Screening Of Phosphorus Utilization Efficiency At Seedling Stage And Its Cloning Analysis Of Highly Phosphorus Utilization Efficient Gene PHR1 In Hulless Barley

Hulless barley is a distinctive crop on the Qinghai-Tibet Plateau,and also becomes the only kind of crop which can be grown above the altitude of 4500 meters in plateau areas because it has well drought and cold resistance.Phosphorus fertilizer is an indispensable mineral resource for plant growth and development,however,its utilization efficiency in agricultural production is very low,the application of phosphate fertilizer is a key factor in the eutrophication of surface waters.Therefore,to solve the problem of efficient utilization of plant phosphorus nutrition is not only a great help for agricultural production,but also can ensure the rational and effective use of the world's phosphate resources and prevent water pollution.In this study,the multiple indexes were synthetically evaluated for phosphorus use efficiency of 52 hulless barley accessions by investigating the biomass,root/shoot ratio,phosphorus utilization efficiency and acid phosphatase activity at the seedling stage.The results showed that the comprehensive evaluation value(D)of phosphorus utilization efficiency is from 0.2627 to 0.8154 with an average of 0.5081.The 52 hulless barley accessions were clustered into four groups based on D value.The first group,0.2627?D?0.0.3720,processed 11 accessions including long awn-white naked barley?Egazong?Zharen?Qiongjie yellow six-rowed barley?Mandu?white naked barley?white naked barley?short awn naked barley?branched naked barley?Naimu and white naked barley,which are relatively weaker phosphorus use efficiency with the average D value of 0.3245;There are 23 accessions were clustered into the second group with D value of 0.4063?D?0.5555 and the average D value of 0.5252;16 Hulless barley accessions,which the D value is 0.5829?D?0.7193 with the average D value of 0.5968,were clustered into the third group;The remaining 2 accessions of hulless barley including Amandu and Lhasa purple naked barley,which had relatively best phosphorus use efficiency with the D value 0.7811?D?0.8154 and the average D value of 0.7983.Homologous cloning methods were implied to obtain the complete sequence of the phosphorus efficient gene PHR1(1139bp)with a complete open reading frame of 1101 bp from 29 to 1129 in hulless barley.Bioinformatics analysis showed that sequence of PHR1 gene in hulless barley is highly homologous to the closely related species,and it encodes 366 amino acids with a molecular weight of 40,033.05 Da and an isoelectric point of 5.14.It has two typically conserved domains of the MYB-CC family.The predicted protein does not have a transmembrane structure without signal peptide structure,while it was not belonged to secreted protein family,almost all outside the cell.The result of this study provided theoretical and practical basis for breeding new well qualify hulless barley with high-phosphorus use efficiency.