RNA Interference Suppression of v-ATPase B and Juvenile Hormone Binding Protein Genes Through Topically Applied dsRNA on Tomato Leaves: Developing Biopesticides to Control the South American Pinworm, Tuta absoluta (Lepidoptera: Gelechiidae)

Abstract

The South American pinworm Tuta absoluta (Meyrick) (Family: Gelechiidae) is one of the most devastating lepidopteran pests in the developing countries of South America, Africa, and Asia. This pest is classified as the most serious threat for tomato production worldwide. In the present study, we analyzed RNAi-mediated control through exogenously applied dsRNA delivery on tomato. The dsRNA treatments were made to target the juvenile hormone binding protein and the v-ATPase B. Both mRNA targets were cloned, validated by sequencing, and used to produce each dsRNA. After treatments the relative transcript expression was analyzed using qRTPCR to assess to efficacy of RNAi. A leaf-dip assay was used to provide late 2nd instar larvae three feeding access periods: 24, 48, and 72 h, to evaluate the effect of gene silencing of each target. Larvae were fed tomato leaves coated with five different RNAi concentrations (10, 20, 30, 40, and 50 micrograms/centimeter-squared), that suppressed two genes (juvenile hormone protein, JHBP, and vacuolar-type adenosine triphosphatase enzyme, v-ATPase). Treatments with dsRNA showed a significant increase in mortality at 24, 48, and 72 h after ingestion (P < 0.01, α = 0.05), along with reduced leaf damage, and increased feeding deterrence. The results suggest that these two RNAi products may provide a suitable treatment for control of this and other lepidopteran pests.

Effect of silencing Bemisia tabaci TLR3 and TOB1 on fitness and begomovirus transmission

“…Feeding on transgenic plants expressing dsRNA showed a down-regulation of around 90% in B. tabaci aquaporin (AQP) mRNA level 24 hr post-feeding ( Raza et al., 2016 ). The difference in the level of silencing might be due to the variation in concentration of dsRNA, exposure period, target mRNA copies, delivery method, and the host’s defense mechanism ( Ramkumar et al., 2021 ).…”

Current Scenario of Exogenously Induced RNAi for Lepidopteran Agricultural Pest Control: From dsRNA Design to Topical Application

“…This lepidopteran, which feeds on mesophyll, was subjected to tests with RNAi of the genes: v-ATPase B (keeps the midgut lumen alkaline by increasing amino acid absorption) and JHBP (essential for development and reproductive maturation). Topical application on the leaf surface resulted in 70% of larval mortality for the two target genes [102]. The Asiatic rice borer (Chilo supressalis) is one of the world's main crop pests.…”

Current Scenario of Exogenously Induced RNAi for Lepidopteran Agricultural Pest Control: From dsRNA Design to Topical Application

“…This lepidopteran that feeds on the mesophyll was subjected to tests with RNAi, whose genes: v-ATPase B (keep the midgut lumen alkaline by increasing amino acid absorption) and JHBP (essential for development and reproductive maturation). Topical application on the leaf surface resulted in 70% of larval mortality for the two target genes [104].…”