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Pseudomonas syringae pv. actinidiae

PSA lesions on kiwifruit leaves

Pseudomonas syringae pv. actinidiae (Psa) causes canker on kiwifruit (Actinidia spp.). The disease was first reported in Japan and Korea in 1984. Around 2008 there was a very serious outbreak in Italy which has spread throughout Europe affecting predominantly 'Hort16A' (Actinidia chinensis). The highly aggressive strain Psa-V produces an abundance of inoculum and can spread rapidly by aerosols. It infects through natural openings such as stomata, wounds, hydathodes and lenticels. Control options are very limited. Currently they include cutting out infected material and removing secondary infected plants. Maintaining hygiene within orchards is (particularly equipment) very important. Topical applications such as copper-based bactericidal sprays and biological control agents, and the use of elicitors (Actigard, also known as Bion) which induces systemic acquired resistance are currently being trialled.

We have sequenced a number of Psa genomes from New Zealand and other countries where the disease occurs. This information has helped us understand the phylogenitic relationships between strains, design a robust detection system that is specific for Psa-V, and identify effectors and pathogenicity factors unique to the virulent isolate.

Sequenced strains

See here for an overview of sequenced strains

Getting started

The Psa whole genome sequencing project is a collaboration between Plant & Food Research and Massey University. We have high-quality draft sequences of 25 Psa isolates from around the world. Two of these isolates, Psa V-13 and the type strain ICMP 9617, have been completely sequenced. If you would like to access the Psa whole genome project please contact Matt Templeton. Consult the User's Guide for information on using the wiki software.