Immune responses of Helicoverpa armigera to different kinds of pathogens

Abstract

BackgroundInsects react against pathogens through innate immunity. The cotton bollworm Helicoverpa armigera (H. armigera) is an important defoliator and an extremely destructive pest insect of many crops. The elucidation of the mechanism of the immune response of H. armigera to various pathogens can provide a theoretical basis for new approaches to biologically control this pest.ResultsFour kinds of pathogens Bacillus thuringiensis, Klebsiella pneumoniae, Candida albicans, and Autographa californica multiple nucleocapsid nucleopolyhedrovirus harbored green fluorescence protein and polyhedron (AcMNPV-GFP) were used to challenge the insect. The cellular and humoral immune responses to the pathogens were analyzed in the challenged H. armigera. The results show that in the five kinds of haemocytes, only granulocytes phagocytized the Gram-negative and Gram-positive bacteria and fungi. All haemocytes can be infected by AcMNPV. Fourteen immune-related genes including pattern recognition receptors (PRRs) such as peptidoglycan recognition proteins (HaPGRP and HaPGRP C) and Gram-Negative Bacteria-Binding Protein (HaGNBP), and antimicrobial peptides (AMPs) such as cecropin-1, 2 and 3 (HaCec-1, 2 and 3), lysozyme (HaLys), attacin (HaAtt), gallerimycin-like (HaGall), gloverin-like (HaGlo), moricin-like (HaMor), cobatoxin-like (HaCob), galiomicin-like (HaGali), and immune inducible protein (HaIip) appeared in different expression profiles to different pathogen infections. The transcripts of 13 immune related genes (except HaPGRPC) are obviously up-regulated by Gram-positive bacteria. HaCec-1 and 3, HaMor, HaAtt, HaLys, HaIip, HaPGRP and HaGNBP are greatly up-regulated after fungal infection. HaGNBP, HaCec-2, HaGall, HaGlo, HaMor, HaCob, HaGali obviously increased in Gram-negative bacterial infection. Only five genes, HaGNBP, HaCec-1, HaGali, HaGlo, and HaLys, are weakly up-regulated after viral infection. The AMP transcripts had higher expression levels than the PRR transcripts after the microbial challenge.ConclusionsThese data suggest that the granulocytes are the major phagocytes in H. armigera. All haemocytes can be infected by AcMNPV. The transcripts of 14 immune related genes have different expression patterns in H. armigera infected by different pathogens, which means that the immune-related genes may have different functions against various kinds of pathogens.

Insect natural products and processes: New treatments for human disease

“…AMPs and are commonly found in dipterans and lepidopterans and have, for example, been reported in Drosophila melanogaster, Aedes aegypti, Anopheles gambiae, Musca domestica, B. mori and Helicoverpa armigera as well as in vertebrates and parasitic nematodes (Lee et al, 1989;Bulet and Stocklin, 2005;Pillai et al, 2005;Jin et al, 2010;Wang et al, 2010). Often, as with D. melanogaster, B. mori and H. armigera, cecropin multifamily genes are present which are expressed at different times during development as well as in response to different pathogens (eg.…”

“…Often, as with D. melanogaster, B. mori and H. armigera, cecropin multifamily genes are present which are expressed at different times during development as well as in response to different pathogens (eg. Wang et al, 2010). In H. armigera, HaCec-1 and HaCec-3 are greatly up-regulated after fungal infection while HaCec-2 is up-regulated by bacteria (Slocinska et al, 2008;Wang et al, 2010).…”

“…Wang et al, 2010). In H. armigera, HaCec-1 and HaCec-3 are greatly up-regulated after fungal infection while HaCec-2 is up-regulated by bacteria (Slocinska et al, 2008;Wang et al, 2010). The cecropins are amongst the best studied AMPs and can kill Gram-positive and Gram-negative bacteria, fungi, protozoans, viruses, nematode worms as well as tumour cells (eg.…”

Identification and Phylogenetic Analyses of Two Isoforms of the Antibacterial Gene Diptericin from the Larval Tissue of Musca domestica (Diptera: Muscidae)

“…Many studies have described the enhancement of the insect immune system and induction of AMPs due to stress and/or bacterial challenge (26)(27)(28)(29)(30)(31)(32)(33). Elution and sequencing of the induced bands were performed and the generated sequences were blasted to defensin, diptericin, and attacin sequences.…”

Análise do transcriptoma de <i>Podalia orsilochus</i> (Cramer, 1775).

“…Contudo, apesar de um grande número de moléculas envolvidas em respostas de defesa ter sido identificado a partir de diferentes espécies de insetos, pouca informação sobre suas aplicações está disponível, assim como os fatores envolvidos nas suas atividades e o local específico de ação (TIAN et al, 2010;ZHAO et al, 2010).…”