Evaluting dwarfism in transgenic tobacco dwarf plants

• Main Authors: Shakib, Ali Mohammad, Orouj lou, Mahnaz
• Format: Publication
• Language: Persian
• Published: Karaj (Iran) Agricultural Biotechnology Research Institute of Iran 2004
• Subjects: DWARFISM; ENANISMO; ENTRE NOEUD; INTERNODES; INTERNODIOS; NANISME; plant head; TABAC; TABACO; TOBACCO

The RAP1 gene which has been isolated and cloned from sorrel plant (Rumex acetosa L.) expresses only in reproductive stage in male and female organs. When this gene was transferred to tobacco plant, produced mutants in that some important traits were affected. To evaluate these effects, three transgenic lines as well as two control lines including and transgenic with the GUS gene were used. Seeds were non-transgenic cultured on MS selection medium containing 100 mg/lit Kanamycin. After growing, plants were transplanted into soil in pots and maintained under greenhouse conditions. Detecting of the RAP1 gene was verified using specific primers by PCR. During growth period different traits such as, number of nods, size of internodes, height and amount of chlorophyll in leaves were evaluated. Effects of IAA and GA3 hormones, quality and quantity of light on plant height were also studied. Results showed that dwarfism of mutant plants was because of the RAP1 gene expression. Size of cells in stem tissue in transgenic plants was smaller than those in control plant cells but number of cells was not different. Chlorophyll amount in leaves of transgenic plants was decreased. Flowering in transgenic plants began three weeks earlier. Transgenic plants responded positively to GA3 and IAA. The height of transgenic plants increased after treatment with GA3 and compared to non-treatment plant showed significant difference but no difference was seen among the three transgenic lines treated with GA3. The same results observed when plants were treated with IAA but difference was seen among transgenic lines. Based on these results it seems that this gene affected phytochrome B and was not efficient. This defect probably cause the auxin not to be produced or to be inactivated. The hormone defection affect GA biosynthesis and the transgenic plants were shorten because of the lack of,defection, and or inactivation of GAs.