Gibberellin Signaling Promotes the Secondary Growth of Storage Roots in Panax ginseng

Abstract

Gibberellins (GAs) are an important group of phytohormones associated with diverse growth and developmental processes, including cell elongation, seed germination, and secondary growth. Recent genomic and genetic analyses have advanced our knowledge of GA signaling pathways and related genes in model plant species. However, functional genomics analyses of GA signaling pathways in Panax ginseng, a perennial herb, have rarely been carried out, despite its well-known economical and medicinal importance. Here, we conducted functional characterization of GA receptors and investigated their physiological roles in the secondary growth of P. ginseng storage roots. We found that the physiological and genetic functions of P. ginseng gibberellin-insensitive dwarf1s (PgGID1s) have been evolutionarily conserved. Additionally, the essential domains and residues in the primary protein structure for interaction with active GAs and DELLA proteins are well-conserved. Overexpression of PgGID1s in Arabidopsis completely restored the GA deficient phenotype of the Arabidopsis gid1a gid1c (atgid1a/c) double mutant. Exogenous GA treatment greatly enhanced the secondary growth of tap roots; however, paclobutrazol (PCZ), a GA biosynthetic inhibitor, reduced root growth in P. ginseng. Transcriptome profiling of P. ginseng roots revealed that GA-induced root secondary growth is closely associated with cell wall biogenesis, the cell cycle, the jasmonic acid (JA) response, and nitrate assimilation, suggesting that a transcriptional network regulate root secondary growth in P. ginseng. These results provide novel insights into the mechanism controlling secondary root growth in P. ginseng.

Identification of WAT1-like genes in Panax ginseng and functional analysis in secondary growth

“…One of the key elements that influences the yield and quality of P. ginseng is the promotion of secondary growth of the storage roots. Recent research has demonstrated that treatments with exogenous nitrate or gibberellins (GAs) significantly accelerated the storage root secondary growth of P. ginseng (Geem et al 2022;Hong et al 2021b). In these studies, the protein-protein interaction network analysis of two secondary growth promoting factors revealed that the auxin activated signaling pathway would be fundamentally integrated into the hormonal regulation networks for storage root formation (Geem et al 2022;Hong et al 2021b).…”

“…Recent research has demonstrated that treatments with exogenous nitrate or gibberellins (GAs) significantly accelerated the storage root secondary growth of P. ginseng (Geem et al 2022;Hong et al 2021b). In these studies, the protein-protein interaction network analysis of two secondary growth promoting factors revealed that the auxin activated signaling pathway would be fundamentally integrated into the hormonal regulation networks for storage root formation (Geem et al 2022;Hong et al 2021b). To further investigate the core genetic networks affecting the auxin-connected storage root thickening process in P. ginseng, we reanalyzed the RNA-seq data of nitrate-treated roots of 1-year-old P.ginseng (Geem et al 2022).…”

Pseudo-Chromosomal Genome Assembly in Combination with Comprehensive Transcriptome Analysis in Agaricus bisporus Strain KMCC00540 Reveals Mechanical Stimulus Responsive Genes Associated with Browning Effect

“…Interestingly, chorismate mutase and 4-aminobenzoate synthase were somewhat up-regulated throughout the observed time course, whereas 4-coumarate CoA ligase was up-regulated at later time points. In studies aiming to identify browning phenotype-correlated genes through combining genetic analysis and QTL, many QTLs included melanin biosynthesis pathway genes such as CM, PALs, and PPOs [ 46 , 47 ]. These findings confirm our explanation of how browning is regulated and further indicate that targeting these genes in molecular breeding methods such as CRISPR-Cas9 might lead to browning-insensitive types.…”

“…Gene Ontology (GO) term was inferred from manually annotated data from the A. bisporus JB137 database, and enriched GO terms were determined based on EASE score from a modified Fisher’s exact test, p < 0.05 [ 40 , 41 , 42 ]. Enriched GO genes were further analyzed with Gene Set Enrichment Analysis (GSEA), as described in Hong et al [ 43 , 44 , 45 , 46 , 47 ].…”

Comparative Transcriptome Analysis between Two Potato Cultivars in Tuber Induction to Reveal Associated Genes with Anthocyanin Accumulation

“…Gene ontology (GO) term enrichment analysis was performed using DAVID [ 67 ], and enriched GO terms were determined by Fisher’s exact test ( p < 0.05). Enriched GO genes were further analyzed with gene set enrichment analysis (GSEA, v4.1.0, US), as in [ 68 , 69 ]. Network analysis was performed with GeneMANIA app (v3.5.2, US) in Cytoscape (v3.9.0, US) [ 70 , 71 ] with WRKY44 as query gene.…”