| In Hevea brasiliensis,the latex regeneration is the key factor in rubber production.The glycolysis in latex of Hevea brasiliensis is a vitally important link in biological metabolic network,which is believed to play an essential role in latex regenerating basically because glycolysis can provide the initial materials and energy for rubber biosynthesis,especially like carbon skeleton serving as a core element of rubber molecular structure.Therefore,Latex glycolysis’ s acceleration can strengthen latex regeneration ability and then improve rubber yield.The phosphofructokinase(PFK)controls metabolic rate of glycolysis as the key enzyme.In this study,seven ATP-and two PPi-phosphofructokinase genes were isolated from rubber tree,and named as Hb PFK1-7 and Hb PFP1-2.By use of a phosphofructokinase-defective mutant of E.coli,strain RL257,its functional complementation results indicate that Hb PFK1-4 and Hb PFP1 possess phosphofructokinase activy.Based on above,the recombinant protein of Hb PFK1-2 were re-expressed and then they were examined and found to have enzyme activity,which provide a further evidence.Cluster and phylogeny analysis show that PFK family has a vast difference of amino acids in same species,and their divergence is earlier than the species in plant.The expression characters of Hb PFK1-7 and Hb PFP1-2 were studied by real time PCR analysis.They were all specifically expressed in different tissues and Hb PFK2 is the major member with high transcripts in latex.The Hb PFK1-7 and Hb PFP1-2 have different degree response to 7 plant hormones,wounding,TPD,high temperature and low temperature treatment.Tapping treatment enhances the content of citric acid,reduces the activity of PFK,and decreases first then increases the transcripts of Hb PFK2.On the contrary,ET treatment reduces the content of citric acid,enhances the activity of PFK,and decreases the transcripts of Hb PFK2.In conclusion,it is speculated that Hb PFK2 is involved in latex regeneration,and related with yield of rubber tree.The activity of Hb PFK is also obviously regulated by citric acid in latex,indicating the content of citric acid may affect the glycolysis in latex.This study contributes to indicate the regulative mechanism of Hb PFK in latex glycolysis,and reveal the close relation between latex glycolysis and rubber yield. |
