Identification and expression profiling analysis of the sucrose metabolic pathway genes in sugarcane (Saccharum spp.).

BACKGROUND: Sugarcane (Saccharum spp.) is a major C4 crop with high photosynthetic efficiency, cultivated globally in tropical and subtropical regions as the primary source of sugar. Sucrose biosynthesis is a central physiological process determining sugar accumulation; however, comprehensive genomic characterization and expression profiling of key sucrose metabolic genes remain limited. METHODS: Four genes involved in sucrose metabolism, viz., sucrose phosphate phosphatase (SPP), soluble acid invertase (SAI), neutral invertase (NI), and cell wall invertase (CWI), were investigated in the commercial sugarcane hybrids CoC 671 and Co 11,015. Coding sequences of SPP (1157 bp), SAI (643 bp), NI (665 bp), and CWI (669 bp) were amplified, sequenced, and subjected to sequence homology and phylogenetic analysis. Expression profiling of pyrophosphate-dependent phosphofructokinase (PFP), SPP, NI, and CWI was performed by quantitative real-time PCR (qRT-PCR). RESULTS: Homology analysis revealed that the identified genes shared > 85% sequence similarity with orthologs from Sorghum bicolor, Zea mays, and Hordeum vulgare. Phylogenetic analyses resolved two major clusters, with sub-clustering corresponding to related genera, suggesting evolutionary conservation of sucrose metabolic genes. qRT-PCR analysis showed that PFP, SPP, and NI transcripts were significantly upregulated in high-sucrose commercial hybrids, suggesting their potential involvement in source tissue carbon metabolism associated with sucrose accumulation. In contrast, CWI expression was elevated in low-sucrose genotypes (ISH 176 and GU 04 (42) RS-6), whereas transcript accumulation was markedly reduced in high-sucrose genotypes. CONCLUSION: This study provides molecular insights into sucrose metabolism in sugarcane, highlighting the regulatory roles of SPP, SAI, NI, and CWI. The findings identify key candidate genes for targeted genetic improvement and breeding strategies aimed at enhancing sucrose accumulation in commercial sugarcane hybrids.