Decaffeination this trait could be bred into other coffee plants by crossing them with "C. charrieriana", or an equivalent effect could be achieved by knocking out the gene for caffeine synthase in normal coffee plants. Tea may also be decaffeinated, usually by using processes analogous to the direct method or the CO process, as described above. The process of oxidizing tea leaves to create black tea ("red" in Chinese tea culture) or oolong tea leaves from green leaves does not affect the amount of caffeine in the tea, though tea-plant subspecies (i.e., "Camellia sinensis sinensis" vs. "Camellia sinensis assamica") may differ
Camellia sinensis catalyzes the conversion of 7-methylxanthine to theobromine, as well as the final conversion of theobromine to caffeine. Camellia sinensis Camellia sinensis is a species of evergreen shrub or small tree whose leaves and leaf buds are used to produce tea. It is of the genus "Camellia" () of flowering plants in the family Theaceae. Common names include "tea plant", "tea shrub", and "tea tree" (not to be confused with "Melaleuca alternifolia", the source of tea tree oil, or "Leptospermum scoparium", the New Zealand Tea Tree). "Camellia sinensis" var. "sinensis" and "Camellia sinensis" var. "assamica", are two major varieties grown today.