BackgroundJasmonic acid (JA) and methyl jasmonate (MeJA) regulate plant development, resistance to stress, and insect attack by inducing specific gene expression. However, little is known about the mechanism of plant defense against herbivore attack at a protein level. Using a high-resolution 2-D gel, we identified 62 MeJA-responsive proteins and measured protein expression level changes.ResultsAmong these 62 proteins, 43 proteins levels were increased while 11 proteins were decreased. We also found eight proteins uniquely expressed in response to MeJA treatment. Data are available via ProteomeXchange with identifier PXD001793. The proteins identified in this study have important biological functions including photosynthesis and energy related proteins (38.4%), protein folding, degradation and regulated proteins (15.0%), stress and defense regulated proteins (11.7%), and redox-responsive proteins (8.3%). The expression levels of four important genes were determined by qRT-PCR analysis. The expression levels of these proteins did not correlate well with their translation levels. To test the defense functions of the differentially expressed proteins, expression vectors of four protein coding genes were constructed to express in-fusion proteins in E. coli. The expressed proteins were used to feed Ostrinia furnacalis, the Asian corn borer (ACB). Our results demonstrated that the recombinant proteins of pathogenesis-related protein 1 (PR1) and thioredoxin M-type, chloroplastic precursor (TRXM) showed the significant inhibition on the development of larvae and pupae.ConclusionsWe found MeJA could not only induce plant defense mechanisms to insects, it also enhanced toxic protein production that potentially can be used for bio-control of ACB.Electronic supplementary materialThe online version of this article (doi:10.1186/s12864-015-1363-1) contains supplementary material, which is available to authorized users.

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Here we reported the molecular characterization of two novel mycoviruses co-infected in a plant pathogenic fungus, Nigrospora sphaerica that were designated as Nigrospora sphaerica fusarivirus 1 (NsFV1) and Nigrospora sphaerica partitivirus 1 (NsPV1), respectively. NsFV1 has an undivided genome of 6,147 bp, excluding the polyA tail, and was predicted to contain two nonoverlapping open reading frames (ORF1 and 2). The larger ORF1 encoded a polyprotein containing a conserved RNA-dependent RNA polymerase (RdRp) and a helicase domain that have functions for RNA replication, and the smaller ORF2 encoded a putative protein with an unknown function. The NsPV1 was consists of two genome segments, which were in lengths of 1,796 bp and 1,455 bp, respectively. Each of the two dsRNAs had a single ORF and were deduced to encode proteins with homology to viral RdRp and coat protein (CP), respectively, in the family Partitiviridae. Phylogenetic analysis showed that NsFV1 was placed within the newly proposed family Fusariviridae, while NsPV1 was belonging to the genus Gammapartitivirus in the family Partitiviridae. This was the first description of mycovirses infected the fungus N. sphaerica.