The physiology of ex vitro pineapple ( Ananas comosus L. Merr. var MD-2) as CAM or C3 is regulated by environmental conditions: proteomic and transcriptomic profiles
Pineapple is one of the most important tropical crops worldwide. The use of Temporary Immersion Bioreactors (TIB) for the first stages of pineapple propagation enables precise control of plant growth, increases the rate of plant multiplication, decreases space, energy and labor requirements for pineapple plants in commercial micropropagation. Once the plantlets are ready to be taken from the reactors, they are carefully acclimatized to adapt to natural environmental conditions, and a facultative C3/CAM metabolism in the first two months of growth is characteristic of pineapple plants, depending on environmental conditions. We subjected two sets of micropropagated pineapple plants to C3 and CAM-inducing environmental conditions, determined by light intensity/relative humidity (respectively 40μmol.m-2s-1/85% and 260μmol.m-2.s-1/50%). Leaves of pineapple plants grown under CAM inducing conditions showed higher leaf thickness and more developed cuticles and hypodermic tissue. Proteomic profiles of several proteins, isoenzyme patterns and transcriptomic profiles were also measured. Five major spots were isolated and identified, two of them for the first time in Ananas comosus (OEE 1; OEE 2) and the other three corresponding to small fragments of the large subunit of Rubisco (LSU). PEPC and PEPCK were also detected by immunobloting of 2DE at the end of both ex vitro treatments (C3/CAM) during the dark period. Isoenzymes of SOD and CAT were identified by electrophoresis and the transcript levels of OEE 1 and CAT were associated with CAM metabolism in pineapple plants
