Salt-tolerant Adaption Of Jerusalem Artichoke Plant Based On The Physiological And Proteomic Analysis

Fructans as the primary storage form of carbon exists in only a few species,including Jerusalem artichoke,which contains much saccharide in tubers and possesses appropriate salt resistant characteristic.Jerusalem artichoke(Helianthus tuberosus L.)is considered as a candidate bio-energy plant for improvement and utilization of intertidal zone,saline-alkali soil and bare place.Salt stress results in severe reduction of output that restricts economic value of Jerusalem artichoke.In-depth understand of influences by salt stress on the growth,physiology and proteome response mechanisms of Jerusalem artichokes provides theoretical basis on high yield in saline-alkali soil and efficient utilization of solonchak.In this thesis,two Jerusalem artichoke varieties(JiangSu DaFeng N.1 and HeNan PuYang M.1)were conducted as experimental materials.Hydroponics and soil culture were conducted to explore the differences of salt-tolerant ability in two varieties of Jerusalem artichokes.Multi-salt-density gradient were presupposed to research salt stress on the morphology,cell microstructure,growth,accumulation of biomass,photosynthetic capacity,ion absorption and distribution,osmotic adjustment substances,antioxidant systems and levels of endogenous hormone responses to analysis different salt resistant characteristics of two genotypes of Jerusalem artichokes.Additionally,technologies of proteomics were applied to research the expression responses of proteins in tow genotypes of JAs and 41 protein spots were authenticated by mass spectrometry and functional identification;the function and location in cells of determinate proteins were used to analysis discrepancies of salt resistance mechanisms deeply and provided theoretical basis on excavation of stress resistance gene in JAs.The results obtained were listed as follows:(1)When compared to control,the biomasses in two JAs were significantly inhibited by salt stress,and dry matter accumulation and water content in M1 were remarkably higher than in N1.Salinity had a negative influence on the biosynthesis and accumulation of photosynthetic pigment;on the one hand,salinity significantly reduced the Chl-a and T-Chl contents in N1 genotypes,which resulted in the decrease on photosynthetic intensity;on the other hand,salinity damaged the chloroplastic which acted as the apparatus of photosynthesis in different extent between multifarious salt concentration.Stress caused by ions poison and osmotic stress will also affect the growth of JAs;two genotypes of JAs resisted salt injury through increasing the content of proteins and soluble sugar,which played important roles in the process of adjusting osmotic balance.Under salt stress,soluble sugar content in leaves and stems of M1 were significantly high than in N1,opposite result occurred in roots,indicating different regulatory mechanism in two genotypes to oppose salt stress.Salt stress also inhibited the autioxidant enzyme activities in N1 genotypes significantly.According to the levels of hormones,improving contents of IAA and GA3 in M1 helped to adapt to the salt environment;however,N1 genotype increased ABA content to enhance the capacity of salt tolerance.All above revealed that different genotypes of JAs owned distinguishing characteristic of growth balance and stress resistance to salt stress.(2)In earth,longterm salt treatment affected the internal structure of chloroplast photosynthesis organs and synthesis of and accumulation of photosynthetic pigment,which were the dominant factors that restricted photosynthesis significantly with increasing salt concentration.Longterm salt treatment resulted in ion poisoning and osmotic stress,which mostly inhibited the growth of JAs.Antioxidant system response to salt stress under short-term salt treatment in seedlings existed much difference compared to Longterm salt treatment.Salt stress affected the distribution and redistribution of assimilation product in different parts of plants,which leaded to the yield reduction.Firstly,the yield of JA was associated with the source of assimilation product;secondly,the yield also influenced by the strength of bank,which directly related to cell structures of Jerusalem artichoke tuber.Salt stress severely damaged cell structure and distribution of N1 varieties in the tuber;factually,abnormal transport mechanism and superfluous energy metabolism all resulted from severe degeneration of vascular structure in tuber and the yield of tuber was significantly limited.It was of great significance that better cultivated varieties and proper saline environment should be selected becomingly to improve the yield of JA tubers.(3)To investigate the molecular response mechanisms to salt stress in JAs,we conducted a comparative proteomic analysis of leaves were conducted and 41 protein spots showed significant changes in abundance among 998 detached protein spots under salt stress.Matrix-assisted laser desorption ionization tandem time-of-flight mass spectrometry(MALDI-TOF/TOF MS/MS)was applied to identify the protein followed by similarity searches across EST database.Two genotypes Jas showed different response mechanisms in proteomics according to stress-responsive proteins,which categorized into 7 functional groups including photosynthesis(12.20%),translation and transcription(2.44%),carbohydrate and energy metabolism(26.83%),stress and defense responses(21.92%),cell structure(2.44%),protein synthesis,folding and degradation(17.07%),material metabolism(9.76%),amino acid metabolism(4.88%).As a whole,photosynthesis,carbohydrate metabolism and energy production,stress response,protein synthesis and modification and ROS scavenging-associated enzymes played crucial roles in the salt tolerance of JAs.All the results provided comprehensive insights into differences in the response mechanism induced by salt stress and initiated novel research directions between two genotypes of JA plants under salt stress or other abiotic stresses.