Crossword Genius

Vital supplier finds gate by vine has changed (6,4)

Ross

I believe the answer is:

portal vein

I'm a little stuck... Click here to teach me more about this clue!

'vital supplier' is the definition.
Although both the answer and definition are singular nouns, I can't understand how they can define each other.

'gate by vine has changed' is the wordplay.
'gate' becomes 'portal' (I've seen this in another clue).
'by' means one lot of letters go next to another.
'has changed' is an anagram indicator.
'vine' with letters rearranged gives 'vein'.
'portal'+'vein'='PORTAL VEIN'

'finds' is the link.

Can you help me to learn more?

(Another definition for portal vein that I've seen is " What supplies liver".)

I've seen this clue in The Daily Express.
Want a hint initially instead of a full solution? Install my app