A Facile Catalyst-free Pudovik Reaction for the Synthesis of α-Amino Phosphonates

Some imines were synthesized by the reaction of 5-amino 1-naphthol with substituted aromatic aldehydes in ethanol under reflux conditions. Dialkyl phosphites underwent addition with aromatic imines to give novel α-amino phosphonates. All the title compounds were characterized by elemental analysis, IR, 1H, 13C, 31P NMR and mass spectral data. All the newly-synthesized compounds (4a–j) exhibited moderate antibacterial and antifungal activity.Keywords: 5-Amino-1-naphthol, imines, dialkyl phosphite, α-amino phosphonates, antimicrobial activit

Biotechnological Means for Genetic Improvement in Castor Bean as a Crop of the Future

Not AvailableProfitable cultivation of castor bean is beset with problems of vulnerability of cultivars and hybrids to a multitude of insect pests and diseases. The presence of the toxic proteins ricin and hyperallergenic Ricinus communis agglutinin (RCA) in the endosperm restricts the use of deoiled seed cake as cattle feed. Due to this crop’s low genetic diversity, genetic engineering can be an efficient approach to introduce resistance to biotic and abiotic stresses as well as seed quality traits. Recently, castor oil gained attention as a sustainable second-generation feedstock for biojet fuel that would reduce carbon dioxide emissions. Because of a growing interest in castor oil as a biofuel and the presence of the powerful toxin ricin in its seed, metabolic pathways and regulatory genes involved in both oil and ricin production have been analyzed and characterized. Genetic engineering of castor bean offers new possibilities to increase oil yield and oxidative stability, confers stress tolerance, and improves other agronomics traits, such as reduced plant height to facilitate mechanical harvesting. However, difficulties in tissue culture-based regeneration and poor reproducibility of results are major bottlenecks for genetic transformation of castor bean. Despite advances in tissue culture research over the past four decades, direct or callus-mediated adventitious shoot regeneration systems that are genotype-independent remain a much sought-after goal in castor bean. Genetic transformation attempts to develop insect resistant and ricin-free transgenic castor bean lines have been based on shoot proliferation from meristematic tissues. This chapter describes new transformation methods under development and the progress achieved so far in genetic engineering of castor bean for agronomically desirable attributes.Not Availabl

Cultivar variability in the Agrobacterium-rice cell interaction and plant regeneration

Thirteen cultivars of rice (Oryza sativa) were tested for plant regeneration from calli initiated from the scutella of mature seeds by water stress treatment using a high concentration of agarose, and examined for their response to Agrobacterium tumefaciens LBA4404, carrying a plasmid pTOK233, harboring genes for kanamycin resistance (nptII), hygromycin resistance (hpt) and ??-glucuronidase (gus). Plant regeneration frequency was considerably increased in most of the cultivars when the calli were treated with water stress, as compared with untreated controls. In particular, the cultivars Dongjinbyeo, IR43, Nagdongbyeo and Sinseonchalbyeo showed an increased frequency of shoot regeneration. Expression of GUS was detected in all of the co-cultivated cultivars. Based on GUS expression at 3 days after co-cultivation with A. tumefaciens, three rice cultivars (Dongjinbyeo, Hwayoungbyeo and Nagdongbyeo) were judged highly susceptible to A. tumefaciens, while Milyang 23, Nonganbyeo and Samgangbyeo cultivars were weakly susceptible. Plantlets were readily regenerated when the hygromycin-resistant calli were transferred to a regeneration medium containing hygromycin. Intense blue staining was observed in GUS assays of leaf segments, roots and flower organs from regenerated plants. Stable integration and expression of the introduced hpt and gus genes were confirmed by Southern blot analysis of the transformants. Therefore, Dongjinbyeo and Nagdongbyeo cultivars proved to be both highly susceptible to A. tumefaciens and highly responsive to plant regeneration.close91