Editing header of a fasta file

Hello everybody, I’ve been using sed but for simple steps and now I can’t do this:
I have this header:

>ENSP00000451042.1 pep chromosome:GRCh38:14:22438547:22438554:1 gene:ENSG00000223997.1 transcript:ENST00000415118.1 gene_biotype:TR_D_gene transcript_biotype:TR_D_gene gene_symbol:TRDD1 description:T cell receptor delta diversity 1 [Source:HGNC Symbol;Acc:HGNC:12254]

and I would like to obtein this:

>gene_symbol:TRDD1

Does anybody can help me?