Multi-omics profiling of Amorphophallus muelleri seeds: Insights into germination and ABA regulation

Amorphophallus muelleri, a naturally occurring variant of konjac, holds considerable ecological, economic, and medicinal significance due to its high konjac glucomannan (KGM) content. While the importance of seed germination as a complex physiological process is widely recognized, the regulatory network governing konjac seed germination remains largely unexplored. To better understand the fundamental molecular processes, we conducted a simultaneous examination of the transcriptome and non-targeted metabolome profiles of A. muelleri seeds at seven stages of germination, including dry seed, seed protrusion, seed germination; seedling coating outcrop, seedling cotyledons formation, seedling leaf with brown, and seedling leaf with green. Transcriptome and metabolome analyses revealed a reprogramming of seed metabolism during germination, marked by changes in phytohormones, flavonoids, starch, and sucrose. The levels of abscisic acid (ABA) were found to decline, particularly post-germination. A CYP707A gene (DN5757_c0_g1) linked to ABA catabolism was associated with reduced ABA levels during seed germination. The upregulation of mRNAs encoding cinnamic acid 4-hydroxylase (C4H) correlated with an increase in p-coumaric acid levels. Full activation of photosynthesis facilitated seedling growth at the post-germination stage. Using weighted gene co-expression network analysis (WGCNA), two modules linked to plant hormone biosynthesis, phenylpropanoid metabolism, and flavonoid biosynthesis were identified. Significantly, further results suggest that ABA may inhibit the germination process by involving gene expression. Using an exploratory multiomics dataset, our findings provide a comprehensive understanding of the germination process of A. muelleri seeds, elucidating the temporal-specific expression patterns of key candidate genes and metabolites, as well as shedding light on the role of ABA in the germination of konjac seeds.