Articles
Non transformative plant-mediated delivery of dsRNAs targeting the leafhopper Scaphoideus titanus, vector of grapevine flavescence dorée phytoplasmas
Article number
1454_44
Pages
313 – 320
Language
English
Abstract
RNA interference (RNAi) has demonstrated its potential as control strategy of plant pests.
The exogenous application of double-stranded RNAs (dsRNAs) with insecticidal activity may work well in protecting plants from chewing insects.
Conversely, plant-mediated delivery of dsRNAs is still challenging for sap-sucking insects.
It has been shown that, although quite laborious, trunk injection and petiole absorption can mediate systemic uptake of dsRNAs in plants by xylem transport.
This opens novel perspectives not only for the control of xylem restricted insects but also for phloem feeders, as electropenetrography showed that several phloem-feeders may feed on mesophyll and xylem too.
In this work, grapevine-mediated dsRNA delivery via petiole absorption was used to silence four targets of the leafhopper Scaphoideus titanus, vector of flavescence dorée phytoplasmas.
Candidate genes were selected as either involved in phytoplasma transmission or able to significantly reduce S. titanus survival once silenced.
Detached Vitis vinifera leaves were inserted in 1.5-mL tubes containing 200 μL of diluted dsRNAs (20 μg leaf‑1) and used to feed S. titanus for 48 h.
Insects were then transferred on potted grapevines for two weeks to evaluate survival probability, prior to gene expression analysis. dsRNAs were successfully absorbed and translocated from the petiole throughout the grapevine treated leaf.
Although silencing efficiency achieved via insect microinjection is more effective, leafhoppers fed on treated leaves showed a decreasing expression of transcripts indicating that at least a partial uptake of dsRNAs occurred in S. titanus. RNAi-based solutions are still not applicable to crop protection in the EU, but this work provides an important proof of concept: dsRNAs absorbed by plants can be applied to silence target genes of phloem-feeders.
The exogenous application of double-stranded RNAs (dsRNAs) with insecticidal activity may work well in protecting plants from chewing insects.
Conversely, plant-mediated delivery of dsRNAs is still challenging for sap-sucking insects.
It has been shown that, although quite laborious, trunk injection and petiole absorption can mediate systemic uptake of dsRNAs in plants by xylem transport.
This opens novel perspectives not only for the control of xylem restricted insects but also for phloem feeders, as electropenetrography showed that several phloem-feeders may feed on mesophyll and xylem too.
In this work, grapevine-mediated dsRNA delivery via petiole absorption was used to silence four targets of the leafhopper Scaphoideus titanus, vector of flavescence dorée phytoplasmas.
Candidate genes were selected as either involved in phytoplasma transmission or able to significantly reduce S. titanus survival once silenced.
Detached Vitis vinifera leaves were inserted in 1.5-mL tubes containing 200 μL of diluted dsRNAs (20 μg leaf‑1) and used to feed S. titanus for 48 h.
Insects were then transferred on potted grapevines for two weeks to evaluate survival probability, prior to gene expression analysis. dsRNAs were successfully absorbed and translocated from the petiole throughout the grapevine treated leaf.
Although silencing efficiency achieved via insect microinjection is more effective, leafhoppers fed on treated leaves showed a decreasing expression of transcripts indicating that at least a partial uptake of dsRNAs occurred in S. titanus. RNAi-based solutions are still not applicable to crop protection in the EU, but this work provides an important proof of concept: dsRNAs absorbed by plants can be applied to silence target genes of phloem-feeders.
Authors
F. Canuto, C. Marzachì, D. Bosco, L. Galetto
Keywords
RNAi, phloem-feeders, insect vectors, Vitis vinifera
Groups involved
- Division Plant Genetic Resources, Breeding and Biotechnology
- Working Group Genetic Transformation and Gene Editing
- Working Group Horticultural Biotechnology and Breeding
- Division Ornamental Plants
- Division Vegetables, Roots and Tubers
- Division Temperate Tree Fruits
- Division Vine and Berry Fruits
- Division Horticulture for Development
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