Expression of exogenous dsRNA by Lecanicillium attenuatum enhances its virulence to Dialeurodes citri

Abstract

The results indicate that this method, which uses tens of thousands of hyphae to inject dsRNA to improve the virulence of transgenic fungi, can play a greater role in the prevention and control of pests in the future. © 2018 Society of Chemical Industry.

Strategies for the production of dsRNA biocontrols as alternatives to chemical pesticides

“…Dialeurodes citri is a citrus fruit pest which causes soot disease in citrus crops in many locations globally. Currently, only chemical pesticides are used to control D. citri ( Yu et al, 2019 ) . L. attenuatum , an entomopathogenic fungus which causes decreased population size in D. citri , has been explored as a natural alternative to chemical pesticides.…”

“…However, application of the wild type fungi only results in low mortality rates and therefore, it has not been successfully implemented as a biological agent. Different strains of L. attenuatum were developed to produce dsRNA specific to four of the C. citri immune responses, under the control of a constitutive promoter PtrpC ( Yu et al, 2019 ). The fungi produced hpRNA which was subsequently processed by the fungal RNAi machinery into siRNAs.…”

“…Although siRNAs are not usually effective for RNAi in insects (typically dsRNA >80 bp is required for entry via the midgut ( Huvenne and Smagghe, 2010 ; Yu et al, 2013 )), in this case the delivery method is not through ingestion but via a fungal host. RNAi activity was detected by day three of infection with live fungi producing hpRNA, and mortality was slightly increased in two of the targets ( Yu et al, 2019 ).…”

Immune-Related Genes of Megalurothrips usitatus (Bagrall) Against Beauveria brongniartii and Akanthomyces attenuatus Identified Using RNA Sequencing

“…Beauveria spp. are the most widely used biological control agent against many pests, and Akanthomyces attenuatus has been extensively studied in the control of pests, such as mosquitoes, aphids, whitefly, and thrips (Montalva et al, 2017 ; Yu et al, 2019 ; Amobonye et al, 2020 ; Woo et al, 2020 ). Yang et al ( 2020 ) found that conidial suspensions, as well as crude protein extracts of Beauveria brongniartii isolate SB010 and A. attenuatus isolate SCAUDCL-53, were pathogenic against M. usitatus .…”

Integration of dsRNA against host immune response genes augments the virulence of transgenic Metarhizium robertsii strains in insect pest species

“…For example, transgenic Metarhizium acridum strains expressing dsRNAs that target genes encoding the α and β subunits of F 1 F 0 ‐ATP synthase in Locusta migratoria displayed a 3.7‐fold increase in virulence (LC 50 ) compared with that of the wild‐type strain (Hu and Xia 2019). Moreover, transgenic Lecanicillium attenuatum expressing dsRNAs that target the genes encoding for prophenoloxidase‐activating factor and lysozymes in Dialeurodes citri exhibited a 3.62‐ and a 2.91‐fold increase in virulence (LC 50 ) compared with that of the wild‐type strain, respectively (Yu et al ., 2019). These studies demonstrated that transgenic fungi expressing dsRNAs specific to insect immune response‐associated genes serve as potential vectors to facilitate the application of dsRNAs for pest control in the field.…”