Journal Article

Studies on the aetiology of kiwifruit decline: interaction between soil-borne pathogens and waterlogging

Musetti, Rita, Pagliari, Laura, Firrao, Giuseppe, Ermacora, Paolo, Savian, Francesco, Tarquini, Giulia, Ginaldi, Fabrizio, Sandrin, Nicola, Martini, Marta

2020

Overview

Aims In 2012, Italian kiwifruit orchards were hit by a serious root disease of unknown aetiology (kiwifruit decline, KD) that still causes extensive damage to the sector. While waterlogging was soon observed to be associated with its outbreak, the putative role of soil microbiota remains unknown. This work investigates the role of these two factors in the onset of the disease. Methods Historical rainfall data were analysed to identify changes that might explain KD outbreak and mimic the flooding conditions required to reproduce the disease in a controlled environment. A greenhouse experiment was thus designed, and vines were grown in either unsterilized (U) or sterilized (S) soil collected from KD-affected orchards, and subjected (F) or not (N) to artificial flooding. Treatments were compared in terms of mortality rate, growth, and tissue modifications. Results KD symptoms were only displayed by FU-treated vines, with an incidence of 90%. Ultrastructural observations detected tyloses and fibrils in the xylem vessels of all plants, irrespective of the treatment. Phytopythium vexans and Phytopythium chamaehyphon , isolated from roots of FU plants, emerged as the associated microorganisms. Conclusions We succeeded in reproducing KD under controlled conditions and confirmed its association with both waterlogging and soil-borne microorganism(s).

• Publisher: Springer International Publishing,Springer
• Subject: Biomedical and Life Sciences / decline / Ecology / etiology / greenhouse experimentation / Health aspects / kiwifruit / Life Sciences / meteorological data / Microbiota (Symbiotic organisms) / mortality / Plant Physiology / Plant Sciences / Rain and rainfall / Regular Article / root diseases / soil / Soil microbiology / soil microorganisms / Soil Science & Conservation / tyloses