Identification of single nucleotide polymorphisms (SNPs) in selected rice phosphate transporter (OsPHT) genes

Abstract

Phosphorus (P) is one of the fundamental elements for plant growth and development. Due to the scarcity of viable P in the soil for plants, P deficiency was often the culprit that restrained plant’s wellbeing. Plasma membrane phosphate transporters (PHT) are a group of proteins responsible for phosphate (Pi) uptake from soil and further allocation to plant organs and tissues. The PHT can be further categorized into constitutively expressed low-affinity Pi transporter or high-affinity Pi transporter that are induced upon Pi starvation. Significant variability in P use efficiency has been observed among different rice varieties. Genotypic differences such as single nucleotide polymorphisms (SNPs) could be responsible for the variation observed aside from the well-studied phenotypic responses. Nevertheless, the occurrence of the SNPs in OsPHT genes remain unexplored. Therefore, the objective of this study was to analyse and profile the SNPs in five selected high affinity OsPHT genes which are responsible for P uptake under P deficiency. The SNPs mining was conducted using Rice SNP-Seek Database against 3024 rice varieties with Oryza sativa japonica cultivar Nipponbare as the reference sequence. Results showed that a total of zero, seven, three, one and ten non-synonymous SNPs was identified in OsPHT1;2, OsPHT1;3, OsPHT1;6, OsPHT1;9 and OsPHT1;10, respectively. A base substitution of C to A at position 16028497 of chromosome 10 of OsPHT1;3 was found to change tyrosine to a stop codon. This could result in a truncated protein which has only 213 amino acids as compared 526 amino acids in the complete protein. The large number of non-synonymous SNPs in OsPHT1;10 could explain the redundant function of this gene in the translocation and uptake of P in rice. In short, the identified SNPs especially the non-synonymous SNPs could potentially disrupt the biosynthesis of phosphate in rice which requires further investigation.