Physiological And Proteomic Analysis Of Heat-tolerant Spinach Leaves In Response To Heat Stress

For recent years,with the increase of global greenhouse effect,heat stress becomes the more and more important environmental factor in plant growth.Therefore,the research of the molecular mechanism of responses to heat stress is of great significance for improving resistance and genetic breeding in plants.The Spinach(Spinacia oleracea L.)is of the Amaranthaceae spinach(Spinacia)and has good nutritional value as a common green leafy vegetable.It is also an important economic crop and resistant to low temperature,but sensitive to high temperature.Physiology and proteomics methods were used to study the mechanism of resistance to heat stess in spinach Sp75.After 60 days old spinach Sp75 was under 37 ~oC for 0 h,24 h,48 h,72 h,96 h and 120 h,its external morphology was observed and the membrane permeability,osmotic adjustment substance,antioxidant enzyme activity,antioxidant content,as well as leaf photosynthesis related parameters were determined.By the methods of two-dimensional electrophoresis and mass spectrometry to research the leaf proteome in spinach Sp75 under 37 ~oC for 0 h,24 h,48 h and 72 h research,86 different kinds of proteins were determined and they were mainly involved in photosynthesis,carbon and energy metabolism,metabolism,stress resistance,protein fate and other processes.By physiologyical and proteomic results,we mainly found that:(1)Under heat stress,a lot of osmotic substances were accumulated to maintain cell structure in spinach Sp75.(2)Decreased light-harvesting,damaged thylakoid,inhibition of electron transfer and the Calvin cycle were caused in leaf blade.(3)The processes of the peroxidase,catalase,glutathione-ascorbic acid cycle and other processes were enhanced to remove excess ROS.(4)The processes of carbon and energy metabolism,ATP synthesis and TCA cycle were restrained and glycolytic pathway were enhanced.(5)The process of amino acid metabolism was enhanced.(6)The process of protein synthesis and degradation were inhibited,the folding and transport of protein were enhanced.These results provide important information for us to explore the mechanism of resistance to heat in spinach.