Genome-wide identification, phylogeny, and expression profile of the sucrose transporter multigene family in tobacco

Abstract

The transportation and distribution of sucrose in plants is mediated by sucrose transporters (SUTs), which also participate in various plant developmental and resistance processes. However, no such study of the tobacco SUT family has been reported yet. In the present study, 11, 5, and 4 SUT genes were identified from the genomes of Nicotiana tabacum, Nicotiana sylvestris, and Nicotiana tomentosiformis, respectively. The exon–intron structures of the tobacco SUT genes were highly conserved in the three tobacco species. Gene loss, duplication, and chromosome exchange occurred in the NtSUT family during the formation of allotetraploid common tobacco. Expression profiling analysis revealed that the expression patterns of the NtSUT genes in common tobacco were closer to those in N. sylvestris plants. The NtSUT2s and NtSUT4 genes were ubiquitously expressed in various tobacco tissues, while the NtSUT1s gene was highly expressed in the maturing leaves, indicating their functional conservation and differentiation. The transcriptions of the NtSUT2t, NtSUT3s, NtSUT4, and NtSUT5s genes in tobacco plants were dramatically induced under Pi starvation, drought, and salinity stresses, but their highest expression levels occurred in different tissues, suggesting the multiple roles of NtSUTs in plant resistance to various abiotic stresses. This study provides useful information for the further functional characterization of SUT genes in tobacco.