Table 1 Candidate TEs located nearby immune-related genes. TE length is indicated as full-length (FL) or truncated (T). In the case of truncated elements, whether the insertion is a solo LTR, a TIR or 5′ truncated (5′) is also indicated. NS, not significant. NA, not analyzed

FBti0019457

pogo (DNA)

3R: 29760415

1146 bp (T: TIR)

Fst, nSL [52]

kay (4434 bp 5′)

Expression. Component of the JNK pathway, essential for antimicrobial peptide release [56, 57]. Upregulated in imd and bsk mutant LPS-induced S2 cells, and downregulated in Rel mutants [58]. Upregulated in larvae infected with P. entomophila (gram-negative) [46], and after 4 h of infection with P. entomophila [41].

FBti0020046

Doc (non-LTR)

3 L: 6040416

2305 bp (T: 5′)

Allele age [59]

Jon65Aiv (281 bp 3′)

Expression. Upregulated after septic injury with mixed bacteria: M. luteus (gram-positive) and E. coli (gram-negative) [60]. Downregulated after 4 h of infection with P. entomophila [41]. Downregulated after oral infection with the avirulent gacA P. entomophila [61].

FBti0020057

BS (non-LTR)

3 L: 7130011

126 bp (T: 5′)

H12, nSL [52]

CG15829 (338 bp 3′)

Expression. Upregulated after infection by septic injury with mixed bacteria (gram-positive and gram-negative), and regulated by Rel [60]. Upregulated after 4 h of infection with P. entomophila [41]. Upregulated in transgenic flies expressing a SINV replicon (alphavirus) [62].

CG8628 (739 bp 5′)

Expression. Upregulated in microbiota associated flies vs. germ free flies [63], after infection with several pathogens (gram-positive and gram-negative, fungi, protozoa) [64], and downregulated after 4 h of infection with P. entomophila [41].

FBti0018883

Burdock (LTR)

2R: 9151357

6413 bp (T: LTR)

NS

CG8008 136 bp 3′)

Expression. Induced by LPS (gram-negative) in an IKK-dependent manner in S2 cell cultures [65]. Upregulated after E. coli (gram-negative) infection in S2 cells [66].

FBti0019381

Juan (non-LTR)

3R: 15132112

2995 bp (T: 5′)

NS

CG42788 (180 bp 5′)

Expression. Downregulated in response to P. rettgeri (gram-negative) infection in females [67].

FBti0019602

Juan (non-LTR)

X: 8031495

4249 bp (FL)

NS

CG2233 (12 bp 3′)

Expression. Downregulated in PEBP1 mutant L3 larvae, which are more resistant to M. luteus (gram-positive) and E. coli (gram-negative) infection [68]. Latitudinal expression differentiation after infection with E. coli and M. luteus mix in temperate vs. tropical populations [69].

FBti0061105

G5 (non-LTR)

2R: 7317828

51 bp (T: 5′)

NS

Dscam1 (46 bp 3′)

Expression. Required in hemocytes for efficient phagocytosis and binds to E. coli (gram-negative) [70].

FBti0062242

BS (non-LTR)

3R: 16041234

102 bp (T: 5′)

NS

Pnr (3′UTR)

Expression. pnr is a modifier of the Toll pathway and RNAi mutants show Imd pathway hyperactivation when infected with E. cloacae (gram-negative) and M. luteus and E. faecalis (gram-positive) [71].

tdn4

BS (non-LTR)

2R: 18807871

800 bp (T: 5′)

NA

CG15096 (479 bp 3′)

Expression. Downregulated in Oregon R and Rel-mutant flies with microbiota compared to axenic flies [72], and after P. entomophila infection [41].

tdn8

Transpac (LTR)

3 L: 12863675

5500 bp (FL)

NA

CG10943 (816 bp 5′)

Expression. Upregulated in Oregon R and Rel-mutant flies with microbiota compared to axenic flies [72], 24 h after infection with O. muscaedomesticae (protozoan) [64], and after P. entomophila infection [41].

tdn17

pogo (DNA)

X: 21399382

2067 bp (FL)

NA

lcs (2,067 bp 5′)

Expression. Involved in virus response, downregulated in males infected with sigma virus [73]. Upregulated in young fly guts [72].

FBti0019386

invader4 (LTR)

3R: 16189464

347 bp (T: solo LTR)

CL test, TajimaD, Phenotypic [74]

Bin1 (5′UTR)

Survival. Mutant larvae are more sensitive to fungal A. fumigatus (fungi) infection [75].

FBti0019985

roo (LTR)

2R: 9871090

434 bp (T: solo LTR)

TajimaD, iHS, H12, Phenotypic [76]

cbx (first intron)

Survival. Mutant flies are more sensitive to S. aureus (gram-positive) septic infection, but not to S. typhimurium (gram-negative) infection [77].

FBti0019564

mdg1 (LTR)

X: 3785867

189 bp (T: LTR)

TajimaD [78]

tlk (intron)

Survival. Involved in antimicrobial humoral response to gram-negative [57]. tlk knockdown, together with other five genes knocked-down, reduces phagocytosis of E. coli (gram-negative) and S. aureus (gram-positive) in S2 cells [79].

FBti0020119

S (DNA)

3 L: 15554974

1732 bp (FL)

NS

AGO2 (first intron)

Survival. Involved in defense response to virus infections [80, 81], and interacts with Imd pathway proteins during gram-negative infection [82].

FBti0020137

S (DNA)

3 L: 17799864

1732 bp (FL)

NS

NUCB1 (first intron)

Survival. Mutants are more resistant to V. cholerae (gram-negative) oral infection [83].

FBti0061506

1360 (DNA)

2 L: 17432071

48 bp (T: TIR)

iHS [52]

Dif (first intron)

Survival and expression. Transcription factor involved in defense response to fungus and gram-positive bacteria and mediates Toll pathway activation [84,85,86,87,88]. Dif mutants are susceptible to fungi and gram-positive bacterial infection [88, 89]. Upregulated in guts from P. entomophila infected flies [41].

FBti0018877

BS (non-LTR)

2R: 9945496

131 bp (T: 5′)

NS

Mef2 (first intron)

Survival and expression. Adult Mef2 mutant males are more sensitive to E. cloacae (gram-negative) and M. marinum (gram-positive) septic infection [90]. Upregulated after 4 h of infection with P. entomophila (gram-negative) [41].

FBti0018868

297 (LTR)

2R: 23877783

414 bp (T: LTR)

NS

TM4SF (1 bp 5′)

A tetraspanin transmembrane protein, which modulate immune-signaling in Drosophila [53].

ken (340 bp 3′)

JAK-STAT. Member of JAK-STAT pathway [91]. JAK-STAT pathway plays a role in immune response in D. melanogaster [54].