Development and use of a monoclonal antibody to detect semi-digested proteins of the English grain aphid, Sitobion avenae, in the guts of ladybird beetle predators |
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Authors: | Shu-jing Gao Xiao-rong Zhou Bao-ping Pang Joop JA van Loon & Gui-qin Zhao |
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Institution: | College of Agriculture, Inner Mongolia Agricultural University, Hohhot 010019, China;, Institute of Grassland, Chinese Academy of Agricultural Sciences, Hohhot 010010, China;, Laboratory of Entomology, Wageningen University, P.O. Box 8031, 6700 EH Wageningen, The Netherlands;, and College of Grassland Science, Gansu Agricultural University, Lanzhou 730070, China |
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Abstract: | A monoclonal antibody (McAb), EGA-4A9, was developed to detect the semi-digested proteins of the English grain aphid, Sitobion avenae (Fabricius) (Hemiptera: Aphididae), in predatory ladybird beetles (species of the genera Adonia , Coccinella , Hippodamia , and Propylea ) using the gut homogenate of Adonia variegata (Goeze) (Coleoptera: Coccinellidae) adults which had fed on S. avenae as immunogen. The McAb was selected by screening hybridoma lines for antibodies that bound with the semi-digested aphid proteins in ladybirds. A double antibody sandwich enzyme-linked immuno-sorbent assay (ELISA) using ClonotypingTM System/HRP showed that it belonged to the IgG2a isotype. It did not cross-react with any of the 21 arthropod species tested besides the ladybird beetles fed on S. avenae with an indirect ELISA. It could still detect the semi-digested proteins in the gut of a ladybird adult, kept at 25 °C, that had ingested one aphid 6 days before. The extended antigen detection period and the high specificity of the antibody indicated that EGA-4A9 could be used to study interactions between English grain aphids and their ladybird predators in the field. Between 28 and 72% of coccinellids collected from the field were positive for English grain aphid protein by ELISA. The percentage of McAb-positive predatory ladybird beetles was positively correlated with the density of S. avenae in wheat fields. |
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Keywords: | Adonia variegata ELISA predation gut content analysis Coleoptera Coccinellidae Hemiptera Aphididae semi-digested protein |
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