RESUMO
The regeneration of adventitious roots (ARF) in excised plant parts is essential for the survival of isolated plant fragments. In this study, we explored the complex mechanisms of ARF in Larix kaempferi by conducting a comprehensive proteomic analysis across three distinct stages: the induction of adventitious root primordia (C1, 0-25â¯days), the formation of adventitious root primordia (C2, 25-35â¯days), and the elongation of adventitious roots (C3, 35-45â¯days). We identified 1976 proteins, with 263 and 156 proteins exhibiting increased abundance in the C2/C1 and C3/C2 transitions, respectively. In contrast, a decrease in the abundance of 106 and 132 proteins suggests a significant demand for metabolic processes during the C2/C1 phase. The abundance of IAA-amino acid hydrolase and S-adenosylmethionine synthase: in the C2/C1 phase, underscoring the role of auxin in adventitious root induction. The decrease in abundance of photosynthesis-related proteins during the C2/C1 phase highlights the significance of initial light conditions in adventitious root induction. Moreover, variation in cell wall synthesis and metabolic proteins between the C2/C1 and C3/C2 stages suggests that cell wall metabolism is integral to adventitious root regeneration. Gene Ontology enrichment analysis revealed pathways related to protein modification enzymes, including deubiquitinases and kinases, which are crucial for modulating protein modifications to promote ARF. Furthermore, the increased abundance of antioxidant enzymes, such as peroxidases and glutathione peroxidases, indicates a potential approach for enhancing ARF by supplementing the culture medium with antioxidants. Our study provides insights into metabolic changes during ARF in L. kaempferi, offering strategies to enhance adventitious root regeneration. These findings have the potential to refine plant propagation techniques and expedite breeding processes. SIGNFICANCE: The main challenge in the asexual reproduction technology of Larix kaempferi lies in adventitious root regeneration (ARF). While numerous studies have concentrated on the efficiency of ARF, proteomic data are currently scarce. In this study, we collected samples from three stages of ARF in L. kaempferi and subsequently performed proteomic analysis. The data generated not only reveal changes in protein abundance but also elucidate key metabolic processes involved in ARF. These insights offer a novel perspective on addressing the challenge of adventurous root regeneration.
RESUMO
Lignin is a complex biopolymer formed through the condensation of three monomeric precursors known as monolignols. However, the mechanism underlying lignin precursor transport remains elusive, with uncertainty over whether it occurs through passive diffusion or an active energized process. ATP-binding cassette 36 (ABCG36) plays important roles in abiotic stress resistance. In this study, we investigated the transport functions of LkABCG36 (Larix kaempferi) for lignin precursors and the potential effects of LkABCG36 overexpression in plants. LkABCG36 enhanced the ability of tobacco (Nicotiana tabacum) bright yellow-2 (BY-2) cells to resist monolignol alcohol stress. Furthermore, LkABCG36 overexpression promoted lignin deposition in tobacco plant stem tissue. To understand the underlying mechanism, we measured the BY-2 cell ability to export lignin monomers and the uptake of monolignol precursors in inside-out (inverted) plasma membrane vesicles. We found that the transport of coniferyl and sinapyl alcohols is an ATP-dependent process. Our data suggest that LkABCG36 contributes to lignin accumulation in tobacco stem tissues through a mechanism involving the active transport of lignin precursors to the cell wall. These findings shed light on the lignin biosynthesis process, with important implications for enhancing lignin deposition in plants, potentially leading to improved stress tolerance and biomass production.