Comprehensive insights into host‐pathogen interaction between brown planthopper and a fungal entomopathogen by dual RNA sequencing

Abstract

BACKGROUND The brown planthopper (BPH) is one of the most destructive pests of rice, causing tremendous yield and economic losses every year. The fungal entomopathogen Metarhizium anisopliae was previously proved to have great potential for BPH biocontrol. Genome‐wide insight into the insect‐fungus interaction is crucial for genetic improvement of M. anisopliae to enhance its virulence to BPH but still has been poorly explored. RESULTS Using dual RNA‐seq approach, we present here a global view of host and fungal gene expressions in BPH adults during the fungal infection. The results revealed that BPH could initiate strong defense responses against the fungal attack by upregulating the expressions of a large number of genes, including genes involved in cuticle formation, immune response, cell detoxification and biomacromolecule metabolism. Correspondingly, the fungal entomopathogen could induce a series of genes to infect and modulate BPH, including genes involved in fungal penetration, invasive growth, stress resistance and virulence. Three host defense‐related genes (NlPCE4, NlPOD1 and NlCYP4DE1) were chosen for further function analysis. RNAi‐mediated knockdown of NlPCE4 caused a significant decrease in BPH survival, but no obvious effects on the survival rates were detected by the suppression of NlPOD1 and NlCYP4DE1. Combination of dsRNA injection and fungal infection could significantly enhance the BPH‐killing speed, as synergistic mortalities were observed in co‐treatments of RNAi and M. anisopliae infection. CONCLUSION Our study provides a comprehensive insight into molecular mechanisms of host‐pathogen interaction between BPH and M. anisopliae and contributes to future development of new efficient biocontrol strategies for BPH biocontrol.

Topical Fungal Infection Induces Shifts in the Gut Microbiota Structure of Brown Planthopper, Nilaparvata lugens (Homoptera: Delphacidae)

“…Aerial conidia of Ma456 produced on PDA plates were washed with 0.02% Tween 80 solution and adjusted to a final concentration of 1 × 10 8 conidia/mL using a hemocytometer. BPH nymphs (24 h after molting at the fifth instar) were prepared for topical fungal infection following previous protocol [ 14 ]. Briefly, batches of 30–40 nymphs on 3-cm high rice seedlings in uncaged cups were sprayed with 1 mL conidial suspension using a handheld micro sprayer.…”

“…In the insects–fungi interaction model, immune aspects in insects have been extensively studied in individuals or tissues (hemolymph and fat body) that are traditionally attributed to immune responses [ 10 , 11 , 12 ]. A large number of immune-related genes have been found to be up-regulated in the whole BPH body after topical infection with M. anisopliae based on comparative transcriptomic analysis [ 13 , 14 ]. Nowadays, accumulating studies have revealed that the gut also plays an important role in shaping insect immunity.…”

“…In this study, we aim to investigate how gut microbitoa in BPH respond to topical infection with a fungal entomopathogen, M. anisopliae , which has great potential for BPH biocontrol [ 3 , 14 ]. Building on the literature and preliminary research, we hypothesized that the gut microbial community homeostasis would be disturbed after fungal infection by topical route in BPH.…”

Ecología química y genes involucrados en la interacción entre insectos tenebriónidos y hongos entomopatógenos

“…El metabolismo de las proteínas fúngicas (tanto las rutas anabólicas como las catabólicas) también se encontró aumentado, lo que indica que existe una alta tasa de intercambio de proteínas. Estos hallazgos coinciden con los encontrados por Wang et al (2021) y puede estar relacionado con el hecho de que el patógeno se está adaptando para invadir al huésped y, por lo tanto, necesita redirigir su maquinaria proteica hacia el proceso infectivo. Además, los procesos redox y la respuesta al estrés mostraron altos niveles de expresión, lo que sugiere que el patógeno fúngico está tratando de superar las barreras del sistema de defensa inmune de T. castaneum.…”

“…Recientemente, Wang et al (2021) realizaron un estudio de RNA-seq dual en Nilaparvata lugens asperjados con una suspensión de conidios de M. anisopliae. Estos autores informaron que 2.773 y 3.895 genes fúngicos se expresaron en los adultos infectados con hongos a las 48 hs y 72 hs después del tratamiento, respectivamente, lo que representa aproximadamente el 0,01 % del total de lecturas encontradas.…”