BACKGROUND: @entity4335 is the third leading source of vegetable oil in the world after @entity1460 and oil palm. The accumulation of gene sequences, especially expressed sequence tags (ESTs) from plant cDNA libraries, has provided a rich resource for genes discovery including potential antimicrobial peptides (AMPs). In this study, we used ESTs including those generated from @entity4335 cDNA libraries of seeds, pathogen-challenged leaves and deposited in the public databases, as a model, to perform in silico identification and consequently in vitro confirmation of putative @entity8582 activities through a highly efficient system of recombinant @entity8582 prokaryotic expression. RESULTS: In total, 35,788 were generated from cDNA libraries of pathogen-challenged leaves and 187,272 ESTs from seeds of @entity4335 , and the 644,998 ESTs of @entity4335 were downloaded from the EST database of PlantGDB. They formed 201,200 unigenes. First, all the known AMPs from the @entity8582 databank (APD2 database) were individually queried against all the unigenes using the BLASTX program. A total of 972 unigenes that matched the 27 known @entity8582 sequences in APD2 database were extracted and annotated using Blast2GO program. Among these unigenes, 237 unigenes from @entity4335 pathogen-challenged leaves had the highest ratio (1.15  %) in this unigene dataset, which is 13 times that of the unigene datasets of @entity4335 seeds (0.09  %) and 2.3 times that of the public EST dataset. About 87  % of each EST library was lipid-transfer protein (LTP) (32  % of total unigenes), @entity68225 , histone, endochitinase, and gibberellin-regulated proteins. The most abundant unigenes in the leaf library were endochitinase and @entity68225 , and LTP and histone in the pub EST library. After masking of the repeat sequence, 606 peptides that were orthologous matched to different @entity8582 families were found. The phylogeny and conserved structural motifs of seven AMPs families were also analysed. To investigate the antimicrobial activities of the predicted peptides, 31 potential @entity8582 genes belonging to different @entity8582 families were selected to test their antimicrobial activities after bioinformatics identification. The @entity8582 genes were all optimized according to @entity526 codon usage and synthetized through one-step polymerase chain reaction method. The results showed that 28 recombinant AMPs displayed expected antimicrobial activities against @entity526 and @entity7178 and @entity19868 strains. CONCLUSION: The study not only significantly expanded the number of known/predicted peptides, but also contributed to long-term plant genetic improvement for increased resistance to diverse pathogens of @entity4335 . These results proved that the high-throughput method developed that combined an in silico procedure with a recombinant @entity8582 prokaryotic expression system is considerably efficient for identification of new AMPs from genome or EST sequence databases.

EST-based in silico identification and in vitro test of antimicrobial peptides in XXXX .

@entity4335 :: ('3708', 'Species') :: ['B. napus', 'Brassica napus', 'B.napus'] @entity526 :: ('562', 'Species') :: ['Escherichia coli', 'E. coli'] @entity19868 :: ('5180', 'Species') :: ['Sclerotinia sclerotiorum'] @entity8582 :: ('D000667', 'Chemical') :: ['AMP'] @entity1460 :: ('3847', 'Species') :: ['soybean'] @entity7178 :: ('1270', 'Species') :: ['Micrococcus luteus'] @entity68225 :: ('106421680', 'Gene') :: ['defensin']
@entity4335 :: (3708,Species) :: ['Brassica napus']
