جستجوی مقالات مرتبط با کلیدواژه "t-dna" در نشریات گروه "زیست شناسی"

Agrobacterium rhizogenes is a soil-borne, gram negative bacterium which induces hariy root disease in plants. A DNA sequence in the bacterial plasmid called T-DNA (transferred DNA) is transferred in to the plant genome upon infection. T-DNA carries the rooting-locus (rol) genes: rolA, rolB and rolC. Somme plants also contain, naturally, the homologues of rol genes. In this study, the effects of bacterial rolC gene and its homologous in tobacco, trolC, was evaluated in transgenic plants in a completely randomized design experiment with 3 replications. The expression of rolC and trolC genes in transgenic tobacco seedlings was under the control of dexamethasone inducible promoter. Different concentrations of dexamethasone (0, 1, 3, 10 and 30 µM) were used in order to induce the expression of transgenes. Our results showed that the presence of only very low quantity of dexamethasone (1µM) in the culture medium induces the expression of genes and affect significantly the growth of seedlings. Phenotypically, the length of seedlings was shorter in both transgenic plants than control and the roots of transgenic seedlings were twisted and the leaves were smaller and pale green. Since these characteristics are present in both transgenic seedlings, we can conclude that the bacterial rolC gene has preserved its ancestral function after insertion into the plant genome during evolution.

A gene family called Strictosidine synthase like (SSL) exists in Arabidopsis thaliana genome. Orthologs gene in Catharanthus roseus is involved in monoterpenoid indole alkaloids biosynthesis. A member of gene family (SSL6) has been induced by various biotic and abiotic stresses. To further analyse of the functional role of the gene in response to salt stress, the SSL6 T-DNA insertional mutant (ssl6) was used in response to 0, 100 and 200 mM NaCl. Therefore, several morphological, physiological and molecular traits including the percentage of seed germination, root length, Catalase (CAT), Peroxidase (POD) and Superoxide dismutase (SOD) enzyme activity, and relative expression levels of AAO3, RD29A, NCEDD3 and P5CS1 were measured. The obtained data have been analyzed using a factorial experiment (with two factors) based on completely randomized design (CRD) with three replications. The obtained results demonstrated that the percentage of germination, root length and activity of SOD, POD and CAT enzymes were significantly higher in ssl6 genotype when compared with the wild type Col-0. The expression level of responsive genes at 3 and 6 h after salt stress treatment were significantly increased in ssl6 mutant genotype compared to Col-0 genotype. Results of this study for the first time reported that SSL6 genes in involved in plant responses to salinity stress and suppression of SSL6 gene resulted in increased tolerance to salt stress in Arabidopsis.