Study On The Physiological And Biochemical Changes And Differential Protein Expression Of Sugar Beet Under Salt Stress

Two different salt tolerance varieties of sugar beet,T510 and 210 were chosen to be the objects of this study and let them growth in 3 concentration of NaCl:0(CK),140mmol/L(LS),280mmol/L(HS),then study on their different protein expression.Salt stress related physiological and biochemical indexes are also be determined and analysed.The results showed that the two seedlings under CK had no difference in dry weight.Between CK and LS,T510 had no difference in dry weight of whole plant,but 210 was significantly decreased,and there was large difference between T510 and 210.In the HS,T510 and 210 both decreased significantly compared with CK,and the 210 were significantly lower than that of T510.On the protein level,there were significant differences between CK and salt stress both in T510 and 210,and there was also significant change between T510 and 210.By proteomics technology 129 protein spots showed significant change were decreased:For T510,in LS-CK the main difference proteins are about metabolism(25.00%)and photosynthesis(33.33%),in HS-CK the main difference proteins are about metabolism(26.09%)and photosynthesis(26.09%),in HS-LS the main difference protein is about photosynthesis(36.36%).For 210,in LS-CK the main difference proteins are about energy(34.78%)and photosynthesis(26.09%),in HS-CK the main difference protein is about photosynthesis(32.00%),in HS-LS the main difference protein is about Protein modification and processing(19.05%).For T510-210,in LS the main difference protein is about energy(17.14%),in HS the main difference protein is about photosynthesis(42.86%).In all the spots be decreased,the largest group is the photosynthesis(24.03%),followed by energy(17.83%)and metabolism(14.73%).These are the mainly proteins in significant change protein spots show that photosynthesis is the most affected protein in salt stress,and proteins of energy and metabolism are closely related to salt stress.In other stress related physiological and biochemical indexes,the two seedlings have no difference in CK.In salt stress,the relative water content of leaves is lower than it in CK,the content of soluble protein,permeability of plasma membrane,contents of MDA,antioxidant enzyme activity,ATPase activity,contents of osmotic adjustment substances are all higher than them in CK.And these are associated with the different protein expression about antioxidant enzyme(such as ascorbate peroxidase and manganese superoxide dismutase),proteins about ATP(such as ATP synthase delta chain and ATP synthase gamma chain),proteins about osmotic adjustment substances(such as Choline monooxygenase and S-adenosylmethionine synthase).We found that T510 can keep a higher energy response higher efficiency(such as anti oxidase catalytic)in LS within aerobic respiration related protein expression decreased or unchanged.And we also found that the expression of Phosphoenolpyruvate carboxylase family protein increase which is associated with C4 carbon sequestration pathway.This is help in reducing stomatal opening to retain moisture and guarantee the carbon fixation.These may be have regard to that T510’s accumulation of dry weight in LS.Between T510 and 210 in salt stress,we found that the expression of protein involved in photorespiration is higher in 210 than it in T510.This means that 210 need photorespiration for the stress to a certain extent,but T510 is not so dependence on it,in LS T510 even can reduce it on offset of Photosynthesis.The difference of protein expressions lead to the result that in salt stress the relative water content of leaves between T510 and 210 has no significant differences,the permeability of plasma membrane and contents of MDA in T510 were lower than them in 210,the antioxidant enzyme activity,ATPase activity,contents of osmotic adjustment substances in T510 were higher than them in 210.Above all,sugar beet can improve the activity of salt stress related enzymes and increase the synthesis of osmotic adjustment substances by change the relevant protein expression.And the difference of dry weight accumulation and salt tolerance between the two seedlings is caused by the difference of protein expressions of energy and photosynthesis.