Identification and characterization of NAC transcription factor and their expression patterns under various treatments in Lycoris radiata

As one of the most extensive plant-specific transcription factors (TFs), the NAC family is essential for plant growth and development and their response to environmental stress. However, its functional characterization in Lycoris, particularly in Lycoris radiata, a commercial and agricultural crop that produces Amaryllidaceae alkaloids, has not yet been completed. In this study, the transcriptomic database of L. radiata was used to identify 42 LrNAC genes, which were then classified into 15 subgroups as per the phylogenetic tree that was constructed via NAC family members of Arabidopsis thaliana. This research comprises basic bioinformatics analyses, such as protein sequence length, molecular weight, and the identification of its conserved motifs. For the gene expression analysis, LrNACs were expressed in all tissues and had tissue-specific expression based on real-time quantitative PCR (RT–qPCR). The transcriptomic profiles of the genes were very different, indicating that these LrNACs have various functions in L. radiata growth and development. Furthermore, the LrNACs gene expression patterns in response to drought, salt, heat, cold stresses, and treatments with Abscisic Acid (ABA) and Methyl Jasmonate (MeJA) were characterized. The gene-gene interaction network analysis revealed the presence of synergistic effects between various LrNAC genes' responses against abiotic stresses. Among them, LrNAC08 and LrNAC09 are potential regulators in plants' responses to salt and drought stress due to their coordinated expression under various stress conditions. Additionally, the expression of LrNAC29 is linked to its role in ABA signaling, indicating its involvement in Lycoris's salt stress response. The results of this study could provide valuable information for further functional analysis of LrNACs and for the improvement of stress resistance in L. radiata.