Genetic map is a linear arrangement of the relative positions of sites in the chromosome or genome based on the recombination frequency between genetic markers. It is the important basis for genetic analysis. Several kinds of software have been designed for genetic mapping, but all these tools require users to write or edit code, making it time-costing and difficult for researchers without programming skills to handle with. Here, MG2C, a new online tool was designed, based on PERL and SVG languages.Users can get a standard genetic map, only by providing the location of genes (or quantitative trait loci) and the length of the chromosome, without writing additional code. The operation interface of MG2C contains three sections: data input, data output and parameters. There are 33 attribute parameters in MG2C, which are further divided into 8 modules. Values of the parameters can be changed according to the users’ requirements. The information submitted by users will be transformed into the genetic map in SVG file, which can be further modified by other image processing tools.MG2C is a user-friendly and time-saving online tool for drawing genetic maps, especially for those without programming skills. The tool has been running smoothly since 2015, and updated to version 2.1. It significantly lowers the technical barriers for the users, and provides great convenience for the researchers.

The basic leucine zipper (bZIP) transcription factors play important regulatory roles, influencing plant growth and responses to environmental stresses. In the present study, 132 bZIP genes identified in the tobacco genome were classified into 11 groups with Arabidopsis and tomato bZIP members, based on the results of a phylogenetic analysis. An examination of gene structures and conserved motifs revealed relatively conserved exon/intron structures and motif organization within each group. The results of an investigation of whole-genome duplication events indicated that segmental duplications were crucial for the expansion of the bZIP gene family in tobacco. Expression profiles confirmed that the NtbZIP genes are differentially expressed in various tissues, and several genes are responsive to diverse stresses. Notably, NtbZIP62, which was identified as an AtbZIP37/ABF3 homolog, was highly expressed in response to salinity. Subcellular localization analyses proved that NtbZIP62 is a nuclear protein. Furthermore, the overexpression of NtbZIP62 in tobacco significantly enhanced the salt stress tolerance of the transgenic plants. The results of this study may be relevant for future functional analyses of the bZIP genes in tobacco.

As the last stage of plant development, leaf senescence has a great impact on plant’s life cycle. Genetic manipulation of leaf senescence has been used as an efficient approach in improving the yield and quality of crop plants. Here we describe an ethyl methane sulfonate (EMS) mutagenesis induced premature leaf senescence mutant yellow leaf 1 (yl1) in common tobacco (Nicotiana tabacum L.). The yl1 plants displayed early leaf yellowing. Physiological parameters and marker genes expression indicated that the yl1 phenotype was caused by premature leaf senescence. Genetic analyses indicated that the yl1 phenotype was controlled by a single recessive gene that was subsequently mapped to a specific interval of tobacco linkage group 11 using simple sequence repeat (SSR) markers. Exogenous plant hormone treatments of leaves showed that the yl1 mutant was more sensitive to ethylene and jasmonic acid than the wild type. No similar tobacco premature leaf senescence mutants have been reported. This study laid a foundation for finding the gene controlling the mutation phenotype and revealing the molecular regulation mechanism of tobacco leaf senescence in the next stage.

Leaf morphology and plant height are two agronomic traits closely related to tobacco (Nicotiana tabacum L.) yield and quality. The study of leaf morphology and plant stature mutants will greatly contribute to the fields of plant architecture breeding and developmental biology. Here, we report the characterization of a spiral leaf and dwarf (sld) mutant identified from an ethylmethane sulfonate (EMS)-induced common tobacco population. The sld mutant displayed the phenotype of wrinkled, spiral, and miniature leaves, with the growth point as the central axis and plant dwarfing with shortened internodes. The inheritance pattern of the sld mutant phenotype was manipulated by a recessive nuclear monogene, which was linked to six tobacco simple sequence repeat (SSR) markers from linkage group 5 via gene mapping. Utilizing an F₂ population, the sld mutant gene the sld mutant gene was located between the co-segregated markers PT51778, PT54913, and the marker PT61414, with an equal genetic distance of 0.16 cM. Taking advantage of a BC₁F₁ population, the markers PT51778, PT54913, the sld gene, and the marker PT61414 demonstrated co-segregation, located between the markers PT40040 and PT60933, respectively, with a genetic distance of 1.37 cM and 6.32 cM, respectively. These findings will be helpful in cloning the sld gene and in the further characterization of the regulatory genes controlling the spiral and dwarfing phenotypes in tobacco.