrtaceae and it is feared that it may result in significant damage to native ecosystems where these plants occur. The fungus is also of considerable concern to plantation forestry industries that propagate Australian Eucalyptus species. In May 2013, symptoms of a rust disease resembling those of P. psidii were observed on an ornamental Myrtaceous shrub in a garden in South Africa. The fungus was identified based on DNA sequence data of the ITS and 5.8S nrRNA gene regions and here we report, for the first time, the presence of P. psidii in Africa.

A unique genotype of the rust pathogen, Puccinia psidii, on Myrtaceae in South Africa

“…Puccinia psidii was first discovered in South Africa on a single, non-native ornamental plant in a garden (Roux et al 2013). Early efforts to find additional sources of infection in that region failed.…”

“…It seems most likely that the pathogen has been distributed widely across South Africa with the nursery trade. Myrtus communis, the host on which it was first detected (Roux et al 2013), is highly susceptible to infection. Puccinia psidii infection was found in every visited nursery that sold this plant in the greater Tshwane and Ekhuruleni Municipal areas of Gauteng Province.…”

“…The fungus has subsequently been reported Unique Pucinnia psidii genotype in South Africa 3 from North America (Marlatt and Kimbrough 1979) and Hawaii (Uchida et al 2006), China (Zhuang and Wei 2011), Japan (Kawanishi et al 2009), Australia (Carnegie et al 2010), Africa (Roux et al 2013), New Caledonia (Giblin 2013;Machado et al 2015) and Indonesia (McTaggart et al 2015). All of these reports, outside Brazil, were attributed to a single genoptype of P. psidii (Machado et al 2015), dubbed the pandemic genotype .…”

“…Myrtus communis tree, in a private garden on the south coast of KwaZulu-Natal (Roux et al 2013). Subsequent to its detection, many articles have been published in garden and botanical magazines as well as in the media to raise awareness about the disease in South Africa (Roux 2015;Roux and Pegg 2014 isolates from Australia, were used in the genetic analyses (Table 1).…”

Estudo molecular do desenvolvimento de <i>Puccinia psidii</i> Winter <i>in vitro</i> e no processo de infecção em<i> Eucalyptus grandis</i>

“…Após o primeiro relato do patógeno no Brasil, P. psidii foi detectada infectando diferentes Myrtaceae em vários países da América do Sul e Central, incluindo o Caribe (COUTINHO et al, 1998;GLEN et al, 2007;GRAÇA et al, 2011) e moveu-se rapidamente para novos territórios como Califórnia, Flórida e Havaí nos Estados Unidos (MARLATT; KIMBROUGH, 1979;UCHIDA;ZHONG;KILLGORE, 2006), Japão (KAWANISHI et al, 2009), Austrália (CARNEGIE et al, 2010CARNEGIE, 2015), China (ZHUANG;WEI, 2011), Nova Caledônia (GIBLIN, 2013, África do Sul (ROUX et al, 2013) e mais recentemente Indonésia (MCTAGGART et al, 2016). A propagação do agente patogênico pelos continentes sugere que seus uredósporos podem ser dispersos pelo vento, pólen contaminado e principalmente pela troca de material vegetal infectado assintomático entre esses países.…”