[i]Spodoptera frugiperda[/i] immune response to the nematobacterial complex [i]Steinernema carpocapsae-Xenorhabdus nematophila[/i]. Conférences Jacques Monod "Immunologie Intégrative des Insectes : Contrôle des Infections

Bigourdan, Audrey

Duvic, Bernard

Girard, Pierre-Alain

Huot, Louise

NEGRE, Nicolas

Pages, Sylvie

English

Archive Ouverte en Sciences de l'Information et de la Communication

HAL Id: hal-02166484
https://hal.archives-ouvertes.fr/hal-02166484
Submitted on 5 Jun 2020
HAL is a multi-disciplinary open access
archive for the deposit and dissemination of sci-
entific research documents, whether they are pub-
lished or not. The documents may come from
teaching and research institutions in France or
abroad, or from public or private research centers.
L’archive ouverte pluridisciplinaire HAL, est
destinée au dépôt et à la diffusion de documents
scientifiques de niveau recherche, publiés ou non,
émanant des établissements d’enseignement et de
recherche français ou étrangers, des laboratoires
publics ou privés.
Spodoptera frugiperda immune response to the
nematobacterial complex Steinernema
carpocapsae-Xenorhabdus nematophila
Louise Huot, Audrey Bigourdan, Pierre-Alain Girard, Sylvie Pages, Nicolas
Negre, Bernard Duvic
To cite this version:
Louise Huot, Audrey Bigourdan, Pierre-Alain Girard, Sylvie Pages, Nicolas Negre, et al.. Spodoptera
frugiperda immune response to the nematobacterial complex Steinernema carpocapsae-Xenorhabdus
nematophila. Conférences Jacques Monod ”Immunologie Intégrative des Insectes : Contrôle des In-
fections”, Jun 2019, Roscoff, France. ￿hal-02166484￿
Louise Huot, Audrey Bigourdan, Pierre-Alain Girard, Sylvie Pagès, Nicolas Nègre, Bernard Duvic 
 
 
DGIMI, INRA, University of Montpellier, France 
Spodoptera frugiperda immune response to the nematobacterial complex 
Steinernema carpocapsae-Xenorhabdus nematophila 
   
In both tissues, the immune responses take place 
between 0 and 10 h post-infestation. Despite little 
variations, they then remain induced until the end 
of the infectious process. 
Post-infestation temporal evolution of representative immune genes’ induction 
levels in the hemocytes and in the fat body 
  
Relative RT-qPCR quantifications were performed on triplicate samples with the Rpl32 housekeeping gene as 
reference. Differential expression was assessed with  Student t tests and black dots indicate genes with 
insignificant variations (p-value > 0.05). Clustering analyses are based on Pearson correlation coefficients. 
 
The S. carpocapsae-X. nematophila nematobacterial complex (NBC) is a natural symbiotic association between a 
nematode and a bacterium that is pathogenic for insects. The nematode infests its hosts via the intestinal tract and 
releases its bacterial symbiont in their hemocoel. The bacterium then grows extracellularly and participates in host 
killing by secreting virulence factors. Due to its originality and use in biocontrol, this NBC’s interactions with insects 
have been extensively studied. However, still little is known about the insects’ immune responses to the dual 
infection. Here, we provide a topologic and transcriptional analysis of the immune response of a lepidopteran 
model, Spodoptera frugiperda, to the NBC. Our main goals are (i) to describe the structure of the immune response 
that is induced after infestation and (ii) to identify candidate genes that are likely to interact with each NBC partner. 
Parasitism 
Symbiosis 
S. carpocapsae 
Nematode 
X. nematophila 
Gram negative bacterium 
Death in 
~ 24 h 
Temporal  RT-qPCR analysis of the immune 
responses 2 
Despite only weak and variable immune responses 
are induced in the midgut (not shown), all the main 
components of the hemocytes’ and fat body’s 
immunities are strongly induced at 15 hpi. The 
hemocytes’ response is particularly diversified at 
the humoral as well as at the cellular level whereas 
the fat body’s response is more targeted against 
Gram negative bacteria.  
1 RNAseq on immunocompetent tissues 
Discovery of candidate new immune genes 4 
The GBO cluster is predicted to encode secreted 
proteins with homologs in lepidopterans and 
bacteria. We hypothesize they were acquired by 
HGT from bacteria and highjacked to perform 
antibacterial immune functions. 
  
The Unk cluster is predicted to encode secreted 
peptides and small proteins that we hypothesize 
to be anti-nematode immune factors only found 
in the genus Spodoptera.  
v 
In the two tissues, X. nematophila is the main inducer of most of the selected genes, and 
especially of the well known antibacterial ones. However, S. carpocasae is the main inducer 
of some melanization and encapsulation-related genes as well as of most lectins, which are 
candidate immune receptors. Overall, these results suggest that the hemocytes and the fat 
body both respond by adapted ways to each NBC partner. 
3 RT-qPCR dissection of the immune responses 
Conclusion & Outlook 
Introduction 
Methodology & Results 
Here, we show that the hemocytes’ and fat 
body’s immunities are strongly induced after 
infestation by the NBC. The immune responses 
are diversified and correspond to mixes of 
bacterium- and nematode-induced ones. They 
involve many genes that could take part in the 
response to each partner, including the Unk and 
GBO ones, which had never been reported in 
other interaction models. At this stage, our main 
objectives are (i) to characterize the interactions 
of these genes with the NBC and (ii) to improve 
our analysis of the midgut immune response.   
(A) 
Imd 
Toll 
GNBP 
PGRP 
AMP 
Lysozyme 
(B) 
Serine 
protease 
Serpin 
Melanization 
-related 
(C) 
Krueppel-like 
Scavenger 
Integrin 
Tetraspanin 
Immunoglobulin 
Phagocytosis 
Coagulation 
(D) 
JNK 
Cytokine 
Jak/Stat 
TGF-β 
Insulin 
Lectin 
IMPI-like 
ROS-related 
Unknown 
Signaling 
Immune genes expression variations in the hemocytes and in the fat body at a 
middle time point of 15 h post infestation 
  
