Analysis Of The Function And Localization Of Several Seed-related Peroxisomal And Mitochondrial Proteins

Seed is an important stage of plant life cycle.Seed development and germination is accompanied by extremely frequent nutrient metabolism and energy conversion.Peroxisomes and mitochondria are both multi-functional organelles with key roles in energy metabolism and are closely related in their metabolic functions.Peroxisomal functions in fatty acid degradation and hormone biosynthesis are important to oil seed germination.Hence,peroxisome-related mutants often show severe germination defects,which,however,is not well understood at molecular level.Moreover,there are few studies about the role of peroxisomes in starch seeds.Besides of peroxisomes,mitochondria are also closely related to seed germination.During seed germination,mitochondria develop from a metabolically quiescent pre-mature form into a metabolically active mature form.Mitochondria are double membrane enclosed organelles.However,during seed germination,how plant mitochondrial membrane lipids contribute to mitochondrial biogenesis and seed germination process is unclear.This thesis is divided into three parts,which investigate the physiological roles of peroxisomes and mitochondria in seeds in different aspects.In the 1^st part,we focused on citrate synthase?CSY?,a peroxisomal enzyme of the glyoxylate cycle,and investigate how the glyoxylate cycle is involved in oil seed development and whether it has similar roles in oil seeds like Arabidopsis and in starch seeds like rice.Protein redundant with AtCSY1 was found in the Arabidopsis seed development stage;rice Oscsy mutant was obtained by gene-editing technology.In the 2^nd part,we performed subcellular localization analysis of several putative peroxisomal proteins,which were identified through bioinformatic prediction and highly expressed in seeds,and identified two novel peroxisomal proteins in rice.In the 3^rd part,we aimed to figure out how PLTP1,a putative phospholipid transfer protein in mitochondria highly expressed in seed imbibition,is involved in mitochondrial biogenesis.It was found that the seed germination ability of the two mutant lines?pltp1-13 and pltp1-20?was different.In general,this thesis analyzed the subcellular localization,gene expression and/or physiological function of several seed related organellar proteins,and generated and preliminarily analyzed the relevant mutants.This work will be helpful for future efforts to deeply investigate the role of peroxisomes and mitochondria during seed-related physiological processes.