香樟 NAC 基因家族的全基因组鉴定 及盐胁迫下的表达分析.

【Objective】The present paper aimed to investigate the important role of NAC gene in the growth and development of Cinnamomum camphora and its role in salt stress, and to clarify the response mechanism of C. camphora under salt stress. 【Method】The genome-wide NAC genes of C. camphora were identified and analyzed by bioinformatics to investigate the mode of response to abiotic stress in C. camphora. By identifying the members of NAC family of C. camphora,the paper aonducteda systematic analysis in terms of physicochemical properties, phylogenetic analysis, conserved motifs and gene structures, chromosomal localization and inter-species covariance, cis-acting element prediction and expression patterns.【Result】A total of 103 CcNAC genes were identified, the amino acid counts ranged from 137 to 1136, the isoelectric points from 4.54 to 10.00, the relative molecular masses from 15 644.40 to 129 859.29 u, and the mean hydrophobicity of all proteins was negative, indicating hydrophilicity. Subcellular localization was predicted to be in the nucleus and cytoplasm. A phylogenetic evolutionary tree was constructed with Arabidopsis thaliana NAC gene sequences, which classified CcNAC genes into 16 subfamilies. The NAM subfamily had the most members, with 17 CcNAC genes, while 25 CcNAC genes were not included. Conservative motif and gene structure analysis revealed that CcNAC genes were found to contain 2-8 introns and 10 motifs. Among these, motif3 appeared to be particularly stable in the genetic evolution of C. camphora genes, while motif9 and motif10 were distributed across the NAM subfamily. Chromosome localization and replication event analysis revealed that 103 genes were distributed across 12 chromosomes, with the highest number of genes（13） found in CcNAC genes distributed across chromosomes Chr02, with the lowest number of genes found on Chr10 and Chr11, which contained two genes each; Fragment duplication was the main mode of amplification for the CcNAC family. Multi-species co-linkage analysis revealed that CcNAC genes formed 162 pairs of co-linkage genes with CcNAC genes, indicating a closer relationship than with other species. The CcNAC genes were more closely related to the CcNAC genes and to those of other species than to any other. The CcNAC gene promoters contained several abiotic stress, growth and development, and hormone response elements. The results of the qRT-PCR showed that in leaves, the expression levels of the CcNAC058 and CcNAC092 genes were maximised under low salt stress. In roots, the expression of CcNAC007, CcNAC033, CcNAC058 and CcNAC092 genes increased with increasing salt concentration.【Conclusion】The NAC gene family may be involved in the process of salt stress response during the growth and development of C. camphora. The CcNAC092 and CcNAC058 genes exhibite significant responses in both leaves and roots under salt stress. It is hypothesised that CcNAC058 and CcNAC092 are the key genes contributing to the ability of the CcNAC to produce self-defensive behaviours under salt stress. [ABSTRACT FROM AUTHOR]