A Preliminary Study On Chlorophyll Synthesis And Protein Complex Changes In Rice Leaf Color Mutant 812HS

The purpose of the present study is to reveal the biochemical mechanisms of chlorophyll deficient in the leaves of leaf color mutant 812HS.The leaf color mutant 812HS and and its wild-type 812S were used as the materials to investigate the content changes of thylakoid membrane protein complexes by Blue-native polyacrylamide gel-electrophoresis(BN-PAGE).1.Photosynthetic pigment contents in 812HS and 812S were at the same level on July 14.However,the chlorophyll content in mutant 812HS was 26.2%less than wild-type 812S on July 24.And from then on,the chlorophyll content in mutant 812HS was always less than wild-type 812S.It is is consistent with the leaf color phenotype of the mutant.On July 14 and July 24,the value of F0 and Fv/Fm in 812HS and 812S has no significant difference.However,from August 4 to August 24,the value of F0 in mutant 812HS was much higher than it in 812S and the value of Fv/Fm in mutant 812HS was less than wild-type.2.The contents of three intermediates for chlorophyll synthesis ALA,PBG and Urogen? in 812HS were higher than those in 812S,but the contents of the other intermediates Proto?,Mg-Proto ?,Pchlide,Chla and Chlb were significantly lower.3.We found that 5%-13%gradient separation gel,4%condensed glue and 3%of DM is the best conditions of BN-PAGE.After many experiments,we successfully separated 7 thylakoid membrane protein complexes.After using 1D BN-PAGE as the fist dimension and SDS-Urea-PAGE as the second dimension,we found that protein spots in mutant 812HS was less than 812S.4.The optical density analysis of thylakoid membrane protein complexes between mutant 812HS and wild-type 812S showed that many thylakoid membrane protein complexes contents significantly reduced in mutant 812HS.For example,the contents in LHC ? and PSI core was much lower than wild-type.In summary,all these results indicated that chlorophyll deficient in 812HS was caused by the decrease of the contents of thylakoid membrane protein complexes and a possible inefficient synthesis from Urogen? to Proto ?.