|ZHANG, FANGMEI - Chinese Academy Of Agricultural Sciences|
|LI, XIANGRUI - Chinese Academy Of Agricultural Sciences|
|ZHANG, YUNHUI - Chinese Academy Of Agricultural Sciences|
|ZHOU, XUGUO - University Of Kentucky|
|CHENG, DENGFA - Chinese Academy Of Agricultural Sciences|
Submitted to: Frontiers in Physiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/29/2015
Publication Date: 5/20/2015
Citation: Zhang, F., Li, X., Zhang, Y., Coates, B.S., Zhou, X., Cheng, D. 2015. Bacterial symbionts, Buchnera, and starvation on wing dimorphism in English grain aphid, Sitobion avenae (F.) (Homoptera: Aphididae). Frontiers in Physiology. 6:155. DOI:10.3389/fphys.2015.00155.
Interpretive Summary: Aphids are insects that feed on liquid portions of crop plants by use of piercing and sucking mouthparts, and are detrimental to plant health due to their spread of plant diseases in corn, soybean and wheat production systems in the United States. Aphids have a unique biology where the number of highly mobile individuals that develop wings is related to local environmental conditions, such that more winged individuals are borne when parents develop on plants that are a poor food source. This allows of greater movement of aphid populations when crop plants are near harvest and results in potential spread to other crops in proximity. The change in proportion winged aphids is an interesting case where the trait of an insect is altered direct response to environmental conditions instead of being controlled by genetically inherited factors. Furthermore, aphid health is influenced by a symbiotic amino acid synthesizing bacteria living within their body. In order to understand this complex system, a USDA researcher worked with University and foreign collaborators to document the effects of diet and absence of a symbiotic bacteria on modulating the proportion of winged aphids in laboratory studies. These results are important in understanding mechanisms that control movement of these insect crop pests, and may lead to novel strategies for the control of crop damage.
Technical Abstract: Wing dimorphism in aphids can be affected by multiple cues including both biotic (nutrition, crowding, interspecific interactions, the presence of natural enemies, maternal and transgenerational effects, and alarm pheromone) and abiotic factors (temperature, humidity, and photoperiod). Virtually all phloem-feeding aphids carry Buchnera, an obligate symbiotic proteobacteria. Buchnera has a highly reduced genome size, but encode key enzymes in the tryptophan biosynthetic pathway and is crucial for nutritional balance, development and reproduction in aphids. In this study, we investigated the impact of two nutritional-based biotic factors, symbionts and starvation, on the wing dimorphism in the English grain aphid, Sitobion avenae, a devastating insect pest of cereal crops (e.g., wheat) worldwide. Elimination of Buchnera using antibiotic rifampicin significantly reduced the formation of alates (winged morphs), body mass and fecundity in S. avenae. Furthermore, the absence of this primary endosymbiont may disrupt the nutrient acquisition in aphids and alter transgenerational phenotypic expression. Similarly, both survival rate and the formation of winged morphs were substantially reduced after neonatal (< 24h old) offspring were starved for a period of time. The combined results shed light on the impact of two nutritional-based biotic factors on the phenotypic plasticity in aphids. A better understanding of the wing dimorphism in aphids will provide theoretical basis for the prediction and integrated management of these phloem-feeding insect pests.