Identification and characterization of caleosin in Cycas revoluta pollen

Oil bodies are essential energy storage organelles that are generally present in the seeds of plants. Caleosin protein has been identified in the seed oil bodies of Cycas revolutaseed. In this study, mature Cycas revoluta pollen grains were collected from cycad elliptical cones. However, the isolation and identification of oil bodies protein from mature Cycas revoluta grains have never been experimentally determined. Ultrastructural studies have shown that the oil bodies were present in pollen Cycas revoluta grains. Lipid analysis showed that oil bodies are predominantly composed of triacylglycerol. Complete cDNA fragments encoding the caleosin were obtained by PCR cloning. Phylogenetic tree analyzes showed that cycad pollen caleosin is closely related to the caleosin of Cycas revoluta seeds. Fresh Cycas revoluta pollen grains were allowed to germinate for 48 h in a germination medium containing 2% sucrose and 0.01% H3BO3. Pollen germination were recorded periodically from day one to day 10 and the results showed that the Cycas revoluta pollen elongate the tube and increasing of triacylglycerol(TAG) after 4 days.