BLAST a probe sequence by one-click

You can add a web link to blast the probe sequence from annotations tab.

https://www.ncbi.nlm.nih.gov/blast/Blast.cgi?CMD=Put&QUERY=[SEQUENCE]&PROGRAM=blastn&FILTER=L&DATABASE=nr&ALIGNMENTS=100&DESCRIPTIONS=100

Also watch a tutorial movie to add web links.

How to define web links

Reference:

NCBI BLAST URLAPI