Melatonin plays key roles in development and confers stress tolerance to plants. Serotonin N-acetyltransferase (SNAT) is either the enzyme involved in the last step or the penultimate enzyme of phytomelatonin biosynthesis. To date, SNAT genes have not been characterized in tobacco (Nicotiana tabacum), an economically important plant species. The sequence of the Acetyltransf_7 conserved domain was used as a query sequence, and 12 NtSNAT candidate genes were in turn identified in the genome of tobacco. These NtSNATs could be divided into two groups based on the phylogenetic tree. NtSNAT1 and NtSNAT2 clustered together with the other typical SNATs, but the other 10 NtSNATs separately clustered outside of the typical SNATs. These 10 NtSNATs have only motif 1, whereas representative SNATs, such as NtSNAT1 and NtSNAT2 or a SNAT from cyanobacteria, have five motifs. In addition, NtSNAT1 and NtSNAT2 are highly homologous to the characterized OsSNAT1, 62.95 and 71.36%, respectively; however, the homology between the other 10 NtSNAT genes and OsSNAT1 is low. Concomitantly, it is hypothesized that NtSNAT1 and NtSNAT2 are the homolog of SNATs, whereas the other 10 candidates could be considered NtSNAT-like genes. Furthermore, both Nicotiana tomentosiformis and Nicotiana sylvestris, two diploid ancestor species of N. tabacum, have two SNAT candidates; therefore, it is speculated that gene rearrangement or deletion during the process of genomic stabilization after whole-genome duplication or polyploidization led to the preservation of NtSNAT1 and NtSNAT2 during the evolution of tobacco from the ancestral diploid to the allotetraploid. NtSNAT and NtSNAT-like genes were differentially expressed in all organs under different stress conditions, indicating that these genes potentially associated with plant growth and development and stress resistance. Under different stress conditions, the expression of NtSNAT1 was significantly upregulated upon high-temperature and cadmium stresses, while the expression of NtSNAT2 did not significantly increase under any of the tested stress treatments. These results provide valuable information for elucidating the evolutionary relationship of SNAT genes in tobacco and genetic resources for improving tobacco production in the future.

褪黑素在发育中起关键作用，赋予植物抗逆性。血清素ñ-乙酰基转移酶（SNAT）是植物降钙素生物合成的最后一步涉及的酶或倒数第二个酶。至今，SNAT 烟草中尚未鉴定基因烟草），具有重要经济意义的植物物种。使用Acetyltransf_7保守域的序列作为查询序列，其中12网络地址转换候选基因又在烟草基因组中鉴定。这些网络地址转换根据系统发育树可以将它们分为两组。 NtSNAT1 和 NtSNAT2 与其他典型群集在一起 SNATs，但其他10 网络地址转换分别在典型值之外 SNATs。这10个网络地址转换s仅具有主题1，而代表 SNATs，例如 NtSNAT1 和 NtSNAT2 或一个 SNAT来自蓝细菌，有五个图案。此外，NtSNAT1 和 NtSNAT2 与特征高度同源 OsSNAT1，分别为62.95和71.36％；但是，其他10个之间的同源性网络地址转换 基因和 OsSNAT1低。同时，假设NtSNAT1 和 NtSNAT2 是...的同系物 网络地址转换，而其他10名候选人可以考虑 网络地址转换类基因。此外，两者烟草 和 烟草，两个二倍体祖先种 烟草，有两个 SNAT考生; 因此，推测全基因组复制或多倍体化后基因组稳定过程中的基因重排或缺失导致了基因组的保存。NtSNAT1 和 NtSNAT2 烟草从祖先二倍体到异源四倍体的进化过程中。 网络地址转换 和 网络地址转换类基因在不同胁迫条件下在所有器官中差异表达，表明这些基因可能与植物的生长发育和抗逆性有关。在不同的压力条件下，NtSNAT1 在高温和镉胁迫下显着上调，而 NtSNAT2在任何测试的压力处理下都没有明显增加。这些结果提供了宝贵的信息，以阐明的进化关系。SNAT 烟草中的基因和遗传资源，以改善未来的烟草生产。