Abstract
In C(4) plants, the enzymatic machinery underpinning photosynthesis can vary, with, for example, three distinct C(4) acid decarboxylases being used to release CO(2) in the vicinity of RuBisCO. For decades, these decarboxylases have been used to classify C(4) species into three biochemical sub-types. However, more recently, the notion that C(4) species mix and match C(4) acid decarboxylases has increased in popularity, and as a consequence, the validity of specific biochemical sub-types has been questioned. Using five species from the grass tribe Paniceae, we show that, although in some species transcripts and enzymes involved in multiple C(4) acid decarboxylases accumulate, in others, transcript abundance and enzyme activity is almost entirely from one decarboxylase. In addition, the development of a bundle sheath isolation procedure for a close C(3) species in the Paniceae enables the preliminary exploration of C(4) sub-type evolution.