Identification and expression analysis of phosphate transporter (PHT) gene family in Lupinus albus cluster root under phosphorus stress

According to global estimation, 5.7 billion hectares of agricultural land contain limited phosphorus (P) availability leading to insufficient plant growth and productivity. Internal phosphate transporters play an essential role in mediating P mobilization and uptake from the soil. White lupin ( Lupinus albus ) is a cluster root (CR) forming crop with great potential to survive under P limited soil. However, it is imperative to identify and characterize the phosphate transporter (PHT) gene family in plants to validate their involvement in solving P deficiency problems. The recent availability of white lupin high-quality genome allowed us an exhaustive searches in the whole genome and identified five phosphates transporters subfamilies, including 35 putative genes that are unevenly distributed on 16 chromosomes. The LaPHT1 subfamily contained eight genes, LaPHT2 subfamily have three, LaPHT3 subfamily have eight, LaPHT4 subfamily have nine, and LaPHO subfamily has seven. Gene structure and duplication were also examined in detail. Syntenic analysis revealed that white lupin PHT family members had maximum the collinear relationship with those in L. angustifolius followed by Phaseolus vulgaris but showed the least collinear relationship with those in Arabidopsis. Gene ontology (GO) analysis revealed that the in white lupin PHT genes were enriched in functions regulated P uptake, transport, and recycling mechanisms. RT-qPCR was performed to evaluate the transcript levels of LaPHT genes in different parts of CR under P deficient hydroponic culture. Our study would provide better understanding the genetic evolution and expression phosphate of phosphate transporters in L. albus CR under P deficiency. It will also be helpful for further functional-based studies to solve P deficiency-related issues and mitigate P stress responses.