The Identification Of Maize Chloroplast Proteins Interacting With Small Heat Shock Protein 26 Under Heat Stress

Small heat shock proteins(sHSPs)play an important role in enhancing plant stress tolerance.Early research shows that heat stress induce the expression of the small heat shock protein26(sHSP26),and the subcellular localization of sHSP26 locates in chloroplast by the immune electron microscopy technology.But it was no study to identify these chloroplast proteins interacting with sHSP26 and its protecting function to PSⅡ.Therefore,exploring that sHSP26 protects PSⅡand interactes with these chloroplast proteins will provide a theoretical basis for understanding sHSP26 enhancing maize tolerance.This study used zhengdan 958 as experimental material to identify these chloroplast proteins interacting with sHSP26 and its protecting function to PSⅡ under heat stress by two-dimensional electrophoresis,mass spectrometry identification,western blotting,yeast two hybrid technology.The main results were as follows:1,After pretreatment with antibody-sHSP26(AT-sHSP26),maize chloroplasts were exposed to heat stress,then chloroplast proteins were extracted and identified by two-dimensional electrophoresis(2-DE)and mass spectrum analysis technology.Compared to control(treatment with IG),after treatment with AT-sHSP26,these proteins related to photosynthesis,including ATP synthase alpha,beta and gamma subunits,oxygen-evolving enhancer protein 1(OEE1),chlorophyll a/b binding protein,cytochrome b6/f complex iron-sulfur subunit,photosystem I(PSI)reaction center subunit IV A and iron-sulfur center,the expression of which were downregulated.This study indicated that these proteins were affected by sHSP26.In addition,after prtreatment with the AT-sHSP26,the oxygen evolution rate of chloroplasts PSⅡwas significantly reduced under heat stress,which suggested that sHSP26 protected the activity of PS?? under heat stress2,In order to further study whether these proteins interacting with sHSP26 or not,the yeast two-hybrid technology was used.In the yeast two-hybrid system,PGBKT7-sHSP26 was used as bait plasmid.six chloroplast proteins which are related to sHSP26,including ATP synthase alpha,beta and gamma subunits,oxygen-evolving enhancer protein 1(OEE1),chlorophyll a/b binding protein,photosystem I(PSI)reaction center subunit IVA were connected to p GAD and used as prey plasmid.The results showed that four proteins,including ATP synthase subunit β,chlorophyll a/b binding protein,oxygen-evolving enhancer protein 1 and photosystem I reaction center subunit IVA,strongly interacted with sHSP26.In summary,these study results confirmed that sHSP26 might protect the activity of PSⅡby interacting with the chloroplast proteins.These results provided a theoretical basis for further understanding the mechanism of sHSP26 protecting maize chloroplasts.