IPA: //ˌfoʊtəʊˈsɪnθeɪt//
KK: /ˈfoʊtoʊˌsɪnθeɪt/
A substance produced by plants during the process of converting sunlight into energy, which is used for growth and development.
The plant stored the photosynthate in its roots for later use.
Photosynthate → It is formed from "photo-" (from Greek "phōs", meaning light) and "synthate" (from Greek "synthesis", meaning putting together). The word refers to substances produced by plants through the process of photosynthesis, where light is used to put together organic compounds.
Think of 'light' ('photo-') being used to 'put together' ('synthate') food for plants — that's how photosynthate refers to the products of photosynthesis.
No commonly confused words.