Electronic Nose Differentiation between Quercus robur Acorns Infected by Pathogenic Oomycetes Phytophthora plurivora and Pythium intermedium.

Piotr Borowik,Miłosz Tkaczyk,Przemysław Wacławik,Sławomir Ślusarski,Rafał Tarakowski,Tomasz Oszako,Leszek Adamowicz,Marcin Stocki

doi:10.3390/molecules26175272

Abstract

Identification of the presence of pathogenic oomycetes in infected plant material proved possible using an electronic nose, giving hope for a tool to assist nurseries and quarantine services. Previously, species of Phytophthora plurivora and Pythium intermedium have been successfully distinguished in germinated acorns of English oak Quercus robur L. Chemical compound analyses performed by HS-SPME/GC-MS (Headspace Solid-Phase Microextraction/Gas Chromatography–Mass Spectrometry) revealed the presence of volatile antifungal molecules produced by oak seedlings belonging to terpenes and alkanes. Compounds characteristic only of Phytophthora plurivora or Pythium intermedium were also found. Methylcarveol occurred when germinated acorns were infected with Pythium, while neophytadiene (isomer 2 and 3) occurred only when infected with Phytophthora. Moreover, isopentanol was found in acorns infected with Phytophthora, while in control, isopentyl vinyl ether was not observed anywhere else. Among the numerous volatile compounds, isopentanol only occurred in acorns infected with Phytophthora and methylcarveol in acorns infected with Pythium.

Highlights

With the increase in international trade of plants and plant source materials, such as seeds, new threat are arising from the accidental introduction of insects or pathogens into new environments
The isolates of Phytophthora plurivora and Pythium intermedium used in the colonisation test were obtained from the oomycete culture collection of the Forest Research Institute (IBL)
The species used in the assay Phytophthora plurivora and Pythium intermedium were transferred to V8A media prepared with 800 mL/L distilled water, 200 mL/L V8 juice (Tymbark, Poland), 18 g/L agar-agar (BTL, Poland) and 3 g/L CaCO3

Summary

Introduction

With the increase in international trade of plants and plant source materials, such as seeds, new threat are arising from the accidental introduction of insects or pathogens into new environments. Identifying potential hosts and the particular location of their occurrence in a nursery allows managers to avoid potential infection of plants by appropriate crop rotation. They can grow acorns from oaks in locations where Phytophthora alni has been found, as it does not cause them serious harm, and grow alder seeds where Phytophthora quercina has been found. Scientists and plant health inspectors need new, efficient tools like electronic noses (e-noses) to act early and efficiently

Methods

Results

Discussion

Conclusion