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Multi-omics Integrative Analysis Of Puccinellia Tenuiflora In Response To Na2CO3 Stress

Posted on:2021-05-12Degree:DoctorType:Dissertation
Country:ChinaCandidate:Y X ZhangFull Text:PDF
GTID:1360330605967110Subject:Cell biology
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As a major environmental factor,alkali-salinity limits plant growth and agricultural productivity.The alkali-salinity stress can cause ionic,osmotic,and secondary oxidative stress.Previous studies focused on ion and osmotic stress mostly.While,the detailed mechanism in response to oxidative stress induced by saline-alkali stress is still not clear.Puccinellia tenuiflora is a salt-tolerant pasture,and is widely distributed in the saline-alkali land of Northern China.Thus,P.tenuiflora is considered as a good model for studying the saline-alkali tolerant mechanisms.It is very significant in researching on the tolerant mechanism in response to oxidative stress induced by saline-alkali stress in P.tenuiflora.In this study,we investigated alkali-salinity tolerant mechanism in P.tenuiflora leaves and roots at the transcriptional,translational and post-translational levels.By combining transcriptomics,proteomics,redox proteomics and molecular genetics approaches,we analyzed the molecular regulatory mechanisms of the Na2CO3-stressed P.tenuiflora at the genome-wide level.Transcriptomics studies showed that expression patterns of 13,290 and 15,859 genes were changed in Na2CO3-stressed leaves and roots,respectively.These gene expression patterns indicated that Na2CO3-responsive mechanisms might be different.In leaves,photosynthesis,transcription regulation,protein synthesis and degradation,and basal metabolism were important.While,stress and defense,signal transduction,membrane and transport pathways were crucial in stressed roots.Most importantly,more than thirty genes encoding key components of the LLG-FER signaling pathway were found in alkali-salinity responsive network in P.tenuiflora roots for the first time.Quantitative proteomics and redox proteomics studies showed that,under Na2CO3 stress conditions(0.5 h and 6 h),the abundances of 189 proteins were increased or decreased;62 peptides were more oxidized or reduced in leaves.Meanwhile,the abundances of 347 proteins and the redox modification levels of 168 peptides were regulated by Na2CO3 treatment in roots.The change patterns of abundances and redox states of these proteins implied that signaling,membrane trafficking and cytoskeletal remodeling,ROS homeostasis,stress and defense,gene expression and protein turnover,carbohydrate metabolism,amino acid metabolic pathways were pivotal to alkali-salinity adaptation in P.tenuiflora.The results indicate that P.tenuiflora applied several strategies to cope with Na2CO3 stress,including:(1)modulation of photosynthetic efficiency by regulating the abundances and redox levels of proteins involved in photosynthetic electron transport,ATP production and carbon assimilation;(2)regulation of membrane trafficking,protein transmembrane transport,lipid transport,and small molecules(water,ions,and metabolites)transport through modification of protein redox status;(3)maintaining intracellular ROS homeostasis by altering the abundances and redox states of important antioxidant enzymes;(4)LLG1-FER-FLS2 signaling pathway played important roles in roots of P.tenuiflora in response to Na2CO3 stress.In addition,PutLLG1 was preferentially expressed in roots and induced at the transcriptional level in response to saline-alkali stresses.LLG1 interacts with FER and acts as chaperones and co-receptors for FERONIA receptor kinase signaling.Moreover,oxidation level of on cysteine site(Cys130)located in conserved motif was increased significantly by Na2CO3 treatment,which suggested that the redox regulated Cys130 may affect its function.Within the LLG1,four pairs of disulfide bonds(Cys50-Cys98,Cys66-Cys76,Cys77-Cys121,Cys85-Cys130)formed with eight conserved Cys residues are detected.Yeast two-hybrid assays indicted that different Cys residues mutants have various effects on the strength of interaction between PutLLGl and PutFER.The protein interaction strength of PutFER and PutLLGC85/130A was obviously weaker than other combinations.We speculate that Cys85-Cys130 may regulate the conformation of PutLLG1 to affect its interaction with PutFER,thus activate the downstream signal pathway finally.These results provide new clues for understanding the regulatory mechanism of plant saline-alkali stress response in halophytic grass,and lay the foundation for the development and utilization of plant resources in saline-alkali land,and improving crop varieties by using molecular design breeding techniques.
Keywords/Search Tags:Puccinellia tenuiflora, alkali-salinity stress, transcriptomics, redox proteomics, signaling
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