The Changes In Physiological Characteristics Of Wheat Leaves And Identification Of Differentially Expressed Proteins In Wheat Spikes Under Low Temperature Stress

The low temperature is one of the major abiotic stress factors in the growth and development of plants.It severely restricts the crop production,stable production such as spikes,grain number,grain weight.Recently years,with the frequency increaseing of spring freeze stress in Huang Huai area,the Wheat suffered from more and more serious damage under low temperature stress.Therefore,it is of great significance to study the mechanism of damage and to cultivate new varieties with strong resistance to reduce the injuried under low temperature.In this study,SW601,chuan 77-1293,Zheng Hua 0840-3(LT sensitive)and Yuan xie 62,Longmai 157,fanmai 5(LT insensitive)were studied as experiment materials.Using the method of hydroponics,the changes of(MDA)content,superoxide dismutase(SOD)activity,peroxidase(POD)activity,catalase(CAT)activity were studied under low temperature stress for 4h?12 h?24h?48h?72 h at 0?in different wheat varieties leaves.Meanwhile,the changes of proteomes with SW601(low temperature sensitive materials)and Long mai 157(low temperature insensitive materials)at room temperature and under low temperature for 12 h and 72 h at 0?were analyzed by two-dimensional gel electrophoresis and mass spectrometry electrophoresis.The main results were showed as follows:With the extension of stress time,the content of MDA were increased in SW601,Sichuan 77-1293,Zheng Hua 0840-3(LT sensitive)and Yuanxie62((LT insensitive).While the changes trend of MDA content is "up-down-up" in Longmai 157 and fanmai 5(LT insensitive).Howerer,the content of MDA reached the maximumu at 72 h in the Whole of varieties under low temperature stress.While the POD and SOD activity trend was increased and then decreased in SW601,Zheng Hua 0840-3,Chuan 77-1293 and was increasing in Longmai 157,fanmai 5 and Yuanxie62.under low temperature stress,Above materials,the CAT activity was increased with the extension of stress time and reached the maximumu at 72 h.Compared with CK(0h),the increased range of CAT activity greater than the other Low temperature sensitive materials.2.two varieties SW601(LT sensitive)and Longmai 157(LT insensitive)were used to analyze the total protein profile under low temperature at12 h and 72 h at 0?by two-dimensional electrophoresis and matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry method.While using the spike of under normal growth temperature condition as control The results show that there are 800 to 900 protein spots for each variety within the range of to p H 4 to 7.After 12 h and 72 h of low temperature,120 up-regulated and 92 down-regulated protein spots were found in SW601,while 101 up-regulated and 60 down-regulated protein spots in Longmai 157..We selected 54 proteins spots which were significantly expressed and the expression ratio>2 under 2 temperatures stress condition.There were 43 protein spots identified by mass spectrometry analysis.Using protein Blast methods,the identified cold stress responsive proteins were classified into 7 groups including stress /defense,photosynthesis,protein metabolism,carbohydrate metabolism,signal transduction,energy pathways and other unknown function.Some of the expressed proteins were enhanced significantly in LT insensitive varieties Longmai 157 such as ascorbate peroxidase,Cu/Zn superoxide dismutase,late embryogenesis abundant(LEA),while they were not expressed in LT sensitive SW601.These protein may related to metabolic regulation or response characteristics of wheat spike under low temperature stress.stress-responsive protein spots(ratio>2)in both two materials showed significant changes,of which 43 were successfully identified.These cold stress responsive proteins were involved in stress /defense,photosynthesis,protein metabolism,carbohydrate metabolism,signal transduction,energy pathways and other unknown function,which may be relevant to many biological processes.Among these differentially expressed proteins,ascorbate peroxidase,Cu/Zn superoxide dismutase,late embryogenesis abundant(LEA)were enhanced significantly in LT insensitive Longmai 157,but were not expressed in LT sensitive SW601.This may related to metabolic regulation or response characteristics of wheat spike under low temperature stress.