Comparative transcriptome analysis, identification and expression analysis of sucrose phosphate synthase genes in high and low starch cassava (Manihot esculenta Crantz) genotypes

The identification and characterization of the sucrose phosphate synthase ( SPS ) genes family have been carried out in several plant species; nevertheless, studies on the analysis of SPS genes in cassava are limited. We report the study of four SPS genes; ( sucrose phosphate synthase 3 F, sucrose phosphate synthase 1F, sucrose phosphate synthase family protein and sucrose phosphate synthase 2 F) identified from transcriptome analysis (NCBI Bio project ID: PRJNA998707) of the total RNA isolated from storage roots of TME-419 and H-165 cassava varieties. The sequence analysis revealed that the expression of SPS genes was mainly between the third and sixth months of storage root development in the two cassava varieties. However, TME-419 variety recorded 3.4-fold higher in expression of SPS than H-165 variety. Variations observed in the level of expression of the SPS genes and the reliability of the selected differentially expressed genes was validated via reverse transcription-polymerase chain reaction. The chromosome position of the SPS genes were located on Chr 18, Chr 15, Chr 14 and Chr 16 for sucrose phosphate synthase family protein, Sucrose phosphate synthase 3 F, Sucrose phosphate synthase 1F and Sucrose phosphate synthase 2 F respectively. The correlation analysis showed that the expression of SPS genes is positively correlated with the level of sucrose and starch contents in the cassava storage roots. This implies that high expression of SPS genes in cassava storage roots has the ability to expedite the rate of starch accumulation, which is important for the cassava industry, food security, and breeding of elite cassava and related starch-producing crops.