[show abstract][hide abstract] ABSTRACT: A bacterial mannitol-1-phosphate dehydrogenase (mtlD) gene driven by the constitutive cauliflower mosaic virus (CaMV) 35S promoter was transferred into tomato plants using an Agrobacterium tumefaciens-mediated transformation protocol in an attempt to improve abiotic stress tolerance in the transformed plants. Transgene integration
was confirmed by PCR analysis and Southern blot analysis, and transgene expression was confirmed by reverse transcription
(RT)-PCR and direct mtlD (EC 220.127.116.11) activity. Upon exposure to low temperature stress (4°C) in a cold chamber, transgenic
plants survived up to 48h, while non-transformed plants were unable to survive and gradually died. Transgenic plants subjected
to the chilling stress showed a significant decrease in electrolyte leakage and increased lipid peroxidation, as assessed
by measuring malondialdehyde (MDA) content. Under the cold condition, transgenic plants also showed a significant increase
in the activities of antioxidant enzymes (superoxide dismutase and catalase) and in relative water content (RWC) in comparison
to non-transformed plants. Drought (polyethylene glycol in medium) and salinity (sodium chloride in medium) tolerance tests
revealed that transgenic lines exhibited a higher tolerance for abiotic stresses than non-transformed plants. These findings
indicate that the introduction of a bacterial mtlD gene into tomato conferred tolerance to abiotic stresses to the transformed tomato plants.
-Abiotic stress-Mannitol-1-phosphate dehydrogenase gene-Cotyledonary leaves-
Plant Cell Tissue and Organ Culture 04/2012; 103(2):267-277. · 3.63 Impact Factor
[show abstract][hide abstract] ABSTRACT: In an attempt to improve chilling stress tolerance, an Arabidopsis C-repeat binding factor 1 (At-CBF1) gene driven by the inducible promoter RD29A was co-transferred into tomato var. Shalimar. Marker (NPTII)-free transgenic were obtained in T(1) generation because of unlinked integration of CBF1 and NPTII genes. Reverse transcription-polymerase chain reaction confirmed the expression of CBF1 in T(1) transgenic lines. Study of expression pattern in T(1) transgenic line showed a gradual increase with increasing chilling stress period and also confirmed the reversibility of expression on removal of stress. The transgenic plants exhibited no morphological and agronomical differences as compared to non-transformed plants. When young transgenic plants were exposed to chilling stress (4°C) for 3 days, increased survival (50%) was observed in transgenic lines than non-transformed plants (10%). Transgenic plants subjected to the chilling stress showed a significant decrease in membrane injury index and lipid peroxidation and also increased significantly free proline content in the leaf tissues as compared to non-transformed plants. Thus, these findings indicate that marker-free transgenic tomato plants expressing Arabidopsis CBF1 gene provided protection and conferred cold tolerance to transgenic tomato without any phenotypic variation.