Expression Analysis of Genes Associated with Sucrose Accumulation in Transgenic Sugarcane Lines Expressing a Mutansucrase Gene

Delfan, Mina; Nazarian-Firouzabadi, Farhad; Zahedi, Bahman

doi:10.22034/pgr.2026.2089379.1035

Expression Analysis of Genes Associated with Sucrose Accumulation in Transgenic Sugarcane Lines Expressing a Mutansucrase Gene

Document Type : Original Article

Authors

Mina Delfan ¹ ^¶

Farhad Nazarian-Firouzabadi ¹

Bahman Zahedi ²

¹ Department of Plant Production and Genetic Engineering, Faculty of Agriculture, Lorestan University, Khorramabad, Iran

² Department of Horticultural Sciences, Faculty of Agriculture, Lorestan University, Khorramabad, Iran

10.22034/pgr.2026.2089379.1035

Abstract

Sugarcane (Saccharum officinarum L.) is a prominent industrial crop characterized by its exceptional capacity for culm-localized sucrose accumulation. This accumulated sucrose serves as the primary substrate for diverse biopolymer-synthesizing enzymes. Among these, mutansucrase utilizes sucrose to synthesize mutan, a polysaccharide of high industrial and biomedical value. Heterologous expression of mutansucrase in sugarcane is hypothesized to simultaneously partition stalk sucrose toward mutan production and modulate the transcriptional profiles of key endogenous genes governing carbohydrate metabolism. In this study, we employed semi-quantitative RT-PCR to evaluate the expression levels of core sucrose biosynthetic and catabolic genes, specifically sucrose-phosphate synthase (Sps), sucrose synthase (Susy), soluble acid invertase (Sai), and neutral/alkaline invertase (Inv) in both leaves and stem tissues of transgenic mutansucrase-expressing lines (B9, B11 and B38) and non-transgenic controls. The results of present study demonstrated that the expression of endogenous machinery involved in sucrose metabolism was significantly modulated by heterologous mutansucrase activity. Specifically, Sps transcript levels were upregulated in transgenic lines relative to wild-type controls, whereas Susy expression exhibited no substantial variation between the experimental groups. Conversely, both Sai and Inv transcripts were more abundant in control plants than in the transgenic counterparts. Among the evaluated transgenic population, line B38 exhibited the most pronounced alterations in gene expression. Taken together, these findings indicate that transgenic mutansucrase activity triggers targeted transcriptional reprogramming of the host plant’s sucrose metabolic pathway. We propose that the depletion of the internal sucrose pool by the exotic enzyme activates a compensatory feedback mechanism aimed at replenishing the substrate. Consequently, targeted genetic strategies overexpressing key sucrose biosynthetic genes could increase substrate availability, thereby metabolic flux toward enhanced mutan biopolymer production.

Keywords

Ectopic expression

Gene expression

Biopolymer

Genetic engineering

Sucrose metabolism

Subjects

Genetic engineering

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