Genome-Wide Characterization and Expression Analysis of the NF-X1 Family during Development and under Salt Stress in Tomato (Solanum lycopersicum L.)

The human NF-X1 transcription factor (TF) is found in eukaryotes and similar to human NF-X1 protein, plant proteins are also characterized by zinc finger motifs. NF-X1 TFs largely found in plants play a key role in growth, development, and stress tolerance. Although tomato (Solanum lycopersicum L.) is a model plant in molecular studies, little is known about NF-X1 genes, particularly in response to abiotic stress conditions, plant development and fruit ripening. In this study, whole-genome analysis of the tomato NF-X1 gene family was performed, and two SlNF-X1 (SlNF-X1-1 and SlNF-X1-2) were identified. Gene structures, phylogenetic relationships with other species and cis-acting elements were revealed by using different bioinformatic analysis methods. According to publicly available RNA-seq data and RT-qPCR analysis suggest that SlNF-X1 genes could be responsible in response to abiotic stress conditions. Furthermore, it was found that the expression of both genes was up-regulated as fruit ripened. Based on these results, our study may improve the current understanding of SlNF-X1 genes and will be helpful for future studies of the biological function in regulating fruit ripening or response to different abiotic stress conditions.