Glycine betaine has been reported as an osmoprotectant compound conferring tolerance to salinity and osmotic stresses in plants. We previously found that the expression of betaine aldehyde dehydrogenase 1 gene (OsBADH1), encoding a key enzyme for glycine betaine biosynthesis pathway, showed close correlation with salt tolerance of rice. In this study, the expression of the OsBADH1 gene in transgenic tobacco was investigated in response to salt stress using a transgenic approach. Transgenic tobacco plants expressing the OsBADH1 gene were generated under the control of a promoter from the maize ubiquitin gene. Three homozygous lines of T 2 progenies with single transgene insert were chosen for gene expression analysis. RT-PCR and western blot analysis results indicated that the OsBADH1 gene was effectively expressed in transgenic tobacco leading to the accumulation of glycine betaine. Transgenic lines demonstrated normal seed germination and morphology, and normal growth rates of seedlings under salt stress conditions. These results suggest that the OsBADH1 gene could be an excellent candidate for producing plants with osmotic stress tolerance.

Betaine aldehyde dehydrogenase (BADH) is a major oxidative enzyme that converts betaine aldehyde to glycine betaine (GB), an osmoprotectant compound in plants. Japonica rice (salt-sensitive) was genetically engineered to enhance salt tolerance by introducing the OsBADH1 gene from Indica rice (salt-tolerant), which is a GB accumulator. We produced transgenic rice plants overexpressing the modified OsBADH1 gene under the control of the maize ubiquitin promoter. The transgenic rice showed increased OsBADH1 gene expression and OsBADH1 enzyme production, resulting in the accumulation of GB. It also exhibited enhanced salt tolerance in immature and mature transgenic rice seedlings. The adverse effect of salt stress on seed germination, the growth of immature and mature seedlings, water status, and photosynthetic pigments was alleviated in transgenic seedlings.

Lilium cv Acapulco was transformed with a defective cucumber mosaic virus (CMV) replicase gene (CMV2-GDD) construct using Agrobacterium tumefaciens. Four lines were analyzed for gene expression and resistance to CMV-O strain. Expression of the CMV2-GDD gene in the transgenic plants was confirmed by reverse transcription PCR (RT-PCR). When these four lines were mechanically inoculated with CMV-O, no signal of coat protein (CP) messages using RT-PCR was detected in newly produced leaves of two transgenic lines. Dot-immunobinding assay (DIBA) of CP was performed to examine the presence of the CMV in the newly produced leaves of challenged plants. Results, similar to those obtained with RT-PCR of the CP messages, were observed in DIBA. Therefore, our results imply that the two lines show increased levels of resistance to CMV, and CMV-GDD replicase gene is an effective construct that has protection against CMV in Lilium.

In this study, simple sequence repeats (SSRs) specific to marigold were developed using the inter-SSR technique and a SSR-enriched genomic DNA library. In addition, SSRs derived from sunflower (Helianthus annuus) were also tested for transferability to marigold. In total, 38 polymorphic markers with 112 observed alleles were identified in 20 African marigolds (Tagetes erecta L.) consisting of 14 commercial varieties and six Thai landraces, and six French marigolds (Tagetes patula L.). The number of alleles per locus ranged from 2 to 7. The averages of expected and observed heterozygosities were 0.48 and 0.32, respectively. Polymorphic information content values ranged from 0.10 to 0.71, and resolving power (R p ) values ranged from 0.23 to 2.77. The SSRs were successfully applied to the differentiation of the 26 marigold samples into clusters of African commercial varieties, Thai landraces and French marigold. The genetic relationship analysis revealed that the African commercial varieties were more closely related to the Thai landraces than to the French marigold. The results of the study indicate that the SSRs developed are effective for genetic diversity analysis, species classification and individual identification.

No abstract