Effects Of AM Fungi On Photosynthetic Physiology And Proteome Of S. Japonica Leaves Under Salt Stress

The photosynthetic characteristics,soluble sugar and soluble protein and other physiological indicators of Elaeagnus angustifolia leaves in inoculation treatments（GI）and non-inoculated treatments（CK）were measured during stress imposed by concentrations of 0,100,200,or 300 mmol/L Na Cl.And the application of non-labeled quantitative proteomics（Label-free）technique to analyze the proteome of Elaeagnus angustifolia（0 and 300 mmol/L Na Cl treated seedlings）.To reveal the effect of AMF on photosynthetic physiological characteristics of seedlings under salt stress and the molecular mechanism of Elaeagnus angustifolia seedlings response to salt stress.The results show that:The Pn,Tr,Gs,and Ci of E.angustifolia leaves decreased significantly as salt concentration increased in both CK and GI treatments.Moreover,these parameters were significantly higher in GI treatments than in CK treatments（p<0.05）.However,the magnitude of change in these parameters was smaller in GI treatments than in the CK treatment;changes in chlorophyll content in E.angustifolia leaves as salt concentration increased were positively correlated in GI and CK treatments.However,the magnitude of such changes was generally higher in the CK treatments than in the GI treatments;in the GI treatments,Fv/Fm,ФPS II,q P,ETR,and Fv/Fo initially increased with increasing salt concentration,before decreasing;in CK treatments,these parameters declined consistently as salt concentration increased.Moreover,in GI treatments,NPQ and HDR initially decreased as salt concentration increased,before increasing.In CK treatments,NPQ was similar to that of GI treatments,whereas HDR decreased gradually as the concentration of salt increased.The results further reveal that AMF play an important role in improving photosynthesis and chlorophyll fluorescence characteristics in salt habitats.Protein identification and quantitative analysis of the differences in the expression of the application of Label-free technology,and ultimately determine the 75 proteins on changes in response to salt stress,these proteins are mainly involved in metabolism,signal transduction,protein synthesis/protein folding and degradation,ROS removal,photosynthesis,energy et al.Changes in functional classification and physiological protein on expression based on the difference we found that mycorrhizal plants use can alleviate salt stress damage mechanism may be as follows:（1）AMF to accelerate plant secondary metabolism and other important metabolism,accelerate the accumulation of secondary metabolites and derivatives;（2）AMF increased second messenger signal transduction Ca²⁺,enhance the stress signal perception and transmission speed,enable the plant to do the follow-up defense;（3）in a variety of antioxidant pathways（TRX/GRX,GST/GPX,POD）,AMF by improving the clearance of ROS strengthened plant antioxidant capacity;（4）AMF protection protein biosynthesis,folding,transport and inhibition of protein the degradation;（5）in chloroplasts,AMF maintain PSII reaction center conformational stability,accelerate photosynthetic electron transport;in the mitochondria,AMF enhanced The synthesis of ATP provides energy for cell activity.This study is to understand the mechanism of enhancing salt tolerance of mycorrhizal plants,and prove that halophytes and AMF coexist in saline alkali soil improvement,which has a certain application prospect.