title: Jasmonate- and salicylate-induced defenses in wheat affect host preference and probing behavior but not performance of the grain aphid, Sitobion avenae.
abstract: Jasmonate- and salicylate-mediated signaling pathways play significant roles in induced plant defenses, but there is no sufficient evidence for their roles in monocots against aphids. We exogenously applied methyl jasmonate (MeJA) and salicylic acid (SA) on wheat seedlings and examined biochemical responses in wheat and effects on the grain aphid, Sitobion avenae (Fab.). Application of MeJA significantly increased levels of wheat's polyphenol oxidase, peroxidase and proteinase inhibitor 1, 2 and 6 days after treatment. In two-choice tests, adult aphids preferred control wheat leaves to MeJA- or SA-treated leaves. Electrical penetration graph (EPG) recordings of aphid probing behavior revealed that on MeJA-treated plants, the duration of aphid's first probe was significantly shorter and number of probes was significantly higher than those on control plants. Also total duration of probing on MeJA-treated plants was significantly shorter than on control plants. Total duration of salivation period on SA-treated plants was significantly longer, while mean phloem ingestion period was significantly shorter than on control plants. However, no significant difference in total duration of phloem sap ingestion period was observed among treatments. The EPG data suggest that MeJA-dependent resistance factors might be due to feeding deterrents in mesophyll, whereas the SA-mediated resistance may be phloem-based. We did not observe any significant difference of MeJA and SA application on aphid development, daily fecundity, intrinsic growth rate and population growth. The results indicate that both MeJA- and SA-induced defenses in wheat deterred S. avenae colonization processes and feeding behavior, but had no significant effects on its performance.
authors: State Key Laboratory of Crop Stress Biology on the Arid Areas, and the Key Laboratory of Crop Pest Management on the Losses Plateau of Ministry of Agriculture, Northwest A&F University, Yangling, Shaanxi, China.
authors: He-He
authors: HH
authors: Cao
authors: Su-Hua
authors: SH
authors: Wang
authors: Tong-Xian
authors: TX
authors: Liu
mesh_terms: D000818:Animals; D001042:Aphids / Q000187:drug effects / Q000502:physiology*; D003517:Cyclopentanes / Q000494:pharmacology*; D005247:Feeding Behavior / Q000187:drug effects; D005260:Female; D058507:Host Specificity / Q000187:drug effects; D008297:Male; D054883:Oxylipins / Q000494:pharmacology*; D010935:Plant Diseases / Q000276:immunology / Q000469:parasitology*; D018515:Plant Leaves / Q000276:immunology / Q000469:parasitology; D020156:Salicylic Acid / Q000494:pharmacology*; D014908:Triticum / Q000187:drug effects / Q000276:immunology* / Q000469:parasitology*
chemical_list: D003517:Cyclopentanes; D054883:Oxylipins; C011006:jasmonic acid; D020156:Salicylic Acid
keywords: EPG; cereal aphids; induced plant defense; methyl jasmonate; salicylic acid