The octopamine receptor, OA2B2, modulates stress resistance and reproduction in Nilaparvata lugens Stål (Hemiptera: Delphacidae)

Authors: ZHANG, YANJUN - Yangzhou University; JIANG, LU - Yangzhou University; AHMAD, SHERAZ - Yangzhou University; ZHANG, JIEYU - Yangzhou University; Stanley, David; MIAO, HONG - Yangzhou University; GE, LINQUAN - Yangzhou University

Submitted to: Insect Molecular Biology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/2/2021
Publication Date: 9/3/2021
Citation: Zhang, Y., Jiang, L., Ahmad, S., Zhang, J., Stanley, D.W., Miao, H., Ge, L. 2021. The octopamine receptor, OA2B2, modulates stress resistance and reproduction in Nilaparvata lugens Stål (Hemiptera: Delphacidae). Insect Molecular Biology. 31(1):33-48. https://doi.org/10.1111/imb.12736.
DOI: https://doi.org/10.1111/imb.12736

Interpretive Summary: Virtually all organisms, including plants, animals and micro-organisms are subjected to environmental and biological stressors. For example, local temperatures can exert thermal stress on plants, animals and micro-organisms. For very small insects, such as the brown plant hopper, a serious pest of Asian rice crops, high temperatures can inhibit their development and reproduction and extreme heat can be lethal to them. Insects rely on biochemical signaling to respond to stressors, although information on how this works is rather limited, particularly in very small insects. In this paper we report on discovery of a biochemical signaling system brown plant hoppers use to cope with several stressors, including temperature stress, starvation stress and reproductive stress. This new information will be useful to scientists working to create new pest management technologies that are based on disrupting biological processes within pest insects. These new technologies will help reduce some negative environmental impacts of large-scale agriculture by diminishing reliance on chemical insecticides to manage crop pest insects. This will contribute to sustainable agriculture, nutritional security and healthy foods at the global level.

Technical Abstract: The brown planthopper (BPH), Nilaparvata lugens (Stål) is a resurgent pest of rice crops throughout Asia. We recently discovered that octopamine (OA) signaling operates in the BPH mating system, where it mediates a wide range of molecular, physiological and behavioral changes that make up a state change from virgin to mated females. In this work, we found the females express an OA receptor, OA2B2, expression of which increases after mating. Because of the OA actions in post-mated femaels, we considered the possibility that OA operates in other areas of BPH biology. Here, were report on outcomes of experiments designed to test the hypothesis that OA/OA2B2 signaling mediates responses to three abiotic stressors, starvation, high temperature (37°C) and induced oxidative stress. We found per os RNAi-mediated OA2B2 silencing led to significantly decreased survival, measured in days, following exposure to each of these stressors. We selected a biologically costly process, reproductive biology, as a biotic stressor. Silencing of OA2B2 led to decreased total protein content in ovaries and fat bodies, down-regulated expression of vitellogenin (Vg) and Vg receptor (VgR), inhibited fat body Vg protein synthesis, shortened the oviposition period, prolonged the preoviposition period, reduced the number of laid eggs, body weight, and female longevity. The silencing treatments also led to inhibited ovarian development and ovarian Vg uptake. The treatments also resulted in reduced numbers of egg masses and offspring, and lower hatching rates and population growth index. Thses data support our hypothesis that OA2B2 acts in mediating BPH resistance to biotic and abiotic stressors.