I have a set of metatranscriptomic Illumina paired-end reads. I need to align them against the database of plant virus genomes (about 55000 sequences) and calculate coverage for each reference. How can I solve the problem? It is also necessary to assemble these reads de novo. I've tried Trinity on Galaxy but the results seem controversial because BLAST search reveals predominantly bacterial and other non-plant viral sequences. Whether there are some other online services for metagenomic analysis?