It's a rising wine region (4)
I believe the answer is:
asti
'wine region' is the definition.
(I've seen this in another clue)
'it's a rising' is the wordplay.
'rising' says the letters should be written in reverse (in a down clue, letters go up).
'its'+'a'='itsa'
'itsa' back-to-front is 'ASTI'.
(Other definitions for asti that I've seen before include "Sparkling wine named after an Italian Piedmont town" , "Italian white wine" , "- spumante, It. wine" , "Bubbly wine" , "town in Italy" .)