Genome-Wide Identification and Expression Profile of the SNAT Gene Family in Tobacco (Nicotiana tabacum)

Abstract

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 NtSNATlike 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.

Identification of the ALMT gene family in the potato (Solanum tuberosum L.) and analysis of the function of StALMT6/10 in response to aluminum toxicity

“…A total of 14 potato genome StALMT family members are consistent with corresponding members in the publicly reported Arabidopsis ( Kovermann et al., 2007 ). More than 12 ALMT family members in peach and Chinese plum ( Lin et al., 2018 ), 16 ALMT family members in strawberry ( Lin et al., 2018 ) and tomato ( Sasaki et al., 2016 ), 21 family members in apple ( Lin et al., 2018 ), 25 family members in European pear ( Lin et al., 2018 ), 27 family members in Chinese white pear ( Lin et al., 2018 ), 30 family members in common tobacco ( Zhang et al., 2020 ), and 34 family members in soybean have been identified ( Peng et al., 2018 ). In our study, we found 14 ALMT family members in the potato that are distributed on seven different chromosomes ( Figure 1 ); this is similar to the findings reported on the chromosomal distribution of ALMT family members in other species ( Ma et al., 2018 ).…”

Genetic and evolutionary dissection of melatonin response signaling facilitates the regulation of plant growth and stress responses

“…In the Solanaceae plant, SlSANT (tomato) and CsSNAT (cucumber) had conservative functions in salt resistance, while exhibiting distinct roles in heat tolerance 53–56 . NtSNAT1/2 are highly homologous to the characterized OsSNAT1 (62.95% and 71.36%) that were also potentially associated with increasing high temperature and Cd resistance 57 . Ectopic expression of HpSNAT1/2 , VvSNAT1/2 , MsSNAT , and MzSNAT5 could protect Arabidopsis from salinity, drought, salt, and Cd damage 58–64 .…”

“…Upregulation of CsSOD , CsCAT , CsP5CS1 , CsPIP , CsP5CS2 and CsHSP90 improved the salt tolerance of CsSNAT overexpressed cucumber 55 . HSP40 gene also involved in high‐temperature tolerance of tobacco 57,68 . SlASMT and GmASMT could promote the protection of cellular proteins in plants through the induction of transcription factors ( NAC , MYB , WRKY , HSPs , and ERF ), autophagy, and stress signaling under heat and drought stresses 68 .…”

The pathway of melatonin biosynthesis in common wheat (Triticum aestivum)

“…Recently, the functional genes responsible for the Mel pathway have been revealed in rice following a homologous sequence alignment strategy. 20,22,57,73 Similarly, some candidate genes have been functionally validated in various plant species, 24,26,[74][75][76] indicating that the reverse-genetics scheme is effective. Nevertheless, this approach usually necessitates intensive labor input, especially for polyploid species.…”