Effects Of Low Light Intensity On Physiological And Protein Effects Of Photosynthetic Mutant 812HS In Rice

This study compared the differences in photosynthesis and proteomics in leaf of photo-oxidation mutant 812HS between different light. The results were as Fllowing:1.July 16 to August 25, chlorophyll content of mutant 812HS under shading is always higher than control group, and the control group chlorophyll content decreased by 35.2% at August 5, which is consistent with phenotypic traits. Compared to the decline of chlorophyll content, the change of carotenoid content under natural light is relatively small, so the Car/Chl ratio increased. However, the trend of carotenoid content and Car/Chl ratio in 812HS under shading treatment changed little; August 5, leaf photosynthesis efficiency Fv/Fm in rice under natural light were significantly lower than the control group, but this ratio dropped intensely and stabilized in his later. The result indicating that the photosynthetic efficiency is higher in later, the rising of Fo in august 5 also show that the damage of PS II reaction center is the most serious.2.Throughout the experiment, with the enhancement of light, the contents of O2·- and H2O2 in 812HS exhibit an increasing trend. The content of active oxygen in the control group is much higher than the level in 812HS under shade experimental groups.With the increase of active oxygen content, antioxidant enzymes (SOD, POD, CAT) activity are increasing in both rice,and the content of antioxidant enzymes activity under natural light in 812HS was significantly higher than that of shading 812HS, showed strong antioxidant capacity, but the higher MDA content showed itself suffered more severe photo-damage than low light group.3.The results of proteomic analysis are as Fllows:we build the 2-DE maps of total protein from 812HS leaves with high resolution and good repetition.more than 1000 reproducible proteins were detected by ImageMaser 2D platinum software and only 98 spots displayed differential expression with 1.5-Fold abundance. By MALDI-TOF-MS and searching of the National Center For Biotechnology Information database,53 proteins are Identified, including 34 down-regulated and 19 up-regulated. These proteins are involved in energy metabolism,signal transduction, protein destination,storage, and secondary metabolism and unclear classification. Proteins involved in photosynthesis is the most abundant,such as ATP synthase,Rubisco large subunit,Rubisco large chain precursor,Rubisco activase.In summary, the experiment explores the chlorophyll content,antioxidant enzyme activity and the difference of proteomics in 812HS under different light intensity, aiming to reveal the mechanism in antioxidation and proteomics and provides the theory basis of molecular biology for follow-up study on photo-oxidation mutant.