Xylella in Apulia: review finds no evidence of multiple types

There is no proof that multiple types of Xylella fastidiosa are present in Apulia, southern Italy, according to recently available scientific evidence examined by EFSA.

The opinion from EFSA’s Panel on Plant Health is the last of three outputs addressing a number of questions from the European Commission on X. fastidiosa in Apulia. In this one the Panel addresses the question of whether different types of X. fastidiosa exist in Apulia, where a disease outbreak is affecting olive trees and other plants.

A single study raised the possibility that multiple genetic types of X. fastidiosa are present in the area. However, EFSA’s plant health specialists say there is currently no evidence to support this hypothesis.

To reach its conclusion, the Panel reviewed the latest scientific literature and analysed DNA sequencing data retrieved from samples collected in Apulia. All the papers concluded that DNA samples collected from olive trees and other plants belong to the same sequence type, called “ST53”.

For the sequence data analysis, the Panel used a dedicated database established in 2005 that contains the DNA sequences of nearly 300 X. fastidiosa samples. The Panel highlights that further studies with larger sample sizes are needed to provide more comprehensive answers on this issue. These should include an analysis of complete X. fastidiosa genome sequencing.

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