Genome-Wide Identification and Expression Pattern of the NAC Gene Family in Panax notoginseng.

Background: The NAC transcription factor family of genes is one of the largest families of transcription factors in plants, playing important functions in plant growth and development, response to adversity stress, disease resistance, and hormone signaling. In this study, we identified the number of members of the Panax notoginseng NAC (PnNAC) gene family and conducted a comprehensive analysis of their physicochemical characteristics, chromosomal location, evolutionary features, and expression patterns both in different parts of the plant at different growth stages and in response to infection by Alternaria panax.

Methods: The NAC gene family in P. notoginseng was identified using Hidden Markov Model (HMMER) and National Center of Biotechnology Information Conserved Domain Database (NCBI CDD), and their physicochemical properties were analyzed with Perl scripts. Phylogenetic relationships were determined using Clustal Omega and FastTree, and gene structures were visualized with an R script. Promoter regions were analyzed with PlantCARE, motifs with MEME and ggmotif, and transcriptome data were processed using Hical Indexing for Spliced Alignment of Transcripts (HISAT2) and HTseq.

Results: This study identified 98 PnNAC genes in P. notoginseng, analyzed their characteristics (protein lengths 104-882 aa, molecular weights 11.78-100.20 kDa, isoelectric points 4.12-9.75), location (unevenly distributed on 12 chromosomes, no tandem repeats), evolution, and expression patterns (distinct in different parts, growth stages, and after A. panax infection).

Conclusions: PnNAC plays an important role in the growth and development of P. notoginseng and in its response to A. panax. PnNAC could be a candidate gene for further research on and functional analysis of P. notoginseng disease resistance.