The leafhopper Euscelidius variegatus Kirschbaum (Hemiptera: Cicadellidae) is a natural vector of the 'Candidatus Phytoplasma asteris' and a laboratory vector of the phytoplasma associated with grapevine Flavescence dorée. Previous studies indicated that RNA interference (RNAi) by dsRNA injection efficiently works in E. variegatus and that silencing of ATP synthase beta increases mortality and impairs phytoplasma multiplication. Here, a nearly complete female sterility was observed when ATP synthase beta was silenced. The sterility was associated with the absence of mature eggs in the ovaries. On the contrary, male genitalia morphology and sperm motility were similar to those observed in E. variegatus control specimens, treated with dsRNAs targeting green fluorescent protein (dsGFP). An over-expression of hexamerin (amino acid storage protein) and cathepsin L (lysosome proteinase) was observed at transcript and protein level in dsATP-injected females in comparison with dsGFP-injected insects, in both whole body and dissected ovary samples. Conversely, the expression of other genes known to be involved in oocyte development, namely vitellogenin, perilipin and digestive cystein protein, was not altered in dsATP-injected E. variegatus insects in comparison with dsGFP ones. Possible roles of ATP synthase beta, hexamerin and cathepsin L in oocyte and egg development are discussed. Insecticide treatments against vectors are the main strategies to counteract phytoplasma diseases, with negative impact on environment and public health. RNAi is a promising sustainable approach against insect vectors and ATP synthase beta could be a valid target gene, as its silencing, besides increasing mortality and reducing phytoplasma multiplication, induces female sterility.

Silencing of ATP synthase beta induces female sterility in a leafhopper phytoplasma vector

Galetto Luciana
;
Ripamonti Matteo;Abbà Simona;Rossi Marika;Bosco Domenico;Marzachì Cristina
2021

Abstract

The leafhopper Euscelidius variegatus Kirschbaum (Hemiptera: Cicadellidae) is a natural vector of the 'Candidatus Phytoplasma asteris' and a laboratory vector of the phytoplasma associated with grapevine Flavescence dorée. Previous studies indicated that RNA interference (RNAi) by dsRNA injection efficiently works in E. variegatus and that silencing of ATP synthase beta increases mortality and impairs phytoplasma multiplication. Here, a nearly complete female sterility was observed when ATP synthase beta was silenced. The sterility was associated with the absence of mature eggs in the ovaries. On the contrary, male genitalia morphology and sperm motility were similar to those observed in E. variegatus control specimens, treated with dsRNAs targeting green fluorescent protein (dsGFP). An over-expression of hexamerin (amino acid storage protein) and cathepsin L (lysosome proteinase) was observed at transcript and protein level in dsATP-injected females in comparison with dsGFP-injected insects, in both whole body and dissected ovary samples. Conversely, the expression of other genes known to be involved in oocyte development, namely vitellogenin, perilipin and digestive cystein protein, was not altered in dsATP-injected E. variegatus insects in comparison with dsGFP ones. Possible roles of ATP synthase beta, hexamerin and cathepsin L in oocyte and egg development are discussed. Insecticide treatments against vectors are the main strategies to counteract phytoplasma diseases, with negative impact on environment and public health. RNAi is a promising sustainable approach against insect vectors and ATP synthase beta could be a valid target gene, as its silencing, besides increasing mortality and reducing phytoplasma multiplication, induces female sterility.
2021
Istituto per la Protezione Sostenibile delle Piante - IPSP
Euscelidius variegatus
Hemiptera: Cicadellidae
RNA interference
hexamerin
cathepsin L
Flavescence doree phytoplasma
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/20.500.14243/446184
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