dsRNAs targeted to the brown planthopper Nilaparvata lugens: assessing risk to a non-target, beneficial predator, Cytorhinus lividipennis

Authors: DANG, CONG - Zhejiang University; ZHANG, YUPAN - Zhejiang University; SUN, CHUYI - Zhejiang University; LI, RAN - Zhejiang University; WANG, FANG - Zhejiang University; FANG, QI - Zhejiang University; YAO, HONGWEI - Zhejiang University; Stanley, David; YE, GONGYIN - Zhejiang University

Submitted to: Journal of Agricultural and Food Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/16/2021
Publication Date: 12/30/2021
Citation: Dang, C., Zhang, Y., Sun, C., Li, R., Wang, F., Fang, Q., Yao, H., Stanley, D.W., Ye, G. 2021. dsRNAs targeted to the brown planthopper Nilaparvata lugens: assessing risk to a non-target, beneficial predator, Cytorhinus lividipennis. Journal of Agricultural and Food Chemistry. 70(1):373-380. https://doi.org/10.1021/acs.jafc.1c05487.
DOI: https://doi.org/10.1021/acs.jafc.1c05487

Interpretive Summary: Pest insects cause tremendous costs to global agriculture, last estimated at more than $70 billion annually, not including the costs dangerous human and food animal illnesses. This dire situation has focused attention on developing new insect pest management technologies. One promising technology is based on genetically modifying crop plants to express insect-killing molecular constructs. One of the serious problems associated with this new technology is developing new protocols to assess the safety of such crops before they are widely available for agricultural production. Here, we report on a protocol to assess the safety of genetically modified rice plants to manage brown plant hoppers, the most devastating pest insect in Asian rice production. We developed a protocol to assess risks a beneficial insect species that co-occurs with brown plant hoppers and report molecular constructs do not pose risks the beneficial insect species. This is the first protocol to assess risks of genetically modified rice to beneficial insect species. This information will be used to develop much broader risk assessment methods. Such risk assessment tools will eventually lead to deployment of a new insect pest management technology, which will increase availability of high quality rice to very large and rapidly growing human populations.

Technical Abstract: Research and application of RNAinterference (RNAi) technology is a rapidly maturing insect management technology. Before commercial-scale application, however, it is necessary to assess risks to non-target organisms (NTO). Here, we evaluated the influence of RNAi technology, targeted to the brown planthopper, (BPH, Nilaparvata lugens, Hemiptera: Delphacidae), a serious pest of Asian rice cropping systems. We selected the predator Cyrtorhinus lividipennis (Hemiptera: Miridae) as our NTO because it contributes important biological control services by consuming BPH. In this study, we conducted a screen of dsRNAs targeted to BHP by feeding dsRNA, and determined the LC50 values of 11 dsRNA fragments which significantly reduced the BPH survival. We found three dsRNA fragments (dsNlNa, dsNlAup5 and dsNlvATP-A) with highly lethality to BPH. We selected these three fragments to evaluate their effects on the non-target predator, and the corresponding part from the homologous gene in C. lividipennis was a positive control. Combined with sequence similarity, biological parameters, and gene transcription levels, these three dsRNA fragments posed no risks to C. lividipennis at the worst-case when fed with at high concentrations (10X) of dsRNAs. Taking the model for assessing the safety of Bt crops, the findings of this work establishes part of a risk assessment protocol forof RNAi-based products on NTOs. Our results could also contribute to development and deployment of new technologies for BPH management.