Studies On Proteome Of Seed Storability In Wheat

Wheat is an important cereal crop.The amount of wheat germplasm resources that are stored in low-temperature genebanks worldwide is about 850,000 accessions,and there are 51,000 accessions for long term storage in National Genebank of China,which can provide the important material basis for the germplasms innovation and exploitation.However,the decline of seed vigor is irreversible during conservation,and there are differences among different species and varieties.Due to the consistent storage conditions of genebank,the most important factor that affects the loss characteristics of seed vigor is genetic material.Seed storability is a comprehensive feature from the interaction between intrinsic genetic material and external environment,and also represents the ability of seeds which maintain vitality.In this study,in order to investigate the biological mechanism of seed storability,two accessions?TRI₂3248 and TRI₁0230?of wheat with significant differences in storability were used as experimental materials.The difference of seed storability was analyzed by aging treatment?40 °C,75% relative humidity?,low temperature?18 °C?and room temperature?20 °C?storage for 10 years.The protein regulation mechanism of seed storability was analyzed from physiological,biochemical and proteomic aspects to select the difference indicators that could reflect germplasm storability,so as to provide the scientific basis for monitoring of germplasm vigor and the safe conservation of germplasm resources.The main findings are as follows:1.The two accessions of wheat were stored under low temperature?-18 °C?and room temperature?20 °C?condition for ten years,and treated by artificial accelerated aging.Seed vigor monitoring showed that TRI₂3248 had a relatively longer platform phase,and the rate of loss of seed vigor was very low.Therefore,the storability of TRI₂3248 is higher than that of TRI₁0230.2.Proteomic analysis based on iTRAQ showed that there were 53 differentially expressed proteins between storage tolerant and storage sensitive wheat seeds.From the level of protein expression,26 proteins had higher abundance in the storage tolerant seed;and 27 proteins had higher abundance in the storage sensitive seed.The function of these proteins was mainly related to stress/defense,metabolism and storage proteins,which may represent genetic differences between the two materials.3.Proteomic analysis based on iTRAQ revealed that 89 proteins were differentially expressed with the decrease of seed vigor?99%,90%,80% and 60%?,of which 54 proteins belonged to the storage tolerant seed,and 62 proteins belonged to the storage sensitive wheat seed.The functions of these proteins mainly involved in stress/defense,metabolism and storage proteins.For the expression level of these proteins,the storage sensitive wheat seed was higher at different vigor levels.4.Proteomic analysis of two dimension electrophoresis showed that there were 137 differentially expressed proteins in the two accessions of wheat after storage for 10 years at low temperature?-18 °C?and room temperature?20 °C?,of which 93 proteins belonged to the storage tolerant seed,and 105 proteins belonged to the storage sensitive seed.These proteins were involved in 10 functional categories,in which the proportion of stress/defense,energy and storage proteins was high.Moreover,the protein expression level in the storage tolerant seed was higher than that in the storage sensitive seed.Further,according to the changes of relative conductivity,malondialdehyde content,antioxidant enzyme activity,antioxidant content,antioxidant enzyme gene and protein expression,the storage tolerant seed had stronger antioxidant system activity.The proteins associated with ascorbic acid-glutathione cycle were closely related to seed storability,and these differential abundance proteins could be used as early warning indicators for seed vigor monitoring.In summary,the storage tolerant seed had the ability to maintain the regulation of the expression of key proteins involved in stress/defense,protein metabolism,and energy metabolism.So seed storability contained the regulation of the expression of stress/defense proteins to protect against oxidative damage,the regulation of the expression of energy metabolism proteins to supply energy,and the regulation of the expression of store proteins to synthesize intermediate substances,to maintain high vigor of seeds.And the above results can provide a scientific basis for creating a technological system for the safe conservation of crop germplasm resources.