Species-Specific Impact of Fusarium Infection on the Root and Shoot Characteristics of Asparagus.

Roxana Djalali Farahani-Kofoet,Rita Zrenner,Rita Grosch,Jan Graefe,Katja Witzel

doi:10.3390/pathogens9060509

Abstract

Soil-borne pathogens can have considerable detrimental effects on asparagus (Asparagus officinalis) growth and production, notably caused by the Fusarium species F. oxysporum f.sp. asparagi, F. proliferatum and F. redolens. In this study, their species-specific impact regarding disease severity and root morphological traits was analysed. Additionally, various isolates were characterised based on in vitro physiological activities and on protein extracts using matrix-assisted laser desorption ionisation time-of-flight mass spectrometry (MALDI-TOF MS). The response of two asparagus cultivars to the different Fusarium species was evaluated by inoculating experiments. Differences in aggressiveness were observed between Fusarium species and their isolates on roots, while no clear disease symptoms became visible in ferns eight weeks after inoculation. F. redolens isolates Fred1 and Fred2 were the most aggressive strains followed by the moderate aggressive F. proliferatum and the less and almost non-aggressive F. oxysporum isolates, based on the severity of disease symptoms. Fungal DNA in stem bases and a significant induction of pathogenesis-related gene expression was detectable in both asparagus cultivars. A significant negative impact of the pathogens on the root characteristics total root length, volume, and surface area was detected for each isolate tested, with Fred1 causing the strongest effects. No significant differences between the tested asparagus cultivars were observed.

Highlights

Asparagus officinalis L. is a perennial horticultural crop grown over a wide range of soils and under various climatic conditions
A gradual decline in productivity and the growth of asparagus plants can be observed within the growing period due to the ‘asparagus decline’ syndrome [1] mainly associated with the elevated soil densities of pathogenic Fusarium spp
Inwith order to analyse whether thethe efficacy in degrading plant-derived correlated disease severity caused by Fusarium spp. isolates, we tested theircarbon ability sources to utiliseisdifferent with disease severity caused by the isolates, we tested their ability to utilise plant-derived polysaccharides

Summary

Introduction

Asparagus officinalis L. is a perennial horticultural crop grown over a wide range of soils and under various climatic conditions. It can remain profitable for about 10 years in temperate regions that have long growing seasons. A gradual decline in productivity and the growth of asparagus plants can be observed within the growing period due to the ‘asparagus decline’ syndrome [1] mainly associated with the elevated soil densities of pathogenic Fusarium spp. Asparagi and Fusarium proliferatum (Matsush.) are considered the main pathogenic species causing asparagus rots worldwide [3,4,5,6,7] and have been studied the most.

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