The WRKY transcription factors are recognized for their pivotal roles in plant development and stress responses, but their involvement in specialized metabolic pathways, such as crocin biosynthesis, remained largely unexplored until now. Using advanced transcriptomic techniques, the study mapped and characterized these genes in Crocus sativus, providing crucial evidence of their functional significance in the biosynthetic pathway.
The authors' previous research identified various transcription factor (TF) families, including WRKY, bHLH, MYB, and AP2/ERF, in the stigma of Crocus sativus through transcriptomic analysis. Among these, WRKY transcription factors are one of the largest TF families in plants, playing critical roles in regulating secondary metabolite biosynthesis, defense signaling, plant development, and responses to environmental stimuli. WRKY proteins are characterized by one or two conserved WRKY domains, which include a WRKYGQK heptapeptide and a C2H2 or C2HC zinc finger motif. These proteins function by binding to specific cis-regulatory elements in the upstream regions of target genes, influencing their expression.
This study provides a comprehensive analysis of WRKY transcription factors in the stigma of Crocus sativus, focusing on their potential roles in crocin biosynthesis. A total of 34 CsWRKY genes were identified from RNA-sequencing data, with conserved domains and motifs predicted. Phylogenetic and multiple sequence alignment analyses were conducted to explore their functional and evolutionary characteristics. Coexpression correlation analysis linked CsWRKY genes to crocin biosynthesis-related genes, while qRT-PCR revealed their expression patterns across tissues and developmental stages. The findings highlight several candidate CsWRKY regulators involved in crocin biosynthesis, advancing our understanding of these genes' roles in saffron stigma.
This discovery marks a significant advancement in understanding the genetic regulation of secondary metabolites in plants. The findings could have far-reaching implications, including the potential for genetic engineering or breeding programs aimed at enhancing crocin production in saffron, thereby addressing global demands for this high-value crop.
The research contributes to broader scientific efforts to decode plant metabolic pathways and underscores the importance of integrating genomics and biotechnology to optimize natural product synthesis.
The full article can be found on the Journal of the American Society of Horticultural Science electronic journal website at: https://doi.org/10.21273/JASHS05414-24
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