Jinggangmycin increases fecundity of the brown planthopper, Nilaparvata lugens (Stal) via fatty acid synthase gene expression

The antibiotic jinggangmycin (JGM) is mainly used in controlling the rice sheath blight, Rhizoctonia solani, in China. JGM also enhances reproduction of the brown planthopper (BPH), Nilaparvata lugens (Stal). To date, however, molecular mechanisms of the enhancement are unclear. Our related report documented the influence of foliar JGM sprays on ovarian protein content. Here, we used isobaric tags for relative and absolute quantitation (iTRAQ) protocols to analyze ovarian proteins of BPH females following JGM spray (JGM-S) and topical application (JGM-T). We recorded changes in expression of 284 proteins (142 up arrow and 142 down arrow) in JGM-S compared to the JGM-S control group (S-control); 267 proteins were differentially expressed (130 up arrow and 137 down arrow) in JGM-T compared to the JGM-T control group (T-control), of which, 22 proteins were up-regulated in both groups. Comparing the JGM-S to the JGM-T group, 114 proteins were differentially expressed (62 up arrow and 52 down arrow). Based on the biological significance of fatty acids, pathway annotation and enrichment analysis, we designed a dsRNA construct to silence a gene encoding fatty acid synthase (FAS). FAS was more highly expressed in JGM-S vs S-control and JGM-S vs JGM-T groups. The dsFAS treatment reduced fecundity by about 46% and reduced ovarian and fat body fatty acid concentrations in JGM-S-treated females relative to controls. We infer FAS provides critically needed fatty acids to support JGM-enhanced fecundity in BPH. (C) 2015 Published by Elsevier B.V.