Assignment of Pseudomonas syringae pv. actinidiae biovar 4 to Pseudomonas syringae pv. actinidifoliorum pv. nov.
Following the outbreaks of bacterial canker of kiwifruit caused by Pseudomonas syringae pv. actinidiae (EPPO A2 List) in different parts of the world, studies have showed that 4 biovars could be distinguished based on their biochemical, pathogenicity and molecular characteristics. P. syringae pv. actinidiae biovars 1, 2 and 3 are associated with canker and shoot dieback on kiwifruit, whereas strains of biovar 4 are less aggressive, causing only leaf spots. Strains of biovar 1 and 2 have been detected in Japan and the Republic of Korea, respectively. Biovar 3 includes the aggressive strains that are responsible for economic damage on kiwifruit production (e.g. in Italy, France, New Zealand, Portugal, Spain).
Recent studies have been conducted in France on 72 strains of P. syringae pv. actinidiae from different origins (Australia, France, Italy, Japan, Korea, New Zealand) and including all biovars. As strains of biovar 4 were found to be substantially different from those of the other biovars, it was proposed to assign biovar 4 to a new pathovar tentatively called Pseudomonas syringae pv. actinidifoliorum pv. nov. According to the literature, Pseudomonas syringae pv. actinidifoliorum has been detected on kiwifruit (A. deliciosa and A. chinensis) in Australia, France, New Zealand and Spain.
Abelleira A,, Ares A, Aguin O, Peñalver J, Morente MC, López MM, Sainz MJ, Mansilla JP (2015) Detection and characterization of Pseudomonas syringae pv. actinidifoliorum in kiwifruit in Spain. Journal of Applied Microbiology 119(6), 1659-1671.
Cunty A, Poliakoff F, Rivoal C, Cesbron S, Fischer-Le Saux M, Lemaire C, Jacques MA, Manceau C, Vanneste JL (2015) Characterisation of Pseudomonas syringae pv. actinidiae (Psa) isolated from France and assignment of strains Psa biovar 4 to a de novo pathovar: Pseudomonas syringae pv. actinidifoliorum pv. nov. Plant Pathology 64(3), 582-596.