Cellular Metabolic Modulation During The Chaetoceros Muelleri Resting Spore Formation And Functional Analysis Of The Genes Related To Biosilicification In Marine Diatoms

Diatoms are considered one of the most successful phytoplankton in the ocean,which partly due to the presence of solid,silicon cell walls covering their cytoplasm.Under hash environmental conditions,some diatoms will form heavy silicification(thickening of cell walls)resting spores to cope with the stress and germinate again when the stress released.However,little is known about the cellular metabolic modulation involved in during the formation of diatoms resting spores.In the present study,the expression characteristics and related functions of genes which involved in resting spore formation were investigated by cell-whole transcriptome..Meanwhile,the structural characteristics of the genes related to silicification were described.Finally their special characteristic structural domains in the genes related to silicification were revealed by transgenic methods.Nutrients absorption and physiological and ecological indicators analysis showed that about 90%of cells died in the process of resting spore formation and released the nutrients into medium for the viable cells.The surviving cells would continuously absorb nitrogen,phosphorus and silicon and accumulated these nutrients inside the cell.The storage of these elements could be important for the survival of resting spores.Transcriptome sequence analysis revealed that three silaffin-like proteins which related to valve systhesis were found significantly up-regulated in C.muelleri.These three proteins contained exceptionally high abundance of KXXK domains,which may play an important role in the heavy silicification during resting spores formation.A transgenic system of Thalassiosira pseudonana(central diatom as same as C.muelleri)was established.Functional annotation of RXL,KXXK domains in the genes related to silicification was carried out by transgenic method.