Identification and characterization of Pseudomonas syringae pv. actinidiae Psa) in Entre Douro e Minho region (Portugal)

Abstract

Pseudomonas syringae pv. actinidiae (Psa) is the causal agent of bacterial canker of kiwifruit, the most severe disease of this culture at the moment, causing significant economic losses in the main kiwi producing countries. The most characteristic symptoms are leaves with small dark-brown necrotic spots surrounded by a yellow halo and red-rusty exudation on the trunks. This disease was detected in Portugal in 2010 in Entre Douro e Minho (EDM) region. This study aims to identify and characterize the Psa population present in this region. The pathogen was isolated from plant material with symptoms of the disease from different Actinidia deliciosaorchards. Identification and characterization was done by morphological and phenotypical tests (LOPAT, Biolog system, fatty acids profile) and molecular techniques (PCR and BOX-PCR). The results showed that the Psa isolates have similar morphological characteristics, however variability at this level was observed. Results of molecular characterization indicate that Psa isolates from EDM region are similar to the most virulent Psa population (Psa3) identified in Europe and New Zealand.