Multitrophic interaction in the rhizosphere of maize: root feeding of Western corn rootworm larvae alters the microbial community composition.

Flavia Dematheis,Cecilia Flocco,Ute Zimmerling,Stefan Vidal,Kornelia Smalla,Benedikt Kurtz,Siegfried Kropf,Jack Anthony Gilbert

doi:10.1371/journal.pone.0037288

Flavia Dematheis, Cecilia Flocco + Show 6 more

Open Access

https://doi.org/10.1371/journal.pone.0037288

Copy DOI

Abstract

BackgroundLarvae of the Western Corn Rootworm (WCR) feeding on maize roots cause heavy economical losses in the US and in Europe. New or adapted pest management strategies urgently require a better understanding of the multitrophic interaction in the rhizosphere. This study aimed to investigate the effect of WCR root feeding on the microbial communities colonizing the maize rhizosphere.Methodology/Principal FindingsIn a greenhouse experiment, maize lines KWS13, KWS14, KWS15 and MON88017 were grown in three different soil types in presence and in absence of WCR larvae. Bacterial and fungal community structures were analyzed by denaturing gradient gel electrophoresis (DGGE) of the16S rRNA gene and ITS fragments, PCR amplified from the total rhizosphere community DNA. DGGE bands with increased intensity were excised from the gel, cloned and sequenced in order to identify specific bacteria responding to WCR larval feeding. DGGE fingerprints showed that the soil type and the maize line influenced the fungal and bacterial communities inhabiting the maize rhizosphere. WCR larval feeding affected the rhiyosphere microbial populations in a soil type and maize line dependent manner. DGGE band sequencing revealed an increased abundance of Acinetobacter calcoaceticus in the rhizosphere of several maize lines in all soil types upon WCR larval feeding.Conclusion/SignificanceThe effects of both rhizosphere and WCR larval feeding seemed to be stronger on bacterial communities than on fungi. Bacterial and fungal community shifts in response to larval feeding were most likely due to changes of root exudation patterns. The increased abundance of A. calcoaceticus suggested that phenolic compounds were released upon WCR wounding.

Highlights

Diabrotica virgifera virgifera (Western Corn Rootworm, WCR; Coleoptera: Chrysomelidae), is considered one of the most destructive agricultural pests of maize (Zea mays L.) in the US [1]
UPGMA dendrograms of fungal and bacterial communities showed that the different soil types distinctly clustered apart (Fig. 1A and B) and permutation testing confirmed that the soil type dependent differences were significant (P,0.04)
This is the first study on the effects of the WCR maize root feeding on both bacterial and fungal communities colonizing the maize rhizosphere

Summary

Introduction

Diabrotica virgifera virgifera (Western Corn Rootworm, WCR; Coleoptera: Chrysomelidae), is considered one of the most destructive agricultural pests of maize (Zea mays L.) in the US [1]. The larvae hatch in the soil and start to feed on roots, preferably of maize plants. They pass through three larval stages before pupating in the soil. Several American WCR populations have lost ovipositional fidelity to maize fields [13] bypassing the corn-soybean crop rotation strategy. This pest species showed resistances against insecticides [14] and Bt-transgenic plants expressing CryBb1 [15,16]. Larvae of the Western Corn Rootworm (WCR) feeding on maize roots cause heavy economical losses in the US and in Europe. This study aimed to investigate the effect of WCR root feeding on the microbial communities colonizing the maize rhizosphere

Objectives

Methods

Results

Conclusion