Effects Of MNNG On Growth And Develepment In Thalli Of Porphyra Haitanensis And Analysis Of The Different Protein Expression In The Mutants

Porphyra, one of the most important industrial seaweeds, has high nutritive value and is loved by people. Today, it becomes the main way to breed fine strain of Porphyra by mutagenizing thallus cells and developing transgenic system. In this study,protoplasts of Porphyra haitanensis were treated with the mutagen MNNG(N-Methy-N'-Nitro-N-Nitrosoguanidine)to detect the influence on the development of the somatic cells exposed in different concentration of MNNG. As a result,MNNG (7.5 ~120.0μg/mL)had a distinctive inhibition to the growth of Porphyra haitanensis somatic cells,and the influence of MNNG on the development of the cells has a dose-effect. The low concentration(7.5μg/mL,15μg/mL) of MNNG induced the cells developing to the abnormal cell group and protonema.The medium concentration(30μg/mL,60μg/mL)of MNNG induced the cells developing to the gobbet thallus,in the later culturing,the percentage of the normal thallus in the high concentration(120μg/mL) group was higher than that in other groups. Meanwhile,a type of cells which we called"monospore-like"were observed .They are similar to monospores of Porphyra yezoensis in the structure and function.The method of extracting protein specimen and separating them by two-dimensional electrophoresis (2-DE) was optimized for the proteomics analyse of Porphyra haitanensis. Furthermore, this system was used to analysis the difference proteins expressed in thalus cells from NO.2 and NO.9, which had obvious differences on the quality characters. Compared with NO.2 group, four new protein spots appeared in NO.9 group , the expression level of two protein spots were increased and two spots expression were decreased. These protein spots were analyzed by MALDI-TOF mass spectrometry to obtain the peptime mass fingerprinting (PMF). Based on the information of PMF, four of these eight discrepant proteins were identified by searching database on-line. One of protein spots was identified as the small subunit of RubisCO (ribulose 1,5-bisphosphate carboxylase/oxygenase). RubisCO is the key enzyme of the Calvin Benson cycle. It participates in photosynthesis and photorespiration and regulates their relationship. It is the key enzyme of carbon assimilatory. RubisCO was considered to be correlative to the character of thallus thickness of Porphyra.