Put additional backing into call; it's quite an attraction (9)
I believe the answer is:
pheromone
'put additional backing' is the definition.
The definition suggests a singular noun which matches the answer.
'call it's quite an attraction' is the wordplay.
I cannot quite see how this works, but
'an' could be 'one' and 'one' is found within the answer.
'it' could be 'e' ('e' can mean 'electronic' which is similar to 'IT') and 'e' is present in the answer.
This explanation may well be incorrect...
'into' is the link.
Can you help me to learn more?
(Other definitions for pheromone that I've seen before include "Chemical attractor" , "Substance secreted that affects others of same species" , "What attracts" , "Chemical affecting behaviour" , "Chemical signal between organisms" .)