Influence Of Caspase3-like Proteases On Programmed Cell Death Of Endosperm Cells In Winter Wheat (Triticum Aestivum. L) Under Waterlogging

The previous studies showed that the waterlogging brought forward the progression of the endosperm PCD; the large number accumulation of ROS induced oxidative damage of the cell structure and the decrease of the antioxidant enzymes activity in endosperm cells, which caused the endosperm cells PCD occurred earlier in some ways. This study used Hua8wheat as materials and treated with waterlogging in the flowering period, to study the activity changes of the Caspase-like prateases; the distribution of the caspase3-like in cells by biological activity determination, frozen section fluorescence activity detection, immunohistochemistry, immune electron microscope; moreover, the relative expression of the TaeMCAâ…¡ under waterlogging was studied by real-time PCR. The results showed that:1. The Evans blue staining showed that, the endosperm cells began to appear obvious staining at12DAF. With the development of the endosperm, the intensity of Evans blue staining and the death cells increased. The endosperm PCD occurred at about12DAF, and the endosperm PCD gradually extended afterwards.2. It was found that there were several kinds of caspase-like activity in the endosperm cells.3. With the development of the endosperm, the caspase3-like activity increased gradually and reached the peak at12DAF, and decreased a little atl5DAF and18DAF in normal condition. With the treatments of waterlogging, the caspase3-like activity increased and appeared in advance.4. The caspase3-like activity distributed in the endosperm, pericarp and aleurone layer cells, and the intensity of the reaction of brown was stongest at12DAF. The waterlogging induced the caspase3-like proteases appeared earlier and increased than the normal condition in the same stages. 5. Immune electron microscopy oberservation showed that the distribution of the caspase3-like proteases in the endosperm cells had highly specificity, and the caspase3-like proteases distributed in the amyloplasts and proteosomes.6. It was found that the expression of TaeMCA â…¡ remained unchanged with the0DWT treatment1in different periods. However, the waterlogging induced the expression of TaeMCA â…¡ increased in the early stage of development in the endosperm and decreased in the middle and later stages, the expression of TaeMCA â…¡ reacheded the peak at12DAF.Above all, caspase3-like proteases play a role in the PCD of endosperm cells in Hua8wheat in normal condition. The increase of the caspase3-like activity and the overepression of TaeMCAâ…¡ may further explain the cause of the PCD in advance in waterlogging.