Discrimination between regional biotypes of Impatiens glandulifera using a simple MALDI-TOF MS-based method for use with seeds

Michael A Reeve,Kathryn M Pollard

doi:10.1186/s13007-019-0412-1

Abstract

BackgroundWe have recently developed a simple, rapid, and relatively-cheap method for matrix-assisted laser-desorption and ionisation time-of-flight mass spectroscopy (MALDI-TOF MS) sample preparation that is applicable to plant material (in addition to microbial and insect material), and have used this to discriminate between closely-related Impatiens species and between regional biotypes of the invasive weed Impatiens glandulifera (commonly known as Himalayan balsam) using leaf samples. In the current paper, we have developed a complementary MALDI-TOF MS-based method for use with seeds. We have employed a combination of principal-component analysis and blind-tested comparison between reference-sample MALDI-TOF MS spectra and test-sample spectra to discriminate, on the basis of the acid-soluble seed-protein spectra generated by our method, between four regional biotypes of I. glandulifera from within the UK that differ in their susceptibility to the biological control agent Himalayan balsam rust (Puccinia komarovii var. glanduliferae).ResultsPeak-rich and highly-reproducible spectra were obtained and, in blind testing with test seeds collected in 2017 against reference seeds collected in 2017, we observed 100% identification accuracy in 12 blind tests. In blind testing with test seeds collected in 2016 against reference seeds collected in 2017, we observed 92% identification accuracy in 12 blind tests.ConclusionsMALDI-TOF MS analysis of seed material is able to discriminate between regional biotypes of I. glandulifera. MALDI-TOF MS therefore has the potential to improve the efficiency and efficacy of weed biological control using co-evolved natural enemies of invasive non-native plant species, through the matching of biological control agents with susceptible regional biotypes.

Highlights

We have recently developed a simple, rapid, and relatively-cheap method for matrix-assisted laserdesorption and ionisation time-of-flight mass spectroscopy (MALDI-TOF matrix-assisted laser-desorption and ionisation time-of-flight mass spectrometry (MS)) sample preparation that is applicable to plant material, and have used this to discriminate between closelyrelated Impatiens species and between regional biotypes of the invasive weed Impatiens glandulifera using leaf samples
We describe the development of such a complementary MALDI-TOF MS-based method for use with seeds, and demonstrate its utility by successfully discriminating between the same four regional biotypes of I. glandulifera from within the UK, which differ in their susceptibility to the biological control agent P. komarovii var. glanduliferae
Having achieved our primary goal of providing a practical and robust method for generating high-quality MALDI-TOF MS spectra from seeds, we investigated whether this could be used for discrimination between the above regional biotypes

Summary

Introduction

We have recently developed a simple, rapid, and relatively-cheap method for matrix-assisted laserdesorption and ionisation time-of-flight mass spectroscopy (MALDI-TOF MS) sample preparation that is applicable to plant material (in addition to microbial and insect material), and have used this to discriminate between closelyrelated Impatiens species and between regional biotypes of the invasive weed Impatiens glandulifera (commonly known as Himalayan balsam) using leaf samples. CABI initiated a biological control programme against I. glandulifera in 2006, and conducted surveys for natural enemies throughout the weed’s native range [7] Consequent to these surveys, a rust fungus, identified as Puccinia komarovii var. Reeve and Pollard Plant Methods (2019) 15:25 of damage it inflicts on I. glandulifera in the field As part of this biological control programme, extensive studies were carried out using a strain of the rust (IMI 398718) from Kullu Valley, Himachal Pradesh, India. The host-range studies assessed the susceptibility of 74 plant species to the rust, and the test-plant list included native, ornamental, and economically-important European plant species [9, 10] From these studies, the rust P. komarovii var. The rust P. komarovii var. glanduliferae was found to be highly host-specific

Objectives

Methods

Results

Discussion

Conclusion