Phosphate Availability Alters Morphological、 Physiological Characters And Causes Leaf Proteome Changes In Potato

Phosphorus as the basic elements is necessary for plant growth and development. Despite the soil contains sufficient phosphorus, the phosphorus is usually combined with other cation or in the form of inorganic phosphorus which is difficult to absorb and use by plants. Plants have evolved a specific morphological, physiological and molecular mechanism to cope with the change of phosphorus in soil. Potato is important crop. The yield of potato is made up by tubers. It is very important to investigate the growth and development of potato tuber under different P level.In this study, the fresh weight, plant height, root length, total root number and phosphorus, chlorophyll and anthocyanin content of potato seedlings under the different phosphorus treatments(0、0.25、0.5、1.25、2.5m M)were measured. The comparative proteomics of potato leaves were investigated. The results were as following:(1) Under low phosphorus levels, the morphology of potato seedlings showed significant differences compared with control. The phenotype of plant was dwarf, smaller leaves, decreased biomass and higher root/ shoot ratio. The total volume of root, the number of root and plant height were decreased under low P condition. The leaf area was also decreased under low phosphate levels. In addition, the content of phosphorus was increased with the concentration of phosphate increased. Low concentration of phosphorus resulted in that the content of anthocyanins was increased, but the content of chlorophyll was not changed.(2) The differentially expressed protein spots were detected under different levels of phosphorus. The protein spots were 988±45, 750±39, 867±42, 995±35 and 795±28 under 0, 0.25, 0.5, 1.25 and 2.5m M phosphate treatment, respectively. There were no significantly different in number of protein spots between 0 and 1.25 m M levels. The proteins of seedling leaves were induced significantly at 0.25, 0.5 and 2.5m M levels. Forty-nine differentially expressed proteins were detected under low phosphate levels. Twenty-four proteins were up-regulation, nineteen proteins were down-regulation, five proteins were between in somewhere, and one protein was induced.(3) Forty-nine proteins were indentified by mass spectrometry. Of 22.45% were involved in material metabolism, 10.2% were involved in the progress of disease and antioxidant, 8.16% were involved in substances regulate and control of cell, 6.12% were involved in energy synthesis, 16.33% were involved in protein transcription and translation, 2.04% were involved in protein synthesis, 10.2% were involved in putative protein, 4.08% were involved in predicted protein, 4.08% were involved in hypothetical protein and 6.12% were unknown function.(4) A chloroplast manganese stabilizing protein, which was involved in oxidative phosphorylation and photosynthetic phosphorylation of ATP synthase expression, was inhibited under low phosphate levels. The expression of enolase abundance was high, which was indicated that the glycolysis process was quickened under low phosphate levels. Carbonic anhydrase which was to regulate photosynthetic carbon metabolism process through regulating the content of inorganic phosphorus was down-regulated under 2.5m M phosphate level. Heme oxygenase was involved in photosensitive pigment synthesis of the chromophores and adjusted the root morphology. As a key enzyme of metabolic balance, nucleoside diphosphate kinase which enhanced the tolerance of environmental stresses through oxidation-reduction system was upregulated under 0.5m M and 1.25 m M phosphate level.