Quality Characteristics and Starch-Sucrose Pathway Differentially Expressed Genes in Glucomannan-type Amorphophallus konjac and Starch-type A. paeoniifolius ‘yellow’

Purpose This study aimed to clarify the quality differences between glucomannan-type Amorphophallus konjac (AmKo) and starch-type A. paeoniifolius ‘yellow’ (AmPy), and to identify the key differentially expressed genes regulating glucomannan and starch synthesis, exploring the molecular basis of the differences in edible quality between the two types of konjac.

Methods The two varieties of Amorphophallus were used as the research objects. Their quality characteristics were systematically compared, and the genes of starch-sucrose pathway were screened based on transcriptome sequencing.

Results AmKo exhibited extremely significantly higher glucomannan content (82.35%), viscosity (6895.33 mPa·s), and calcium content (0.13%) than AmPy. Conversely, AmPy showed extremely significantly higher starch (64.27%), crude fiber (39.60%), and total alkaloid content (0.12%) than AmKo. Correlation analysis revealed that konjac glucomannan content in AmKo was significantly negatively correlated with crude fiber and total alkaloid content, but significantly positively correlated with granularity, starch, and crude fat. Transcriptome analysis identified peptide chain release factor subunit1 (ERF1), β-glucosidase (bglX), and hexokinase (HK) as highly expressed genes in the glucomannan synthesis pathway of AmKo, whereas granule-bound starch synthase (WAXY), starch synthase (glgA), and glucose-1-phosphate adenosine transferase (glgC) genes were highly expressed in the starch synthesis pathway of AmPy.

Conclusion The direct edibility of AmPy can be attributed to the high expression of starch synthesis genes and the lack of toxic alkaloids and calcium oxalate crystals. These findings provide a theoretical foundation for the germplasm utilization and genetic improvement of Amorphophallus species.