Changes In The Metabolome In Leaves Of Wild Soybean (Glycine Soja Sieb. Et Zucc.) And Soybean (Glycine Max L.) Seedling Under Drought Stress

Drought,as a kind of abiotic stress,affects the growth and physiological function of crops,and eventually leads to plant metabolism disorder and even death.Soybean is widely as an important cash oil crops.Compared with soybean,wild soybean has higher protein content and stronger adaptability to bad environment.In this study,wild soybean and soybean were used as the plant materials.First,the seedlings grew normally in sand medium.When the seedlings grew to the third leaf stage,they were treated with 5% PEG-6000 to simulate the drought stress.After 14 days of drought stress treatment,the growth parameters of the wild soybean and soybean were measured.At the same time,the differential metabolites were analyzed between the leaves of wild soybean and soybean seedlings by gas chromatography-mass spectrometry(GC-MS)based the metabolic method,and the growth status and mechanism of metabolic of wild soybean and soybean was compared,which elucidated the drought tolerance mechanism of wild soybean.The results showed that wild soybean was less affected by drought than soybean.The root length of wild soybean increased and had higher root/shoot ratio under drought stress,while the root length of soybean was significantly inhibited and the root/shoot ratio decreased.In addition,the drought-tolerant energy of wild soybean is derived from the significant accumulation of effective amino acid metabolites such as tyrosine,serine,glycine,proline and effective small molecule carbohydrates and polyols compounds such as xylitol,mannose,mannitol,xylose and compounds related to galactose metabolism such as galactinol,myo-inositol,sucrose,sorbitol,raffinose,glycerol and so on;Organic acid metabolites such as glutaric acid,malonic acid,glucoheptonic acid,jasmonic acid and partial fatty acids;Secondary metabolic compounds such as ferulic acid,salicylic acid,squalene,gallic acid.Furthermore,compounds associated with respiratory pathways such as glucose-1-phosphate,fructose1,6-diphosphate,citric acid,succinic acid,maleic acid,6-phosphogluconic acid,gluconic acid,D-glyceric acid,gluconic lactone were also accumulated significantly in wild soybeans.And this suggests that under drought stress,wild soybean can change growth status and enhance respiratory metabolic pathways such as maintain a stable TCA cycle and significantly enhance glycolysis to produce more energy and enhance the phosphate pentose pathway to create more reducing power to resist drought stress.By comparing the changes of growth response and metabolomics of wild soybean and soybean under drought stress,the study reveals the drought tolerance mechanism of wild soybean,which provides an important reference value for obtaining excellent drought resistance genes of wild soybean and studying the drought tolerance genetic pathway of wild soybean,and lays a theoretical foundation for understanding soybean evolution and breeding of soybean drought tolerance varieties and development of soybean cultivation in arid regions.