In silico characterization of SAMdC from Pokkali rice and its overexpression in transgenic tobacco

Polyamines help to mitigate salt stress in plants. SAMdC or S-adenosyl methionine decarboxylase is a crucial enzyme in the polyamine biosynthetic pathway. Overexpressing the samdc gene of Pokkali (a salt-tolerant Indica rice landrace) in the model plant tobacco through Agrobacterium -mediated transformation resulted in tobacco plants capable of withstanding high salinity (200 mM) stress. The transgenic tobacco plants maintained a steady level of the higher polyamines and resisted ionic imbalance under salt stress. Since appropriate binding of the substrate with the enzyme is essential for an enzymatic reaction, we performed molecular docking experiment of SAMdC enzyme of Pokkali rice and tobacco to get an idea about its commonality in the two plants in the backdrop of Japonica rice and Arabidopsis . In silico characterization of SAMdC revealed that the enzyme used the same substrate in Pokkali rice and tobacco, from where the gene is introgressed and where it is overexpressed.