Principal investigator Collaborators Staff Postdoctoral researchers Graduate students Visiting researchers Alumni

Elena Colombi

B.Sc., M.Sc.


physical: Building 16.10 // The Station Crescent // Oteha Rohe
tel: +64 9 4140800 ext 43811 // email: e.colombi(at)


I studied Agricultural Biotechnology at the University of Florence (Italy). During my BSc and Msc projects I studied the olive knot disease pathogen Pseudomonas savastanoi pv. nerii at the Molecular and Plant Pathology Laboratory in Florence. My Msc project also involved a six month internship at the University of Reading to study the horse chestnut bleeding canker pathogen Pseudomonas syringae pv. aesculi. My projects concerned the plant pathogen interaction, focusing on quorum sensing, the Type Three Secretion System and the HopAB1 effector.


I am working on the kiwifruit bacterial canker disease caused by Pseudomonas syringae pv. actinidiae (Psa).

Before 2008 the canker on kiwifruit caused by Psa was registered on the green kiwifruit in Japan, China, Korea and Italy. At that stage the disease was severe, causing the destruction of the infected vines. The symptoms comprised red exudates, leaf spots and canker. However the spread of these Psa strains remained circumscribed.

Unfortunately from 2008 an aggressive strain of Psa was isolated for the first time in Italy on golden kiwifruits and it became pandemic. Even if this strain shows the same symptoms of the older Japanese and Korean strains, it is particularly virulent on the golden kiwifruit: when an orchard is infected the best thing that a grower can do is to destroy all the vegetative material to prevent the spread of the disease.

Regarding New Zealand the outbreak Psa strain arrived in the North Island in 2010. While researchers were collecting samples from kiwifruit vines a low virulent strain that causes only leaf spots was discovered. This strain was demonstrated to form a different clade from the other strains, compatible with an old introduction in this country.

The big question is why is this new strain is so virulent and causing so much damage?

I will be investigating the genome of the different strains of Psa to try to solve some pieces of this puzzle.


Elena Colombi