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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. [ABSTRACT FROM AUTHOR]

Background: At present, the distinctness, uniformity, and stability (DUS) testing of flue-cured tobacco (Nicotiana tabacum L.) depends on field morphological identification, which is problematic in that it is labor intensive, time-consuming, and susceptible to environmental impacts. In order to improve the efficiency and accuracy of tobacco DUS testing, the development of a molecular marker-based method for genetic diversity identification is urgently needed. Results: In total, 91 simple sequence repeats (SSR) markers with clear and polymorphic amplification bands were obtained with polymorphism information content, Nei index, and Shannon information index values of 0.3603, 0.4040, and 0.7228, respectively. Clustering analysis showed that the 33 study varieties, which are standard varieties for flue-cured tobacco DUS testing, could all be distinguished from one another. Further analysis showed that a minimum of 25 markers were required to identify the genetic diversity of these varieties. Following the principle of two markers per linkage group, 48 pairs of SSR markers were selected. Correlation analysis showed that the genetic relationships revealed by the 48 SSR markers were consistent with those found using the 91 SSR markers. Conclusions: The genetic fingerprints of the 33 standard varieties of flue-cured tobacco were constructed using 48 SSR markers, and an SSR marker-based identification technique for new tobacco varieties was developed. This study provides a reliable technological approach for determining the novelty of new tobacco varieties and offers a solid technical basis for the accreditation and protection of new tobacco varieties. [ABSTRACT FROM AUTHOR]