Study On Physiology Of Highland Barley Seedlings And Related Gene Expression Under Co²⁺ Stress

In this study,highland barley kunlun No.15 was used as the material to analyze the changes of physiological and biochemical indexes and genetic expression of the highland barley seedlings treated with the CoCl₂,clone the highland barley PAL gene and analyze its bioinformatics content.The main research results are as follows:?1?Compared with the control group,the plant height and root length of highland barley seedlings were significantly reduced at the concentration of 30-250mg/L CoCl₂?P<0.05?.The content of soluble sugar,proline and MDA in lea ves increased significantly?P<0.05?.?2?Different antioxidant enzymes of highland barley seedlings have different responses to Co²⁺stress.The activity of SOD,POD and APX was first increased in the root,and the activity was highest when the cobalt concentration was 70mg/L,200mg/L and 70mg/L,MDA and soluble sugar content was first increased in the leaves,and there was a significant correlation between the activities of APX,POD and SOD in the leaves and roots.It indicates that highland barley increases the content of osmotic substances and antioxidant enzyme activity under cobalt stress to resist cobalt stress.?3?The highland barley PAL gene was cloned,with the cDNA length of 2142bp,including a complete open reading frame,encoding 713 amino acids,and named as HvPAL?GenBank login number:MK695675?.The gene contains three highly conserved domains and contains typical PAL enzyme activity center sequences GTITASGDLVPLSYIAA.Mino acid homology with barley,wheat and rice is up to90%.Molecular phylogenetic tree was constructed based on PAL protein sequence,and highland barley and grass plants were gathered into one branch.?4?Under the stress of Co²⁺at a certain concentration,the expression levels of SOD,POD,P5CS,GSH and PAL genes were induced by Co²⁺concentration.Compared with the control group,the POD gene expression of highland barley showed an increasing trend,and PAL,GSH,P5CS and SOD genes showed a single peak curve.SOD gene plays a role under low concentration of 70mg/L Co²⁺treatment.GSH,P5CS and PAL genes play a role in the treatment of 100-150mg/L medium Co²⁺.POD and P5CS genes play a role in high concentration Co²⁺treatment at200-250mg/L.?5?The contents of SOD?POD and proline were positively correlated with the expressions of corresponding genes.POD expression was positively correlated with proline content and P5CS gene expression.It is speculated that under the cobalt stress,highland barley can regulate the enzyme activity by increasing the expression level of related antioxidant enzyme genes at the transcription level,and the antioxidant enzymes can coordinate with each other to improve the barley's resistance to heavy metal cobalt in a complex way.