Triplicate RNAseq data were analyzed with Kallisto/Sleuth using tresholds of 0.01 for p-values, -1 and +1 for log2 
fold changes and 5 for pseudocount means. The immune genes were identified by homology and classified as 
(A) antimicrobial immunity-related, (B) melanization-related, (C) cellular immunity-related and (D) 
« undeterminated ». Black dots indicate genes with insignificant variation. HC : Hemocytes, FB : Fat body. 
Log2 fold change 
Induction levels of representative immune genes after independent injections of the whole nematobacterial complex and of each partner 
  
The tissues were collected 13 h after injection with either 10 nematobacterial complexes (NBC), 10 axenic S. carpocapsae (S.c.) or 200 X. nematophila symbionts (X.n.). RT-qPCR relative quantifications 
were performed on triplicate samples with the Rpl32 housekeeping gene as reference. Statistical differences between treatments were assessed by one-way ANOVA followed by Tukey tests. Top 
panels : antimicrobial immunity-related  genes . Bottom panel s: melanization-related , cellular immunity-related  (Hemocytes only) and « undeterminated  » genes.  
 
Hemocytes Fat body 
-2 
2 
6 
10 
14 
Lo
g2
 f
o
ld
 c
h
an
ge
 
-2 
2 
6 
10 
14 
Lo
g2
 f
o
ld
 c
h
an
ge
 
-2 
2 
6 
10 
14 
Lo
g2
 f
o
ld
 c
h
an
ge
 
-2 
2 
6 
10 
14 
Lo
g2
 f
o
ld
 c
h
an
ge
 
a 
b 
a 
ab 
a 
b 
a 
b 
a 
a 
b 
c 
a 
b 
c 
a 
b 
c 
a 
a 
b 
a 
b 
a 
a 
b 
c 
a 
b 
a 
a 
b 
a 
ab 
a 
b 
a 
a 
b 
ab 
a 
b 
-2 
2 
6 
10 
14 
Lo
g2
 f
o
ld
 c
h
an
ge
 
-2 
2 
6 
10 
14 
Lo
g2
 f
o
lc
 c
h
an
ge
 
-2 
2 
6 
10 
14 
Lo
g2
 f
o
ld
 c
h
an
ge
 
a 
b 
a 
a a 
b 
a 
b 
b 
b b 
a 
a 
a 
b b 
a 
a 
a 
a 
b 
b b 
a 
The Unk cluster 
Unk5 
Unk4 
Unk3 
Unk2 
Unk1 
Tamo 
0 
4 
8 
12 
16 
Unk1 Unk2 Unk3 Unk4 Unk5 
Lo
g2
  f
o
ld
 c
h
an
ge
 
-5 
0 
5 
10 
15 
G
Lo
g2
 …
 5h 
10h 
15h 
20h 
The GBO cluster 
Spod-x-tox 
Def-like 3 
Gal 
GBO2 
GBO3 
GBO1 
0 
4 
8 
12 
16 
GBO1 GBO3 
Lo
g2
 f
o
ld
 c
h
an
ge
 
-5 
0 
5 
10 
15 
G
Lo
g2
 …
 5h 
10h 
15h 
20h 
Hemocytes Fat body 
-2 2 
6 10 
14 
Re… G  
NBC 
S.c. 
X.n. 
Log2 fold change 
-10 10 0 
5 h 10 h 15 h 20 h 
Hemocytes Fat body 
5 h 10 h 15 h 20 h 
Coagulation Phagocytosis 
Nodulation 
Encapsulation 
AMP 
 
Lysozymes, 
LLP, AMP 
AMP 
Unk, IMPI 
Toll 
Imd 
Melanization 
Unk 
Lectins 
IMPI 
IMPI 
Lectins 
Tissue-repair ? 
GBO 
? 
? 
Imd 
Toll 
In the longer term, our goal is to get an 
accurate picture of the dialogue that takes 
place between the three members of the 
interaction in order to identify the precise 
causes of the immune system’s failure. 
-2 
2 
6 
10 
14 
GBO1 GBO3 
Lo
g2
 f
o
ld
 c
h
an
ge
 
-2 
2 
6 
10 
14 
Rel… GB
NBC 
S.c. 
X.n. 
a 
b 
a 
a 
b 
c 
-2 
2 
6 
10 
14 
Unk1 Unk2 Unk3 Unk4 Unk5 
Lo
g2
 f
o
ld
 c
h
an
ge
 
-2 
2 
6 
10 
14 
Rel… GB
NBC 
S.c. 
X.n. 
a a 
a a 
a a 
a a 
b b 
b b 


Spodoptera frugiperda immune response to the nematobacterial complex Steinernema carpocapsae-Xenorhabdus nematophila

https://hal.archives-ouvertes.fr/hal-02166484/document

Spodoptera frugiperda immune response to the nematobacterial complex Steinernema carpocapsae-Xenorhabdus nematophila

Abstract

Similar works

Full text

Available Versions

Archive Ouverte en Sciences de l'Information et de la Communication