A novel betaine aldehyde dehydrogenase gene from Jatropha curcas, encoding an enzyme implicated in adaptation to environmental stress

Abstract

A novel betaine aldehyde dehydrogenase gene, named JcBD1, was cloned by RT-PCR and RACE techniques from Jatropha curcas L., an important plant species as its seed is the raw material for biodiesels. The cDNA was 1769 bp in length with a complete open reading frame of 1509 bp, encoding 503 amino acids with a predicted molecular mass of 54.585 kD and a p I of 5.32. The deduced amino acid sequence showed substantial similarities to BADH enzymes present in other plants, including the absolute conservative region in the possible active site. Southern blot analysis indicated that the JcBD1 gene belongs to a multigene family. Semi-quantitative RT-PCR analyses revealed that JcBD1 gene was expressed in roots, stems, leaves, flowers, and young seeds, but that the expression level was highest in leaves and stems. And the JcBD1 gene was increasedly expressed in leaves undergoing environmental stress like drought (30% PEG), heat (50 °C), and salt (300 mM NaCl). The JcBD1 protein was functionally expressed in Escherichia coli ( E. coli). E. coli cells transformed with the JcBD1 gene obviously grew better than control cells. The enzyme activity of expressed JcBD1 protein was detected. Over-expression of JcBD1 enzyme in E. coli conferred its resistance to abiotic stressors like salt.