EXPRESSION PROFILING OF GENES INVOLVED IN SUCROSE METABOLISM IN DIFFERENT SACCHARUM SPP. AND COMMERCIAL SUGARCANE HYBRIDS

Abstract

A comprehensive analysis of the transcript levels of genes involved in sucrose accumulation is fundamental for the assessment of the function of each enzyme and regulatory mechanism of sucrose metabolism in sugarcane. The expression profiles of genes encoding sucrose phosphate synthase (SPS), sucrose phosphate phosphatase (SPP), soluble acid invertase (SAI), cell wall invertase (CWI), pyrophosphate fructose-6-phosphate phosphotransferase (PFP), fructokinase (FK), hexokinase (HK) and ADP-glucose pyrophosphorylase (ADP-G) in sugarcane was examined using RT-PCR. Different modes of gene expression were observed for each gene revealing the complexity of sucrose metabolizing pathway in sugarcane. Transcript levels of SPS, SPP, SAI, CWI, Sucrose transporter (SUT1 and SUT4) were found to be differentially regulated between high and low sugar commercial sugarcane hybrids. But no definite pattern of expression of these genes was observed in different Saccharum spp. Similarly PFP, FK and HK were also differentially expressed in commercial sugarcane hybrids as compared to different Saccharum spp suggesting the role of these enzymes in the regulation of sucrose metabolism in sugarcane. Expression of Sucrose synthase (SuSy) was uniform in both high and low sugar genotypes of Saccharum spp. and commercial sugarcane hybrids whereas expression of ADP-G was found only in high sugar Saccharum officinarum clone.